An update to a study going since 1990 was completed on the numerous adverse health impacts of air pollution. In 2005 “89% of the world’s population lived in areas where the World Health Organization Air Quality Guideline was exceeded.”
Of course, what happens in China can and often does affect us all the way over here in Minnesota — the world is not all that isolated, and fences don’t keep out bad air or water. So you’ll be disappointed, perhaps, to know that the Midwest (and very little of the world) has low concentration estimates (in other words, the bad air is having negative health consequences for us). Minn. comes in at about 5–10 ug/m3 — about in the middle; not as bad as other areas, but not so good either.
For a more local study (which states “The statewide median concentration exceeded the health benchmark value for benzene, carbon tetrachloride, formaldehyde, and chromium. At specific individual monitoring sites, the median concentrations exceeded the health benchmark value for the additional pollutants chloroform, ethylene dibromide, and arsenic.”), see HERE (compltd’ 2000).
(Source with map HERE: “Exposure Assessment for Estimation of the Global Burden of Disease Attributable to Outdoor Air Pollution,” Michael Brauer, etc.)