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How To Survive The Horrific Health Effects Of Air Pollution

Nov 16, 2018


Air pollution...

You may think:

"What doesn't kill you makes you stronger", right?

And: "If the health effects would be so bad, surely everyone would complain or do something?"

Not so fast...

The health effects of air pollution can be devastating.

In fact, air pollution's effects are so bad that millions of people die because of being exposed.

You may assume... "millions of people die every century"

"or ever decade?"


Every year...

Yes, that's right.

Every single year...

And sure, most air pollution deaths occur in developing nations, especially China and India.

But even in the developed world the effects are frightening. 

More bad news?

These circumstances are not about to change. Air pollution levels are projected to only half in 2030 (if you're lucky).

So what's the solution?

Take matters into your own hands - that's exactly what this guide on air pollution will help you do.

This guide is thus not targeted towards governments or health institutions.

No, this guide is written for you.

You see, only you can save yourself.

Only you can change your life and dramatically reduce your air pollution exposure levels.

In fact, I'll give you a guarantee: with the right strategies, you can reduce your averaged 24-hour exposure levels up to a whopping 90%.


Stay with me to find out...

The grand strategy of beating air pollution: understanding your opponent
and making one calculated move at a time.


But let me first make a disclaimer about this air pollution guide:

Even though you're reading a 25,000 words+ blog post, you don't have to read the entire blog post to get massive benefits. 

Instead, find an interesting topic in the table of contents below and start reading. More reading and more taking action, of course, is better for getting more results.

So let me give you the 30,000 foot overview of what I'm doing in this blog post:

I'll first tell you why so many people in society - even health conscious people - often completely ignore the health effects air pollutants.

Let me explain with an example:

Do you know someone taking supplements and trying to increase their sleep quality or improve their health? What is the statistical chance that person is also watching their air pollution exposure?

That chance is low.

Very low...

So what's the reason most people don't do anything about air pollution?

Several reasons exist, but I think the most important reason is complacency. Most people also assume that the government knows best how to deal with the air pollution problem, and there's little they can personally do to change things.

That attitude can be hazardous to your health.


Governments don't have an incentive to reduce air pollution levels to zero -  at least not for now.

The entire economic system is based upon burning of fossil fuels that create air pollutants. Sure, if there's a cheap way in which the levels of a pollutant can be dramatically reduced, by a filter for example, then governments will support that change.

But stopping all air pollution?

If you'd stop the burning of all fossil fuels, the world economy would not just come to a halt--it would collapse.

The entire economic system of this planet is thus (indirectly) premised upon air pollution -  fossil fuels need to be burned to burned to support that system.

Of course, not all air pollution originates from burning fossil fuels.

The situation is more complex:

In fact, I'll give you an oversight of 13 different air pollutants in this blog post. But let's consider three examples in this summary:

(Just to showcase that air pollution does indeed have health effects...)

  1. Nitrogen dioxide, which kills 6,000 people in Germany and up to 20,000 in the United Kingdom (yes, each year), is a gas that's mainly emitted from fossil fuel burning.

    Power generation and transportation are the two main sources of this pollutant.

    At low doses, you'll experience some breathing problems as well as aggravation of allergies. At higher dosages, however, lung and heart ensue, and finally death (with longer-term exposure to higher doses).

  2. Mold is a fungus and found indoors in 10-50% of buildings in the developed world.

    While not all mold is toxic, it's likely that a building contains toxic mold once it has had water damage...

    If you're lucky, you'll get an irritated nose, dry eyes, cough a lot, have breathing difficulties, and maybe even experience dizziness.

    If you're exposed for a longer period of time or if you're susceptible to moldthen all hell can break loose. Being bedridden, nausea and vomiting, autoimmune disease (in which your body attacks itself), extreme fatigue, an inability to think straight are possible symptoms of mold exposure.

    Some people even die due to the effects of long-term exposure...

  3. "VOCs" - or "Volatile Organic Compounds" - are both an indoor and outdoor pollutant.

    VOCs are substances that easily turn into a gas. Exhaust from fossil-fuel burning transportation vehicles, furniture, paint, fragrance, glue, smoking, and cleaning products are common VOC sources.

    You either inhale these compounds or get exposed when these gases hit your skin. If you breathe these VOCs in higher dosages, your thinking ability may go down, you'll have a headache, and may get sick. In the longer-term, VOCs can damage your nervous system and organs.

That's VOCs, mold, nitrogen dioxide...

Few people are really acquainted with these substances. 

In my full blog post, I'll consider many other compounds as well, such as sulfur dioxide, pollen and germs, asbestos, carbon monoxide, and more. Keep in mind that you don't need to remember all these, you just need to be aware of what's "out there" every day.

Let me tell you why...

I'll give you a simple analogy why air pollution is so dangerous:

Air pollutants are analogous to slow poison drips: if you get a small amount of tasteless and odorless poison in your food every day, you won't notice why you're getting more sick all the time.

In fact, you may even think you need to eat more food to compensate for your illness.

Air pollution is like that - it flies deceptively under the radar. Every day, air pollution does a small amount of damage to your health.

Exposure to pollutant is not like breaking your leg...

Or a car crash...

The effects are slow and subtle, and therefore they are so damaging.

And believe me, it's not your fault. As human being you're not equipped to perceive very slow changes over time...

Let me explain:

As a human being, you don't see the grass growing--you just notice that the grass has grown tall over a couple of days...

Likewise, you don't observe air pollution damaging you like you the obvious problem that emerges if you break your leg...

So what's the solution? I'll give you five solutions which already dramatically lower your air pollutant exposure:

(10 additional solutions are included in the full blog post).

  1.  Simply ventilating buildings can reduce buildup of several indoor air pollutants such as "carbon dioxide".

    Carbon dioxide is the gas you breathe out (as opposed to oxygen that you breathe in).

    Believe it or not, but many buildings have carbon dioxide that are 2-10 as high as optimal. The solution is simply to open up your windows once in a while.

    Don't open up windows all the time if you're living in a high-air pollution area though, because that method brings air pollution into the building.

  2. Avoid areas that have high levels of air pollutants.

    Simple yet effective...

    Examples? Simply walking on the non-read side of the sidewalk can reduce your air pollutant exposure by 30%. Exercising in nature instead of the city gives you a huge reduction as well.

    Avoiding rush hour does the same...

  3. Use an air purifier. 

    Using an air purifier can reduce indoor air pollutant levels up to 90%. I've combined several air purifier reviews in my blog post, which leads to the following recommendation:

    a) As a budget option for rooms up to 200 square feet (18m2) I recommend the Germguardian ($105). The Germguardian is great for a bedroom.

    (26 point score)

    b) For rooms up to 530 square feet (~50 m2), the Coway AP-1512HH is your best choice. This air purifier costs around $200, but blows air purifiers twice or three times the price out of the water. 

      (40 point score)

    c) For bigger rooms (or apartments) up to 1,300 square feet (120 m2), the Alen BreatheSmart 75i is incredible.

    That Breathesmart air purifier is also recommended if you're more prone to be affected by air pollution, which is the case if you're older, young, have breathing issues, allergies, lung disease, or heart disease.

    (High-end air purifier class winner)

    Always follow instructions when using an air purifier. Read my full blog post for more details on how to best use air purifiers.

  4. If you've got issues with pet allergies or what is called "particulate matter" then I'd recommend a HEPA vacuum cleaner.

    Particulate matter?


    Particulate matter denote small particles that are subsumed in the air as a byproduct of traffic, industry, and energy creation - you'll be exposed to that air pollutant if you're living in the city.

    The main benefit of the HEPA vacuum cleaner is that smaller particles can be removed from your house, as well as pet dander.

  5. Insulate your home.

    While insulation may be costly, the benefits can be huge when you're trying to create a clean indoor environment. Remember that modern humans spend 90% of their time indoors. 

    Poorly insulated buildings in polluted cities ensure that you're exposed to air pollution almost 24-7, as polluted air continually enters the building.

    You cannot control your air pollution exposure without insulation.

"You need to filter the air, human? Weirdo!"


Again, ten other pollutant-lowering solutions are included in the full blog post.

You may have one last question: "How do I know how bad air pollution levels are at my location?"

Great insight...

First, get a rough estimate via a nearby measurement in on the World Air Quality Index. Secondly, either get a budget measurement device or a higher-quality one to measure air pollutant levels in your home and workplace. 

While these measurement devices don't measure all air pollutants I've included in this blog post, the particulate matter that's measured by the device above can act as a proxy for many other pollutants.

That method gives you a much better picture than going off feeling or local air quality maps.

That's it.

Ready to get the full picture?

Here we go...

Read the full blog post below

By the way, want a no-fail strategy to reduce your air pollution exposure by up to 90%? Download my 10 air pollution laws infographic below:



Last updated: March 25 2019

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cover photo of this blog post that shows polluted air



1. Carbon Monoxide (CO)
2. Nitrogen Dioxide (NO2)
3. Particulate Matter
4. Volatile Organic Compounds (VOCs)
5. Ozone (O3)
6. Sulfur Dioxide (SO2)
7. Biological Pollutants
8. Radon (Rn)
9. Carbon Dioxide (CO2)
10. Toxic Mold
11. Asbestos
12. Heavy Metals: Airborne Lead And Cadmium
13. Nerd section: Solar Wind And Flares From Space


1. Ventilate Your Indoor Environment
2. Avoid Heavily Air Polluted Areas
3. Use An Air Purifier
4. Use A (HEPA) Vacuum Cleaner
5. Insulate Your Home To Decrease Ventilation
6. Alter Building Construction To Reduce Radon Exposure
7. Eat A Healthy Diet
8. Buy Healthy Furniture, Household Products, And Paint
9. Avoid Damp, Water Damaged, Or Moldy Environments
10. Control Indoor Humidity And Temperature
11. Use Both Indoor And Outdoor Vegetation
12. Wear A Respirator If You're Exposed To Air Pollution
13. Build Resilience With Exercise
14. Avoid A Completely Sterile Environment
15. Consider Your Personal Susceptibility To Air Pollution


*Post can contain affiliate links. Read my affiliate, medical, and privacy disclosure for more information. 

Author: Bart Wolbers. Bart finished degrees in Physical Therapy, Philosophy (BA and MA), Philosophy of Science and Technology (MSc - Cum Laude), and Clinical Health Science (MSc).


Let start on a little detour - you understand what I'm getting at regarding air pollution very soon.

I'm going to talk about facing the reality of an obvious problem first.

And you know what? 

Consciously acknowledging an elephant in the room can be deceptively difficult.


you may be working at an internet company that has losses quarter after quarter, and yet, everyone working there is acting like it's 1998 - having that cheerful attitude they had at the height of the internet stock bubble.

a friend of yours, who has smoked for 30 years, has been coughing for a few weeks now. He tells you: "maybe it's the colder weather that's causing these lung problems?"

your colleague claims to be so busy that she doesn't have time to meet up. But you know that she's spending 6 hours a day on her smartphone and in front of a television.

it's now 10 years since the world has experienced the last global recession. And yet, government projections, companies, and consumer sentiments all assume that the party will continue for several years (and up to a decade)...

cat that is relaxed, that is an analogy for the elephant in the room. Air pollution is also an elephant in the room that's rarely acknowledged
The master of the house: another elephant
in the room that's rarely acknowledged...


I know...

Acknowledging an elephant in the room takes guts. 

But let's face it:

You may not like what you see, but only by consciously acknowledging problems can you change anything.

Many people living in the city are confronted with such an elephant every day...

You may be too.

Which one?

Air pollution is like an elephant. 

A huge pink elephant. Everyone just knows that elephant exists.

And yet, there's a strange phenomenon going on regarding air pollution: most people are unwilling to tackle the problem directly.

That's weird...

Let me tell you why - I'll give an analogy:

Most people know they should exercise, and for that reason they do. If I were to make a rough guesstimate, about 60% of people in my country (the Netherlands) exercise in one form or another.

Many people also know they should watch their diet, and for that reason, they do. To be more precise: most health-conscious people intentionally avoid eating at McDonald's or Burger King 6 times a week.

In the case of air pollution, however, a switch is triggered. 

Let me explain:

Ask the fitness addict who spends 5 evenings a week in the gym and watches her diet meticulously what she does to lower her exposure to air pollution. Or go to a health store and ask the owner what products he's offering to counter air pollutants.

You'll be met with a blank stare...

So ask yourself this simple question:

How many health-conscious people do you know who as carefully watch their air pollution exposure as they care about their exercise or diet?

One percent?

Two percent?

My rough guesstimate is that two percent of health-conscious people watch their air pollution levels - at the maximum.

And yet, if you care about your health you should care about air pollution.

Let me tell you why:

million people die every single year because of the negative health effects of air pollution (on a worldwide basis).[1-4]

Sure, most of these deaths occur in Asia, but even developed countries have air pollution levels that negatively affect your health no matter where you live.

It may sound counter-intuitive, but even in the developed world hundreds of thousands of people still die due to air pollution's effects.

And no, not every decade but every year...

Of course, there are many different causes of air pollution, such as aerosols from sprays,  natural causes such as forest fires or volcanoes, indoor cooking that "kills" air quality, gases, and tiny particles emitted by car or airplanes, and industrial output...

I'll treat all these causes in a subsequent section...

They key is to realize that all these air pollutants place a tremendous burden on your health.

Think about it: 8 million, that's a lot of people dying each year because of the direct effects of air pollution...

The problem with grasping that "8 million" figure is that everyone doesn't necessarily die from air pollution - even when they're exposed.

Of course, I'm not arguing that more people should die. What I'm saying instead is that the statistics are short-sighted.


Let's return to the figure of 8 million "deaths" per year. A death occurs when someone dies while being able to live many more months or years.

Besides the 8 million yearly deaths, at least 100 times as many people's health is negatively affected.

Even if you don't die, air pollution thus still worsens your health.


If I die in 10 years due to an accident (hopefully not), and I've breathed polluted air for 42 years by then, air pollution has still negatively affected my health over that period.

It's also very likely that you, the reader who's living in a developed country is not going to die directly from air pollution.

And yet, your heart and lung health will be negatively affected by dirty air.

(most of my readers come from developed countries right now).

That's bad news...

air pollution is an invisible killer
Immediate perception does not always match reality.
The same is true for air pollution: the problem is worse than you think.


Let's explore why air pollution is so under-emphasized:

Air pollution is called "the invisible killer"...


The stuff you're breathing is like an imperceptible poison drip.

Just imagine that each day, your "loving" partner adds a little bit of arsenic to your meals. Arsenic is a poison and does not have any taste or odor, but you'll start feeling pretty bad once you ingest too much of the stuff.

Over time, even though your partner creates "wonderful" meals for you, incredible damage is being done. 

Your health deteriorates imperceptibly and in time you'll start thinking that you're struck by fate.

Of course that conclusion is completely wrong, but still, if you do think you had "bad luck" you may assume that there's nothing you will do about that situation.

Then your helplessness starts...

The analogy here is that air pollution's health effects are also imperceptible. Due to that imperceptibility, most people are not consciously aware of the air they're breathing--unless, perhaps, they already have lung problems.

That's bad for you, as damage is being done even if you don't think there is. 

I'll tell you...

Don't worry: I'm not preaching despair...

On the contrary:

By taking the problem air pollution head on you can decrease your risks for several health problems, such as lung problems, heart disease, and cancer.

To experience these benefits though, you do need to take action.

To be more precise: you need to take action...

Yes, you...

Don't wait for:

  • the government to change laws so that less air pollution exists
  • a genius comes up with a solution that filters the air perfectly once and for all
  • your health to deteriorate because you're unwilling to face the problem directly
  • being able to move to another location where less air pollution is present

And it's precisely air pollution's invisibility why so few health-conscious people take action in the first place...

Many people:

  • just don't know what to do about air pollution. You may not know either...
  • may have never become fully consciously aware of how bad the health effects of air pollution really are. (After reading this blog post those negative health effects will be undeniable...)
  • think there's nothing they can do about the problem, or that the government is already doing enough...

In this 25,000+ words guide I'll give you the power to take care of your air pollution exposure.

But let's consider why you should not wait for governments and (international) institutions to reduce the health effects of air pollution for you first...

A worldwide campaign has set a goal of halving air pollution deaths worldwide by 2030.[518] Halving air pollution deaths still entails that 4 million people are being killed on a yearly basis.

Many international treaties also tragically fail.


Consider the eight "Millennium Development Goals" that were set in the year 2000 for 2015. The only reason the poverty reduction goal was met is because of China's rapid economic development during that period.

Government policy had little to do with that accomplishment--more free markets did.

And even if governments and health institutions succeed in their goal of reducing air pollution by half, you'll still be exposed to dangerous levels.

An additional valid argument exists, however, that tells you why you should not wait for governments to rescue you:

Governments have (almost) no direct incentive to reduce air pollution. 

yes really...


Reducing air pollution directly hurts economic development. Don't believe me?

