China Air Daily

Beijing’s air pollution regularly makes international headlines. But exactly how bad is the air in the Chinese capital, home to 20 million people? That’s the question China Air Daily strives to answer—in pictures we take every single day from the same spot.

Air pollution expressed as a list of numerical measurements or chemical compounds can be hard to understand. If ever there were a clear case of a picture’s value, this is it. It’s evident that Beijing’s air pollution has gotten worse even in the past year and a half.

Of course, the pictures don’t always tell the whole story. Sometimes wind and rain pick up and clean the air temporarily on what are otherwise heavily polluted days. But, as a rule of thumb, if you can’t see a couple of blocks from where we snap our daily pictures, the pollution is bad.

Still, to prove the point that pictures—even ours—can be deceiving, we offer a second set of pollution data so Air China Daily users can judge for themselves. That second set of data measures what’s known as PM2.5: particles in the air that measure 2.5 microns or smaller. Invisible to the eye, they pose the greatest health hazard, as they can penetrate deep into the lungs. Each month, we compile a chart comparing PM2.5 levels in Beijing, Shanghai, Guangzhou, Hong Kong, and New York. Looking at our pictures and our charts together, it’s easy to see just how many more times Beijing is polluted than New York—visibly, in frequency, and in seriousness of effect.

Using China Air Daily tools, you can also compare Beijing’s air from one day to the next, or compare it to the air in Shanghai, New York, Guangzhou, or Hong Kong. Track the changes in air quality with your own eyes, all the way back to mid-November 2011.

No month since we began shooting our pictures and gathering data has had more blue sky days than it had gray smoggy ones. The scenic Western Hills bordering one edge of Beijing’s sprawl are a destination for hikers looking for fresh air away from the city center. The hills stand clear across the city from the office building on the east side where we take our pictures every day. During some months, as in March 2012, our camera caught the hills in the background just once. On the other thirty days of March, the hills were hidden by 18 miles of dirty air.