Air Quality

Improved air quality reduces heart attacks and hospital visits, avoids hundreds of thousands of child asthma attacks, and prevents millions of lost school and work days in Canada alone. Cleaner air can also reduce damage to crops, forests, surface waters, and infrastructure such as buildings and bridges, and can help address climate change impacts since some air pollutants are also greenhouse gases or contribute to the formation of greenhouse gases.

According to the World Health Organization (WHO) air pollution represents the biggest environmental risk to human health and can severely affect the environment. Even at low levels, air pollution has been clearly linked to increased heart and breathing problems, increased hospitalization and emergency room visits and premature death. Health Canada estimates there are 14,000 to 15,000 deaths in Canada each year due to air pollution from human activity.

Ozone (O3)

Health Effects – Exposure to ozone (O3) can cause respiratory symptoms such as throat irritation, coughing, shortness of breath, and reduced lung function. Ozone exposure can also aggravate existing conditions like asthma or other chronic lung diseases. Sensitive populations such as children, and people suffering from respiratory or cardiovascular conditions are at higher risk, especially during summer months when ozone levels increase.

Environmental Effects – Ozone is absorbed directly by plants through pores in their leaves. Once inside the plant, O3 can damage leaves, reduce photosynthesis, impair reproduction and decrease agricultural crop yields. This can reduce the variety of plants in an ecosystem. While mostly known for its adverse effects on health and the environment, ozone is also a greenhouse gas that contributes to climate change.

Fine Particulate Matter (PM2.5)

Health Effects – Exposures to fine particulate matter (PM2.5) can negatively impact the heart and lungs, and can leadto health issues like asthma attacks, chronic bronchitis, and heart attacks. Exposure to PM2.5 is also linked to increased emergency room visits and hospitalization due to respiratory and cardiovascular problems, as well as increased risk of premature mortality. Children and those with pre-existing cardiovascular and respiratory disease have greater sensitivity to effects.

Environmental Effects – Impacts on the environment can vary depending on the chemical make-up but, mostly, PM can cause changes to soil and water chemistry. This can adversely impact organisms and vegetation. PM2.5 can stain and damage stone and other materials, statues and monuments. PM2.5 also contributes to reduced visibility, which affects cities, airports, and wilderness areas, and can negatively impact tourism and the economy.

Sulfur Dioxide (SO2)

Health Effects – Exposure to SO2 can have negative impacts on respiratory health, including reduced lung function, increased respiratory symptoms, and airway inflammation. Persons with asthma, about 9% of the Canadian population, are especially vulnerable, along with sensitive populations such as children and those with pre-existing respiratory disease. Effects can also include increased emergency room visits and hospitalizations for respiratory causes.

Environmental Effects – SO2 can affect ecosystems both directly and indirectly, and contributes to the formation of PM2.5. Direct effects occur when plants absorb the SO2 through their leaves. Indirect effects occur when sulphur-containing compounds, like the sulfuric acid in acid rain, are deposited onto soil and water. Once absorbed by the plant, SO2 can interfere with photosynthesis and energy metabolism, and can cause decreased plant growth and yield. SO2 can damage materials and structures including objects of cultural importance like statues and monuments.

Nitrogen Dioxide (NO2)

Health Effects – Short-term exposure to NO2 can elicit a range of adverse respiratory effects including decreased lung function, increased respiratory symptoms, and airway inflammation, and cause aggravation of respiratory diseases, particularly asthma and chronic obstructive pulmonary disease. Long-term exposure to NO2 may contribute to allergic responses, asthma development and may increase susceptibility to respiratory infections. Inhalation of NO2 has also been linked to effects on the cardiovascular system, and some reproductive effects.

Environmental Effects – NO2 can affect ecosystems both directly and indirectly and contributes to the formation of ozone. Direct effects occur when plants absorb the NO2 through their leaves, which can lead to lesions and dead tissue, and to altered plant growth and yield. Indirect effects occur when NO2 (and other NOx) reacts with water and oxygen to form acid rain, or when an overabundance of nitrogen adversely affects an ecosystem.

Volatile Organic Compounds (VOCs)

Health Effects – Adverse health effects from exposure to VOCs depends upon the nature of the chemical, the level of exposure, and the length of exposure. Many substances included in this grouping have little effect on health. For those that do, the effects can vary greatly, from irritation (eye, nose and throat), headaches, nausea, dizziness, and the worsening of asthma symptoms, to more severe effects like damage to the liver, kidneys, and central nervous system. Some VOCs, like benzene, are carcinogens, and long-term exposure to them can increase the risk of developing cancer.

Environmental Effects – VOCs contributes to the formation of PM2.5 and O3, which are the main ingredients of smog. Smog reduces visibility in many areas, including cities, airports and wilderness areas and can negatively impact tourism and the economy. PM2.5 and O3 can adversely affect vegetation by damaging leaves, reducing photosynthesis, impairing reproduction and growth, and decreasing crop yields.