Consider these examples:

Let's say you:

  • no longer allow as many airplanes to fly from bigger cities. In that case, people will simply move to another airport and the less polluting city takes an economic hit.
  • instate very high airplane pollution taxes in the US. As a response, US citizens may drive to Mexico and Canada to avoid pollution taxes - these pollution taxes directly hit the US economy.
  • prevent polluting cars and trucks from entering cities. In that case, people will visit another city where their polluting diesel car may still venture. Prices of goods in the less polluted city may also increase because supply lines are harmed.
  • strictly enforce lower air pollutant outputs from factories, ban industry from settling near residential zones, and necessitate industry to buy expensive filtering. Result? The competitive position of that industry goes down relative to other countries--hurting the country's economy.
  • let 50% fewer cars enter cities or have all car owners buy a very expensive air filter on their car-exhaust. Consequence? Car transportation, which is central to the health of most economies, would go down.

There's no clear incentive to fully eliminate the problem of air pollution (yet)...

(Nerd section: from an economic standpoint, the example given above is oversimplified. The health gains due to lowering air pollution also has advantages such as increased productivity and saving healthcare costs. In the short-term, however, pollution probably maximizes economic growth.)

Solution: if you value your health, you have to take your air pollution exposure into your own hands

Again, keep in mind that I'm not trying to make you depressed.

There's good news too:

Air quality has been improving in most of the developing world. Society-wide improvements in air quality are thus possible. Take a look at the levels of common air pollutants that are emitted in the United States:[20]

different emissions levels of air pollutants over the course of decades
(Ammonia levels are not correctly displayed)



Sulfur dioxide emissions have gone down 90%, and tiny particles numbers that are created as a byproduct of industry or transportation (PM2.5 and PM10) have almost halved.

(I'll tell you more about these pollutants in a moment...)

And there's more good news:

Even in more polluted countries such as India or China, the number of people dying from air pollution is steadily going down.

Sure, in absolute terms--because these countries' populations are growing--air pollution takes more lives than ever. Quantified as years of life that are lost per 100,000 inhabitants, however, deaths due to air pollution are going down. 

But again: today air pollution levels are still negative for your health, and in 2030 the same is expected to be true.

A decline is not enough to save yourself--you'll want to minimize your exposure. 

My goal with this blog post on air pollution is two-fold:

  • Help you fully understand the problem of air pollution as well as most air pollutants.
  • Reduce your air pollutant exposure as much as possible, up to a jaw-dropping 95%..

Please keep in mind that this ultimate guide is part of a wider series on the negative health effects of air pollution.

The previous installment of this series treated the topic of "particulate matter". In that guide I claimed that you could reduce the negative effects of exposure dramatically by implementing a few solutions in your life, such as using air purifiers, planting vegetation, and avoiding "hot spot" locations of particulate matter.

Many of these solutions will return later in this blog post - in the fifth section I'll give you fifteen different solutions to reduce your inhaled level of air pollutants.

But first I'll tell you about the history of air pollution. The reason for including that history is that many people think that our ancestors were also exposed to toxic air every day.

Nothing could be further from the truth.

Let thus go back in time: 

health foundations program



Return To Table Of Contents


Contrary to popular assumption, the negative health effects of air pollution didn't originate in the 19th century for us humans...

During the 19th century Industrial Revolution ithe number of factories grew exponentially, creating air pollution en masse (assuming accept that there was such a "revolution" historically).

Air pollution is as old as humanity instead, and goes much farther back in time than humans have existed.

You can, for example, even make claim that dinosaurs became extinct because of air pollution.[5-8]


66 million years ago a meteor 6-9 miles in diameter hit Mexico, creating the Chicxulub crater. Dust enveloped the earth as a result of the meteor impact (together with similarly timed volcanic eruptions) and cooled down the planet.

(Non-flying) dinosaurs were dependent on external heating from sunlight and could no longer survive. 

75% of all other species went extinct as well. The health effects of air pollution are thus as old as this planet...

A cutie who was killed by air pollution...


There's yet another reason to assume that air pollution arose much earlier than the 19th century: 

Already by the discovery of creating fire, your human ancestors started polluting the air they're breathing .[9-12]

The discovery of (intentionally using) fire occurred about 800,000 years ago, and our human species originated ~200,000 years ago.

Keep in mind that thus our it's your human-like ancestors - commonly called hominins - who learned to control fire first. Hominins are millions of years old

That control of fire does not exclusively have beneficial health effects. The obvious downside is that air pollutants are created.

The upside, of course, is that fires generates lots of heat. That heat helped our ancestors survive in colder environments such as Northern Europe.

But remember the dates I just gave you? 

Essentially, the brain development of our ancestors started millions of years before the discovery of fire-control. During most of our hominin history air pollution was thus absent, except the pollution created by natural causes such as volcanoes and forest fires.

Let me give an example...

Your homo habilis ancestor who's shown below had a massively increased brain capacity compared to our common chimpanzee ancestors, and yet, did not control fire:


After the discovery of fire, fireplaces were used in caves. Fires in caves implies that your ancestors also exposed themselves to air pollution from that fire - smoke is very difficult to remove from caves.

Fast-forward a few million years: 

At the onset of civilization and agriculture around 10,000 B.C., humans began to settle in one location. Fire then allowed for indoor cooking.

Of course, indoor fire was also used as heating sources, especially in colder areas of the globe.

The bad news?

Indoor cooking dramatically increases the air pollutants levels you're exposed to compared to creating fires outside. 

It's thus simple to conclude that air pollution did thus not start in the 19th century...

For thousands of years, fires were one of the main sources of air pollution.

Other air pollution sources existed back then as well though. If you were a smith who was working bronze or iron, you'd be exposed to other toxins such as heavy metals.

Lead, a toxic heavy metal, was also used in construction and to preserve wine. Smelting that lead would have negatively affected your health, even though people didn't know about lead's harmful effects (yet) back then.

Air quality was surprisingly considered important back then, even though people did not fully understand why.

Some examples:[13]

  • In ancient Greeks and Romans knew that inner-city air was of lower quality than the air found in nature outside the city
  • Slave traders in the Age of Exploration discovered that slaves did not survive without sufficient ventilation
  • Chimney sweeps had the reputation of being in poor health a few centuries ago

In the middle ages already, your ancestors also invented ways to make indoor fires less polluting.

A "Hearth" was invented, a central fireplace inside a home with an open hole in the roof so that most smoke could exit the building without polluting the entire room. Chimneys that direct the smoke directly away from the indoor environment were only invented in the 12th century.

a central fireplace in the middle ages which would have produced smoke
A late-medieval hearth in an "upper-class" household
with a chimney.

The indoor usage of fireplaces remained relatively primitive well until the 18th century. For most of humanity's written history, indoor air pollution has thus been "part of the deal". 

Only in the late 19th century, with the invention of electricity, was it no longer necessary to have a fireplace in each house for food preparation and heating.

Just seven generations ago, at the ending of the 18th century, the chemical revolution took place. Humans began to scientifically dissect components that are contained in the air and study their effects.

A French chemist called Antoine-Laurent de Lavoisier discovered (and named) oxygen as one of the gases that are subsumed in the air. 

Before Lavoisier, other chemists had already discovered that there was no "uniform compound" which is "air". Instead, chemists knew that air actually is made up of several individual substances.

During the chemical revolution, different chemical elements were measured and categorized, which led to the possibility of studying individual substances subsumed into that air. In turn, that chemical revolution indirectly gave rise to the possibility of actively controlling that air...

A full understanding of air pollution, however, only developed slowly: the pollution problem became (much) worse before it got better. While some problematic periods of air pollution existed in big cities such as London between the 16th and 18th century, the air pollution problem really took off after that time.

Surprisingly, air pollution was mainly considered an "indoor" problem up until the beginning of the 20th century


Factory air pollution was unregulated at the beginning of the 20th century. That changed with a few developments in the 1950s and 1960s, when the harmful effects of air pollution became completely undeniable.

The great smog of London in 1952, during which lethal levels of sulfur dioxide were emitted into the air, killed a total of 10,000 people and made 100,000 ill. That smog led to the first wave of air quality regulations.[16; 17] 

In 1962, a book called "Silent Spring" by Rachel Carson subsequently made the world aware of the side-effects of pesticide use.[18; 19] 

Pesticides are also (partially) spread through the air...

From the 1950s and 60s of the 20th century, humans became painfully aware that their living environment did not just revolve around the house they were living in--the factory nearby, pesticides sprayed on your food or into the air, and traffic could poison the air you're breathing so that your health was affected.

Most people have nonetheless remained very complacent in controlling the air quality in their environment. From the 50s up until today, almost everyone assumes that air pollution is the government's task to deal with, not your individual responsibility.

(Hopefully that attitude will change after you read this guide)

And because of developments in the mid previous century, even teenagers are aware that air pollution affects their health today.

Ask any kid whether he considers smoking or breathing in car exhaust is healthy, and (s)he'll answer "no".

Two hundred years ago, people didn't know that air pollution was (that) damaging.

A simple analogy to understand that absence of knowledge can be made to bacteria and viruses: before the mid 19th century, medical practitioners were not aware of hygiene's importance, nor were bacteria or viruses identified separately.

Initially, viruses were even presumed to be the same thing as bacteria--until scientific experiments proved otherwise.[510] That distinction between viruses and bacteria nevertheless took time to be accepted by the scientific community.

The same is true for understanding air pollution...

Understanding of air pollution's health effects only slowly developed through the last few decades. That development is not done today, as new studies keep emerging. In some ways, air pollution is still misunderstood by the general public.

In developed nations, most people now assume that air quality is a problem that's located outside their homes. Scientific reality, on the contrary, shows that indoor air quality matters as much today as it did during (pre-)history.[13-15] 


Modern human beings spend 90% of their time indoors. Indoor air pollutants levels can also be two to ten times as high as outdoors.[511-513]



In most cases, outdoor air pollutants simply enter buildings but never leave. 

Talk about an unwelcome guest...

Let's therefore quickly determine whether you're affected by indoor air pollution as well. Consider this simple test:

  • Is the air outside the building you're spending time in obviously polluted? (If you're living in a big city the answer is automatically "yes")
  • Is it reasonable to assume that - because you're not actively dealing with the problem air pollution - that the air pollution ends up in your house?

If you answered "yes" twice, then congratulations: you can improve your health without having to spend thousands of hours in the gym, because indoor air pollution can be relatively straightforward to deal with in many cases.

In fact, simply integrating the solutions  I'm suggesting later on in this blog post (section five) will guarantee improvement.

Let's, therefore, start digging into the problem of air pollution... 

Oh, one last thing:

Since writing my previous blog post about reducing particulate matter exposure I've had questions about whether air pollution should not just be accepted as a "given".

That's a great question, actually, but my answer to that question is a resounding "no".

Consider exposure levels of "sulfur dioxide", a common byproduct of industrial processes that's emitted into the air:[20]

sulfur dioxide emission levels graph

As you can see, sulfur dioxide levels were pretty low before the 1850s compared to the late 20th century.

99% of sulfur dioxide contained in the air today ended up there because of human action. So no, nature herself does not put extreme amounts of sulfur dioxide into the air (for longer periods of time).

Additionally, air pollution is also unhealthy, even when coming from natural sources. Air pollution should thus not be accepted as a given. 

And of course, before the Industrial Revolution coal was also burned in homes - creating a sulfur dioxide problem. Nevertheless, the quantities emitted into the air only became extreme with the emergence of the factory system and mass burning of fossil fuels.

You're thus at greater danger today than in 17000, although the nature of your exposure has changed.

The bottom line is this: most air pollutants found in the air today were not present for your evolutionary ancestors in current quantities

Again: you'll want to lower your exposure...

In the next section, I'll look at thirteen different types of air pollutants and their health effects. 

Fasten your seat belt, because that section is going to be somewhat depressing...

By the way, want a no-fail strategy to reduce your air pollution exposure by up to 90%? Download my 10 air pollution laws infographic below:


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Before diving deep into the effects of these many air pollutants, let's grasp two basic air pollution principles first.

The first principle is that while I've divided air pollutants into 13 categories below, in reality, some types overlap. 



Particulate matter, which are tiny particles that emitted by cars and industry, can be created in the atmosphere by reactions of other types of air pollution that ended up there.

An air pollutant called "ozone", can be created when car exhausts react with sunlight. Air pollution can thus exist of chemicals that react within a given environment and create new types of air pollution.

Then there's another important basic principle:

The second principle is that air pollution does (generally) not just remain in the location it's emitted. Examples:

  • I'm living in a relatively clean environment in the Eastern part of the Netherlands.

    A large industrial area can be found in neighboring western part of Germany. When the wind is going in the wrong direction (or the right direction for the inhabitants of that industrial area), some of that air pollution from Germany can arrive at my doorstep.

  • Very tiny particles, called "particulate matter", especially the really small variations, can travel for hundreds and even thousands of miles. Industry, energy creation, and industry are major sources of particulate matter. 

    When emitted in China, some particulate matter can literally end up in the west coast of the US. 

    Yes, really...

  • You can have bad luck if there's almost no wind, as an area that emits lots of air pollution can have its pollutants trapped at the location they were originally emitted.

  • Colder temperatures can prevent (some) air pollutants from being released into the atmosphere, which also negatively affects people living in areas that are net-contributors to air pollution.

The weather can thus determine how much air pollution ends up at your doorstep, not only by creating new types of air pollution but also by steering their trajectory so that they end up in one place rather than another.

One remark: don't be overwhelmed by the enormous list of pollutants that I've listed below. 

Instead, just get a general impression of these air pollutants - you don't have to understand their ins and outs completely to adequately deal with them. 

Of course, if you're interested then read the full sections. To be honest, the solutions given later are more important:

In section five I'm going to break down the solution to lowering your exposure to these toxins in very simple to follow steps. These steps to reduce air pollution levels will work regardless of whether you understand the intricate details of all air pollutants in this section.

Another remark before I'll take you through the list of pollutants: all the information supplied below, while seemingly complex, is still oversimplified

As of this moment, this guide is already over 25,000+ words long. If I had included all important air pollutants and described their full effects, not even 2,500,000 words would not have been sufficient.

Let's now take a deep dive into thirteen different air pollutants. I'll start with an air pollutant you're may be acquainted with: 


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1. CARBON MONOXIDE (CO).[23-27; 29; 58; 59]

Carbon monoxide (CO) is a gas. CO is deceptively dangerous because it cannot smelled or seen. 

Carbon monoxide is created when carbon containing compounds (such as gasoline or coal) are incompletely burned, due to insufficient available oxygen being present. You probably know that "carbon dioxide" is normally created, instead of "carbon monoxide".

Let me explain:

Just imagine burning wood at a fireplace that does not have enough access to fresh air. Over time, oxygen levels around the fireplace will go down. The burning of wood that ordinarily results in "carbon dioxide" will then off-gas "carbon monoxide".

carbon monoxide breathing through firewoodCozy fireplaces: deceptively dangerous...


Most carbon monoxide (CO) is created by human action.


If you drive a car or truck or work in an industry where fossil fuels are used, small amounts of carbon monoxide can be emitted continually into the air.

Indoor sources of carbon monoxide exist as well.

Smoking is a common reason for inhaling carbon monoxide -  from both cigarettes or water pipes. Second-hand smoke is another reason you're being exposed to CO.


After breathing carbon monoxide it's absorbed by a compound called "hemoglobin" in your blood, which is extremely dangerous.

You see, the role of hemoglobin is to transfer oxygen in your blood.

Under the influence of carbon monoxide, that hemoglobin is transformed into something called "carboxyhemoglobin", making the hemoglobin compound impotent. As a result, your blood can no longer properly carry oxygen (and carbon dioxide).

The consequence is that the oxygen that you breathe through your lungs--that is normally diffused into the bloodstream--can no longer be used. Your body's cells end up no longer functioning adequately.

In worst case scenarios you can even die of the consequences of CO poisoning.

Remember that air pollution was called a "silent killer"? That statement is especially true for carbon monoxide. 


You don't initially notice that you're breathing this compound, and may fall asleep (and die because of the body's inability to regulate itself in sleep). 

Over time, you may notice symptoms of CO poisoning. 

These symptoms can include headaches, mental problems (confusion or poor memory), nausea, dizziness, and overall bodily weakness. You may also have a low heart rate or low blood pressure, poor coordination and less of an ability to speak clearly.

Shocking fact?

CO Is currently responsible for 50% of fatal poisonings in the world.

Carbon monoxide also influence how well your mitochondria function.

Mitochondria are the energy-producing factories in your cells. While I'm oversimplifying, oxygen and food are transformed into water and carbon dioxide in the mitochondria. In essence, the process that's present in plants by which plants create oxygen from carbon dioxide and water is reversed in your mitochondria. 

Carbon monoxide thus short-circuits that process in your cells as well so that they can no longer function adequately.

And there's more bad news:

If you're severely poisoned by carbon monoxide, a full recovery can take months.[30; 31]

And it's not just the severe cases of carbon monoxide poisoning that you should worry about.

Smaller exposures matter...

Remember that the exhausts of cars and trucks produce carbon monoxide.[65] Many people are exposed to that pollution without ever nearing the threshold of full-fledged carbon monoxide poisoning. 

In other words, if you're being exposed to small amounts of carbon monoxide every day you probably won't notice any symptoms, but your blood will still carry less oxygen and the energy creation process in your cells will be sub-par.

The more carbon monoxide entering your body, the worse your overall health becomes.

If you're spending lots of time inside vehicles, you're going to be exposed to more carbon monoxide.[32-35] That car exhaust can significantly lower your blood pressure, for example.

Just spending time outside in bigger cities with lots of cars increases your carbon monoxide exposure as well. 

