2. Is air pollution the greatest threat to human health?

As you read this, the people in the Bay Area are breathing the most polluted air in the world

Today I walked out of my house in Berkeley and smelled smoke — a permanent “I’m sitting by a campfire” smell that followed me throughout the day. I wiped off a thin layer of ash from my bike seat. After working outside for an hour, flecks of ash accumulated on my computer screen and between my keyboard keys.   

You read the subtitle right — the California fires that sprung up around the Bay Area in recent days are producing smoke that is causing us to have the worst air pollution in the world (worse than in Mexico City, or Delhi, or Beijing). 

^ Wtf is going on in Chile?
^ That 769 is the center of a fire

My partner happens to study air pollution (the kind of person who gets antsy when I burn too much incense indoors). He told me this morning he plans to book an Airbnb for somewhere with better air quality. I thought he was crazy. Overreacting as a professional commitment, perhaps. 

After doing some research, I realized I’m dead wrong. It turns out that air pollution is one of, if not the, single greatest threat to human health.

Why is air pollution so bad for you?   

Of course, wildfires aren’t the cause of most bad air in the world. Most bad air is particulate air pollution, which is caused by either transportation or industrial processes, like burning fossil fuels that releases Particulate Matter, or PM.

The smaller these particles, the deeper they penetrate into our bodies, the more damaging they are. PM10, particles with diameters smaller than 10 micrometers, travel into our lungs, where they oxidize cells and increase free radical production in the lung — thereby increasing the likelihood of cancer (cite). PM2.5, particles with diameters smaller than 2.5 micrometers, can pass even deeper into our lungs and deposit the toxic stuffs from their surface right into our lungs’ oxygen-rich cells. 

But here’s something I didn’t understand before — the toxins don’t just stay in the lungs. Because our blood carries oxygen from the lungs throughout our entire body, the toxins (and not cute, “wellness influencer” toxins, but  real toxins) end up everywhere. That’s why PMs are bad for pretty much everything you can think of — strokes, clots, cognitive function, inflammation, white matter in the brain. (Who knew tiny, toxic shit inside of you is super, super bad? Maybe everybody but me.) 

Is air pollution the single greatest threat to human health?

A few years ago, Michael Greenstone at the Energy Policy Institute (EPIC) at the University of Chicago (+ a whole cadre of named and unnamed coauthors and research assistants, some of whom are my dear friends), set out to quantify just how bad particulate air pollution is. “MG”, as his employees affectionately call him, is one of the princes in the field of climate change and environmental economics. I won't bother to repeat his biography, but it's so impressive I'm terrified. 

What resulted is the Air Quality Life Index (AQLI). The AQLI answers the question: How much longer would the average person in the world live if they breathed air that met WHO standards for particulate air pollution?

The answer is mind-boggling: 

“Particulate air pollution cuts the average person’s life short by nearly 2 years—more than devastating communicable diseases like tuberculosis and HIV/AIDS, behavioral killers like cigarette smoking, and even war.”

Shut the front door. More than cigarettes? More than WAR, for crying out loud? 

This estimate is based on a relationship between exposure to PMs and life expectancy. In a famous paper, Greenstone measures this number by exploiting the fact that China’s Huai River policy provides people with free coal for heating during the winter if they live north of the river, but not if they live south of it. The policy caused pollution to be 46 percent higher north of the Huai River, and as a result, people there live 3.1 fewer years on average. 

The AQLI uses this relationship, combined with measurements of how bad air quality is around the world, to estimate that the average person takes a hit of 2 life years due to particulate air pollution (though it’s different by country). Other researchers have super nerdy quibbles with Greenstone’s Huai River result (including the aforementioned incense hater), but not with the broad conclusion. While it’s important for policy reasons to keep discussing the precise number, I do believe the bottom line: air pollution is way, way worse than the average person believes, and probably one of the worst killers on earth.

Assorted asides
  • The estimates of how much life expectancy decreases when people are exposed to a 10-μg/m3 increase in particulate matter are pretty large: Greenstone’s number is 0.64 years, Berkeley’s Michael Anderson’s number is .25 years, and others numbers are as big as .77 years

  • More Americans die each year from vehicle emissions than vehicle crashes.

  • I may be a mega-nerd, but the AQLI is legitimately a fun website. Go play around with it. More broadly, I think EPIC is one of the rare research organizations that communicates well with the public. God, the amount of money they must spend on web and graphic designers and comms people makes me jealous. Researchers have a hard time communicating even their most important ideas. Which, you know, is hopefully where this newsletter could be useful. 

Back in California…

I’m refreshing PurpleAir casually, like flipping open Instagram. I’m told California probably has a yearly “smoke season” now. This will probably decrease life expectancy in California, and cause residents tons of other health issues going forward. 

But this year, the fires, pollution, and evacuations are taking place during a pandemic. I can’t even begin to imagine the consequences, but one thing worries me the same people who are most immediately affected by shitty air (those with lung diseases, for example), are also more at risk for Covid-19 complications. 

Which strangers might you give to? 

The California Air Resources board is doing a great job, but they’re a government agency, so you can’t really donate to them (I guess you can pay more taxes). Instead, you can pay attention to local and state politics, and support journalists who cover boring-sounding policy changes (like those which regulate air pollution) that actually end up impacting a lot of people. 

You can, however, donate to the Coalition for Clean Air, which is working to reduce vehicle air pollution in CA by supporting electric vehicles and reducing freight. 

Thanks for reading (and don’t go outside if you’re in the Bay),


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