Comparison of particulate polycyclic aromatic hydrocarbon profiles in different regions of Canada

Atmospheric concentrations of polycyclic aromatic hydrocarbons (PAHs) in Canada for 2000 and 2001 were evaluated to study particulate PAH profiles during cold weather periods. Ten sites from the National Air Pollutant Surveillance network and six sites from the aluminum industry network were selected to represent various site classifications. The following scale of decreasing concentration at fixed sampling stations was found: Söderberg aluminum production>iron and steel production>urban (traffic+domestic heating)>urban (traffic)>rural. The ratio of the cold divided by the warm weather period for each year suggested a clear input of PAHs from domestic heating at several sites. However, analysis of the relative proportions of particulate PAHs, comparison of benzo[e]pyrene relative abundance ratios and cluster analysis suggested that the site differences in the particulate PAH profiles were small with the exception of the aluminum smelter impacted locations. It appears that a relatively stable profile exists for atmospheric particulate PAHs between regions in Canada. The nature of this profile stability likely depends on the particle composition, individual PAH degradation patterns and intensity of the emission source(s). Overall, the results of this study suggest that a simple ratio of two or three PAHs may be insufficient to identify PAH emission sources at fixed sites and are a better indicator of the ageing process.