Lots of appliances likewise emit small amounts of carbon monoxide.[36; 45]


Lawn mowers, leaf blowers, electricity generators that work on fossil fuels, etcetera. Indoor carbon monoxide sources are air conditioning systems, (central) heating, and generators.

Indoor cooking in developing countries also produces carbon monoxide, which may increase blood pressure.[64] The reason for that carbon monoxide creation is that indoor levels of oxygen tend to go down if you cook indoors. 

But let's explore CO's health effects in more detail...

Carbon monoxide exposure is related to many negative health effects, such as:[37-44; 48-51; 55; 57; 60; 66-69]

  • plaque buildup in your blood vessels, heart problems, a greater frequency of brain infractions (dying brain tissues due to a low oxygen supply), and lower overall brain volumes.
  • being more susceptible to heart problems or dementia, years down the road (if you've been poisoned by carbon monoxide).
  • poorer development of the nervous system and brain, especially among children. When pregnant (prospective) mothers are exposed to carbon monoxide, fetuses can be damaged. Children are also more prone to be born prematurely with increased carbon monoxide exposure levels.
  • greater risk of getting diabetes. In diabetes, the body no longer produces the "insulin" hormone or does not correctly use sugars inside cells. Both a decrease in insulin production and sugar usage have detrimental effects on how well your cells are able to produce energy - and your ability to function in life.
  • more allergies, resulting in nasal irritation - especially in children. Lung problems such as asthma also increase with greater carbon monoxide exposure.

Yes, overall that's very bad news. Carbon monoxide is thus not "innocent"...

Health problems due to higher carbon monoxide levels are quick to show up:

If levels increase by 1mg per m3 then a city about 1% more people will die of heart disease and strokes over time - other studies show an even bigger effect.

If you've already got heart disease, lung problems, anemia (low iron in your blood, which already gives you an inability to transfer oxygen well), have multiple diseases, or if you're of young or older age, then carbon monoxide will affect your health even more than normal.

Short-term exposures of carbon monoxide can thus put you "over the top" if you're already sick.

Delicious sight--but not enough oxygen present
to prevent carbon monoxide buildup?

The bright side about carbon monoxide is this: even if you're poisoned, you may recover eventually.[46; 50]

Brain recovery and increased diabetes risk, while sometimes taking years of time, are possible. Unfortunately, stroke risk and heart disease risk do appear to remain higher over time.[51; 54; 55]

Fascinating fact:

Really low levels of carbon monoxide exposure might be beneficial to your health, as there's an adaptive response to exposure.[63]

Don't stress out too much about carbon monoxide right now. Remember: in a later section I'll teach you how to avoid the worst pollutant levels...

Let's move on:

You'll now learn about an air pollutant that most people don't know about, nitrogen dioxide:


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Just as with carbon monoxide, fossil fuel usage is one of the main reasons nitrogen dioxide emissions exist in the first place. Most nitrogen dioxide either originates from traffic emission or power generation (and use).

Industry or agriculture does not emit large quantities of nitrogen dioxide (although they do emit other nitrogen substances).

Nitrogen dioxide is a gas. Inhaling that gas mainly has consequences for your airways and lung health.

Nitrogen dioxide is part of a group of substances called "nitrogen oxides" (NOx). Nitrogen dioxide is the most important type of NOx, and to keep the message relatively simple  I'll, therefore, focus on nitrogen dioxide in this blog post.

At higher concentrations (for nerds: 200 micrograms per cubic meter (m3)), nitrogen dioxide is directly toxic.


Let's consider the following NO2 health consequences. Over time, NO2 exposure:[92-106; 117; 352; 353; 358]

  • increases your all-cause mortality risk.

    All-cause mortality is your general risk of dying, whether that's of lung disease, a car accident, or old age. In fact, with every 10 micrograms per m3 increase in NO2 levels that you breathe, your overall mortality risk goes up.

  • creates lung problems such as asthma (a lung inflammation disease), and COPD (reduced airflow and lung capacity).

    With greater exposure levels nitrogen dioxide also makes you more likely to be taken up in a hospital for lung or heart problems (which is somewhat self-evident). Existing lung conditions such as asthma also become more severe with greater NO2 exposure.

    Fetuses who are exposed to NO2 during pregnancy they also have more respiratory problems later in life.

  • raises your risk for heart and blood vessel diseases, and lead to higher blood pressure, especially with long-term exposure. Heart attacks, heart failure, and brain infarctions also increase with greater exposure levels. 

    (With a brain infarction, part of your brain tissue dies due to low oxygen levels. Bleeding can be a cause of such infarctions.)

  • may even slightly increases women's risk for breast cancer, as well as overall cancer risk.

Not fun, that list...

You may be thinking: "No problem. Not that many people get hurt by nitrogen dioxide..."


Let me  give you a perspective of how damaging NO2 is:

In Germany, it's estimated that up to 8% of all diabetes cases are directly caused by nitrogen dioxide - equaling nearly half a million people. 

That figure alone also tells you why air pollution is not a problem you can choose to ignore if you care about your health.

Another example: over 20,000 people die in the United Kingdom because of this air pollutant on a yearly basis.[107]

Why are the effects of nitrogen dioxide not widely known?

Well, for a long time it was hard to distinguish between the effects of nitrogen dioxide and particulate matter - both air pollutants are co-created in large quantities in modern society. And now the extensive effects of this pollutant are correctly understood, it's time to get more worried...

nitogen dioxide emitted by traffic kills tens of thousands of people each years. Picture shows polluting cars
One very common source of nitrogen dioxide exposure 
- an example of air pollution's poison drip...

More bad news:

Children, elderly people, and people with pre-existing lung or heart problems are hit hardest by exposure to this air pollutant (again).

If you've got lung, airway, or breathing problems, inhaling nitrogen dioxide can exacerbate your symptoms, such as causing an increase in coughing, wheezing, an increase in mucus production, or breathing problems.

And unlike air pollutants that I'll consider later on in this blog post, such as pet dander, the evidence for the negative health effects of NO2 is solid.

Really solid...

When emitted into the air and reaching the atmosphere, NO2 can also react with other chemicals which leads to the production of new air pollutants.

In fact, two air pollutants that can be created through reactions with NO2 are next on the list: ozone (O3) and particulate matter.

The next air pollutant should create an even bigger incentive you to take air pollution seriously:


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So let's consider particulate matter: the "king of air pollutants"--or maybe "most tragic air pollutant" is a better name...

Particulate matter are tiny particles subsumed in the air that are created as a byproduct of traffic, energy production, cooking, and industry.

800,000 people die every year due to particulate matter exposure. Billions of individuals' health is negatively affected due to the same substance.[181; 182]

Due to particulate matter's heavy impact on human health, I've written an extensive blog post (or guide) on the topic before. That guide teaches you how to reduce your particulate matter exposure by 50-90% - even while living in the city.

But let's talk about that stuff quickly:

Particulate matter is commonly measured by size - specifically the "micrometer" metric. One micrometer is a thousand times as small as a millimeter - yes, that's really small.

The problem is that these tiny particles end up in your lungs, your bloodstream, brain, and organs. Once particulate matter enters your body, the damage begins.[183-190] 

Different types of particulate matter exist.

Common measurement categories for particulate matter are:

  • those with diameters smaller than 10 micrometers, called "PM10";
  • smaller than 2.5 micrometers which are named "PM2.5";
  • and smaller than a tenth of a micrometer, "PM0.1"

To put these numbers in perspective: the average human hair has a diameter of 70 micrometers...

2.5 micrometers or 0.1 is thus extremely small and invisible to the human eye.

Particulate matter exposure has many negative health effects--smaller types of particulate matter such as PM0.1 and PM2.5 have stronger negative consequences because they more easily transfer to the blood from the lungs.

The smallest type, PM0.1, may even be able to travel directly from your nose to the brain.

It's often hard to imagine that particulate matter has negative health effects, so let's consider the following analogy:

Most people can imagine that if billions of harmful bacteria are breathed in, that they can be harmful to your overall health. In the case of particulate matter, you can simply imagine that tiny dust particles end up everywhere in your bloodstream, brain, and other organs.

In fact, dust often consists of particulate matter so you don't need to think very far outside the box to understand the effects particulate matter has on your health.

Health effects?


There are many...

But let's consider a shortlist with the most important health effects of breathing in particulate matter. Particulate matter causes:

  • an increase in all-cause mortality, which is your most general risk of death no matter what the origin.[191-196]
  • more lung, heart, and blood vessel diseases, and lung cancer.[197-209; 352; 353] Overall lung function development in children, as well as lung function in healthy people also decrease.
  • surges in stress hormone levels such as cortisol and adrenaline. Yes, you'll immediately become more stressed and even have higher blood pressure levels with particulate matter exposure.[211; 212]

(Many more effects are laid out in my extensive guide on particulate matter.)

Children, elderly, and people with pre-existing lung or heart conditions are hit the hardest by particulate matter (yet again).

While short-term exposures to particulate matter already cause adverse health effects, such as an increase of stress hormones and blood pressure, the negative health effects of particulate matter accumulate the longer you're exposed.

The last two air pollutants I've discussed (particulate matter and NO2) are mainly found outdoors. The next one is found is found everywhere:


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Volatile Organic Compounds or "VOCs": that sounds like a complicated word. 

No worries thoguh...

VOCs are a gas and are made of molecules that have a low boiling point. VOCs are created by "off gassing" from solid compounds.

Simply put, VOCs  evaporate into the air...

VOCs can be created from several sources, such as a byproduct of the burning of fossil fuels or as an off-gassing of chemicals such as solvents.

Sources of VOCs are oil and gasoline that are burned by cars and airplanes, as well as fossil fuels used in energy generation (e.g. power plants).

But VOCs are often found indoors as well.


Coatings, varnish, glue, adhesives, and paint are common VOC sources. Plywood, vinyl flooring, and particleboard are also problematic off-gassing causes. Additional sources are cosmetics, aerosol sprays, air refreshers, cleaning products, and disinfectants.

VOCs are literally everywhere. Examples:

Plastic materials in kids playing toys? Toxic VOCs.[156] 

Getting your hair colored in a salon?[167] More VOC exposure...

That new car smell? That's VOCs being emitted from the interior.

Incense burning or indoor smoking? VOCs...

Buying a new dinner table, sofa, carpet, or cabinet? That furniture is coated with VOCs to preserve the material and make it look shinier.[149; 151; 159; 160; 162; 165] 

A beautiful new painted or coated cabinet will release new gases into the air over the course of years.

How about outdoor VOCs?

Benzene exposure when refueling your car tank, or the exhaust you're smelling when using your lawn mower are common sources.

a picture of furniture, which can off gas VOCs
Counter intuitive VOC indoor air pollutants from chairs, 
cushions, and the couch...

Simply put, VOCs are gases that are emitted from many compounds humans have introduced to the environment.

Indoor VOC levels are generally two to five times higher as outdoors.[152-154] 

Unfortunately, not all VOCs are easily measurable, so the scientific understanding is still incomplete.

The levels of one VOC called "formaldehyde" can be easily estimated, for example. The problem is that thousands of different types exist, which are sometimes hard to measure. New VOCs are also identified over time...

So what are VOCs health effects? Let's jump straight into another list of consequences you'd want to avoid. VOCs:

  • raise your risk of asthma and allergies. VOCs also increase inflammation in the lungs while decreasing your lung function.[148; 150; 154-158; 170] Mothers exposed to VOCs during pregnancy may also confer a higher asthma risk upon their (eventual) kids.
  • may increase heart disease risk while almost certainly giving you more lung disease.[166; 169-171]
  • cause organ damage, particularly to the liver and kidneys, as well as nervous system (neurological) problems.[172-177]
  • probably increase cancer risk.[161; 166; 168] 
  • give you nasal, throat, and eye irritation.[163] Higher VOC exposure levels can cause dizziness and headaches.[161; 164] 

And it's not just breathing that's problematic--VOCs also enter the body through skin exposure.[178-180]

As often the case with air pollutants, currently recommended VOC exposure levels may currently not be stringent enough.[163]

It's safe to assume that less exposure is better. 

(Nerd section: It's not probable that short-term exposure to VOCs is very damaging. The problem starts with longer-term exposure.[154] Additionally, a problem with mapping the health consequences of VOCs, however, is that they are a very broad category that tells you almost nothing about the effects of individual toxins. Some VOCs have been proven to be highly damaging, such as formaldehyde, while many other VOCs have yet to be identified. Data on exposure patterns of different types of VOCs is also limited compared to previously treated pollutants. The topic of VOCs is extremely complex, as toxicology and exposure patterns of thousands of chemicals as well as their interactions would need to be mapped to attain a complete understanding.)

An example of a VOC?

Let's consider one you probably know of: benzene.

Benzene is a natural part of crude oil. 

When you're filling up your gas tank at the gas station, you're being exposed to benzene if the wind is blowing in the wrong direction (at you). Forest fires, volcanoes, and cigarette smoke are other benzene sources.

As a VOC, benzene has many different health effects.

At low levels, benzene causes throat irritation, trouble breathing, skin rashes, eye irritation, increased blood pressure and confusion. [240-243] At higher levels, benzene increases risk for leukemia (cancer of blood and bones), especially in children, but can also cause kidney and liver problems - and finally even death.[237-239; 244-247] 

And although my treatment of benzene is really superficial here, fully considering its effects of different all types of VOCs is impossible in one blog post. 

And remember: even though this list may seem overwhelming, I'll tell you all about simple solutions later on in this blog post.

Stay with me...

Next, I'll consider an air pollutant which many people living in the 70s and 80s are acquainted with:


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5. OZONE (O3)

You probably know about the chemical structure of the oxygen you're breathing (O2), which contains two oxygen atoms.

(Both the atoms of the substance that you're breathing, as well as the compound gas itself, are thus problematically called "oxygen".)

A compound called "ozone" also exists, which contains three oxygen atoms (O3). 

When present at the earth's surface, that ozone is often considered a pollutant. Nevertheless, ozone is also essential for life to exist at this planet at all: in the atmosphere, ozone filters out excessive radiation from the sun.

That ozone in the atmosphere is called "stratospheric ozone". The emission of several air pollutants into the air can damage that protective "ozone layer", but fortunately, that layer is slowly recovering.

Ozone emissions have been going down the last few decades--this air pollutant is thus currently less damaging than it was 30 years ago. Bright spot: again, humanity can improve the environment.

picture of the sky, in which ozone was depleted up until 20 years ago
The protective ozone layer is found
20-30 kilometers up in the sky


On the earth's surface (where you're living unless you're an astronaut), ozone is mainly created through the reactions of other chemicals.

To be more precise:

Chemicals that were treated earlier, such as VOCs and nitrogen oxides, can react with sunlight to create ozone on the earth's surface.

Remember that VOCs and nitrogen oxides (NOx) can be created from many sources, such as exhausts of vehicles that burn fossil fuels, as a byproduct of energy creation, industry, and others.

Even though many previously treated pollutants are more problematic in colder environments because they are more prone to keep on "hanging" in the air, that's not true for ozone - sunlight is essential to ozone creation.

Not all ozone is created by humans though: a greenhouse gas called "methane" is a natural source for ozone when it reacts with sunlight. 

Small amounts of ozone are generally considered safe, but in larger amounts, negative health effects begin to appear. 

You might be thinking: "so what are the health effects of ozone?" 

Ozone exposure increases your:[110-112; 115-117; 119-122; 126-136; 143-147]

  • risk of dying of heart or lung disease if you're exposed to higher concentrations. More ozone exposure also gives you a decline in lung function and increases hospitalizations if you've got existing lung problems. 
  • overall stress levels and inflammation. Inflammation underlies many modern diseases such as heart and brain diseases, and cancer. Of course, more stress is not beneficial for most people either...
  • your risk of having allergies.
  • causes a higher risk for "stillbirth", which is the death of the fetus during pregnancy, and an increase in heart defects of children after they're born.

Fortunately, the effects of ozone exposure have no (proven) effect on your mental health, such as autism, dementia, or decline in thinking ability (cognitive functions).[109]  Your overall risk of death, surprisingly, is not affected by both short-term and overall yearly ozone concentrations either--although there's some conflict of evidence regarding this point. 

And again:

Children, women, older or obese people are more strongly affected by ozone air pollution.[113; 114; 123; 125] 

If you have pre-existing lung or heart conditions ozone will also affect your health more negatively.[129]

Even if you're healthy, you should still be wary of ozone exposure because of its effects on the airways. Your propensity for shortness of breath, wheezing, coughing, and inflammation increases - of course, this process occurs more frequently if you've already got lung problems.

Although there's some contradictory evidence, some studies suggest that your lungs and heart simply have to work harder when you're exposed to ozone.[137-141] Longer-term exposures at higher concentrations are most likely harmful.

Another problem:

Current safety threshold set by institutions such as the US Environmental Protection Agency may not be low enough to prevent harm to those who are more susceptible to ozone's damage.[142]

Fortunately, ozone pollution is not the worst air pollutant out there, but you should be wary of excessive exposure.

Previously treated air pollutants such as particulate matter and nitrogen dioxide are much more damaging than ozone.

To reduce exposure, be very wary of any indoor ozone generating products. Some air purifiers, for example, sometimes generate ozone as a byproduct or even intentionally emit ozone into the air.

