Chinese citizens documented the dark haze that enveloped northern Chinese cities in December 2015 as air pollution levels jumped far above the level considered safe by the World Health Organization. (Jenny Starrs and Jason Aldag/The Washington Post)

Beijing is choking on thick, brown smog after air pollution levels skyrocketed on Monday to more than 20 times what the World Health Organization considers to be safe. The oppressive pollution has prompted China to issue its highest air quality alert so far this year.

Reuters reports authorities are blaming “unfavorable weather” and coal fires for the oppressive smog, which are lit by the poor for heat in winter. But that’s really only half the story — coal-fired power plants are also in overdrive since last week’s wintry blast. Temperatures were running as low as 25 degrees below normal for this time of year in northeast China for much of the past week. When the excessive power use for heating combined with stagnant high pressure, Beijing’s air quality took a nose-dive.

In terms of health impacts, the air quality in Beijing and other parts of northeast China is off the charts. On Monday, the air quality index measured at the U.S. Embassy in Beijing reached a staggering 611 for small particulate matter. In the U.S., the EPA considers an index over 100 to be unhealthy. At an index over 300, the air quality “would trigger a heath warning of emergency conditions,” reads airnow.gov. “The entire population is more likely to be affected.”

Beijing's air quality index (AQI) was 611 on Monday. (airnow.gov)
Beijing’s air quality index (AQI) was 611 on Monday. (airnow.gov)

Particle pollution of this tiny size, just 2.5 micrometers, is incredibly hazardous to health, and even more so at these extraordinary levels. According to the EPA, particles smaller than 10 micrometers are the most dangerous to health because they can embed deep in the lungs. Some of the particles are even small enough to enter the bloodstream directly through the lungs.

Pollution this extreme can cause premature death, aggravated asthma, irregular heartbeats and decreased lung function. Though the young, elderly and sick are particularly vulnerable to air pollution, levels this high effect even the healthiest of people.

An orange air quality alert was issued on Sunday, which required industry to cut production. A windy area of low pressure is forecast to sweep over northeast China on Tuesday and Wednesday which should help to alleviate the pollution concerns in Beijing.


Satellite imagery shows thick brown smog wafting east over China under high clouds. (Japan Meteorological Agency/RAMMB/CIRA)

7月2VS11月30……😷#beijing#北京

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A woman wears a mask as she holds her dog on Monday in Beijing. (Kevin Frayer/Getty Images)

A view from a viewing deck on the China Central Radio and Television Tower on Nov. 29, 2015. (REUTERS)

The Forbidden City is shrouded in haze. (Kevin Frayer/Getty Images)