BEIJING: A blanket of toxic air that has blocked out the sun across most of north China is dominating social media and looming as a serious political challenge. Visibility was reduced to a few hundred metres for much of the weekend in the Chinese capital and many of the city's 20 million went online to vent their fury about ''apocalyptic'' and ''post-apocalyptic'' conditions.
The Beijing News covered the story with the headline ''Blown the Charts'', showing that several air monitoring stations were recording levels higher than their indexes could cope with.
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Even the Communist Party's staid official mouthpiece, The People's Daily, headed a page four article on Sunday with ''What's Going on With the Air?''
Monitors at the United States embassy in the suburb of Liangmaqiao, in Beijing's inner east, said the concentration of airborne PM 2.5 particulates reached 886 micrograms per cubic metre at 8pm on Saturday, believed to be the highest since it began measuring in 2008. Readings above 300 are classed as ''hazardous'' by US environmental standards.
These PM 2.5 particulates, 2.5 microns in diameter or smaller, are considered the most harmful to health because they can penetrate easily into human tissue.
''I can tell you the machine is working properly,'' US embassy spokesman Nolan Backhouse said. The US embassy pollution monitor is published on a Twitter feed, which is blocked by censors in China, but is picked up and placed on several popular Chinese websites and iPhone applications.
Beijing temporarily boosted its air quality for the 2008 Olympics including by improving vehicle emissions standards, banning coal stoves and shifting heavy industry to poorer parts of the country.
But many of those gains appear to have been offset by an explosion in the numbers of cars on the roads.
Air pollution was the top-ranking story on the country's most popular news portals, and Chinese weather reports said cold, moist and windless atmospheric conditions could keep pollution at high levels until Tuesday.