"They found that as the number of fine particles less than 2.5 microns in diameter increased, so, too, did the risk of dying: each jump of 10 micrograms per cubic meter corresponded to a 11 to 17 percent increase in the risk of dying from any cause."

"The average concentration of total suspended particulates (TSP) in the city in 1998 was nearly 600 micrograms per cubic meter, according to the World Resources Institute. Local health experts say about 80 percent of Taiyuan’s suspended particles are "respirable" (less than 10 microns in diameter). This would imply the average concentration of lung-damaging PM10 is more than 450 micrograms per cubic meter — nine times the U.S. standard for annual exposure. Add in high levels of SO2 and nitrogen oxides (NOx) and Taiyuan’s composite air pollution index regularly tops the list among China’s 42 major cities."