Air pollution results from the release of pollutants into the atmosphere. Multiple sources of air pollution contribute, accumulate and interact, resulting in cumulative effects on air quality. The majority of pollutants occur as a result of human activities. Sources can range from large industrial facilities to small internal combustion engines. A pollutant released at one source may affect air quality hundreds or even thousands of kilometres away. Natural processes release pollutants as well, such as wildfires, which are occurring more frequently and are becoming more severe as a result of climate change.
There are various factors that affect air pollution, such as temperature, humidity, wind patterns and precipitation. Individual pollutants differ from one another in their chemical composition, in how they react with other chemicals (including other pollutants) and in terms of their sources, persistence, ability to travel and impact.
Effects of Air Pollution
The cumulative effects of air pollution can affect human health, the environment and the economy in multiple, often interacting ways, such as:
Adverse health effects from poor air quality can include respiratory difficulties like allergies and asthma, as well as more severe conditions such as stroke, heart disease and lung cancer.
Pollutants can contribute to various adverse effects on the environment. For example, acid rain resulting from air pollution can accelerate the degradation of leaves on trees, or the leaching of metals from rocks, causing stress to ecosystems. Other impacts include decreased photosynthesis, resulting in a decrease in productivity and growth of crops and plants. Nitrogen deposits from the air can accumulate in water bodies, resulting in excessive algal and plant growth.
Air pollutants can also cause economic effects including loss of agricultural productivity, increased economic costs due to premature wearing of building materials, equipment and infrastructure (e.g., from acid rain), decreased labour productivity and increased costs of medical care.
To learn more about air pollutants and their effects, see the Air Quality page for the Government of Canada.
Ambient Air Quality and Air Pollutants Emissions in Canada
Did You Know?
Environment and Climate Change Canada tracks air pollutant release data through annual reporting to the National Pollutant Release Inventory which tracks over 320 substances from over 7,000 facilities across Canada.
Common air pollutants that are the main source of smog, acid rain and poor air quality are:
- Sulphur Oxides
- Nitrogen Oxides
- Particulate Matter
- Ground Level Ozone
- Carbon Monoxide
- Volatile Organic Compounds
The Open Science and Data Platform provides a wide range of information related to air quality, including publications and data. For example, the publication “Air Quality – Health of Canadians in a Changing Climate: Advancing our Knowledge for Action” considers human health and the environment and how health effects are influenced by climate change and pollution levels.
The map below features reported pollutant emissions data from the National Pollutant Release Inventory and the Canadian Environmental Sustainability Indicators Program, which provides information to track Canada's performance on key environmental sustainability issues including climate change, air and water quality.
The “Air Quality – Peak Ambient Fine Particulate Matter Concentrations at Monitoring Stations” dataset illustrates the peak level of pollution in our ambient (outdoor) air in various locations across the country. The data indicates the level of pollution in micrograms of pollutant per cubic meter of air and the year reported.
The “Air Pollutant Emissions – Fine Particulate Matter Emission by Facility” dataset highlights all facilities that report the release of fine particulate matter emissions. The data shows the average amount of emission in tonnes and the reporting year.