Ozone may be helpful in certain instances, such as reducing the toxins of household items that have collected mold on them--but it's recommended to be extremely cautious with exposing yourself to ozone if you don't know what you're doing. 

(Nerd section: keep in mind I'm not in favor or against what is called "ozone therapy". Ozone therapy seems to elicit a hormetic reaction in the body, and may or may not have health benefits - I've not closely looked at the evidence yet, so I cannot judge. )

Next, let's consider sulfur dioxide - the air pollutant that was primarily responsible for the great fog of London in the 1950s, which started a wave of air pollution control legislation:


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Sulfur dioxide is actually one of the longest tracked air pollutants.

The reason for that relationship is that sulfur dioxide is a direct byproduct of energy production from coal.

a fire that emits sulfur dioxide
Coal: humanity's angel and devil at the same time.


As coal was used on a larger scale after the Industrial Revolution, nations began to track their coal production and consumption. From that data it has now become possible reconstruct how much SO2 pas put into the air over the last few centuries.[22]

The reason sulfur dioxide emissions were reduced in Europe and North America after the 1970s and 80s, is because SO2 lowering technologies were mandated for energy production industry such as coal plants.

Even in some Asian countries such as China, SO2 emissions are declining today. India, however, still increases its yearly emissions, which is why overall Asian SO2 emission increase.

Sulfur dioxide a few unwanted health consequences. Sulfur dioxide:

  • increases your risk for heart and lung problems.[351-357; 363; 364] 

    With short-term exposure, you'll (just) have an increased risk of shortness of breath or chest tightness, especially if you're breathing actively. Sulfur dioxide can also disrupt your heart rhythm. 

    Due to longer-term sulfur dioxide exposure your cardiac arrest frequency increases - in cardiac arrest your heart stops pumping.

    In fact, every 10 micrograms per cubic meter of sulfur dioxide exposure - a frequently used measurement method for air pollutants levels - linearly increases your chances of dying of a heart or lung disease. The same linear relationship is likely applicable to children's risks of getting asthma (if they're exposed to sulfur dioxide).

  • raises risks for birth defects and pre-term births.[357-359; 363]

    Stillbirth risk and lower birth weight risk also surge with more SO2 exposure. Sulfur dioxide exposure during pregnancy also increases asthma and wheezing in children after they're born.

    Notice a pattern here?

    Many air pollutants are damaging during pregnancy...

  • may lower reproductive fitness.[361; 365-367]

    Unfortunately (or perhaps fortunately), these reproduction-lowering effects have only been established in rat studies.


That's it...

When sulfur dioxide is emitted into the atmosphere, chemical reactions can also help it turn into particulate matter. Acid rain can additionally be created through sulfur dioxide exposure, so the pollutant has a negative effect on the environment. 

Your neighbor is thus not always your best friend when sulfur dioxide emissions are in play...

Next to sulfur dioxide, other sulfur gases such as SO3 are also harmful. I won't cover these other sulfur compounds in order to not complicate this blog too much...

Having said that, I'll now move to the next category of pollutants: air pollutants with indoor origins (most of the time):


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Let's start with a definition: biology is the study of living organisms. All air pollutants included in this subsection are thus (derived from) living beings. 

I'll consider several biological air pollutants, such as allergens including pollen, animal dander, and dust mites.

How you respond to these biological pollutants really depends on you individually. You may be really susceptible to pollen, for example, or not susceptible at all.

If you're having an adverse reaction to biological pollutants, many of the symptoms overlap with what you'd get from exposure to air pollutants such as sulfur dioxide or particulate matter:

  • coughing
  • eye irritation
  • a running nose
  • throat problems
  • sneezing
  • breathing problems

Stronger reactions entail having headaches, becoming ill, dizzy, or depressed. 

Of course, exposure to germs can have more far-reaching consequences.

Biological air pollutants are somewhat different than other pollutants in that your immune system is more prone to consider them invaders.


Some people's immune system responds very heavily towards certain substances entering their bodies. If your immune system reacts very heavily over and over again, you'll feel the consequences - resulting in the symptom list I described above.

Let's consider these biological pollutants in more detail. Examples of allergens are:

  • pollen, which causes hay fever in some people

    You may know someone with allergies: they'll get sick if they eat peanuts or drink milk. You also know some people who are completely unharmed when consuming milk or peanuts - signifying an absence of allergies

    So what's up with allergies, and the substances causing these allergies called "allergens"? 


    Pollen should not be considered an "invader" to your body but can be treated as such if you're allergic. Pollen are emitted into the air by plants and act as a fertilizer for plants of the same species. These pollen can travel hundreds of miles...

    When pollen are reintroduced into the air in the spring at many locations, for example, asthma attack numbers increase, .[320]

    Different people are allergic to different types of pollen. You may be intolerant to the pollen of certain grasses, or to pollen of beech trees while having no problem with grasses at all.

    (Keep in mind that in this blog post I'll only consider substances emitted through the air, and not food allergies.)

    The result for (some) poor humans?

    If you're breathing these substances while allergic, signaling substances such as "histamine" are created as a response to the allergen exposure, and bodily inflammation is increased.

    Springtime: not fun for everyone...

    A surprise about allergies?

    Contrary to 50 years ago, allergies are really widespread today: up to one in four persons has hay fever in developed countries.[331] 40 to 50 million people have one allergy or another in the US alone, 

    And you know what?

    Allergy risk increases by exposure to lots of (smaller) particulate matter and dust mites (a topic I'll treat in a second).[314; 315] Particulate matter exposure also worsens existing allergies.[317-319] 

    In fact, indoor pollutants pose the biggest risk factor for developing allergies.[316]  Suddenly those omnipresent VOCs no longer sound so smart. Many "regular"air pollutants thus contribute to your risk of getting allergies to biological substances. 

    But let's move to the next biological air pollutant:

  • animal dander

    Animal dander are tiny skin particles emitted by furry or feathery animals. Most pets either have fur or feathers.

    Fun fact?


    You can get reptiles pets that do not emit any dander, but their foods such as grasshoppers can be problematic for some allergic people...[321]

    So there's no easy solution for pets...

    You're probably aware that your beautiful cat or dog can get you in trouble, and that they don't just do so by breaking things. 


    Roughly the same immune reaction occurs when an allergic person is exposed to animal dander as happens in someone who's hypersensitive to pollen.[322-324] It's not just dander that sensitizes some people towards these pets, but also microbes associated with these animals.[320; 329]

    picture of a cat that emits animal dander
    "I'm innocent, My fur didn't poison you. Really!"

    It's very sad if family members have allergic reactions to pets, as pets are often considered part of the family. It's tragic to find out that you're allergic to the dog you love so much...

    Let's talk about prevention though:

    Exposure to pets or farm animals when you're young is generally as protective against developing pet allergies.[326-328] Having other bacteria exposures, such as from drinking raw milk or a vaginal birth (as opposed to a C-section) may be protective as well...

    In general, owning cats is also more protective against allergies than owning a dog.[330] 

    (I'm waiting for dog-persons' hate e-mails to arrive)...

    Unfortunately, most of us no longer grow up around farm animals when we're young, no longer drink raw milk, and C-section births have also been increasing in the last few decades.

    Again: tragic...

    Pet allergies, however, are far from completely understood. The coming decades will probably yield lots of exciting new research...

  • Dust mites

    You may know about dust mites: tiny organisms living on furniture and in dust.[332; 333] 

    Mattresses, pillows, and carpets are other preferred dust mite places.[334-336; 342] Couches and cushioned chairs are also breeding grounds. 

    All buildings contain dust mites but different buildings contain different numbers of them.[331] Dust mites thrive in warmer and more humid environments.[338] If you're living in a drier climate, you're lucky: dust mites have a harder time growing there.

    (I'll get back to the topic of sterile environments later--developed countries may have a problem with too much hygiene in some regards).

    But let's get back to dust mites:

    If you're living in developed countries with good hygienic circumstances, you're more prone to be allergic to dust mites than when you're living in a rain forest or a primitive hut in the desert.[333]

    Dust mite allergies usually develop during your childhood or teenage years and are currently non-curable. If you're more intolerant towards dust mites, you'll also have higher risks of having other allergies as well.[339-341]

    But let's move on...

    Just when you thought the topic couldn't get any more disgusting:

  • Cockroaches

    Yes, cockroaches are a bit gross but I'll have to consider them anyway...


    Having cockroaches in your home, for example, increases your risks for asthma.[343; -345] The reason for the allergenic nature of cockroaches is because they emit tiny particles which you may not tolerate.

    If you're sensitive to cockroaches you're also more prone to be sensitive to dust mites, and vice versa.[347] Again, observe that many allergies are interrelated...

    Different types of cockroaches exist in varying climates.[348] Cockroaches found in colder climates are not the same as those thriving in hot and humid conditions.

    Pest control is recommended if you've got a cockroach problem. I'm not an expert on cockroaches (fortunately), but generally, if you've got an insect problem in your home then it's wise to get help.

    Living in the city--yet again--is associated with cockroach allergies increases.[346; 349; 350] 

    Farmboys like me fortunately do very well in the allergy department (you didn't think I was a farmboy right?)

A sad development, all these allergens--as if human-made air pollution weren't menacing enough...

And you know what? 

Allergies are very "weird" from an evolutionary perspective.

Many traditional societies don't have a conception of allergies at all. 

Hay fever was extremely rare in the late 19th century. Specific diseases that are highly interrelated with allergies such as asthma only became more prevalent after the 1960s.[325] 

"Coincidentally" (or not so coincidentally), the number of allergic people has massively increased since humans adopted an indoor lifestyle. 

Spending lots of time indoors thus has its expected downsides...

By the way:

I've decided not to treat germs such as bacteria and viruses in this section. 

Let me explain why:

On the one hand, germs have made human lives miserable and short for thousands of years - they're thus really important. 

Tuberculosis incidences, for example, which are caused by bacteria, are dramatically influenced by air quality. Influenza is another example that's widely known as a pathogen that's carried through the air.

On the other hand: humans have always been exposed to germs. Germs are thus very different than many types of modern air pollution, in that continuous air pollution is novel from an evolutionary perspective.

Even biological types of air pollution such as the dust mites and cockroaches stand in a totally different relationship to you today than 200,000 years ago when your ancestors evolved in Africa.

That's why I excluded germs here...

Next, another indoor air pollutant: 


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8. RADON (Rn)

Back to the topic of gases: radon (Rn) this time. 

Remember that I've considered other gases before, such as carbon monoxide (CO).

And just as is the case with carbon monoxide, it's impossible for you to smell radon. And likewise to carbon monoxide, the only way to know you're exposed to radon is to measure

How does that happen?

Well. radon is created when uranium decays.[72] 

Radon naturally occurs in the the earth's surface and is emitted from there. The more uranium within the soil, the higher your radon exposure generally will be. 

Radon can be found in homes, offices workplaces, and public buildings, but is not found outside homes in any large concentrations. 


Radon quickly dilutes in outdoor air. 

Radon is thus only damaging when it emerges from the soil into buildings such as houses or offices - being trapped there for a while.

Cracks in the floor, spaces around pipes that have not been sealed, and holes in walls are mechanisms by which radon "sips" into buildings. Good isolation of ground floors of buildings ensures that less radon is passed from the basement or crawl space into the actual building.

Basements generally get high radon exposure. Other underground locations such as caves and mines are especially dangerous for radon levels - unless they're properly ventilated.


Poor ventilation "entraps" some of the radon in buildings, resulting in negative health effects. 

Radon has only become problematic is (again) because humans have have moved indoors while insulating their buildings so that little air can enter from the outside.

If you're thinking: "am I at risk", then here's the answer:

You can guesstimate your exposure levels with the following maps:

USEU, or Australian map, for example, gives you a general impression of how likely radon levels are high at your location. 

Don't use that map to speculate about your specific living locations' radon levels though, as two houses located 100 yards apart can have hugely different exposure levels.

On another note...

Want to know a shocking radon fact?

Here it is:

Next to smoking, radon is actually the second most common cause of lung cancer.[70; 71; 75; 77; 82; 84-87]

The risks of these two dangers stack: if you're already smoking then radon exposure will further increase your cancer risks.

Up to 10 times as many smokers die of radon exposure compared to non-smokers. Smokers also have up to 25-times higher risks of dying of radon-induced lung cancer than non-smokers.

That's devastating...

There's no radon exposure "safe zone" regarding lung cancer risk--less exposure is always better, even if you don't smoke.

While the link to lung cancer is strongest, radon exposure is also associated with other diseases:[76; 78; 79-81; 83; 89; 90]

  • Lung diseases, such as "COPD" - COPD gives you breathing and lung problems.
  • Several nervous system diseases.
  • Skin cancer and cancer in bones and blood cells (leukemia), but not lymph system or nervous system cancer.

Unfortunately, the research in these non-lung-cancer health domains is not crystal clear yet. It's thus essential to wait for more high-quality research to be released on those topics.

The relationship between radon and disease is fascinating to me because it's reasonable to assume that radon exposure does cause additional health problems next to 20,000 yearly lung cancer deaths (in the US alone).

In the case of particulate matter, many health effects were also discovered in time. I expect radon to follow the same pattern (to a lesser extent) as well...

Furthermore, radon can also end up in your drinking water.[73-74] It's uncertain whether radon in drinking water has health effects though, as exposure has negative associations with stomach cancer, for example.[81]

Realize that the 20,000 US radon-induced lung cancer deaths figure is immense.

Putting that number into perspective: drunk driving kills 17,400 people each year, drownings 3,900, and home fires "only" 2,800.[90]

Radon air pollution is not part of the common awareness (yet again), the problem is therefore not actively tackled actively.

But enough about radon...

The next air pollutant is carbon dioxide. You probably know that compound from biology class:


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Carbon dioxide is often considered an environmental pollutants--but its true status is more complex - even in your body.

I nevertheless subsume carbon dioxide under air pollutants because high indoor CO2 levels are often a culprit why people function poorly. Let's start with a comparison to understand high CO2 levels in indoor environments.

If you're spending time in the forest or on the beach, the air contains about 400 parts per million carbon dioxide.

(Outdoor CO2 levels have been creeping up due to climate change. CO2 levels used to fall below 300 parts per million in the 19th century.)


That's where you get into trouble.

well-ventilated indoor environment contains up to 1,000 parts per million CO2. But: that 1,000 parts per million almost triples "nature's normal levels" alrady.

And the story gets worse.

Much worse...

Indoor environments such as offices and classrooms can contain levels up to a whopping 5,000 parts per million of CO2.

In the wintertime, classrooms in temperate climates generally have CO2 levels between ~600 and 4,000 parts per million. During the summertime that levels decreases to ~500 to 2,000 parts per million.[299]


Less ventilated a building build up more carbon dioxide.[296] Let's now first consider the problem with too much carbon dioxide.

Here are some carbon dioxide health facts:

  •  With every 100 parts per million CO2 increase in classrooms, attendance dropped 0.2%.[298] Children thus called in sick sometimes due to higher CO2 concentrations.[305]

    Fortunately, kids' test performance was not negatively affected by that indoor air quality. Kids thus still do reasonably well with poor air quality.

    But older people like you and me?

    Different story...

    Teachers are less well off: headaches, fatigue, and an inability to focus all increase with high CO2 levels.[300]

  • If CO2 levels exceed 800 parts per million in offices eye irritation and breathing problems are more likely to occur - although these symptoms may also be explainable by indoor pollutants co-present with carbon dioxide.[301]

    Higher CO2 concentrations also promotes tiredness and dizziness.[302] An increase from 600 to 1,000, (or worse: 2,500 parts per million) even impairs your decision-making ability.[304]

    Reducing both VOCs and CO2 levels, instead improves cognitive performance.[306; 307]


In general, your health immediately declines slightly once your spending time in a room where CO2 levels approximate 1,000 parts per million. 

Getting a good ventilation system in place is one method to keep CO2 levels low.[303] In fact, optimizing CO2 levels is highly underrated for improving indoor air quality (and well-being).

That's it for CO2.

Now I'll tell you about one of the most toxic indoor pollutants - in many instances this one should make you run, not walk: 


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Mold spores are fungi. Fungi are neither plants nor animals but are a separate kingdom in biological classifications.


Look at the wall below:

a picture of toxic mold on a wall

That's toxic mold.

Toxic mold exposure can be devastating to your health. To be clear: not all mold is toxic, but the mold displayed above is. That mold type is known as "black mold", and frequently found in the developed world.

Mold primarily originates from water damage - whether that's from a flood, humid air, or leakages. In humid or wet materials, mold has the ultimate means to multiply and spread.

What materials precisely?

Well, wood products, carpets, cardboard, drywall, insulation, paint, ceilings, wallpaper, and even dust are favorite mold growing places. 

Mold is problematic as an indoor pollutant because up to 10 - 50% of residences and offices in the developed world are contaminated.[218]

No, that 10-50% is not a joke--it's a tragedy.

And that 50% estimation may even be low as people with mold intolerance are affected by an even greater percentage of buildings.

So how can mold hurt you?


If mold builds up in a humid medium such as a damp wall, it can continually emit toxins.

Of course, mold can also build up in your food, but you'll generally throw away moldy food once it's spoiled. A moldy wall can stay in place for decades while emitting toxins that entire time.

