What is in forest fire smoke? Forest fire

Forest fire smoke is made up of a mixture of gases and very small particles that are produced when wood and other organic matter burn. The small particles in forest fire smoke also contain other types of air pollution and have been linked to serious health effects. Smoke also contains toxic gases like carbon monoxide that can be harmful to your health.

Smoke particles are small and can get deep into your lungs and may be absorbed into the bloodstream.

What are the health risks?

Your body will try to protect itself against the smoke particles by making more tears and mucous.

Exposure to wildfire smoke can cause:

  • runny nose
  • scratchy throat
  • irritated sinuses
  • headache
  • cough
  • difficulty breathing
  • chest pain

Certain sensitive populations (children, older adults, pregnant women) may feel the effects of smoke earlier and have more severe symptoms than others in the community. Smoke exposure can worsen existing lung conditions such as COPD and asthma, and worsen cardiovascular outcomes.  Most people will recover quickly from smoke exposure.

If you have uncontrolled coughing, wheezing or choking, or your breathing does not improve when you go indoors, consult your health care provider or call 811 or chat online at ontario.ca/health811.

It is important to note that each person reacts differently to smoke; some are at higher risk of experiencing adverse effects. People in the following groups should reduce their exposure to smoke:   

• Children 
• Seniors 
• Pregnant individuals 
• Those with lung disease (asthma or other chronic respiratory diseases) 
• Those with heart disease 
• Smokers 
• People experiencing homelessness. 
• Those who work outdoors

Keep an eye on your neighbours, family and friends, and people in your care who may be more susceptible to wildfire smoke. Encourage them to seek help if needed and give them tips to protect themselves. 

How can I protect myself and minimize the health effects of fire smoke?

  • Stay out of the smoke as much as possible.
  • If it looks smoky outside, it is best to stay indoors, with the windows closed, whenever possible. If the indoor temperature rises to an uncomfortable level, 
    opening the window may be necessary to avoid heat exhaustion. Ideally, use air conditioning, if it is available, or indoor fans to keep cool, and be sure to
    drink plenty of water to stay hydrated.
  • Reduce or avoid outdoor physical activity when possible.
  • If you have an air cleaner that will reduce levels of small particles in indoor air, use it and stay in the room where it is located, where possible.
  • Use air conditioning (on the recirculate setting) in cars and keep windows closed. Remember, vehicles should never be run in an enclosed space like a garage.
  • Avoid using smoke-producing appliances such as wood stoves and even candles.
  • Limit smoking tobacco as much as possible – smoking puts added stress on your lungs and on those around you.
  • If you have asthma or other respiratory conditions, be vigilant about avoiding smoke and take your prescribed medicine. Speak with your health care 
    provider to get the specific advice that is right for you.

Face masks for wildfire smoke

Women wearing N95 maskUsing a N95 or equivalent respirator can reduce your exposure outside to fine particles found in wildfire smoke. Proper fitting respirators prevent air from travelling through small gaps between the mask and your face. It is generally these fine particles that pose the most significant health risk. Respirators, however, do not minimize exposure to the gases in smoke from wildfires.  

This strategy may greatly benefit those at higher risk of experiencing adverse effects and those who spend extended periods in unhealthy air due to work or other circumstances.

A single-strap dust or surgical mask will not provide adequate protection from smoke. Respirators are not designed to fit children and won't protect them from wildfire smoke. 

Where can I learn more about local conditions? A lake with a tree line in the distance and smoke in the air


Air cleaners - Ideally the choice to purchase an air cleaner is made prior to a smoke emergency, as it may be difficult to access one during the event. High efficiency particulate air (HEPA) filter air cleaners that do not produce excess ozone can help reduce indoor particle levels. Their effectiveness will depend on if the unit is properly matched to the size of the indoor space. Types of units vary from single room to large central room air cleaners. Only portable room units that do not produce excess ozone should be used. See the following link from California Air Resources Board (CARB) that certify air cleaners that produce little to no ozone: California Certified Air Cleaning Devices

Air conditioners - Make sure to set your air conditioners (at home and in your car) to re-circulate indoor air rather than drawing outdoor air.  If the air temperatures become too hot, open your windows and doors.