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Hold Your Breath: The Bay Area's Air Quality Is Worse Than Beijing, Athens, or Mexico City

It's really bad. 

Delhi, India (pictured) has comprable air quality every day to the Bay Area's today.


People are commuting to work wearing protective masks, and the air across the Bay Area has an ugly, almost tactile, sheen. Scattered reports indicates ash falling from the skies in San Francisco, as the ongoing fires in the North Bay turned our air quality terrible.

It’s really bad. So, we turned to the data to see just how bad it actually is.

The answer: Our air quality is awful. Shockingly awful. Think, industrial center in the developing world awful. It makes Athens look pristine, Mexico City like a garden, and Beijing like it was engulfed in pure mountain air.

San Francisco was expected to reach 180 on the Environmental Protection Agency’s air quality index. Much of the Bay Area was forecasted to achieve similar numbers today. You can find those numbers here. That’s a concentration of 111.6 µg/m3 of particulate matter less than 2.5 microns in width, according to the EPA’s calculator.

Okay, so how bad is that?

The World Health Organization keeps a database of annual mean concentration of air pollution in 3,000 cities across 103 countries. We downloaded and read it. Beijing, infamous for its low air quality has an annual mean PM 2.5 measurement of 85 µg/m3.

The Bay Area’s yearly mean for this kind of pollution is 9 µg/m3. We’re now 12 times over that value. There’s no place in the United States that even breaks 20 µg/m3 on a yearly basis. There’s hardly any cities in the entire world, in fact, with similar numbers.

This week’s measurement in the Bay Area is up there with the most polluted cities in the world—places like Bamenda, Cameroon (132 µg/m3); Baoding, China (126 µg/m3); and Delhi, India (122 µg/m3).

The most polluted city in the world by this measurement is Zabol, Iran, which has an unimaginable yearly mean of 217 µg/m3—a city that’s so polluted that a 2017 study in the Preventive Medicine suggested that the harm from 30 minutes of cycling outdoors would outweigh the benefits.

We’re not there, but what we are facing this week is what some of the most polluted cities in the world face, more or less, every day. In other words, bad.


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