And while these toxins are not living organisms in themselves they can be damaging to you.

So what are mold exposure health consequences?

Let me tell you:

In the "best case scenario", mold exposure makes you breathe more poorly, irritated, and give you a headache. Simply put, you'll have a small allergic reaction but are fine afterward.

During the worst case scenario your entire immune system shuts down (or goes nuclear), with a disability, being bedridden, seizures, and finally death as possible consequences.[213] Yes, mold really kills people over time - its health consequences are wildly underestimated.

Of course, there's a large continuum of intermediaries between these two extreme responses to mold.

I've lived in moldy buildings before, and I presume I'm one of the "lucky" people who is not immediately affected by mold (to any great extent at least). Working inside a moldy home and sleeping outside during the summer ensured that I could still perform reasonably well.

Not many people are that lucky...

If you're sensitive to mold, just entering a building can trigger your immune system for the rest of the day.

Keep in mind that there's no scientific consensus on toxic mold - some scientists assume that mold poisoning is a pseudo-scientific concept.[212] I'm very skeptical of that claim.


Consider these mold facts:

  • Mold toxins, also called "mycotoxins", can be detected in urine after exposure. One likely mechanism has also been established: you simply breathe them in through your nose.[215] 
  • Hundreds of studies have established the negative effects of mycotoxins.[216]
  • Upon contact with mold, hypersensitive patients get an inflammatory and immune response.[217; 223] In rat studies, mold can cause extreme inflammation levels.[225] 
  • That inflammatory response has even been demonstrated to exist on the surface of your eye when that eye is affected by mycotoxins - illustrating how far-reaching the effects of mold can be.[222]
  • In lab tests, molds can change DNA and damages nervous system cells.[219-221]
  • Mold can create extreme symptoms in humans, ranging from nasal irritation to (symptoms of) nervous system and autoimmune disease.[226] (In autoimmune disease the immune system turns itself against your own body).


Even established institutions such as the World Health Organization and US Food and Drug Administration consider mycotoxins significant to health in one way or another.[224]

You may think: "so why doesn't everyone complain about mold if up to 50% of buildings are infected?"

Good question...

Answer: there's large variability between your individual capacity to handle mold toxins--there's also no current lab test definitively establishing that capacity.[214] Based on the symptoms seen in thousands of individuals, nevertheless, it's safe to conclude that this variability exists.

One problem with combating mold is that a lot of scientific research still needs to be carried before diagnosis and treatment can be simplified.

But let's consider the question: "why is mold such a big problem today?" from another angle. Why didn't people living in Ancient Greece or the Middle ages have mold problems?

That's simple:

Humans only started relying on fully insulated buildings with airtight ecosystems in the 20th century.

Double walls, triple layer glass, less air circulating from outside into buildings, and maximized energy-efficiency all build on that principle.


If mold grows in an airtight buildings you'll be exposed as long as you spend time in that building. The mold thus stays "trapped" while clean air cannot enter.

A 1,000 or 5,000 years ago things were very different...

Primitive societies live in buildings such as huts. These buildings are often not fully airtight. These people additionally only slept inside--they don't spend their entire day indoors.

Remember that modern humans, on the contrary, spend 90% of their days indoors. Individuals living in hunter-gatherer societies only do so for 33%. 

Your modern airtight home thus becomes a toxic prison if mold grows there...

Another reason why mold used to be less of a problem is because in nature, the conditions in which mold can continually grow and spread are almost never present. Almost no situations exist wherein mold can grow for years in a specific medium while being fully isolated from the environment.

So you might be thinking: "how does mold affect me in the first place?"

The following analogy can help you imagine the effects:

Your body will have an immune response if you ingest moldy food. The same response occurs when you breathe moldy air.

While eating moldy food your immune response activates just once. Breathing mold, however, can force your immune system to continually activate (if you're sensitive).

So if you're spending up to 16 hours inside a moldy home your immune system is triggered all the time. As a consequence you'll become progressively more fatigued in time. 

The consequence is that you can no longer think straight, get tired, dizzy, and that's just the beginning. Again, people end up disabled or even die because they're too weakened to spend any more time in a mold-infested environment... 

That's tit, the mold basics you need to know. Next, number eleven - another danger you may know of: 


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Asbestos is a mineral that can be highly toxic - if the particles become volatile.

The mineral naturally occurs in the soil, especially in rock, and has been mined for most of human history because of its special chemical and engineering properties. 

What properties?

Asbestos' ability to withstand tension and heat make it ideal material in construction.

Fortunately, almost everyone knows that asbestos is toxic today.

And even though asbestos' toxicity was officially understood in the 1920s, governments only recommended scaling back its usage 50 years later.[227; 228] The asbestos industry additionally knew about the negative health effects of their products but kept information hidden for a long time.[229]

Many products made in the 1960s to 80s therefore still contained asbestos, such as insulation in walls and around machinery, piping for sanitation, roofing, floor tiles, and even clothing.

As often is the case with toxins, governments act once a problem can no longer be ignored (and when most damage has already been done). Sadly enough, government policy in response to toxicity is usually reactive. 

If you're living in a developed country today, your governments is probably extremely thorough in preventing asbestos pollution fortunately - giving credit where credit is due...

If asbestos is spotted in a US school, for example, that building will be inspected every three years to see whether the compound is not emitted into the air (unintentionally).

Asbestos is rarely damaging undisturbed. But when disrupted, asbestos-containing materials can enter your body through your airways.

Asbestos particles thus need to be released into the air in order to become health-damaging. 

If you're renovating an older home or you're removing asbestos insulation along water piping, you're at risk for asbestos' negative health effects. Of course, always get professional clean up for asbestos in your home or workplace. 

One of the most deceptive dangers of exposing yourself to asbestos is that it can take years before negative health consequences finally show up.

You won't feel anything - initially...

Two main asbestos health effects exist. Asbestos:

  1. increases your lung cancer risk, or cancer in the lining around the lungs.[230; 231; 235; 236] If you smoke, the lung cancer risk from asbestos exposure will increase.[233; 235]
  2. decreases lung function.[232]

While that's a short list, these health consequences are not fun to experience at all. The list of consequences is somewhat similar to that of radon - with lung cancer as the primarily associated disease.


Don't break the stuff containing asbestos or make it volatile. And if you suspect problems due to asbestos exposure, a CT scan is best to detect lung cancer from asbestos exposure early on.[234] 

That's it...

Just two more air pollutants to cover.

Next up are toxic heavy metals, which are found both indoors as well as outdoors:


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First of all, have a sign of relief:

Airborne heavy metals have, fortunately, been declining steadily (in developed societies). 

Many heavy metals are toxic in very minute amounts. Lead and cadmium are examples of such heavy metals. While a heavy metal such as arsenic or mercury can also be emitted through the air, I'm restricting myself in order not to over-complicate this post (further). 

Keep in mind that heavy metals are not always toxic: you need some heavy metals in your system, such as iron and zinc

But back to the topic of toxic metals: let's being with lead...

Again, first a positive message:

The main reason airborne lead levels have been declining is that lead is no longer added to gasoline (in almost all countries).

Lead was added to fuel sources because vehicles run a lot better with it and engine performance goes up. That higher car performance comes at a terrible cost if you're around those cars of sitting inside of them, as you'll then be breathing in that toxic lead.

I have to give a compliment to governments here: airborne lead levels have fallen between 95-98% in the last decades.

Credit where credit is due...

A few problems though:

Some countries such as Algeria and Yemen still add lead to their gasoline.

Additionally, air travel is tragically not yet mandated to use fuel that doesn't have added lead. If you're living closer to an airfield, you're at risk of being exposed to (much) higher lead levels compared to those who don't live close to an airfield...

That's sad...

But why worry about lead in the air in the first place?

Let me tell you:

Lead affects almost any process in the human body. Lead:

  • lowers IQ in both children and adults.[248-251]

    Even small amounts of lead are damaging. Lead specifically interferes with several brain signaling substances such as "GABA", which is necessary for relaxation, and "dopamine", which is essential for motivation and assertive action.

    If you're exposed to lead as a kid it's difficult to recover your cognitive function later on in life.[255] Why? Well, higher lead exposure at the age of 11 can predict your social and economic status at the age of 38.

    That fact is scary...

  • lowers female fertility, and can even cause miscarriages.[251; 252] 

    There's no easy opt-out for us men though--male fertility is also negatively affected by lead.[278]

  • gives you insomnia and lowers sleep quality.[256] Heavy (toxic) metals often ruin your sleep cycle...

  • increases your risks for getting anxiety, panic disorders, and depression.[257] Why? Lead is simply toxic to the nervous system.[265; 266] 

    The toxic metal even disrupts many basic processes of your (brain) cells.

  • negatively affects organ functions of your kidneys, liver, heart, and brain.[258-263] 
    In high doses, lead causes organ damage. 

    Your blood pressure also rises with more lead exposure. 


So how does lead end up in your body in the first place?

Let's find out:

Once lead enters your body through the airway, the bloodstream spreads it throughout the body.

Lead is even stored in your bones.

Please keep in mind that not all lead exposure thus occurs through air pollution from industry or fuel exhaust.

Lead can also be found in many paints. Buying paint that does not contain lead for your home is thus essential. Lead is still used in some workplaces - which is dangerous as well.[253; 254]

Bottom line: avoid lead like the plague...

Next, the second heavy metal "devil": cadmium...

Even though it's not as well known, cadmium has a similar profile as lead. And just as lead, cadmium is also a heavy metal and can be inhaled through air pollution.[266; 267]

Cadmium can cause organ damage to the liver,[268; 269] kidneys (although some conflicting evidence exists),[270-274] brain and nervous system,[275-277] may promote male and female infertility,[278-279; 282; 286] gives rise to different types of cancer,[287-291; 374; 375] and much more...

(I confess: I'm almost done with these depressing lists...)

Keep in mind that research regarding cadmium is really rudimentary again.


Right now, it cannot be proven beyond a shadow of a doubt that cadmium does not inhibit fertility in humans (yet), even though many animal studies demonstrate that cadmium reduces fertility.

Some institutions insist that more research on cadmium needs to be carried out to definitively establish many of its negative health effects.

And there's (some) truth to that statement...

But I'm already recommending you to reduce your exposure as far as possible anyway. Why? Simple: an extreme number of negative health effects is already observed across the board due to cadmium exposure.[280; 281; 283-285]

I don't need to see 100 more studies on the negative health effects of cadmium - current evidence is already devastating...

The most common source of cadmium air pollution is, surprise, surprise: tobacco smoke.

Pointing at tobacco as the main culprit can give you a false sense of security though.


As a byproduct of industrial processes, such as the refinement of metals such as zinc, aluminum, or iron, cadmium can be released into the air around factories.[292-295] 

metalworker who might be exposed to heavy metals because of treating them at high temperatuersDon't just protect your eyes when working on metal. What you breathe matters as well.

If you're living around a cadmium-polluted area, for example, the amount of cadmium in your blood can be significantly higher than in non-polluted areas.

While tobacco smoke is thus most likely to poison you with some cadmium, high levels of cadmium from industry are most dangerous because you can get exposed to a very large dose instantly

Oh yes, I've got a present for nerds - just to demonstrate how complex the air pollution problem can be: 


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Yes: while this air pollution type may sound counter-intuitive, space nevertheless has effects on the air quality down on earth.

Solar flares, for example, which are momentary increases in the sun's brightness, don't just entail that more light reaches the earth. Instead, mass is literally emitted from the sun that travels here. That mass emitted by the sun is bombarded on the earth.

Although different in character, energy from space is thus a form of "particulate matter exposure"...

If you're interested, watch the following video on particle matter pollution from space.

Contrary to many's expectations, solar flares and winds can have medical consequences. After an eruption from the sun, people with multiple sclerosis are more prone to have an exacerbation and be admitted to the hospital.[514] Your heart and circadian rhythm also respond to solar eruptions.[515; 517] Incidences of headaches, surprisingly, do not go up.[516] 

Of course, energy emitted from space also interacts with the earth's magnetic field, which is another mechanism by which the sun can create a form of particulate pollution. Unfortunately, the research into solar eruptions upon health is really rudimentary now.

That's it: thirteen different types of air pollution.

Please keep in mind that I've not even included all types of air pollution out there. Phthalates, which are contained in many beauty products, are not treated. Other heavy metals that can be polluting as well, such as arsenic or mercury.

Nevertheless, air pollution does have another side-effect that I need to tell you about:

Some types of air pollution have the devastating effect that they block sunlight from reaching the earth's surface.[368-372; 411-413]

Yes, really.

So let's do a quick refresher on sunlight:

Sunlight emits several types of light, such as "infrared" light (part of which gives you heat sensations), "visible" light (consisting of all the colors of the rainbow), and "ultraviolet" light (which can give you a sunburn).

You need ultraviolet light exposure on your eyes to create more "dopamine". Dopamine is a brain signaling substance that gives you motivation and well-being, while making you more assertive. 

Ultraviolet exposure to your skin is also essential to help you feel good and to produce vitamin D.

Both particulate matter and ozone preclude ultraviolet light from reaching the earth's surface.

One study - unfortunately published in Chinese - demonstrates that high air pollution levels lower ultraviolet light exposure from the sun up to 50%. 

That 50% reduction is insane.

Let's explore some examples that make you familiar with the effects of such a reduction:

If I'd be exposed to sunlight in the mid-summer in the Netherlands under heavy air pollution, ultraviolet light levels are reduced to mid-spring or early-fall levels.

Say goodbye summer...

Another example:

If I'm in southern Spain for a summer holiday and there's heavy smog there, the sun's strength would be equal that of southern Norway's level.

For nerds: southern Spain's UV index of 10 would be reduced to 5 (the estimated maximum at Oslo, Norway).

Very sad...

Keep in mind that the examples above signify extreme air pollutant levels. Nevertheless, you can always expect an effect of "sun blockade" if particulate matter or ozone are present...

Still think city life is optimal?

air pollution blocks sunlight and specifically ultravoilet light
Much worse than "winter is coming":
winter is staying forever.


Getting your daily sunlight in polluted environments is thus not optimal.

(Nerd section: of course, the pollutants described above also interact, and their negative effects accumulate if you're exposed to a higher number of pollutants. Higher dosages are also more damaging...

Oh by the way, congratulations.

You've now completely read trough the depressing list of air pollution health effects. The next step is to look at measuring these effects in your unique circumstances and finding solutions.

The topic of air pollution measurements is treated first...

health foundations program



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In this section I'll tell you why measuring air quality is necessary - at least, if you want to control and minimize the air pollution you're exposed to.

Remember that I laid out thirteen different air pollutant categories in the previous section. Measuring all these pollutants would be very time-consuming.

Don't worry though: you don't have to measure every air pollutant in your environment.

I'll tell you why soon...

Before you start measuring air quality, I highly recommend peeking at measurements carried out by existing (health) institutions.

Air quality is measured 24-7 in most of the developed world. That real-time data allows you can estimate the air quality in your environment.

Estimate is the key word there though...

Before reading any further, make sure you get an estimate of the air quality at your location.

(For nerds: besides local measurements of emissions, satellites, and air transport models of pollutants add additional predictive power to such measurements.)

That air quality index bright side is that many outdoor air pollutants I consider most important are taken into account in that index:

  • Particulate matter with sizes smaller than 10 and 2.5 micrometers (PM10 and PM2.5)
  • Ozone (O3)
  • Carbon monoxide (CO)
  • Sulfur dioxide (SO2)

The bad news?

Not every station around the world is equipped to measure all pollutants. Only PM2.5 or PM10 are measured routinely, for example. 

In almost all cases I recommend taking some measurements into your own hands.

Let me tell you why...

You cannot exclusively rely on the air quality index that's measured close to your working or living place. 

The air quality map I've posted above only give you a general impression of what to expect in your living and working area. A general impression is just that: a general impression or estimate. 

Why my recommendation?

Well, air quality can vary a lot within half a mile distance.

(Even though I've made the same argument in my guide about particulate matter, I'll include it here for completion sake.)

Don't believe me?

Look at the maps of different cities below. First London:

air pollution measurement in London - air quality index

Observe that in the city center there's more than a 2-fold difference between the 23 and 56 readings, even though these readings are made a few blocks apart. 

Then there's Bangkok:

air quality index in Bangkok

Again, the difference between 53 and 129 is more than 2-fold within a two block distance. Then, lastly, there's Sao Paolo:

air quality index in sao paolo

In this case, just one street makes the difference between a 34 and 59 reading.

All of these readings, moreover, also change quickly when the wind turns direction or wind speeds ramp up or slow down. 

Other examples:

Sunlight that suddenly reaches the earth's surface (when clouds dissipate) create lots of ozone in an instant, changes in traffic may create new pollutant patterns (particulate matter, nitrogen dioxide, carbon monoxide), and industry that turns on affect almost all readings instantly in a given place.

Let me make it even clearer why the air quality index of your environment only gives you a general impression:

  • If you're living near a busy road, particulate matter emissions may be much higher compared to buildings 2 blocks further away, especially if there are tall building between these two blocks - tall buildings trap air pollution.
  • If you're living close to a polluting factory, nitrogen dioxide levels can be far higher closer to that factory than at a few streets distance.
  • Ozone can travel very far, so if you're living in a rural area the wind can carry that ozone to your place - even though you think you're safe. 
  • VOCs can be emitted into the air, and eventually rain down on an entirely different location--VOCs are also not measured in air quality indices.

