Everyone I know in Northern China has been writing about the recent sieges of off-the-scale air pollution, especially in Beijing. Much of the political and press controversy involves "PM 2.5" -- the fine-particulate pollution that is threatening to human health, that is closely monitored in the rest of the world, but for which the only known, publicly available data in China has come from an "unauthorized" measuring site on the roof of the U.S. Embassy in Beijing. Its hourly readings are sent out via Twitter, @BeijingAir. Twitter feeds are of course blocked in China, and so are available only to those outside the country or others who know how to get around China's Great Firewall. Here is a background installment on the PM2.5 wars, and one in which the Chinese environmental authorities explain why the "time is not ripe" to release these literally life-and-death figures.

I don't have time to do a full take-out now, but please check these references:

- An alarmed story on the WSJ's China Real Time Report site, which includes a link to an incredible video taken yesterday in Beijing. The video's site is in Chinese, but you'll get the point.

As you see the video, bear in mind that what you might take for swirling "fog" on a moist morning in Seattle or along the Maine or California coast is in fact toxic air. That's the point of the recent controversy, since the government has insisted on calling it "fog."

- A very detailed but important analysis by Steven Q. Andrews at China Dialogue, of just how dangerous the air in Beijing is, and why the Chinese government is still blocking honest reporting of the problem. Eg (emphasis added):

The average annual PM 2.5 concentration of approximately 100 micrograms per cubic metre for the last two years [shown by the US Embassy monitor] is ... 10 times higher than the World Health Organization guidelines of 10 micrograms per cubic metre. In comparison, annual average fine particulate concentrations in America's most polluted city, Los Angeles, were at 15 micrograms per cubic metre in 2010.  In a recent study of over 500 cities around the world, the WHO found that urban areas in Mongolia, Madagascar, Kuwait and Mexico had the highest PM 2.5 concentrations, but the pollution levels measured were only about half as severe as Beijing....

One of the most authoritative studies on the health effects of pollution, by C Arden Pope and others, published in 2009, found a decrease of 10 micrograms per cubic metre in a city's fine-particulate concentration was associated with an estimated increase in life expectancy of approximately 0.6 years. This indicates that if Beijing's fine particulate concentration even reached the polluted levels of Los Angeles, life expectancy may increase by over five years. Back in 1999, Chinese premier Zhu Rongji stated his own fears that air pollution in Beijing would shorten his life "at least five years" - and fine particulate concentrations have not improved since then.

There is no reason for the Beijing government to continue to wait before publicly reporting and accurately describing the hazardous air. As a first step, the government should stop describing dangerous levels of air pollution as excellent air quality. Because fine particulate and ozone levels are already measured, they should be reported to the public. With every additional polluted blue sky day the government reports, it continues its misinformation campaign that has misled the public and helped prevent real improvements in the city's air.

- A China Daily (!) report saying that difficult as the circumstances might be in central Beijing and other big cities, they're likely to be worse in the exurbs, since there's much less effort to control pollution sources. Meta-point: over the past five or six years, the Chinese media have had more leeway to cover environmental stories, and some of them have made use of it.

- A note from a scientist pointing toward a satellite photo of last month's smog epidemic, showing how enormous a swath of China was in fact blanketed. Thumbnail below, showing an area of China roughly comparable in scale to the Bos-Wash corridor in the northeastern United States:

Shortly I'll have a follow up on why cost-cutting at NASA and NOAA are endangering some of the programs by which the United States collects the kind of pollution and atmospheric-status information that allow these measurements. For now, just a reminder that pollution and environmental exhaustion is a first-order challenge to China (and the world). In my view, it is the number-one threat to the continuation of the Chinese economic boom. I have lived through a lot of these "foggy" days in Beijing and send sympathies to those there now.