Wildfire smoke can affect everyone's health, even at low levels. As wildfires become more frequent and severe, it is important to be prepared and take steps to reduce exposure.
Wildfire smoke contains harmful air pollutants, including fine particulate matter (PM2.5) and gases. Smoke can travel hundreds of kilometres, affecting communities far from active wildfires. People in Ontario can be affected by wildfire smoke from across Canada and the United States. Air quality and visibility can change quickly and vary one area to another.
Ways to Stay Informed
Check the local forecast in your area for current conditions and alerts through the Weather Network or the WeatherCAN App.
Air Quality Warnings and What They Mean
The Air Quality Health Index (AQHI) is a tool developed by Environment and Climate Change Canada that helps people understand current and forecasted air quality conditions and take steps to protect their health during air pollution events, including wildfire smoke.
The AQHI uses a scale of 1 to 10+, with higher numbers indicating a greater health risk. It provides health guidance for both the public in general and people at risk from air pollution.
Ontario and Environment and Climate Change Canada use a colour-coded air quality warning system:
- Yellow Warning - Air Quality: Issued when the AQHI is forecast to reach the high-risk category (7 or higher).
- Orange Warning - Air Quality: Issued when the AQHI is forecast to reach, or has reached, the very high-risk category (10+).
Check the AQHI regularly during wildfire season to stay informed about local air quality conditions and health risks.
Health Effects and Symptoms of Wildfire Smoke
Exposure to wildfire smoke can irritate the eyes, nose and throat, and affect the lungs and heart. Pay attention to how you and those in your care feel.
Act right away if the following signs of illness appear.
Mild Symptoms include:
- Sore throat
- Eye irritation or watery eyes
- Runny nose and sinus irritation
- Mild cough
- Headaches
More serious symptoms include:
- Wheezing or asthma attacks
- Shortness of breath
- Severe cough
- Chest pain
- Heart palpitations
Seek medical attention if you experience serious symptoms. Call 911 if you think you are having a medical emergency, such as a heart attack or stroke.
It is normal to feel anxious, stressed, sad or isolated during a wildfire smoke event. If these feelings become difficult to manage, contact your health-care provider.
Who is at Greater Risk?
While wildfire smoke can affect anyone, some people are at greater risk of health problems, including:
- Infants and young children
- Pregnant people
- Older adults
- People with chronic health conditions, such as heart or lung disease, diabetes or cancer
- People who work, exercise or spend long periods outdoors
- People who smoke
Everyone responds differently to wildfire smoke. Pay attention to how you feel and reduce your exposure if smoke is causing symptoms. Check on family members, neighbours and others who may need support.
If you are at greater risk, speak with your health-care provider about managing your health during wildfire smoke events.
Protect Yourself from Wildfire Smoke
Before wildfire smoke affects your area:
- Know if you or your family members are at higher risk from smoke exposure.
- Keep an adequate supply of medications, food and water.
- Have replacement filters available for HVAC systems and portable HEPA air cleaners.
- Know where you can go for cleaner indoor air if needed.
- Check the AQHI for local air quality conditions and forecasts.
Reduce Your Exposure
When air quality is poor:
- Limit time outdoors and avoid strenuous physical activity.
- Consider wearing a well-fitted respirator, such as an N95 or equivalent, if you must be outside.
- Keep indoor air as clean as possible by:
- Using a portable HEPA air cleaner:
- Keeping windows and doors closed when temperatures are comfortable.
- Using high-efficiency air filters in your HVAC system.
- Setting your HVAC system to recirculate mode.
- Limiting sources of indoor air pollution, including:
- Smoking and vaping
- Burning candles or incense
- Using wood stoves
- Products that release strong fumes or volatile organic compounds (VOCs)
- Take breaks from the smoke in public buildings with cleaner indoor air, such as libraries and community centres.
- When driving, keep windows closed and use the recirculate setting on your vehicle's ventilation system.
- If wildfire smoke is causing symptoms, move to a location with cleaner air and follow advice from your health-care provider.
For most people, exposure to heat is a bigger risk to health than exposure to wildfire smoke. If you cannot get cool inside, seek cooler spaces in your community or go outside, even if there is wildfire smoke. This is safer than staying in indoor environments that are too hot.
Air Quality, Extreme Heat and Emergencies
Wildfire smoke can happen at the same time as extreme heat events or emergencies so it is important to be prepared. To help you prepare for and stay safe during extreme heat events and other public health threats.
Controlled Burns in Simcoe County Forests
A controlled burn is a planned fire that trained workers set on purpose. It is different from a wildfire because:
- It happens only in a designated area.
- Experts always watch it closely.
- It is carried out only when the weather and the site conditions are safe.
Some people may be more sensitive to smoke, including children, older adults, and anyone with breathing problems such as asthma or lung disease.
To help reduce smoke exposure:
- Consider staying indoors during the burn.
- If you have a health condition, follow your health-care provider's advice.
- Limit outdoor activities, if see or smell smoke.
- Keep windows and doors closed to prevent smoke from entering our home or workplace.
If you have questions or concerns about a controlled burn in Simcoe County, you can visit their website or call their Forestry Department at 1-800-263-3199.
Additional Resources
Health Canada - Wildfire smoke, air quality and your health: Overview
Environment and Climate Change Canada - Weather Alerts for Canada and WeatherCAN
FireSmoke Canada - A wildfire smoke forecast map and tool.
Updated July 15, 2026
