Air Pollution, Your Health, and Your Family's Health

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Air Pollution and Asthma
Child with an inhaler. Sourced from the CDC. NO2 is associated with higher asthma rates, SO2 is associated with asthma attacks once you have asthma, both are invisible and expensive/difficult to measure as a consumer. And we have the only low-profile tech to effectively filter both.

Child with an inhaler. Sourced from the CDC. NO2 is associated with higher asthma rates, SO2 is associated with asthma attacks once you have asthma, both are invisible and expensive/difficult to measure as a consumer. And we have the only low-profile tech to effectively filter both.

This is part 2 of a 4 part series about air pollution and how it could harm you. Today, we talk about how different types of air pollution can affect you. Most people in the US think they need not worry much about air pollution, owing to the fact that we are in the top 5% for clean air worldwide. Yet air pollution is likely one of the largest causes of asthma, and outdoor pollution in the US regularly kills off an estimated 200,000 people per year* (or ~0.06% of the population).

We've focused in prior posts on particulate matter pollution in developing countries. We haven't focused on invisible chemical pollution in developed countries.

So let's focus on the fact that one in twelve kids will get asthma in the US. This year in the US, asthma will kill an average of 10 people per day, and cost $56 billion to manage. This is more than Apple makes in profit each year (the money, not the number of deaths).

There is significant research to suggest NO2 pollution from traffic, specifically, is linked with higher asthma rates. These articles, respectively, indicate that up to 6x asthma rates are associated with 1/3 legal max US NO2 levels, and 3x asthma rates associated with up to 1/4 legal max NO2 levels. Later research shows that the effect persists when living up to 500m from major highways (1/3 a mile). These results show when children are exposed to pollution from 0-2, they have these increased chances of lifelong asthma at age 8. These strong relationships are not demonstrated in relation to PM when you account for NO2 pollution. In other words, it's the pollution you can't see that is harming your kids in the US. Keep in mind that in developing countries, this NO2 pollution problem is worse, but it typically also has visible PM.

Top: PM pollution is very easy to see. It's what people wrongly associate with as all air pollution. Bottom: Traffic pollution in Boston is pretty much invisible, because you cannot see NO2 pollution.

Top: PM pollution is very easy to see. It's what people wrongly associate with as all air pollution.
Bottom: Traffic pollution in Boston is pretty much invisible, because you cannot see NO2 pollution.

Why this is important:

Infants lungs are one of the only organs that change in more than size after they are born. In other words, they are the only organ that really develops outside of the womb, and this persists until age 8. Infants are most vulnerable to lifelong effects of air pollution.

What about older children?

Research from California shows that the average female lung capacity increases by 0.876L from age 11 to 15 (to 3.15L), and the average male lung capacity increases by 1.5L (to 3.8L). For each 25% increase in NO2 exposure relative to legal maximum, the study showed a ~0.1L decrease in this lung capacity growth. In other words, 25-50% of total lung capacity growth could be decreased by exposure to NO2 pollution within legal limits. What about PM2.5 pollution? The research shows that it takes an increase in PM2.5 pollution equal to the full legal limit of PM2.5 pollution to have a .06L decrease on lung capacity in this time. In other words, NO2 exposure is far more associated with decreased lung capacity growth in older children.

So pretty much, traffic is not good for children.

Healthy living involves avoiding traffic pollution exposure in children. Yes, I stole this picture from another website

Healthy living involves avoiding traffic pollution exposure in children. Yes, I stole this picture from another website

One thing to make very clear: these studies are not prognostic. They compare changes in lung capacity both latitudinally (ie for different pollution exposures happening in the same year to differing populations) and longitudinally (it for the same population types exposed to differing pollution levels in different sets of years). So we can say there is a very strong link between the air pollution and the findings. Why can we not say air pollution caused the results? Because we didn't do tests whereby we actively reduced pollution exposure to one set of people, and did nothing with another set of people in the same area. Until we carry out these tests, we won't have a 100% sure link (instead we can be like.... 90% sure, given the preponderance of data. But ask any data scientist, 90% isn't enough to make people change their habits. Or ask any smoker, where 100% certainty of knowledge isn't enough). There are no currently available ways to reduce exposure to NO2 pollution (literally give us 6 months and you'll have one), so the only way to do tests would be to increase exposure of air pollution to some populations, and this would be extremely immoral.

The other option would be to filter air pollution for individuals, and then show a difference to general population. I bet you can guess where I'm going with this!

What about adults?

Who do you think the 200,000 people dying per year are? More seriously, here is a very in depth report about PM pollution (a much larger problem in the 3rd world, but a not-terrible proxy for NO2 pollution), and health. No one expects you to read this entire report, cause it's long and dense. And it literally refers to cities as "Human Settlements." The take-away is that nearly all the deaths that occur in the US from air pollution come as the result of heart attacks or stroke. You know who gets heart attacks and strokes? Hint: it is not infants and children. Air pollution exposure in infancy and childhood can cause lifelong respiratory disease, or just decrease your lung capacity for your entire life, and thus later increase your chances of stroke and heart attacks. In other words, exposure to air pollution in the US, particularly traffic pollution, is a lot worse for you and your family than you ever thought.

What about raising kids abroad?

