Air pollution refers to contamination of the atmosphere by gaseous or particulate substances that are harmful to plant, animal, or human health or cause damage to property or the environment. It may lead to smog or acid precipitation (rain, fog or snow) or, over longer time periods, trigger changes in climate or in the earth’s ozone layer. Because Saskatchewan has a small population and little industry, air is generally good quality. Sources of air pollution can be anthropogenic (caused by human activity) or natural. Anthropogenic sources in Saskatchewan include thermal power generation (from coal and natural gas), transportation, industrial smokestacks (pulp and paper mills, oil refineries, mining operations), and chemical pesticide application. Natural-source pollution includes particles from wind-blown soils (see dust storms), road dust, pollen and spores, and smoke and ash from forest fires and burning crop residue.
Energy production causes much of Saskatchewan’s air pollution. Toxic, acidic, and greenhouse gases are released by the combustion of fossil fuels (coal, oil and natural gas) in vehicles, domestic and industrial heating, and thermal power generation. Saskatchewan is a producer and consumer of fossil fuels, and relies heavily on coal for electricity. Fossil fuel combustion produces pollutants such as carbon dioxide (CO2), sulphur dioxide (SO2), and nitrogen oxide (NOX). These pollutants have been implicated in possible human-induced climate change. Saskatchewan has the second highest per capita emissions rate for CO2 in Canada. Another contributor to poor air quality is the burning of crop residues. This smoke can produce respiratory ailments as well as obstruct visibility for traffic.
Saskatchewan’s air quality is monitored by Environment Canada’s two nationwide air-sampling networks: the National Air Pollution Surveillance Network (NAPS) and the Canadian Air and Precipitation Monitoring Network (CAPMoN). NAPS continuously monitors levels of sulphur dioxide, carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3), and total suspended particulates in fifty-five urban centres across the country, including Regina and Saskatoon. Air-monitoring stations in Estevan, Prince Albert, and Lloydminster are also part of the NAPS network but are operated provincially by Saskatchewan Environment and Resource Management. CAPMoN is a rural-based network that includes one air-monitoring station in Saskatchewan, located at Bratt’s Lake 50 km south of Regina. Environment Canada issues daily air quality forecasts for Regina and Saskatoon, based on the Air Quality Index, derived from measurement of ground-level ozone and particulate matter. The Air Quality Index ranges from “poor” to “excellent”; air quality in both Regina and Saskatoon consistently rates as “good.”
Transboundary air pollution across the Canada–United States border is also monitored in Saskatchewan. In keeping with the Saskatchewan Clean Air Act and the 1991 United States–Canada Air Quality Agreement, the Transboundary Monitoring Network was established to measure the flow of air pollutants across the Saskatchewan– North Dakota (Burke County) border. Environment Canada, Saskatchewan Environment, SaskPower, and the North Dakota Department of Health jointly operate a network of air-monitoring stations near the Boundary Dam and Shand power stations (see Souris River).
Iain Stewart