Ontario's Air Pollution: What's The Main Source?

Ontario's air pollution levels are considered low, with 93% of cities in the province meeting Canada's very good or good air quality standards in 2016. However, air pollution in Ontario comes from a variety of sources, including industrial and commercial facilities, transportation, and natural sources such as forest fires. The province has taken steps to improve air quality, such as eliminating coal as a fuel for electricity generation and implementing emissions testing programs for commercial vehicles. Despite these efforts, air pollution continues to be a concern, particularly in neighbourhoods located near industrial facilities and major roadways, where the risk of exposure to pollutants is higher.

Residential sources

Ontario's air pollution levels are considered low, contributing to a generally ""healthy" air quality status. In 2016, 93% of cities in the province met Canada's "very good" or "good" air quality standards, which are among the most stringent in the world. However, air pollution in Ontario still poses a significant risk to human health and the environment.

Residential wood-burning, especially during the winter months, is a significant source of air pollution in Ontario. It contributes to the fine particulate matter (PM2.5) in the air, which can have far-reaching health effects. PM2.5 is unique in that it can bypass the lungs and enter the circulatory system, causing harm throughout the body.

Other residential sources of air pollution include the use of gas stoves, frying foods, lighting candles or incense, and vacuuming. These activities can release various pollutants into the air, including volatile organic compounds (VOCs) and nitrogen dioxide (NO2). Additionally, residential locations are often affected by outdoor air pollution, such as wildfire smoke, which can enter homes through heating, ventilation, and air conditioning (HVAC) systems.

To mitigate indoor air pollution, residents can take several measures. For example, refraining from activities that produce high levels of pollutants, such as frying foods or burning incense, can help improve air quality. Using a portable air cleaner with a HEPA filter or a DIY air filter made with a box fan and air filters can also help purify the air in specific areas of the home. Additionally, residents can refer to the AQHI health guide to evaluate their sensitivity to air pollution and take appropriate precautions.

Industrial sources

Ontario's air pollution levels are considered low, and the province has taken several steps to improve air quality. For instance, Ontario was one of the first places in the world to stop using coal to generate electricity. However, industrial sources remain a significant contributor to air pollution in the province.

Industrial processes and facilities are a major source of air pollution in Ontario. The law in Ontario regulates contaminants released by industrial and commercial facilities, and businesses must comply with certain standards. Despite these regulations, industrial facilities can still release various contaminants into the air, including those from industrial heating systems, manufacturing operations, and power-generating stations.

The ore and mineral industries sector was the most important source of SOX emissions in Ontario in 2022. Additionally, the oil and gas industry in Ontario is a significant contributor to NOX emissions, although emission reductions from the transport and electric utilities sectors have helped to offset this.

Industrial processing and general solvent use are also major sources of air pollution in Ontario, accounting for 15% and 26% of emissions, respectively, according to the Ontario Ministry of the Environment and Climate Change in 2016. Furthermore, industrial activities contribute to the formation of smog, which is a combination of pollutants in the air, including ground-level ozone and PM2.5. Ontario's smog season spans from May to September, during which PM2.5 and ozone levels are typically at their highest concentrations.

Ontario's industrial emissions also have a local impact, with neighbourhoods located near industrial facilities potentially experiencing higher concentrations of pollutants than what is measured by monitoring stations.

Forest fires

The effects of forest fires on air quality extend beyond the immediate vicinity of the fire. Emissions from wildfires can travel large distances, affecting areas far removed from the fire location. This was evident in the 2024 global wildfires, which released an immense amount of carbon monoxide and significantly impacted the atmosphere.

Climate change and human activities are closely linked to the increasing frequency and severity of forest fires. Human activities, such as burning fossil fuels, transportation, and industrial processes, release greenhouse gases and black carbon emissions, contributing to climate change. As a result, weather patterns become more erratic, increasing the likelihood of wildfires, especially in regions experiencing drought conditions.

To mitigate the impact of wildfires on air pollution and public health, effective strategies are necessary. This includes implementing preventive measures, such as prescribed burning for fuel management, and developing public health surveillance systems to monitor the effects of climate change on populations in Ontario.

Transportation

Ontario's air pollution levels are considered low, contributing to a generally ""healthy" air quality status. In 2016, 93% of cities in the province met Canada's "very good" or "good" air quality standards, which are among the most stringent in the world. However, transportation is a significant contributor to air pollution in the province.

Ontario has taken steps to reduce pollutants from transportation. In 2022, the province implemented an enhanced emissions testing program for commercial trucks and buses, integrated with the Ministry of Transportation's annual safety Motor Vehicle Inspection Station program. Ontario has also worked with the federal government, the state of Michigan, and the United States Environmental Protection Agency to better understand ozone formation and transport in the shared airshed.

In addition to efforts by the government, individuals can take precautions to limit their exposure to air pollution, especially during periods of high pollution levels. This includes avoiding areas with a lot of major roadways, as people living close to major roads have been found to have a mortality rate advancement of 2.5 years and a significant increase in all-cause mortality of 18%.

Fossil fuels

Ontario's air pollution levels are considered relatively low, and the province has taken steps to improve air quality over the years. Notably, Ontario was one of the first places in the world to eliminate coal as a fuel for electricity generation, which has significantly reduced emissions. However, the province still faces challenges due to transboundary pollution from neighbouring industrial regions in the United States.

The transportation sector is a significant contributor to air pollution from fossil fuels. Vehicle emissions, particularly from diesel engines, release harmful pollutants such as nitrogen oxides, carbon monoxide, formaldehyde, benzene, and polycyclic aromatic hydrocarbons. These emissions have been linked to adverse health effects, including respiratory problems, asthma, and increased hospital admissions.

Industrial facilities are another major source of fossil fuel-related air pollution in Ontario. Metal smelting, for example, contributes to the release of pollutants that can lead to acid rain, impacting waterways, forest growth, and agricultural productivity. Additionally, the combustion of fossil fuels in power plants and factories releases NO2, a byproduct linked to millions of new asthma cases in children annually.

Residential sources also play a role in Ontario's air pollution. Activities such as winter wood-burning and BBQing contribute to fine particulate matter (PM2.5) pollution, which can have significant health impacts. According to the World Health Organization, PM2.5 concentrations should not exceed an average of 10 μg/m3 annually. While most cities in Ontario met this standard in 2019, a few cities, including Hamilton, Bainsville, and Windsor, exceeded the recommended levels.

The economic impact of air pollution from fossil fuels is also significant. According to Greenpeace, air pollution from burning fossil fuels costs Canada an estimated US$38 billion annually and leads to approximately 21,000 premature deaths in the country. The report highlights the need for a transition to renewable energy sources to improve air quality and create a more sustainable future.

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