This is a far cry from it's like in Beijing, with 4.5x higher PM2.5 and 2-3x higher SO2 and NO2 than in the US. Or in parts of India, where PM2.5 is 10x higher than in the US, and people have only 70% the lung function of other countries, and up to half of people pretty much have asthma.

Conclusion: Try to reduce your children's exposure to traffic pollution. It's actually really bad.

What about indoor pollution?

This is an entire other can of worms. Indoor pollution can be dust, cigarette smoke, or droppings and dander from cockroaches, mice, and other pests. Getting rid of cigarette smoke is easy. Stop smoking. If you live in low-income housing and have mold or pests, do a web search for organizations to help remove these harmful things, or speak with your child's pediatrician about what to do about this. Fixing smoking or mold is more important that controlling outdoor pollution exposure, cause your infant will spend 90% of time inside. For dust, just get a HEPA filter. For indoor NO2 from gas stoves, pretty much Blue Skies (my company) has the only effective NO2 filter, so sign up there (more on this in the post two weeks from now).

Thanks for reading!

- Jason Munster

*This study has some serious caveats. They don't look at NO2 pollution from traffic, and as we discussed in our last post, NO2 pollution from traffic is the dominant type. They also don't look at the effect of SO2.

Can I Exercise or Run in this Pollution?

Short answer: no. Longer answer: only if it is raining or just rained.

It's been two months since a post. Sorry, been working on a low-cost solution to fix stuff discussed herein, applying for grants, and continuing my PhD. Back on track for one per month after this post, though.

So. Air pollution. It's comprised of four major life-threatening pollutants: PM2.5 (particles 1/30th the diameter of a human hair), SO2, NO2, and ozone. SO2 becomes battery acid in your lungs, so that sucks. NO2 becomes nitric acid, which can strip lead from glass. Ozone is great high up in the sky cause it blocks UV, but on the ground it's toxic and kills plants and hurts humans.

All of these things absorb into rain and then fall to the ground. In other words, a rainstorm scrubs them out. That smell in the air after a rainstorm? Often it's the smell of clean air. It's what air is supposed to smell like. This is why we get acid rain. All that stuff goes into the rain, and that rain can cause pits in statues. Imagine what all that pollution does in your lungs if it can pit statues from being in rain.

The sky in Beijing after rain (right) is cleared of pollutants. Rain removes most pollution.

The rest of the time, if there is pollution, here is what happens:

Exercise involves breathing more than not exercising. You breathe more, you breathe deeper. Deeper into your lungs. So if you exercise, you are exposing more of what you breathe deeper into your lungs. Breathe in pollution, mess up your lungs.

Exercise. You live in a developed country? It's likely that every minute of exercise adds more than that amount of time to your life. What about if you are in a polluted area? The jury is still out. Most mortality studies are based on widely available statistics, and are inexpensive. If you want to start studies specific to exercising air pollution, that becomes more expensive. So there is not much data on it.

You breath up to 3x as much volume when you exercise. It penetrates deeply and rapidly into your lungs. Moreover, you are breathing 3x the volume in through the exact same amount of nose, mouth, and lungs that you always have. That means air is moving a lot faster. Many of our defenses, like the mucus that lines our airways, becomes less useful if pollutants are moving so fast past them that it can't be captured. So we breathe faster in exercise, making air move 3x as fast, reducing our ability to filter things.

That's what I like to call a hand-waiving argument. I offer few hard, tested facts. Unfortunately, I can't find solid sources one way or another on this. Most experts, however, indicate that exercising in air pollution is a bad idea. A few doctors disagree, but I've yet to find a pulmonologist (lung doctor) who disagrees. In other words, the actual experts I've talked to all think that exercising during awful pollution is bad.

The Chemistry

Okay, let's get more detailed. Many pollution masks filter PM2.5. I'm skeptical of their sealing ability during exercise (if you don't have a good seal, you breathe in non-filtered air through the leaks, and you aren't filtering anything). Moreover, no one filters SO2 and NO2. So pretty much, go ahead and filter your PM2.5. You're still making battery acid in your lungs. In other words, don't exercise without a gas mask that can filter PM2.5.

Some say to exercise in parks. Why? It turns out that trees and plants can "filter" PM2.5 and other chemicals by pulling them out of the air. This works great if you are in, say, the US or Sweden, two of the cleanest countries in the world. In China, or worse yet in India, this filtration will be overrun rapidly. So pretty much, don't exercise in parks.

How about gyms? In the western world, gyms do a pretty good job of filtering outside air of PM, but they do not filter SO2 and NO2. In the developing world, not so much. They might run their air through ACs, which have filters, but it's unreliable to assume that they spent the tremendous amount extra to get ACs that do filter air pollution. So, still dangerous.

What to do? It depends on where you are. It turns out that pollution in Northern China (represented by a whopping 500 million people living there) is heavily SO2 impregnated in winter, and less so in summer. In other words, don't exercise in winter. Great, right? We all already get fatter in winter. Now we have that pushing us. Pollution in summer is not as bad with the SO2. If you trust vogmask to get a good seal (I don't), then get a mask and run with it. Again, I wouldn't recommend that.

So, in short, wait for low air-pollution days to exercise, and then get it all in at once. Or wear a gas mask. Or wait til I come up with something better. Cause that's coming.

Thanks for reading!

- Jason Munster