Health Effects of SO2 and Sulphates
Sulphur dioxide (SO2) a primary air pollutant is generated when sulphur-containing fossil fuels or ores are burned. Much of this eventually turns into sulphate (SO4) in the atmosphere which is thus a secondary pollutant.
Industry accounts for over 80% of all SO2 produced in Ontario. Ontario Hydro and ore smelting processes alone produce over half of the total SO2. Non-industrial, area sources of SO2 emissions include transportation and residential heating.
Over 80% of all SO2 emissions in Ontario come from four industries : Algoma Steel, Falconbridge, Inco and Ontario Hydro.
Health Effects
Sulphur dioxide and sulphates increase mortality.
Throughout the world, researchers have found that as sulphur dioxide and sulphate levels increase, mortality rates rise. Vigotti* and others (1996) compared air pollution data from four monitoring stations with death statistics in Milan. They found higher SO2 levels were related to an increase in the number of deaths. Studies in Helsinki, Athens and Beijing have found similar results. In a study of six US cities, Dockery* and others found sulphates were strongly associate with higher death rates due to ling cancer and cardiopulmonary disease. Sulphates and SO2 levels are both linked to increases in mortality. Although levels of these pollutants have decreased substantially, they continue to lead to early death throughout the world.
Sulphur Dioxide and Sulphates increase respiratory conditions such as asthma and bronchitis tend to increase during period of elevated sulphur dioxide or sulphates. A study in Paris by Dab* and others in 1996 measured SO2 levels and hospital admissions over a five year period. They found that admissions for all respiratory problems were related to SO2 levels. Similar research has been done on sulphates. While studying secondary pollutants in southern Ontario, Bates and Sizto* discovered that increased respiratory admissions to hospitals followed high sulphates days. Burnett* and others confirmed and extended this study. Sulphur dioxide and sulphates pose a significant risk to people with respiratory conditions.
People report more respiratory symptoms on higher sulphur dioxide and sulphate days. Symptoms such as coughing, wheezing and chest pain were associated with sulphates, as reported by Ostro* and others in 1993. Similar effects have been found with SO2. In addition, both sulphates and SO2 affect lung function. Pengelly* and others found that asthmatic children living in areas of higher SO2 displayed a decrease in lung capacity. Although SO2 and sulphate pollution do not seem to cause respiratory disease they do aggravate existing conditions.
SO2 and sulphates irritate your lungs, SO2 and sulphates can send you to the hospital and even kill you!
What is being done?
The Ontario Ambient Air Quality Criterion for SO2 is 250 ppb for a one hour period, and 100 ppb for a 24 hour period.* In 1994 there were 79 exceedances of the one hour standard at 15 stations across the province. Recent evidence would suggest that these standard are in need of revision. In accordance with the Canada-United States Air Quality Agreement, the U.S. must cap annual electrical utility SO2 emissions at 8.95 million tonnes by the year 2010. Canada is committed to capping its SO2 emissions at 3.2 million tonnes annually by the year 2000.
* At room temperature, 100 ppb SO2 converts to 270 micrograms per cubic meter (ug/m3).
What can you do?
REDUCE YOUR OWN EMISSIONS: Practice energy conservation and investigate emissions-free energy, such as solar power. Use public transportation, car pool, walk, rollerblade or cycle. If you do drive, keep your car well-maintained.
BE INFORMED: Request information from local government, the Ministry of the Environment , Environment Canada, plant managers and environmental groups.
BE INVOLVED: Start or join a citizens' group. Write letters to the Minister of Environment and to your local MPP. Register complaints about air quality.

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