Ontario Region
Air pollution and smog are major problems in Ontario. The residents of Ontario are exposed to the greatest number of poor air quality days in the country and some of the worst air quality overall.
Ontario's large population -- a third of Canada's total -- and proximity to the United States' most populated region make it vulnerable to smog, acid rain, persistent organic pollutants (POPs) and climate change. Transboundary air pollutants from the U.S. account for up to 50 per cent of smog in southwestern Ontario.
The principal cause of air pollution is human activity. Transportation is the number one cause, followed by several industrial sources, including fossil fuel-fired power generation, iron and steel, cement and concrete manufacturing, petroleum refining, pulp and paper, base-metal smelting and chemical processing. Residential wood stoves are also a significant source of air pollution in the form of particulate matter in Ontario.
Some of the pollutants in Ontario's air include fine soot, also known as particulate matter (PM), nitrogen oxides (NOx), sulphur dioxide (SO2), carbon monoxide (CO), volatile organic compounds (VOCs) such as benzene, and toxic metals such as mercury, ground-level ozone, polyaromatic hydrocarbons, dioxins and furans.
Air quality is often worse near the shores of the Great Lakes, as breezes off the lakes concentrate pollutants a short distance inland. Through continued monitoring programs, Government of Canada scientists are working to better understand the role that the Great Lakes play in air quality in Ontario.
Learn More about:
