Impacts of Air Pollution

Air pollutants can affect Canadians’ health, the natural environment and the economy.

Human health impacts

  • Fine particulate matter (PM2.5) and ground-level ozone (O3) can affect human respiratory and cardiovascular systems. The young, the elderly and those with acute illnesses are at greater risk of such effects. PM2.5 and ground-level O3 have been associated with hospitalizations, increased respiratory and cardiovascular mortality, asthma exacerbation, decreased lung function, lung inflammation and changes in heart rate variability.[1] In 2009, 8.1% of Canadians 12 years and older had been diagnosed with asthma by a health professional. This rate did not significantly change from 2001 to 2009.[2]
  • Impacts range from minor breathing problems to premature death. The more common effects include changes in breathing and lung function, lung inflammation, and irritation and aggravation of existing heart and lung conditions (e.g. asthma, emphysema and heart disease).[1]  There is no safe level for PM2.5 and O3 that does not pose risks to human health.
  • Negative health effects increase as the concentrations of pollutants in the air increases. Even modest increases in concentration (e.g. PM2.5 and O3) can cause small but measurable increases in emergency room visits, hospital admissions, and premature death.[1],[3]

For more information on human health impacts, see

Environmental Impacts

  • Ground-level ozone damagesvegetation, including crops, flowers, shrubs and forests, by interfering with plants’ ability to produce and store food. This damage makes them more susceptible to disease, pests and environmental stresses.[4]
  • Nitrogen oxides (NOx) and sulphur dioxide (SO2) can become acidic gases or particulates, and cause or accelerate the corrosion and soiling of materials.  Together with ammonia, they are also the main precursors of acid rain. Acid rain affects soils and water bodies, and stresses both vegetation and animals.[5]

For more information on environmental impacts, see

Economic impacts

  • The health effects from PM2.5 and ground-level ozone can reduce work attendance and overall participation in the labour force. In terms of increased health care costs, missed days of work, and reduced worker productivity, air pollution costs Canadians and the Canadian economy billions of dollars per year.[6]
  • Increased ozone levels also reduce the growth of crops, plants and trees, leading to economic losses in agriculture and forestry. For example, the impacts of ozone on agriculture are known to cost Canadian farmers millions of dollars in lost production each year.[7]

For more information on economic impacts, see


[1] Health Canada (2008) Human Health in a Changing Climate: A Canadian Assessment of Vulnerabilities and Adaptive Capacity.

[2] Statistics Canada (2009) Health Fact Sheets: Asthma, 2009, 82-625-X.

[3] Toronto Public Health (2004) Air Pollution Burden of Illness in Toronto: 2004 Summary.

[7] Environment Canada - Damage to Infrastructure and Canadian Industries.