Climate Change and Public Health Factsheets

Climate change, forest fires and your health

Forests and wooded areas cover more than 50% of Canada. Yet, because of climate change, Canadian forests are increasingly under threat from fires which destroy about 2.5 million hectares each year.

What causes forest fires?

  • Lightning
    • nearly half of all fires are caused by lightning
    • 81% of fire damage to forests is caused by lightning
  • Human activity
    • smoking and campfires can also cause forest fires.

How do higher temperatures from climate change affect Canada's forests?

Experts predict that if climate change continues to increase temperatures that the fire season and the frequency and intensity of forest fires will increase. Higher temperatures can cause:

  • forests to be drier
  • fires to start more easily and make them harder to put out
  • summers to be more dangerous because of the combined effect of high temperatures and low humidity.

By the year 2040, compared to the late 1990s, forests fires will:

  • last on average 30 days longer
  • happen 25% more often
  • burn 46% larger forest areas

Forest fire smoke - a danger to our health

Forest fires directly threaten nearby people and properties. Smoke from forest fires can affect many more people.

Generally, everyone living in areas reached by smoke will be affected. Health problems are more likely in sensitive groups, such as people with existing heart or lung problems, children, and the elderly.

Breathing affected by smoke - even far from the fire

The best way to measure exposure to forest fire smoke is to look at the amount of air pollutants from the fire in the air, also known as particulate matter, particularly particles smaller than 2.5 millionths of a metre or PM2.5. These tiny particles can float in the air for a long time and can reach people far away from the fire site. People can breathe these smaller particles deep into their lungs, which can affect their health.

In Canada, immediate health concerns from forest fires are increased respiratory complaints due to smoke inhalation. Exposure to smoke can also cause worsening of heart and lung diseases. The elderly and young infants can be at increased risk.

What is in forest fire smoke?

Forest fire smoke is a mixture of:

  • water vapor
  • carbon monoxide
  • carbon dioxide
  • nitrogen oxides
  • hydrocarbons
  • other chemicals containing carbon
  • particles of different sizes (particulate matter)
  • traces of minerals.

Forest fire smoke is also responsible for more:

  • emergency room visits;
  • doctor visits; and
  • hospitalizations for breathing problems, such as asthma and COPD.

For example, in 2003, British Columbia experienced a catastrophic fire season with nearly 2,500 fires which burned more than 265,000 hectares of forest. That year, doctor visits for asthma were significantly higher than usual in the southeastern region of the province.

Long term health effects under study

  • As forest fires increase in length and intensity, their effects on human health will also increase.
  • While it is well established that smoke from forest fires makes respiratory problems worse, new evidence also link it to heart-related problems.
  • Since Canadians are usually only exposed to forest fire smoke occasionally and for a short time, more evidence is needed to confirm the long-term effects of forest fire smoke on both heart and lung health.

What you can do

Lower your exposure to protect your lungs

If you know that there is forest fire smoke that could affect you, you can still lower your exposure to it. The actions below will depend on how much smoke is in the air and how sensitive you are to it:

  • Be prepared - people with heart or lung problems should make sure they have enough medications on hand before the fire season.
  • Talk to your family doctor or health care professional if you are concerned about your health or the health of a family member.
  • Listen to public advisories and consider evacuation- if the situation should become extreme, especially if you are sensitive to smoke.
  • Consider filtering your air
    • air conditioners - use filters to keep smoke particles from coming inside.
    • indoor air cleaners - use HEPA filters to remove particles.
    • respirators - more rarely, people who work outside or who need to spend a lot of time outside may need respirators. They should be fitted to make sure they work properly.
  • Avoid exercising outdoors - because active people breathe in more air and therefore may inhale more pollutants from the air.
  • Go somewhere with clean air- such as a shopping mall or a shelter set up by public health authorities or emergency responders.

Check smoke forecasts where you live

Canada has excellent tools to monitor forest fire smoke and forecast where it will drift:

  • The Air Quality Health Index from Health Canada and Environment Canada has real-time air quality ratings and forecasts. It gives health messages based on air quality monitoring. It is available in cities across Canada where air quality monitors are found.
  • The Western Canada BlueSky Smoke Forecasting System has hourly forecasts of smoke from forest fires up to 60 hours in advance. These forecasts are publicly available online. They cover all of Western Canada, northwestern Ontario, the southern portions of the Yukon, Northwest Territory and Nunavut, and the US Border States.

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