On Scale of 0 to 500, Beijing’s Air Quality
Tops ‘Crazy Bad’ at 755
Fashionably masked women on Saturday outside an amusement park in Beijing. The World Health
Organization has standards that judge an air-quality score above 500 to be more than 20 times the
level of particulate matter in the air deemed safe. CreditAlexander F. Yuan/Associated Press
BEIJING — One Friday more than two years ago, an air-quality monitoring device atop the United
States 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 United States Environmental Protection Agency, had crept above 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
immediately 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, before
it was quickly deleted by the embassy from the Twitter feed. According to the Environmental
Protection Agency, 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.
“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 “postapocalyptic,” “terrifying” and “beyond belief.”
The municipal government reported levels as high as 500 on Saturday evening from some monitoring
stations. The Chinese system does not report numbers beyond 500. Nevertheless, readings in central
Beijing throughout the day were at the extreme end of what is considered hazardous according to the
United States Environmental Protection Agency standards. (By comparison, the air quality index in
New York City, using the same standard, was 19 at 6 a.m. on Saturday.)
Pollution levels in Beijing had been creeping up for days, and readings were regularly surging above
300 by midweek. The interior of the gleaming Terminal 3 of the Beijing Capital International Airport
was filled with a thick haze on 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.
Still, there was little warning that the United States Embassy reading would jump above 700 on
Saturday. Some people speculated that the monitoring system, which measures fine particles called
PM 2.5 because they are 2.5 microns in diameter or smaller, might have malfunctioned once it got
beyond 500.
But Nolan Barkhouse, an embassy spokesman, said the monitor was operating correctly.
It was unclear exactly what was responsible for the rise in levels of particulate matter, beyond the
factors that regularly sully the air here. Factories operating in neighboring Hebei Province ring this
city of more than 20 million. The number of cars 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. Meanwhile, one person hiking at the Great Wall in the hills at Mutianyu,
north of Beijing, took photographs of crisp blue skies there.
Xinhua, the state news agency, reported on Dec. 31 that Beijing’s air quality had improved for 14 years
straight, and the level of major pollutants had decreased. A municipal government spokesman told
Xinhua that the annual average concentration of PM 10, or particles 10 microns in diameter or
smaller, had dropped by 4 percent in 2012, compared with one year earlier.
Chinese officials prefer to publicly release air pollution measurements that give only levels of PM 10,
although foreign health and environmental experts say PM 2.5 can be deadlier and more important to
There has been a growing outcry among Chinese for municipal governments to release fuller air
quality data, in part because of the United States Embassy Twitter feed. As a result,
Beijing began announcing PM 2.5 numbers last January. Major Chinese cities have had the
equipment to track those levels, but had refused for a long time to release the data.
The existence of the embassy’s machine and the @BeijingAir Twitter feed have been a diplomatic sore
point for Chinese officials. In July 2009, a Chinese Foreign Ministry official, Wang Shu’ai, told
American diplomats to halt the Twitter feed, saying that the data “is not only confusing but also
insulting,” according to a State Department cable obtained by WikiLeaks. Mr. Wang said the
embassy’s data could lead to “social consequences.”

On Scale of 0 to 500, Beijing`s Air Quality Tops `Crazy Bad` at 755