Air quality is thus a decentralized and local phenomenon.

A 28 - 59 air quality reading in Sao Paolo on the map above thus only tells you that overall air quality is good to average. 

And if you look at Bangkok, you observe that no area is really safe.

To get real-time estimate of the air quality at your location, I recommend getting an air quality meter.

For a budget option, click the following picture:

That budget option helps you measure particulate matter (PM2.5), humidity, and temperature. 

PM2.5 is one of the most important air pollutants out there.

For a higher-quality option click the following picture:

That higher-quality air quality monitor measures particulate matter (PM2.5 and PM10), two VOC indications (formaldehyde and total VOCs), temperature, and humidity. 

I don't recommend getting independent testing equipment for nitrogen dioxide, sulfur dioxide, and ozone.


In most cases, higher particulate matter levels are associated with higher nitrogen dioxide, sulfur dioxide and ozone levels, and vice versa


Most of these air pollutants have the same sources, such as industry, energy production, and fossil fuels used in transportation.

Of course, if you do want maximum certainty, by all means buy testing equipment for nitrogen dioxide, sulfur dioxide, and ozone.

More testing is always better, although I'm not describing how to do so in this guide. I'm just supplying you with an account that works for most people.

You're probably part of "most people", and this guide will this help you.

Moreover, I would only recommend testing for cadmium or lead - the heavy metals treated before - when you strongly suspect you're exposed to higher levels.


If you're living near industry where metal is smelted  you could consider testing for cadmium. Battery production, mining, waste incineration other types of metalwork are other instances in which cadmium testing is advised. 

You can buy a heavy metal test (to test blood levels) here.

Dictum: know thy environment (as opposed to "know thyself").

The air quality meter displayed above thus covers most outdoor air pollution instances. But what about indoor air pollution?

Let's find out...

Remember that the main indoor air pollutants (covered in this guide) are:

  • Radon
  • Carbon monoxide and dioxide 
  • Toxic mold
  • Asbestos

Let's go over these options one by one.

To test for radon, firstly, you simply need a radon testing kit

Homes, school, and workplaces can be tested with such a kit. If you want to test (many) different locations, I'd recommend buying an electronic radon detector.


Secondly, indoor testing of carbon monoxide is highly recommended as a general insurance policy:

The best solution to carbon monoxide poisoning (or even breathing the substance without symptoms appearing) is to use carbon monoxide meters near critical places such as central heating systems.[52; 53]

Click the image below to find a carbon monoxide meter:

Measuring carbon monoxide output at critical locations prevents most of the damage from occurring in the first place. Remember that low exposure levels, once they becomes high enough, are damaging.

You may think: "but what I you do get poisoned?"

Accurately knowing whether you're poisoned by CO is not so simple.[25-27; 61] 

Analyzing carbon monoxide in your breath can only yields information about your short-term exposure levels. Regular oxygen saturation tests are also useless for spotting poisoning. 

A blood test is a better solution. But if you get above a certain threshold on that lab test, you'll only know that you've been previously exposed to carbon monoxide--you don't know for how long you're exposed or what the expected development will be...

The most important solution is to remove yourself from the situation and use oxygen therapy (at the hospital). Of course, also remove the source of CO poisoning (in your home)

Additionally, there's CO's cousin:

Thirdly, "how about carbon dioxide?"

You may think: " Sure, you can measure carbon dioxide levels but is that really necessary?"

Answer: yes.

Carbon dioxide detectors are not cheap, unfortunately, as they're not as widely used as carbon monoxide meters.

(You can buy a carbon dioxide detector HERE.)

But why measure your carbon dioxide levels in the first place? 


CO2 levels give you an indication when you should open up your windows. Many people have no clue how high their indoor carbon dioxide levels get without actual measurement.

Gut feelings are not good enough...

Remember: you can increase brain performance and well-being by simply making sure enough clean air enters the building you're in. Taking care of CO2 in your indoor environment is one of the simplest air quality actions you can take...


Testing for toxic mold, fourthly, is more complex.

Visual cues are the best way of finding out whether buildings are water damaged. 

Beware of false negatives when going off visual cues though: if you see water damage or mold, it's safe to assume that the environment is toxic. If you don't see water damage or mold, however, you cannot definitively conclude that you're 100% safe.

Mold diagnosis is highly complex. 

Click HERE for a methodology that can be used to rule mold toxicity out (or in).

Lastly: in some instances you may want to test for asbestos. 


Answer this question: can it reasonably be expected that asbestos is present in your building?

To answer that question you need to know that buildings constructed before the 1990s are prone to contain asbestos. 

Always make sure to inspect older buildings.

The most important sign to look for is the degradation of building materials. Walls, pads on stoves, piping encasement, insulation, vinyl floors, may all have cracks or falling apart. Signs of dust near building material is also problematic.

If building materials are degrading then make sure to test for asbestos.

Either get a home testing kit for asbestos or call an EPA-approved asbestos testing service. The exact testing procedures are listed in the respective links...

Never (further) disturb asbestos until it's safely removed from the building.

That's it...

All basic air pollutant measurements you need to know about. 

Now there's just one more air pollution area to cover:  reducing your exposure as much as possible. 

The good news:

Time to enter the kingdom of heaven.


Well, even in the city you can reduce your air pollutant exposure levels up to 90%.

Let's find out how...

By the way, want a no-fail strategy to reduce your air pollution exposure by up to 90%? Download my 10 air pollution laws infographic below:


Return To Table Of Contents


I know what you're thinking:

"That list of 13 pollutants was overwhelming."

"There's no safe place on this planet unless I move to the North Pole"

"Air pollution is everywhere in my city so there's nothing I can do"

I know that feeling...

But there's no need to stress. 


In this section I'll teach you solutions for air pollution reduction that are simple to understand. The more of these solutions you implement, the lower your exposure (and health risk) will be.

Don't get bogged down by the sheer amount of info: if you just implement two solutions instead of none, you'll still have enormous benefits...

I'll also tell you which strategy lowers which specific air pollutant.

Ready for one last tour de force?

"Abandon all fear, those who enter here..".

Here we go:


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(Reduces exposure to carbon monoxide (CO), carbon dioxide (CO2), radon, and any pollutant associated with cooking or heating)

Yes, sometimes solutions are very simple...

This tip might sound like common sense, but ventilation is absolutely necessary to reduce toxic buildup over time. 

Hopefully you've got a view like this when opening your windows...


If buildings are not ventilated gases accumulate over time. Examples are the aforementioned radon and carbon dioxide (CO2).

Just opening your windows a few times a day, for a short period of time, allows these gases to leave the building.

Without opening windows, indoor CO2 levels start to approximate dangerous levels such as  2,000 - 5,000 parts per million over time.

Opening windows thus brings those levels 75 - 90% down.

Beware though:

Opening up your windows all the time can be very damaging to the indoor air quality if you're living in a polluted area.


If you're spending time in buildings next to the highway or airport, opening up your windows will bring many new air pollutants inside (e.g., particulate matter, carbon monoxide, ozone, nitrogen dioxide).

So how should you deal with that situation?

There's a simple rule:

Get a CO2 detector and keep windows open long enough for its levels to come down. If CO2 levels go down radon exposure also goes down. 

Once CO2 levels are low again, close your windows so that fewer outdoor air pollutants enter inside.With low CO2 levels you can also reasonably expect that oxygen levels are high again.

An additional situation also exists in which opening windows is highly recommended:

If the levels of indoor pollutants exceed the levels of outdoor pollutants,  open your windows until indoor air pollution levels off.



Let's say you're using products that contain lots of VOCs, such as paint, household or "cleaning" products, or preservatives for woodIf you're painting the walls inside your house and you're keeping the windows closed, VOC levels can increase 1,000-fold.

Yes, that 1,000 fold is not a typo. 

Using household products that contain VOCs can also increase indoor pollutant levels dramatically. In those cases, it's smarter to temporarily open up your windows to let air pollutants leave your home.

Another example:

Indoor cooking and heating may necessitate having good ventilation in place.

Remember: most of the yearly air pollution deaths occur because of indoor air pollution. 

Using a wood stove or fireplace is especially dangerous. 

EPA-certified stoves and fireplaces emit 80-90% lower air pollutants. Additionally, always turn on your range hood when cooking and make sure you've got a chimney for your stove in the first place.

cooking meat on the fire which necessitates good ventilation
Not only the air pollutants are dangerous here, the charring is so as well.


Wood stoves should always be well-maintained as they lose efficiency over time. More pollutants will escape if stoves are not kept airtight. You should be especially careful with burning plastic or waste products - doing so creates extremely toxic pollutants. 

If pollutants originate through indoor heating systems they also need to be removed from buildings properly. Of course, opening up windows counteracts the goal of indoor heating-- it's thus important to strike a good balance.

You may think: "who burns wood anyway nowadays?" 

Don't presuppose that everyone uses electric cooking methods on this planet.

2 million people are killed on a worldwide basis every year due to indoor cooking with open fires.

"Modern" gas cooking stoves can be dangerous as well, although some contradictory evidence exists.[390-392] Gas stoves are still widely used in the developed world--again: make sure to use a range hood.

And how about indoor mold? Opening windows won't work--I'll return to that topic soon.

Bottom line: proper indoor ventilation can prevent many indoor air pollutants from building up

And you've got lucky:

The second strategy is just as simple as the first one...


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(Reduces exposure to all air outdoor pollutants, depending on circumstance, including nitrogen dioxide, PM0.1 and PM2.5, and carbon monoxide)

Imagine this:

If you want to avoid air pollution, you should avoid getting near the smoke emitted from a campfire right?


That's self-evident...

The same principle applies when you want to avoid air pollution in cities:

Avoiding busy streets, industry, and polluted industry environments can dramatically lower the amount of air pollution you're exposed to.

Yes, it's that simple...

Here are some guidelines:[104; 376-383; 430; 431]

  • When walking on the pavement in the city, moving on the side of buildings instead of the roadside can reduce your air pollutant exposure levels by 30%.

    Yes: an obscene 30% reduction in air pollution exposure by just changing the way you walk...

    Still believe avoiding air pollution is impossible?

  • Air pollution levels around high-rise buildings are especially dangerous, as pollutants get trapped in between such buildings.

    Thus: avoid metropolitan down towns as much as possible if you want to reduce air pollution...

  • Being outside while your neighbors are operating a wood stove inside their homes dramatically increases your exposure levels. These wood stoves are mainly used in poorer neighborhoods during the fall and wintertime.


    Close windows during the evening during during that time if neighbors burn wood (or worse: other materials such as plastics).

  • Being inside a vehicle in a busy city such as Hong Kong can expose you to dramatic air pollutant levels.

    Carbon dioxide levels tend to get extremely high in vehicles over time, as well as smaller particulate matter levels which are tough to filter out by cars' ventilation systems.

    Make no mistake: just spending time on the road already produces small but noticeable changes to the blood, heart, and nervous system functioning.[384; 385] Minimizing road time can thus dramatically reduce your air pollution exposure.

    Simply put: commuting is dangerous and will increase your exposure to air pollution compared to what you're exposed to by just living in a big city. The more you travel on big and busy roads (such as during rush hour) the higher your risk.

    Avoiding rush hour can thus cut your air pollution exposure...

  • Keeping your windows closed in the car can reduce particulate matter exposure. The more ventilated cars are -  with polluted air entering the car - the greater the health risks become.

    However, closing windows also traps air pollutants. It's therefore best to temporary open up windows in cleaner areas to drop pollutant levels, and close the windows again once you enter a dirty environment.

  • Surprisingly, subway travel is relatively safe compared to using a tram, diesel bus, or being a pedestrian.

    In a subway you're exposed to more coarse particulate matter that has less dangerous health effects than their finer counterparts. 

  • Fascinating fact: the health benefits of actively commuting to your job that way still outweigh the negative health effects of air pollution. 

    You can thus cycle through polluted areas and still improve health. Avoid busy streets as much as possible to reduce the polluted air you breathe in when using a bicycle though. 

  • Principle: avoid exercising in an area that contains lots of air pollution. 


    Exercise in toxic areas dramatically increases the number of air pollutants ending up in your lungs. You're being exposed to more ozone and particulate matter, for example, if you're exercising.[124; 422]  The reason for that increased exposure is that you're breathing quicker and deeper.

    Problematically, children filter out that particulate matter even less well through their upper airways.[423] 

    You thus need to exercise at the right place at the right time: nature is your best bet once again...

happy animal that's exercising in nature
"You're not exercising in nature, human?! That's crazy!"  


Bottom line:  

Plan your trips and exercise sessions so that you dramatically reduce the number of air pollutants you're breathing in.

But what if you've got lots of air pollution indoors precisely because you're living in a big city?

In that case:


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(Reduces exposure to almost all air pollutants except a few gases)

In my previous blog post on particulate matter's disastrous health effects and strategies to reduce its damaging effects, I've integrated seven existing air purifier reviews. I.e., the outcomes of seven high-quality air purifier reviews were combined into one new review. 

With that method I'm ensuring you're getting the highest quality product at the lowest price. 

I'll use the results of that review's outcome in this blog post as well.

I've distinguished between 3 categories of air purifiers:

  1. a budget option costing around $100;
  2. an all-round air purifier costing around $200;
  3. an air purifier for larger spaces, costing up to $800.

I'll cover the basics of my previous recommendations here--if you want to read the full details, consider the HEPA air purifier section in my particulate matter blog post.

Let's first consider what kind of air purifiers I've included in my recommendations:

All of the air purifiers under consideration use 1) "true HEPA filters", together with 2) "carbon filters".

These filters have different purposes. True HEPA filters are targeted towards particles and can capture up to 99,97% of particulate matter (when the filters are working properly). Carbon filters, on the other hand, filter out (most) gases (such as VOCs)

(Prices listed below as per 4 November 2018.)

I've listed the best air purifiers below, together with their testing scores and main features:

  1. Coway AP-1512HH (40 points total).

    Coming in at $205, this model blows air purifiers costing twice or three times the price out of the water.

    The Coway filters 530 square feet (~50 m2) areas and filter replacements are less expensive than models listed below ($45).

    This air purifier is a great longer-term investment: filtering efficiency and effectiveness stay high year after year.

  2. Winix 5500 (36 points total).

    Costing $145 and filtering 360 square feet (or 33 square meters), the WInix model is great for non-tech-savvy people.

    This air purifier is easy to use and replacing filters is intuitive and simple. Filters are more expensive than the number one model though ($60).

  3. Honeywell HPA300 (27 points total).

    The Honeywell cleans areas up to 465 square feet (43 m2), costs around $200 and is specialized towards filtering biological air pollutants that trigger allergies.

    This air purifier is thus great if you want to counter hay fever, for example.

    Filter replacements are on the more expensive side ($60) though...

  4. Germguardian (26 points total, best budget option).

    This air purifier is pretty effective and only costs $105 - filtering up to 200 square feet (18 m2).

    Of course, filtering capacity for this model is lower compared to $200 versions. Nevertheless, a Germguardian is ideal for medium-sized bedrooms. Filter replacements can be more expensive in the long run for this model (again).


But let's say 300+ square feet filtering air purifiers are not good enough for you. 

You may even want to filter an entire apartment with one air purifier...

In that case:

For 1) cleaning bigger rooms or; 2) if your health is heavily affected by air pollution, I'd recommend the following air purifiers:

  1. Alen BreatheSmart 75i

    This is the Rolls Royce of the air purifiers (or Lamborghini, depending on your car type preference). The upside about this model it's extremely silent compared to other models while filtering up to 1,300 square feet (120 m2).

    This air purifier also comes with a lifetime guarantee and can be specialized towards particles (allergens, dust, and particulate matter) or towards gases (VOCs, cooking odor, smoke).

    Living in a big city or are you allergic to airborne substances? Use the particle specialization.

    Are you cooking indoors, have lots of VOC emitting furniture, or do people smoke inside the building? Grab the gases specialization.

  2. Coway Airmega 400

    If the previous model was a Rolls Royce, then this is a Mercedes - less expensive but very high-quality nonetheless.

    Upside? The Airmega 400 filters 1,560 square feet (~140 square meters) and is highly energy efficient.


That's it...

The best air purifiers that exist out there. Again, for a full review and my complete methodology read the air purifier review section of my particulate matter blog post. That section also contains many scientific references telling you why I think air purifiers are a great solution.

Oh, one more thing:

While air purifiers can reduce indoor pollutant levels up to 90%, you still need to use air purifiers correctly:

  • Replace different types of filters as prescribed by the companies producing them. 

    On average, HEPA filters (for particles) and carbon filters (for gases) need to be replaced every 6 months . Not replacing HEPA or carbon filters can even increase the number of toxins in the air.

  • Very often air purifiers contain a pre-filter that removes dust, which spares the more expensive-to-replace HEPA filter. A pre-filter generally needs to be cleaned every week or two.

  • Don't use your air purifier while having your windows opened.

    If buildings are very poorly insulated air purifiers may not work: so much polluted air enters the building that the air purifier is incapable of removing most of the new pollutants.

    You can thus not open your windows very often when using an air purifier--air purification and opening your windows needs to be alternated to allow the air to be clean and for CO2 to be removed.

