Believe it or not, pollution from eastern Asia is beginning to have measurable effects on air quality in western North America, a researcher from the University of Washington claims. Pollutants traceable to Asia include carbon monoxide, a direct byproduct of combustion: Peroxyacetyl Nitrate (PAN), indirectly caused by combustion; and particulates, says Dan Jaffe, an associate professor who studies atmospheric chemistry and air pollution.