Beijing was covered in a dense toxic haze this past week culminating in an off-the-charts toxicity level reading of 755 on Saturday. The municipal government in Beijing does not record numbers above 500, and some speculated the monitor had broken, but a spokesman for the U.S. Embassy, which took the measurement and reported it on its @BeijingAir Twitter account, said that it was operating correctly. The U.S. Environmental Protection Agency considers levels between 301 and 500 “hazardous” and does not have a scale for levels above 500.
The World Health Organization has standards that judge a score above 500 to be more than 20 times the level of particulate matter in the air deemed safe. Beijing residents online described the air as “postapocalyptic,” terrifying,” and “beyond belief.”
Xinhua, the state news agency, reported last month that air quality in Beijing had improved for 14 years straight.
A Chinese Foreign Ministry official told American diplomats to halt the Twitter feed in 2009. He called it “not only confusing but also insulting” and in indicated that the data could lead to “social consequences.”