    Measurement is the only method to know when the air is clean and low in CO2.

  • Place your air purifier nearby a ventilation exchange.[414; 420; 421] By doing so, air will get filtered immediately upon entering the room.


Do do recommend buying an air purifier if you're  

  • living in a big city,
  • having lots of lung or heart problems, or are in poor general health. In those cases it becomes more important to breathe clean air.

If you're located in a smaller city or in buildings outside the city, the question of whether to use purification depends on how bad the air pollution is. In that case, again, you'll need to measure...

You don't need an air purifier if you're 

  • living in the Amazonian rainforest with the next neighbor at a 5-mile distance
  • in any other area that's verified to be very clean

It's your call...

picture of a rural area in which you probably don't need an air purifier
Your home? No need for an air purifier unless you're smoking inside or using a polluting wood stove.


That's it again...

So what's next?

I'll now tell you how to reduce your allergen, dust (mite), and particulate matter pollution even further:


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(Reduces exposure to dust mites, allergens, smaller particles (PM2.5 and PM0.1)

Just like there's a quality difference between regular air filters and HEPA air filters, there's also a difference between regular vacuum cleaners and HEPA vacuum cleaners.

Let me explain why a HEPA vacuum cleaner may yield indoor air quality benefits:

Some particles stay in the air for longer periods of time, such as smaller particulate matter (PM2.5 and PM0.1) or pet dander. These smaller types of pollutants are best cleaned with a HEPA vacuum cleaner.[393] 

If you've got allergies, or a lung or heart disease, a HEPA vacuum cleaners also become more important (to maximally lower your particulate matter exposure). And if you're cleaning a home or office because it has leaded paint, then a HEPA vacuum cleaner is highly recommended as well(combined with respirators, which are treated later on). 

But note: not everyone needs a HEPA vacuum cleaner.

Don't waste your money...

Being more precise:

Some particles quickly settle on the floor, such as dust (and their resulting dust mites). For those types of pollutants you just need regular vacuum cleaner. 

Vacuuming is one of the most important methods to reduce dust mite numbers.[337] 

(Unfortunately, casings on pillows and mattresses are proven not to work conclusively in preventing dust mites.)

If gases or heavier particles (PM10+) are your main indoor pollution problem, you don't need a HEPA vacuum cleaner either. 

Again, please realize there's no universal solution for dealing with air pollution...

Bottom line: if you're living in a polluted city or if you've got pets in your home, a HEPA-vacuum cleaner gains a higher priority.

(Remember that most particulate matter is emitted in cities (transportation), industry, or through polluting types of energy production - that stuff is everywhere)

In terms of HEPA-vacuum cleaners, you've got two options:

  • For maximum efficiency, HERE's a heavy-duty model with true-HEPA filtering - that thing is effective enough for construction cleanup.

  • If you've got a smaller house and regular model (while still having HEPA-capacity) then THIS model will be amazing.

Just as with using an air purifier with HEPA filter, using a HEPA vacuum cleaner correctly is paramount. If you don't replace filters over time, efficiency will go down.



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 (Reduces exposure to all outdoor air pollutants such as particulate matter and different gases (ozone, carbon monoxide, sulfur dioxide, nitrogen dioxide)

Remember I told you that buildings in the develop world are insulated so that they have low levels of ventilation nowadays. 

So you may say: "wait a second, don't allergies generally increase with poorer building ventilation systems?"

"And now you're recommending insulation, which decreases ventilation...?"


So why do I recommend to decrease ventilation (in some instances)?

I'll tell you in a second...

Let me first sketch a background:

In the developing world, buildings often have better ventilation, but through indoor cooking lots of pollutants are emitted  - it's not just ventilation that matters...

You see, ventilation can help you or work against you.

If you're living in a metropolis, increasing ventilation entails that more air pollutants enter the interior of your home all the time - which is a bad deal.

Circumstances matter...

picture of a island paradise, in which proper home ventilation is not necessary
It's probable that no no extreme insulation is needed 
against outdoor air pollution protection in this case...


Principle: with poor ventilation (and thus good insulation) it's possible (and smart) to stay indoors at moments when air pollution levels are very high.

Let's consider why insulation works:

On average, closing all windows alone can reduce air exchange by 50%.[418] Making all windows and doors airtight will lower air exchange much further - my guesstimate is upward of 90%.

Of course, the only reason you'd want to stay indoors is that you'd lower your air pollution exposure that way.

Spending time in an insulated building at peak pollution times dramatically lowers your exposure to pollutants. Of course, if your indoor environment is tremendously polluted as well, then staying indoors to avoid outdoor air pollution won't be of much help.


If lots of indoor air pollutants in the form of VOCs are emitted from your furniture, you may also be worse off being insulated. Burning incense, using detergent, or stir-frying, for example, can already have small but noticeable effects on your health, .[419]

The best solution combines insulation, moving indoors and using a high-quality air purifier (which was the third strategy mentioned above) at strategic moments. Remember: to know when you should move inside you need to measure air quality...

And while it's common sense the following advice bears repeating: avoid smoking inside the house. Smoking is one of the worst ways to pollute your indoor environment. Of course, other people's health will also be negatively affected if you smoke indoors.

Another reason why highly-insulated places are better is that humidity will not build up as quickly there. 

Higher humidity levels, due to improper insulation, increases the chances of mold buildup - a topic I'll get back to soon. 

Of course, improving insulation on an existing home takes time and money - which is the downside of this strategy.

While it's not a quick solution, it's nevertheless a strategy you should consider if you live in a polluted environment and don't want to move. Proper insulation of buildings is a necessity in air polluted environments, as without insulation you're exposed to that pollution 24-7.

The following strategy also (often) has to do with insulation:

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(Reduces exposure to radon)

Remember radon, the radioactive substance entering buildings from the soil?

Fortunately, you can always control how much radon enters buildings.  

Keep in mind that having a newer building type does not exclude you from testing radon levels. The structural integrity of the building is what fundamentally matters, as well as whether radon levels are high around the building in the first place.

Homes are the most common source of radon exposure.  

Yes: even if you're exposed to low radon levels I recommend doing something about the problem. 

The first action to take is to test indoor radon levels. If radon levels are elevated you can take action for reducing them.

Testing for radon exposure can be really inexpensive. Again, you can buy a radon testing kit for basic testing. If you want to investigate many environments for their radon levels, however, buy an electronic radon detector.

A problem with testing for radon is that levels vary throughout the year, with seasons, and by changing weather. Radon is thus ideally tested for longer periods of time to get a complete picture of your exposure levels.

You've got several options if high radon levels are detected: a building might need an anti-radon barrier in the basement, increased ventilation under the floor or on ground level, better insulation between the basement to the main floor, etcetera.

Most of these alterations entail making changes to the construction of the building. Bringing in a radon expert can help you with this problem. 

Again, 100% of buildings can be fixed for radon exposure. The quintessential problems are that radon levels are not universally measured or that problems are not proactively solved.

Just measure and take action. 

The following strategy is simple again, and yet, not universally applied:


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(Reduces the negative effects of all air pollutants)

Surprise, surprise:

If you're eating at MacDonald's and Burger King twice a day, air pollutants are simply going to hit your health harder.

Yes, really...

Many vitamins, minerals, and food groups have been demonstrated to lower the negative health effects of air pollution:[394-400; 405-410; 500; 501]

Let's go through these foods and nutrients one by one:

  • Vitamin B, C, D, and E:

    To get sufficient numbers of highly absorbable vitamins, make sure to consume lots of high-quality organic shellfish, fatty fish located low on the food chain, fruits, vegetables, eggs, and animal proteins (especially organ meats).

  • Fish consumption...

    Let me explain:

    Remember that as a response to inhaling more particulate matter, your heart rhythm could get disturbed? That effect can be attenuated by consuming high-quality omega 3 fatty acids that are mostly found in shellfish and fish.

    I don't recommend fish oil supplements, however, as it's very easy to get the right dosage of healthy fatty acids through fish consumption. Fish oil supplements are also very prone to become rancid.

    Don't go overboard with fish consumption either, as you may end up with too many omega 3 fatty acids (that are found in fish) in your body.

    Hence: having shellfish a few times a week, or fatty fish such as wild salmon, mackerel, anchovies once or twice, is sufficient to get your needs met.

    Most (but not all) studies are positive towards using fish (oil) for air pollution harm prevention.  

  • B vitamins:

    These nutrients have the same effect as fish consumption on your heart rhythm. Clams, organ meats (liver and kidneys), shellfish, beef, fish, milk, eggs, green veggies, and fruits are great B-vitamin sources.

    These vitamins specifically appear to reduce the stress response associated with air pollution.

  • Vitamin D:

    This vitamin  reduces some of the lung problem side effects occurring from air pollution exposure, such as asthma (if you're lucky) or lung cancer (in worst-case scenarios).[491-493]

    Having higher vitamin D levels is also protective against many of the downsides of having lung and heart diseases in general.[494-496] Optimizing vitamin D status by getting enough sunlight (and eating animal foods in the wintertime in colder environments) is thus preventive.

  • "antioxidants" found in fruits and vegetables:

    Some of the cell damage occurring because of air pollution can be undone by the antioxidants in these foods .[401; 402; 404; 501]

    Beware: don't rely on antioxidant supplements as it's very easy to go overboard on them - doing so damages your health instead of improving it.

    Antioxidants prevent part of the blood pressure elevation that you'll get when inhaling lots of PM2.5. Air pollution still has negative health consequences when consuming antioxidant-rich foods though--the consequences are just less harmful.

  • Curcumin: 

    The plant called "turmeric" contains a chemical called curcumin. Curcumin may lower inflammation that's caused as a result of air pollution. 

    You can buy standardized curcumin extract supplements online or mix 10-15 grams of turmeric powder with black pepper in a spice shot (my inexpensive solution).

    Curcumin additionally has a proven track record to protect against the effects of smoking, cadmium exposure, and keeping your lungs healthy if you've got lung disease.[497-499]

    (Nerd section: while soy is sometimes conceived as protective, I think that's a false positive conclusion. Reason: lots of health-conscious people consider soy a health food, and therefore it's associated with lowered damaging effects of air pollution. In reality, it's unlikely that soy is protective against air pollution.)

  • Broccoli sprouts:

    Yes, another food source that's been tested to inhibit some of the negative effects of air pollution. Consuming a drink with a broccoli sprout extract has ben tested to reduce a nasal allergy after inhaling diesel exhaust, for example, and detoxes air pollutants from your body.

  • Choline:

    This compound which is found mostly found in animal foods (and soy lecithin for vegans) may also be protective against inflammation induced by air pollution.[502; 503]

eating healthy food aids your body's ability to cope with pollution
Couunter-intuitive air pollution harm-reduction strategy...

Don't get too bogged down on the specific food recommendations above though: many food sources high in antioxidants such as dark chocolate or berries have not been studied yet.

I do expect that many other healthy foods, which may not be listed above, still help you reduce the negative health effects of air pollution.

Your favorite oysters, spices, and spinach probably all contribute...

On another note:

The effects of nutrition on reducing air pollution's effects go really deep: the skin is an additional mechanism by which air pollution affects your health.

The more ozone you're exposed to, for example, the more vitamin C and E are depleted in your skin.[416] The skin itself may also age faster when exposed to particulate matter.[417]

Eating a nutrient-rich diet thus becomes more and more important with greater air pollution levels...

Next, an indoor air tip: 


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(Reduces exposure to VOCs, heavy metals)

Yes: your furniture is likely polluting your indoor air.

New furniture very often emits formaldehyde, an example of a VOC.[476] Household and cleaning products, drapes, cushions, laminate flooring, varnishes, and scented products also commonly emit VOCs.[477-481] Even printers and copying machines emit VOCs. 

Because thousands of different VOCs exist, I'm not going to consider them all individually.

I just have this recommendation instead:

Reduce your VOC exposure by mainly mostly buying natural products.

A hardwood or stone floor is better than laminate, for example. Cushions from organic wool or cotton are better than cushions with a coating.

I know furniture and indoor products that do not emit any VOCs are much more expensive so the goal here is to slowly transition to more natural products.

One strategy to get more natural products is to live smaller: perhaps you don't need a gigantic house and can opt for a smaller house while affording more natural in-home materials.

You can even buy low VOC paints in different colors, such as pastel and white.

Just look around, natural alternative are almost always available...

And keep this principle in mind:

The number of VOCs emitted by new furniture is initially high but levels off after time.

It's thus recommended to remove packaging from furniture outside so that VOCs are not released in your home. You can even leave furniture outside for a while so that the most damaging gases are gone.

Make sure to store any products that emit lots of VOCs - such as regular paint - sealed and removed from your living areas.

And let's move to another paint-related topic:

Heavy metal levels in paint have been very high but have been dramatically reduced in the last few decades.

Selling paint with lead has been forbidden since 1978. Nevertheless, realize that that exposure to leaded paint is possible: if you're considering buying a home that's built before 1978, I'd be very wary of the paint there.

Let professionals remove that leaded paint first.

Conclusion: unnatural in-house materials will give your home unnatural air - avoid like the plague.

The following air quality tip is indoor quality-related as well: 


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(Reduces exposure to mold)

Remember mold toxins?

These toxins are produced by fungi and are dangerous if emitted by damp walls or bathrooms that remain wet.

And you know what?

If you're susceptible to negative health effects of mold then just getting a HEPA air purifier will not fix your issues. 

In such cases you might need to fully remove yourself from the toxic situation, leaving (almost all) your belongings behind.


The problem is that most possessions inside a building are almost certainly contaminated if mold is found there.

Material such as paperwork or pieces of clothing, insofar they are porous to water, are usually lost forever when infested. Even washing belongings will not always remove all the mold toxins as washing machines can re-introduce mold into clothing or bedding.

If you do bring material with you, make sure that material is stored airtight so that no potential mold can be released.

Only some possessions can be de-contaminated from mold over time - these belongings are often made of "inert" materials such as glass or metal.

So what's next? What if you do decide to move?

In that case you'll have to live in a mold-free environment for some time.

If you're mold sensitive, a few weeks outside a toxic environment is often sufficient to realize your environment was damaging. Beware: removing yourself from the toxic environment can make your symptoms worse initially. 

If you do get re-introduced to mold after a mold-free period, your symptoms will generally be more extreme. The upside is that such re-introductions solidify your understanding that mold is truly the culprit and that mold-illness is not "all in your head".

Staying in hotels or having a tent in your backyard is often not radical enough of a solution if you're really mold-sensitive.

Yes: mold issues can be that extreme...

If you're mold sensitive you'll often have to live in an RV or an environment that's verified as mold-free.

To determine whether a location is "safe" for you to spend time in long-term, it's best to live in that location for a couple of weeks, but if and only if you've been fully symptom-free previously.

moving to another region should be your last option to avoid air pollution. One option is to buy an RV
A great way to test for mold susceptibility -
if you've got the cash for an RV. I certainly don't (yet)...

If you're really susceptible to mold's negative health effects you might need to avoid (strong) mold pollution for the rest of your life  - in the most extreme case scenarios.


Many people who have successfully removed all mold from their lives still get extreme reactions to minute quantities of mold if they're re-exposed.

Let me explain:

It may be unimaginable but even spending 30 seconds in a mold-infested building can cause extreme immune reactions in the most mold-sensitive people.

Such reactivity is a sign of poorer overall health, but fortunately, that reactivity may improve in time.

Overall, if you suspect mold toxicity, it's better to be safe than sorry at first...


That's simple:

Years of your life can be spent being negatively affected by mold if you don't act proactively. Again, mold grows in insulation or drywall, and is not always visible to the naked eye.

Without testing you'll never know for sure whether your health issues are caused by mold.

On another note:

There's (anecdotal) evidence that the combination of electromagnetic frequencies in the environment (WiFi, cell towers, smart devices) makes mold much more aggressive. Placing a WiFi router in a mold infested cabinet may thus create exponentially more toxins.

Still want to undo mold damage?

In that case it's best to get a qualified mold inspector (and cleaner) to investigate your house or office to make sure it's fully cleaned. DIY bleach, vinegar, or other store-bought products do not solve the problem completely and may make issues worse long-term.


Just realize that the topic of avoiding mold is enormously complex. 

Keep in mind that I'm doing no justice at all to the complexity of avoiding and treating mold issues here. Exhaustively treating the basics of mold probably needs a 500 or 1,000-page book.

I'll probably be writing a full blog post on this topic in the future.

For now, I'd strongly recommend you visit the "mold avoiders" Facebook group if you're suspecting any issues mold-related in your life. That group has tons of free information that help you overcome mold problems.

Successfully dealing with mold takes building up lots of experience. As a mold-sensitive person, you'll slowly learn what types of exposures trigger you and which don't. Mold toxicity is not a problem which you can usually beat in a week...

Let's now consider a simpler strategy:


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 (Reduces exposure to dust mites, toxic mold, VOCs)

Both very high and very low humidity levels are not optimal for your health.[462; 463] I'm talking about "relative humidity" here, which is water vapor measured as a percentage of the total amount of vapor in an area. 

Controlling indoor humidity levels is a great way to reduce indoor air pollution...

In fact:

Reducing indoor humidity below 50% is one of the keys to lowering the number of dust mites.[308-310; 312; 313]

And by lowering humidity to 0 - 35% for just a couple of hours a day you can reduce dust mite numbers up to 95%. Additionally, a  longer-term 50% humidity level is great for countering dust mites buildup.

