Source: Toronto Star

Black carbon (BC) particles are generated through incomplete combustion processes including combustion of fossil fuels and biomass. These two sources are most commonly from vehicles and residential wood burning for heating. BC has an overall warming effect on the global climate and long-term exposure to it has been associated with cardiopulmonary mortality.

Dr. Robert Healy, Senior Environmental Officer at The Ontario Ministry of the Environment and Climate Change, spoke about the Ministry’s work on assessing the sources of fossil fuel and biomass burning black carbon in Ontario at the SOCAAR Seminar on November 30th, 2016.

The research team assessed BC emissions from air quality stations located across Ontario. There are stations at 9 different locations in Toronto, Hamilton, and Windsor which were selected to represent near-road, residential, and background locations. Aethalometer measurements, based on the physical property of BC to absorb light, were used to investigate the sources of BC.
From datasets collected between June 2015 and May 2016, the research team concluded that fossil fuel combustion was the dominant contributor to ambient black carbon at all sites in every season. The highest seasonal biomass burning relative mass contribution was observed in winter at a background site on the Toronto Islands. Furthermore, the highest fossil fuel contributions were observed at near-road sites. An unexpected observation was that every site in Ontario showed higher black carbon emissions from fossil fuel in the summer than in the winter. This is likely because the transboundary influence of fossil fuel BC from the United States is highest in the summer. Looking ahead, the research team will be working with environment Canada in British Columbia and Quebec to assess importance of residential wood combustion and wild fires and their impact on air quality in these locations.