Half the people I know in Beijing have been writing, Skyping, Tweeting, blogging, and rasping about the dire air-pollution situation these past few days. A few data points:

Readings today from the indispensable (and highly controversial) @BeijingAir feed:


For explanation of the readings, see this chart from the EPA and other government health agencies. Take-home message: air quality readings in the high 300s, like those prevailing in Beijing recently, are defined as "Hazardous" and only rarely occur in North America or Western Europe:

In case you can't read the "Hazardous" description, it says that readings over 300 "would trigger a health warnings of emergency conditions. The entire population is more likely to be affected." For real-time reading of comparable US AQI levels, see this map.

A view this weekend of the Central Business District of Beijing, near our former apartment:


A few days ago near the former Olympic district north of town:
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The punch line in this Olympic-zone picture is that on the left side of the shot you should be able to see a huge office-tower complex, and on the right the Olympic Birds Nest stadium, but they're lost in the "haze."

For reference, Here's how things looked from our apartment a month before the Beijing Olympics:


And a wider-angle shot out the same window during the miraculous several-month clear spell that followed (a) the Olympic clean-up and (b) the dramatic slowdown in factory operations in late 2008 and early 2009 because of the world economic crisis.


Here is why this matters:

1) Environmental catastrophe is, far and away, the main destructive side-effect of China's economic miracle of the past three decades, and the main threat to its continuation.

2) The Chinese government has been doing more to address the problem than most Westerners recognize, but less than it has to. And -- the underappreciated point -- it has been much less "transparent" about its environmental problems than it needs to be.

A major failure of transparency is one I've mentioned several times before, and that even became the subject of a Wikileaks controversy: the Chinese government's refusal even to measure the most hazardous form of air pollution.* This is the fine-particulate matter known as "PM 2.5," which covers particles small enough to penetrate into the deepest recesses of the lungs and do damage there. China's official readings instead cover "PM 10" -- the much larger particles that can make the sky look dark but are less injurious to people. The BeijingAir feed is the only known source of PM 2.5 readings in China, and it is controversial because its instruments are on the roof of the US Embassy in Beijing. Some Wikileaked cables reveal how angry Chinese officials at the US "embarrassing" them by letting people know how bad the air situation really was. But now even the China Daily thinks the Chinese officials should be telling their people more. Barbara Demick of the LA Times updates that controversy this past week. More background in this series of posts: #1, #2, #3, #4.

*[ Should say "refusal until now," since there have been rumblings of a plan to start measuring and reporting PM 2.5 levels. As the valuable China Dialogue has reported and I meant to include. I'm not aware of any sources of PM 2.5 measurements yet available other than @BeijingAir. ]

"Hey, Beijing has bad air!" is not a news flash. But this is a truly dire challenge for China and the world more generally and worth even more attention than it gets.