Wildfire Smoke

Wildfire Smoke Response Strategy

The TPH Wildfire Smoke Response Strategy is TPH’s protocol for responding to deteriorations in air quality due to wildfire smoke. Updated for 2025, this strategy incorporates lessons learned from 2023 and 2024, provincial guidance, and expertise from TPH’s internal Air Quality Response Committee. This committee was established following the Toronto Board of Health’s directive to annually review and update the strategy as needed.

Environmental health, including exposure to air pollution, is one of the nine key indicators identified in TPH’s 2023 Population Health Profile. Climate change is recognized as a significant risk to environmental health, with increasing trends of extreme heat, prolonged heat waves, more frequent extreme weather events, and more wildfires impacting Toronto and Ontario. On a global scale, wildfires pose a growing concern, with smoke affecting air quality, ecosystems, communities, and public health well beyond the fire’s immediate vicinity.

Responding to Wildfire Smoke:

• Responses are activated when a Special Air Quality Statement (SAQS) or Air Quality Warning (AQW) is issued when wildfire smoke is impacting air quality in Toronto.
• Guidance to the public at each level is derived from the AQHI Health Messages developed by Environment & Climate Change Canada (ECCC).
• Monitoring Activities: TPH activities align with peak wildfire season, as defined by ECCC, from May through September.

Wildfire Smoke Response Plan Activation Grid

Air Quality Statement and Advisory Status	Response Level
No smoke event SAQS or AQW issued	Monitoring
Wildfire smoke event SAQS issued	Wildfire smoke response activation
Wildfire smoke event AQW issued and expected to last more than one day (regardless of SAQS issuance)	Wildfire smoke response enhancement

Monitoring

No smoke event SAQS or AQW issued

	Guidance to the Public and Key TPH Actions
Guidance for those who are at-risk	Enjoy outdoor activities and no need to modify behaviours.
Guidance for general population
Toronto Public Health Key Actions	Monitor for potential deterioration of air quality.

 

Wildfire Smoke Response Strategy Activated and Enhanced Response Levels

Guidance to the Public and Key TPH Actions

	Activated	Enhanced
Guidance for those who are at-risk	Reduce or reschedule strenuous activities outdoors. Seniors, pregnant people, infants, young children, people who work outdoors, people involved in strenuous exercise outdoors, and people with existing chronic health conditions should take it easy.	Avoid strenuous activities outdoors. Children, the elderly, pregnant individuals, and those with existing chronic health conditions should also avoid outdoor physical exertion.
Guidance for general population	Consider reducing or rescheduling strenuous activities outdoors if you experience symptoms such as coughing or throat irritation.	Reduce or reschedule strenuous activities outdoors, especially if you experience symptoms such as coughing and throat irritation. Consider reducing outdoor activities where possible.
Guidance for everyone	Monitor the AQHI for deteriorating conditions when planning outdoor activities and events. Protect your home from outdoor air pollution through running HVAC systems, changing filters according to manufacturer’s instructions and keeping windows and doors closed. Eliminate sources of indoor air pollution, such as tobacco smoke, candle smoke, and indoor grilling, and the use of chemical-based products that can affect indoor air quality, like toxic paint, finishers, and glues. Reduce energy use and avoid vehicular and industrial emissions as much as you can to limit exposure. For those who must be outside, a well-fitted and properly worn respirator such as the N95 mask can reduce smoke inhalation risks, but needs to be used carefully, with consideration that: The mask must form a tight seal to work properly. The mask can protect against particles but not gases found in smoke. Masking will not protect eyes. During extreme heat events, wearing a mask may add to heat stress in some people. Prioritize staying cool. Some individuals may find it difficult to tolerate mask use, particularly individuals with underlying respiratory, cardiac or other health conditions. Listen to your body. If you need to remove your respirator mask, try to move to an area with cleaner air before removing it.
Toronto Public Health Key Actions	Monitor for changes in air quality and SAQS status and the potential escalate or de-escalate to the appropriate activation level. Liaise and coordinate with stakeholders and the provincial government (e.g. MECP, Ministry of Health, Public Health Ontario). Amplify ECCC or MECP webpages and statements and provide public health guidance to the public. Monitor for health system impacts.	Monitor changes in air quality and AQA status to identify potential to de-escalate to the appropriate response level. Participate in a City-wide emergency response if requested. Liaise and coordinate with the Board of Health, City Councillors, other City Divisions, stakeholders, and the provincial government (e.g. MECP, Ministry of Health, Public Health Ontario). Amplify ECCC or MECP webpages and statements and provide public health guidance to the public. Promote the Cleaner Air Spaces Network. Monitor for health system impacts.

