BEIJING — One Friday more than two years ago, an air-quality monitoring device atop the U.S. Embassy in Beijing recorded data so horrifying that someone in the embassy called the level of pollution “Crazy Bad” in an infamous Twitter post. That day the Air Quality Index, which uses standards set by the Environmental Protection Agency (EPA), had topped 500, which was supposed to be the top of the scale.
So what phrase is appropriate to describe Saturday’s jaw-dropping reading of 755 at 8 p.m., when all of Beijing looked like an airport smokers’ lounge? Though an embassy spokesman said he did not have comparative data, Beijing residents who follow the Twitter feed said the Saturday numbers appeared to be the highest recorded since the embassy began its monitoring system in 2008.
The embassy’s @BeijingAir Twitter feed said the level of toxicity in the air was “Beyond Index,” the terminology for levels above 500; the “Crazy Bad” label was used just once, in November 2010, by an embassy employee. According to the EPA, levels between 301 and 500 are “Hazardous,” meaning people should avoid all outdoor activity. 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.
In online conversations, Beijing residents tried to make sense of the latest readings.
Most Read Stories
“This is a historic record for Beijing,” Zhao Jing, a prominent Internet commentator who uses the pen name Michael Anti, wrote on Twitter. “I’ve closed the doors and windows; the air purifiers are all running automatically at full power.”
Other Beijing residents online described the air as “post-apocalyptic,” “terrifying” and “beyond belief.”
The municipal government reported levels as high as 478 Saturday in central Beijing, according to The Associated Press. It was not clear why that number was lower, but even that level is considered hazardous according to EPA standards. (By comparison, the air-quality index in New York City, using the same standard, was 19 at 6 a.m. Saturday.)
Pollution levels in Beijing had been creeping up for days, and readings were regularly topping 300 by midweek. The interior of the gleaming Terminal 3 of the Beijing Capital International Airport was filled with a thick haze Thursday. The next day, people working in office towers in downtown Beijing found it impossible to make out skyscrapers just a few blocks away. Some city residents scoured stores in search of masks and air filters.
It was unclear exactly what was responsible for the rise in levels of particulate matter, beyond the factors that regularly sully the air in Beijing. Factories operating in neighboring Hebei province ring the city of more than 20 million. The number of vehicles on Beijing’s streets has been multiplying at an astounding rate. And Beijing sits on a plain flanked by hills and escarpments that can trap pollution on days with little wind.
Xinhua, the state news agency, reported Dec. 31 that Beijing’s air quality had improved for 14 years straight, and the level of major pollutants had decreased.