| This work examined the chemical character and geographic origins of Toronto particulate matter smaller than 2.5 microns (PM2.5). PM2.5 has been linked with increased human morbidity and mortality in Ontario. The influence of local emissions, long range transport of air, and atmospheric chemical processes on the seasonal and diurnal behaviour of PM2.5 mass & number concentrations, and chemical composition variation via real-time mass spectrometry of individual aerosol particles was studied. Toronto PM 2.5 levels were found to be affected by anthropogenic activities like traffic and construction, and natural processes like forest fires and intercontinental dust transport. Nine distinct emission sources contributing to Toronto PM 2.5 were identified by use of the novel use of single particle data. The importance of the Midwestern United States and Southern Ontario as Toronto PM2.5 source regions was confirmed and evidence for a relationship between local smog advisories and Toronto organic nitrate aerosol discovered. |
