Human activities like burning fossil fuels and vehicle emissions generate of variety of aerosol particles like black carbon, organic, sulphate, and nitrate particles. The interaction between black carbon and other aerosol particles can change the physical and chemical properties, such as light absorption of black carbon particles. Understanding the chemical nature of these aerosol particles is important in evaluating their environmental impacts.

Alex Lee, a post doctoral fellow in the University of Toronto’s Department of Chemistry presented his research on using an Aerodyne soot particle aerosol mass spectrometer (SP-AMS) to characterize the chemical composition of black carbon at the latest SOCAAR seminar.

His research examined air quality at two different Canadian locations: the urban environment of downtown Toronto and the industrial environment of the Alberta Oil Sands. Lee was able to better understand the mixing state of particles containing black carbon and other aerosol components by operating the SP-AMS which is equipped with a light scattering module. He found that in downtown Toronto most black carbon particles are thinly coated, less than 25 weight per cent, with traffic related organic materials. Black carbon particles originating from biomass burning are also thickly coated by organic particles. In Alberta’s oil sands region, about 10 to 35 weight per cent of organics are internally mixed with black carbon particles.

The results show that the SP-AMS is capable of providing high time resolution measurements to examine the formation mechanisms of black carbon particles, and identify potential sources of black carbon.