Road traffic and air pollution

Learn about sources of traffic-related air pollution, its health effects and how to minimize your risk.

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What are the sources of traffic-related air pollution?

The main sources of traffic-related air pollution are:

  • cars
  • buses
  • transport trucks

When engines burn fuel (gasoline or diesel), air pollutants that can affect your health are emitted, such as:

Additional air pollution is created when some of the gasoline used by engines evaporates without being burned, and by tire and break wear.

Traffic-related emissions also contribute to smog.

Exposure concerns

Most Canadians are exposed to air pollution from traffic on a daily basis while:

  • walking
  • riding in a vehicle
  • at home
  • standing along busy streets

Strict regulations have been introduced to decrease pollution and greenhouse gases from vehicles. These regulations have resulted in reduced emissions due to:

Although technology improvements have reduced vehicle emissions, there is still cause for concern because:

  • older trucks and cars remain in use
  • these vehicles emit more pollutants and greenhouse gases
  • vehicle numbers are high in densely populated urban areas
  • the total kilometres travelled by Canadian vehicles continues to increase

What are the health effects of traffic-related air pollution?

Health Canada has concluded that exposure to traffic-related air pollution:

  • causes development and worsening of asthma symptoms in children
  • may cause worsening of asthma symptoms in adults
  • may cause allergies to worsen
  • likely reduces lung function

Air pollution from traffic has also been linked to many other negative health effects, including:

Air pollution may worsen symptoms for people with existing heart and lung conditions.

Risks to young children

Children can be more sensitive to air pollution than people in other age groups. This is because children breathe in more air in relation to their body weight. This means that they breathe in more contaminants, so air pollution can affect them more.

The body's defense and lung systems are also not fully developed yet. Therefore, the health of young children may be more affected by air pollution.

Children living in areas with heavy traffic have a higher risk of having breathing problems than other children. Exposure to traffic pollution worsens asthma in children and increases the risk of asthma development.

Children can also be exposed to traffic pollution when commuting to and from school. To learn more about children's exposure to diesel exhaust from diesel school buses visit: School buses and diesel exhaust.

How can you minimize your risk?

You can minimize your risk of health effects from traffic-related air pollution by:

  • choosing low-traffic routes for:
    • cycling
    • walking
    • running
  • exercising in parks and green spaces, away from major roadways
  • reducing outdoor air pollution in your home:
    • keep windows and doors closed, and use air conditioning if the weather is warm
    • set your heating, ventilation and air conditioning (HVAC) system to recirculate when the outdoor air quality is poor, and bringing in fresh air when the outdoor air has improved
  • considering local traffic patterns and avoiding high-traffic areas when choosing a:
    • school
    • daycare
    • place to live
  • limiting time spent outdoors when pollution levels are high, especially for vulnerable groups, such as:
    • infants
    • children
    • diabetics
    • the elderly
    • those with heart or lung problems
  • avoiding idling your vehicle in your garage; pollutants can enter your home from the garage whether the garage door is open or closed

The Air Quality Health Index

The Air Quality Health Index (AQHI) can help you learn about local air pollution and its impact on your health. The AQHI measures the air quality in relation to your health on a scale from 1 to 10. It provides advice for making decisions to protect yourself and those in your care from the risks of air pollution.

Check the AQHI in your community regularly. If it is not available in your area, check your provincial environment ministry website for local air quality information.

Talk to your health care provider about other ways to protect your health when air pollution levels are high. This is especially important for people with heart and lung conditions.

Reducing traffic-related air pollution

You can help reduce pollution from traffic by:

  • choosing alternate ways to travel, such as:
    • walking or cycling
    • public transit
    • carpooling
  • maintaining a steady driving speed, while avoiding heavy braking or acceleration when possible
  • warming your engine with a block heater on cold days before starting it (emissions are higher when the engine is cold)
  • consulting the Fuel Consumption Ratings Search Tool before buying a vehicle
  • turning off your engine when stopped for more than 10 seconds, unless you are in traffic or at an intersection
  • reducing fuel consumption and emissions by:
    • maintaining your vehicle's engine
    • keeping your tires properly inflated as indicated by the manufacturer

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