Still no bodies.
“Breathing in this air is taking its toll: the Beijing Shijitan Hospital reported treating 20 percent more patients than usual at its respiratory health department. Most of them were coughing and sought treatment for various respiratory illnesses. In addition, official media reports that Beijing’s main children’s hospital has recently seen 9,000 patients per day, a third of them with respiratory diseases.” [Care2.com]
I believe Beijing to have an air temperature inversion problem from the East China Sea, similar to the Los Angeles problem giving rise to the (habitual) smog.
Thus “smog” must pre-date any industrialization in Beijing.