BEIJING - (AP) -- Beijing suffered its worst air pollution of the year on Monday, with monitoring sites throughout the city reporting extremely hazardous levels of pollutants.
City authorities issued a rare orange alert, the second highest of four danger levels. Schools suspended outdoor activities and polluting factories were required to reduce production.
Visibility was cut to several hundred meters (yards). People complained of a smoky, pungent odor, and many wore tight-fitting face masks.
"I felt like my lungs were blocked," said Xu Pengfei, a security guard outside an office building in downtown Beijing. "We have to stand in the open for many hours a day, and the pollution really affects us."
The city said the levels of hazardous tiny PM2.5 particles in the air exceeded 600 micrograms per cubic meter at several monitoring sites late Monday afternoon. The U.S. Embassy in Beijing reported 646 micrograms per cubic meter at 6 p.m.
Outside Beijing, the readings were was as high as 976 micrograms in the region of Liulihe.
Several cities in the northern province of Hebei also reported extremely polluted air.
The World Health Organization considers the safe level of PM2.5 particles to be 25 micrograms per cubic meter on a 24-hour average basis.
Liu Juntang, a businessman whose company develops environmental technology, said face masks could not give protection from the tiny pollutants.
"The air pollution is all encompassing, and it requires both the government and individuals to shoulder the responsibility to clean up the air," Liu said.
Beijing has vowed to clean up its notoriously foul air and had been doing fairly well this year, with generally cleaner air than in 2014.
But the city was hit by unusually cold days and early snow in November, and winter heating was turned on. For the entire month, the capital hardly saw any blue skies and was shrouded in persistent smog.
The air quality worsened on Friday and continued to deteriorate throughout the weekend, prompting the city government to issue an orange alert on Sunday. Authorities said they didn't issue the highest red alert because they expect the air quality to improve by Wednesday.
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