Lower indoor temperatures - such as 18-20 degrees Celsius - are also protective against dust mites compared to higher temperatures (such as 21 degrees).[331]

Very long soaks of clothing and bedding in warm water with laundry detergent and bleach can also kill dust mites, but that "solution" will expose you to more VOC chemicals.[311] 

No bueno...

More good news:

An indoor humidity level of around 50% is great for preventing mold growth.[463]


Fungi grow best if humidity levels reach 60%. Building materials also damage more easily with higher humidity levels. Paint may peal with high humidity, for example, and moisture is more prone to build up between walls.

That moisture feeds mold buildup in turn.

There's more:

With higher humidity levels more VOCs are emitted from building materials.[464; 474; 475] 

Bad news...

In general, avoid exceeding the 60% humidity level. Optimal humidity levels can have big health benefits - you'll improve work performance and may even improve sleep quality.[462]

To reach that 50% level, you would need some air humidification during the wintertime in colder climates. Steam humidifiers are the best - they do not emit pathogens into the air. 

The problems with remaining high humidity levels during the wintertime, however, is that windows can start freezing - you'll need to strike a good balance.

But let's consider the opposite end of the spectrum:

Very low humidity levels can increase eye irritation and respiratory symptoms.[465-473]

With humidity levels under 40% people begin to show those symptoms. Bacteria and viruses also spread more easily at lower humidity levels.

Keep in mind that I'm only giving guidelines:

The effects of different humidity conditions are extremely complex.[462] In the wintertime, low humidity increases the amount of particulate matter in the air, for example. During the summertime, the opposite happens.

Each pollutant is individually affected by humidity levels...

There's thus "no one size fits all" solution for all circumstances. In most situations, a 50% relative humidity is best.

But let's consider some red flags in relation to controlling indoor humidity:

Having a basement that has lots of water, pipes that leak, or a damaged roof may all contribute to humidity problems inside the house. (Central) heating systems can also be sources of higher humidity levels.

Simply put, structural damage to any building is dangerous as humidity levels can easily get out of control - an issue I considered with mold earlier.

Additional solutions to lower humidity levels are ventilating buildings, avoiding hot showers, , using your kitchen exhaust, removing rugs, and ventilating rooms where washing machines or dryers are placed. For the worst-case scenarios, use a dehumidifier.

So what's next? 

I'll now help you prevent air pollution from showing up at your doorstep in the first place.


Let's summon the forest gods (or vegetation in plain English)!


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(Reduces exposure to all types of outdoor air pollution)


No shit Sherlock!

This strategy is extremely simple:

The more plants around your residence or workplace, the lower exposure levels to air pollutants will be.[440] Depending on what study you look at, the effects of vegetation are either really minor or extremely large.[441]

In some instances vegetation can increase the level of air pollutants though.[442]


Vegetation, and trees more specifically, reduce ventilation. Planting lots of trees next to a road will entrap some of the air pollution emitted by cars, increasing air pollution levels at that road while reducing air pollution in adjacent areas.

That principle should teach you an important lesson:

Plant as much vegetation around your house as possible.

Pines and conifers are especially effective. Even green roofs will help reduce air pollution levels.

The levels of some of the worst outdoor air pollutants types, such as ozone (O3), particulate matter (PM) and nitrogen dioxide (NO2), can be reduced dramatically. Heavy metals such as lead or cadmium can be captured by these plants as well.

That's great news...

Up to a whopping 90 kilograms of PM10 and 35 kilograms of PM2.5 per year alone by covering more than 90% of the roof by Pinus mugo var. pumilio (Dwarf Mountain Pine).[443]

Other good pine options are: 

  • Pinus mugho (Slowmound)
  • Pinus pumila (Dwarf Blue)

Additionally recommended plants are:

  • Acer palmatum "Shaina" (Japanese Maple)
  • Acer palmatum "Mikawa-Yatsubusa" (Another Japanese Maple)
  • Magnolia

The Japanese Maples have been tested as excellent reducers of ozone (O3). Magnolias are great for NO2 reduction.

Why plants such as pines?


Pines effectively reduce air pollutant levels because of their large surface areas - pines become a "living wall" between outside air pollution and the buildings you're spending time in.

pines as a living wall against air pollution.
Blue dwarf  pines: excellent particulate matter
"air purifiers".

Let's consider some other science-backed plant species that are optimal for creating a wall around your house:[444-452]

  • Taxus baccata (English Yew).
  • Taxus media (Anglojap yew) 
  • Hedera helix (Common Ivy)
  • Pinus sylvestris (Scots Pine)
  • Ligustrum lucidum (Chinese privet or wax-leaf privet)
  • Euonymus japonicus (Japanese spindle) 

Some regular ground-level plants such as Spiraea japonica (Japanese meadowsweet) and Philadelphus pekinesis are also helpful. These plants have only been tested in Chinese studies though...

The lesson is that ground-level plants should be really dense (again), which increases their filtering capacity.[451] 

The difference in how well different plant species capture air pollution varies many-fold, so it's essential to buy the right types...

Keep in mind that rain or wind will lower the amount of air pollution that's captured by vegetation. I do not see great methods to reduce plant's exposure to rain or wind (yet), however.

Simple pine trees: building a wall of them around your house is 
one of the best air purifiers out there.


But let's further simplify my message:

Your best bet for dramatically reducing in-home air pollution levels is to combine several strategies:

  1. high pine trees around the perimeter of your home to capture air pollution located a few feet into the sky.
  2. a wall of lower conifers or pines to capture air pollution at the ground level - using the taxus species for example.
  3. rooftop vegetation that captures air pollution that passes the perimeter anyway (and also captures some air pollution emitted by airplanes).

Evergreen plants are also better than plants that leave their leaves during the wintertime. Fortunately, pines are evergreens. 


And even if air pollutants enter your home, use another line of defense: indoor plants

Indoor plants have been proven to lower the amount of VOCs and ozone, for example.[482; 484; 485; 489] Make sure to treat your indoor plants well: giving plants more light will increase their filter-ability.[483]

The following plant species have been tested to reduce VOC levels:[489]

  • Hemigraphis alternata (Red ivy)
  • Hedera helix (Common ivy)
  • Hoya carnosa (Wax plant)
  • Asparagus densiflorus (asparagus fern) 

Spider plants, moreover, seem to be specifically effective in removing particulate matter from the air.[487] 

Bonus: indoor plants also reduce CO2 levels.[508]

More light for plants also improves their CO2 reduction. Consequence? An indoor air quality improvement due to plants translates to fewer symptoms if you have lung disease.[486] 

And in case you're wondering: no, I don't remember all these Latin names from memory--but these names may nevertheless help you get the right plants into your home when you ask the gardener.

You may have one question left:

Should you massively "abuse" this vegetation strategy?

I think you should...

In fact, you don't have much of a choice if you're living in a big city: using more vegetation is one of the only ways to save yourself.

Quick tip: use HEPA vacuum cleaner from a distance on indoor plants. Air pollutants accumulate on the plants' leaves and can only be fully removed by vacuuming.

In the next strategy, you'll learn how to combat outdoor air pollution if you have to be in a disastrous environment anyway: 


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(Reduces exposure to particulate matter, mold, common allergens from pets or plants)

I know: wearing a respirator is going to look strange (especially in developed countries):

In Asia, however, wearing respirators is more socially accepted, especially during periods of extreme pollution with lots of smog. 

Protecting yourself is highly recommended if you're working with a lawn mower, you're sawing wood, or using a leaf blower.

Nevertheless, a respirator can cut particulate matter exposure by up to 95% - a huge effect. Unfortunately, respirators don't filter out gases such as VOCs or ozone, so avoiding spending time in polluted areas is always your best option...

What if you do wear a respirator though?

Well, wearing respirator can, for example, lower your blood pressure and heart rhythm.[431-433] 

Just those two effects alone signify that wearing a respirator has a -stress-lowering effect.

The reason government and health institutions don't widely recommend wearing respirators is that they want to wait for more higher-quality studies that definitively show that heart and lung conditions can be prevented by wearing them.

For me, instant blood pressure and stress reductions are more than enough.[506; 507] 

One thing: keep in mind that wearing a respirator makes breathing more difficult.


Almost done!

But let's first take your pollutant-protection one step further:


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(Reduces consequence of all the negative health effects of air pollution)

I already hear the excuses coming: "I'm going to skip my sprints today and stay inside - the air pollution is too extreme today".

"No need to take my bike, the air quality index is bad today"

That's a recipe for disaster...

Air pollution is not an excuse to avoid exercise. In fact, the better your physical shape, the more protected you will be against the negative effects of air pollution.[425]

When to exercise?

In general, early morning exercise in less polluted areas is safest.[424] 


Ozone levels usually peak in the evenings because of the effect of sunlight. Other air pollutant levels - such as nitrogen dioxide and particulate matter, drop off during the nighttime.

There's another reason why you should exercise anyway, even in polluted air:

The benefits of exercise still outweigh the downsides of air pollution for most people, even in air-polluted areas.[427-429] Wear a respirator, if necessary, and avoid toxic environments when doing so...

Only if you've got severe lung or heart issues or in poor general health would I recommend to exercise exclusively at non-air-polluted locations:

picture of the woods. Exercising in woods can help prevent exosoure to pollutants
The perfect place to exercise: even if you have lung problems... 


Bottom line: move your body... 

Just two more solutions to go: 


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Reading all the above solutions would almost gives you the impression that you should never ever breathe in anything else than 21% oxygen and some CO2.

Nothing could be further from the truth.

Complete sterility is probably devastating to your health.


From the first moment of birth, getting exposed to bacteria is essential. With a vaginal birth as opposed to a C-section, you'll get exposed to bacteria from the vaginal fluid, for example.[454; 455]  

Drinking raw milk may also be protective against allergies. If you've exposed to a lower number of pathogens causing infections may also have an increased risk of developing hay fever and other allergies.[455]

And yet, exposure to certain germs such as those found in raw milk is lower than ever today.[456; 457] 

Unfortunately, the research into optimal exposure levels and patterns to germs such as bacteria and viruses is still in its infancy today. Nevertheless, overly clean environments are almost certainly not conducive to your health.

So let's zoom out and look at the difference between germs and modern pollutants:

Not all modern air pollutants are problematic: their type, nature of the exposure, and the number of pollutants are the problem.

In modern society you're exposed to much more ozone, nitrogen dioxide, and mold than our ancestors were ever exposed to.

More household cleaning product usage also causes more respiratory problems such as asthma.[460] For every year you're living in a developed nation such as Australia, your asthma risk goes up.[461]

The bottom lone is this:

If you do  create a sterile environment in your home or workplace that's completely free of air pollutants, you'll probably need to compensate by getting natural exposure levels up. You'll want to breathe in air that's found in forests and other (relatively) clean natural environments. 

You cannot spend 24-7 in an environment that contains air purifiers...

Let's explore that concept of sterility a little further:

The germs you're exposed to today are totally different from the ones  your ancestors were exposed to


With the onset of human civilization roughly 10,000 years ago, our relationship to viruses and bacteria changed forever.

Let me explain:

When you begin to stay in one place practicing agriculture, that environment becomes more conducive to spreading certain germs. Increasing population densities also change the dynamic of spreading germs even further - high population densities become hotbeds for some types of germs.[458; 459]

Consider this 30,000-foot view on air pollution:

In modern society, you're thus exposed to many pollutants that are completely unnatural from an evolutionary perspective, such as lots of fine particle matter PM0.1, ozone (O3), and nitrogen dioxide (NO2). 

You're also exposed to different germs than your ancestors 100,000 years ago and you almost never breathe the air that's found in locations that are unaffected by human action - such as Northern Canada or Scandinavia.

Air pollution is thus a complex problem. I highly recommend spending at least a few hours a week in nature, to make sure you're breathing air that's ancestrally normal. 

Play with your kids in the sand...

Bottom line:

Both an underexposure to substances that can be helpful in the long-run, and an overexposure to harmful substances can also explain the wave of allergies and lung problems that's plaguing developed countries.

Of course, the overexposure part of the equation is precisely the main topic of this blog post. I nevertheless assume that overexposure and underexposure go hand-in-hand here...


One last strategy:


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This strategy is simple but has to be mentioned...

Remember: if you're young, old, have existing lung or heart problems, then you're especially susceptible to the negative health effects of air pollution. The fetus is very susceptible to air pollution's effects as well.[434-439]


If you've got asthma, for example, you have to be especially careful when exercising outdoors in polluted environments - and be more careful with indoor pollution.

The more susceptible you are to the effects of air pollution, the more action you need to take to reduce air pollution's effects on your health.

In the worst-case scenario, if you cannot reduce your air pollution levels at all, then there may be one solution: move.

Of course, moving should (almost) never be your first option...

Nevertheless, if you've got severe lung or heart problems and living in an extremely polluted city in Asia, I'd seriously consider moving to a less polluted environment when you've got cash...

There are other cases as well:

If you want maximum (mental) performance, I'd also minimize your air pollution exposure.

If you're a professional athlete or high-performer then you might want to avoid spending two weeks in a metropolitan city - even if your health can easily handle it...

Let's consider why:

Polluting your lungs can be the difference between reaching the  first place or second place on a 400-meter sprint. You don't want to spend two weeks in a polluted place if performance is your goal...

But let's say you're in pretty good health and you don't care about performance.

Should you not worry about air pollution at all in that case?

Not at all: air pollution will always do some damage to your health, independent of circumstance.

Less is more with air pollution.

Over the course of 10 or 30 years, the health effects of air pollution will slowly degrade your health.

So let's conclude: 


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After reading all of these solutions, I caution you against being optimistic about air pollution.

Don't assume the problem is going to take care of itself. My introduction of this blog post tells you why:

After air pollutants are identified, governments and institutions take decades to remove them  from your environment. The health damage these air pollutants do affects your health right now.

Sure, some bright spots exist.

In developed countries the emission of several types of air pollutants have been declining over the years. Ozone, lead, or particulate matter emissions come to mind.

But don't get too comfortable though:

If you're already susceptible to heart disease, just spending time in a car, the inner city, or near a factory already massively increases your risk for a heart attack.[403]

Also remember that 20,000 people in the UK die every year because of nitrogen dioxide. And 8% of diabetics in Germany, which are a jaw-dropping 500,000 people, have the disease because of that same air pollutant.

Let's put those numbers into context:

If a dictator would kill 20,000 people in Europe, everyone would be protesting the street tomorrow--no, tonight...

But air pollution?

Nothing seen, nothing heard...

And I get it...

You may have become somewhat depressed when understanding all the negative health consequences air pollution can have.

You don't have to feel down though:

You can exert control over your air pollution exposure...

Fifteen solutions are enough to save yourself.

Maybe not today, maybe not tomorrow, but in a year you can implement many of them and dramatically cut your risk for disease.

Do the world a favor:

Save yourself.

Save yourself first...

And if you save yourself, you can save other people during the rest of your life as well.

Spread the news. You'll make the world a better just one action at the time. Making the world a better place does not have to cost any money.

A few words can change a lot of hearts. I hope my words do - and yours can do so as well. Become your own hero, and become a hero for others in turn...

The world needs you.

Spread the message, and help people save themselves...

*Post can contain affiliate links. Read my affiliate, medical, and privacy disclosure for more information.

Author: Bart Wolbers. Bart finished degrees in Physical Therapy, Philosophy (BA and MA), Philosophy of Science and Technology (MSc - Cum Laude), and Clinical Health Science (MSc).

Read my other blog posts:

How Noise Pollution Slowly Degrades Your Health Without You Even Noticing (+Simple Solutions)

Particulate Matter: This Air Pollutant Devastating Health Effects (+Remarkable Remedies)

Rethinking Magnesium: Why You're Deficient And Need To Supplement (Quick Fix)

Beat Insomnia Tonight: The 50 Most Remarkable Sleep Quality Tips

Conquer (Chronic) Stress: The Ultimate Guide To Stress Relief.

Want to do additional in-depth reading on science of the health effects of air pollution, consider:

  1. NIH on some of the basics on the health effects of air pollution
  2. World Health Organization: basic statistics, different pollutants, and policy
  3. Environmental Protection Agency air quality standards
  4. Environmental Protection Agency on air quality standard methodology
  5. An in-depth explanation of the air quality index
  6. How air pollution costs billions of dollars each year in health care costs, in Asia
  7. Air quality standards in China, one of the most polluted countries
  8. Time magazine: air pollution costs trillions per year
  9. The combined health and economic costs of air pollution
  10. Scientific methodology of different air quality indexes
  11. Systematic review: exercise and polluted air
  12. Systematic review: air pollution and dementia risk
  13. Systematic review: how air pollution affects body composition
  14. Systematic review; air pollution and blood pressure (which is a good predictor of heart disease)
  15. Systematic review: the pro-aging effects of air pollution when measured in telomere length
  16. How a long-term policy approach with lots of measurements advances both environmental and human health
  17. Popular science: how children are more affected by breathing bad air
  18. University of Colorado on the toxic effects of indoor air pollution
  19. Scientific American: most cancer actually caused by breathing toxic air
  20. Khan Academy: a economic perspective on how pollution can be profitable (but not ecologically)

health foundations program

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