Even in a city known as one of the world’s most polluted, the last few days in Beijing have been unusually disgusting. A choking smog has blanketed the city of 20 million people, blocking out the sun and flooding hospitals with patients seeking help for heart and respiratory ailments. Contributing factors include unusually cold temperatures (which boosted the burning of coal), growth of steel, smelting, and petrochemical factories outside the city, and emissions by Beijing’s 5 million vehicles. Officials announced emergency measures that include shutting some factories and limiting car use. Meteorologists say the noxious air will linger until a cold front blows in on Jan. 15 and 16.
Pollution is more than an annoyance for China's city residents. A study released by Greenpeace and Peking University’s School of Public Health found that exposure to ultrafine particulates helped cause 8,572 early deaths in Beijing, Shanghai, Guangzhou, and Xian in 2012. The official reading for the most dangerous particulates—known as PM2.5—has recently soared as high as 993 micrograms per cubic meter in Beijing, the highest level since Chinese environmental officials started releasing measurements a year ago. The World Health Organization says anything over 25 is unhealthy.