Concentration and Source Origin of Trace Metals in PM2.5 Collected at Selected Canadian Sites within the Canadian National Air Pollution Surveillance Program

Abstract

Airborne particulate matter (PM) is a complex mixture of thousands of organic and inorganic species that emerge from a wide range of natural and anthropogenic sources. Numerous epidemiological studies have confirmed that PM and especially the respirable fraction of PM, the PM2.5 (for particles < 2.5 μm diameter), has adverse effects on human health. Although there is no evidence to pinpoint any single feature or component of PM as the cause for the observed epidemiological effects, it is apparent that metals contribute, at least in part, to the toxic and carcinogenic effects associated with exposure to airborne PM and for this reason have been the object of several epidemiological studies (Goldoni et al. 2006; Kawata et al. 2007; Lippmann et al. 2006). In addition, trace metals are proven to be useful tracers and are extensively used to identify sources of emissions to be targeted by the emission reduction policies (Querol et al. 2001; Lee et al. 2003; Gotschi et al. 2005; Querol et al. 2006; Querol et al. 2007b; Viana et al. 2007; Jeong et al. 2008). Therefore, monitoring of elemental composition of PM has become a crucial part of air quality programs in many countries around the world.