During the winter pollution season in Beijing, everyone gets wrecked by the bad air.
But I see people who seem to think pollution takes a vacation for the summer. Take as an example this netizen on Zhihu who asks how to store a purifier for the summer when it’s not needed.
But here’s what Beijing and China’s pollution map looks like as I write this on July 5, 2017.
What The Data Says
Is summer air in China anywhere near safe? We analyzed the US Embassy in Beijing’s PM2.5 data from 2008-2017.
The good news: First, people’s intuition is right. The winter is worse. Beijing’s winter averages 104 micrograms versus 81 in the summer.
The bad news: But “better” is still far from “safe.” Beijing’s average is still 3 times above the World Health Organization’s 24-hour limit (25 micrograms) and 9 times the annual limit (10 micrograms)!
The Midsummer Bump
There’s another weird trend in the data. See that bump in June and July? The summer is better, but Beijing consistently sees worse pollution in June and July. That’s right now!
We analyzed PM2.5 in 10 major cities across China, and the trend was the same–better in summer, but still unsafe.
While the skies may seem bluer these days, it doesn’t mean the air is safe.
A lot of air-breathers put away their masks in the summer, but if you see me on the streets of Beijing this July, you’ll see me wearing a mask!
Thomas is an Associate Professor of Behavior Science at the University of Chicago Booth School of Business and the founder of, a social enterprise to help people in China breathe clean air without shelling out thousands of dollars for expensive purifiers.