 

Health Impacts of Wildfire Smoke

Wildfire smoke is a complex mixture of particulate matter, gases including carbon monoxide (CO), carbon dioxide (CO₂₎, Nitrogen Oxides (NO_x), polycyclic aromatic hydrocarbons (PAHs), and volatile organic compounds (VOCs). The particulate matter in wildfire smoke, particularly those particles less than 10 microns in size (PM₁₀), can irritate the eyes and upper respiratory tract. Particles smaller than 2.5 microns in size (PM_2.5) can penetrate deep into the lungs and are associated with various adverse health effects.. PM_2.5 can constitute up to 90% of the total particle mass of wildfire smoke.

Commonly Health Symptoms from Smoke Exposure:

Mild symptoms:

• Sore throat 
• Eye irritation 
• Runny nose 
• Cough 
• Headaches

More severe symptoms:

• Wheezy breathing 
• Difficulty breathing
• Chest pain
• Dizziness
• Heart palpitations

Chronic Health Effects

Exposure to wildfire smoke can exacerbate existing respiratory and cardiovascular diseases, including: 

• Asthma
• Chronic obstructive pulmonary disease (COPD)
• Congestive heart failure

In addition to physical effects, wildfire smoke exposure can also worsen mental health such as:

• Anxiety
• Depression
• Post-traumatic stress disorder
• General distress caused by natural disasters and climate change

High-Risk Groups

The Ontario Ministry of Health identifies several groups at higher risk for the negative health effects of wildfire smoke:

• Seniors
• Indigenous people
• People who smoke
• Infants and young children
• People living in rural and remote areas
• Pregnant people
• People involved in strenuous outdoor exercise
• People who work outdoors
• People living in situations of lower socio-economic status such as those with lower income, lower education, those experiencing housing insecurity, and those experiencing uncertain employment
• People with an existing illness or chronic health condition such as cancer, diabetes, or lung or heart conditions

Air Quality Alert Notifications

• SAQS are issued when the AQHI is forecast and/or has the potential to reach the high-risk category (AQHI between 7 and 10).
• AQW are issued for extreme wildfire smoke events where the AQHI is forecast or has reached 10+.
• Termination Notices are issued when the SAQS or AQW has ended due to improved air quality.

ECCC is the lead for issuing and terminating SAQS and AQW in Ontario through the Ontario Storm Prediction Centre.

The Air Quality Health Index (AQHI) helps the public make decisions to protect their health from air pollution. It measures air quality on a scale from 1 to 10+, where higher numbers indicate greater health risks. The AQHI provides guidance for both the general population and at-risk populations.

• Components: The AQHI is calculated using concentrations of ozone (O₃), nitrogen dioxide (NO₂), and particulate matter (PM_2.5).
• Purpose: It informs sensitive populations and the general population about the health impacts of air quality.
• Forecasting: ECCC provides observed conditions and forecast maximums for the AQHI.

Air Quality Monitoring in Toronto

Toronto has four air monitoring stations. ECCC averages the measurements from these stations to produce the AQHI for the city.

Protect Yourself from Wildfire Smoke

Reducing exposure to air pollution, including wildfire smoke, is the best way to protect your health. Consider the following actions during wildfire smoke events:

• Stay Informed: Monitor the AQHI and download the WeatherCAN app for air quality alerts.
• Limit Outdoor Activities: Pay attention to the AQHI and limit outdoor and strenuous physical activities as needed. If you feel unwell or have difficulty breathing, stop activities immediately.
• Prepare a Care Plan: Have a plan in place if heat, breathing, or other symptoms are aggravated by air pollution and smoke.
• Protect your indoor air:
  • Keep windows and doors closed, use air conditioning in warm weather.
  • Set your heating, ventilation, and air conditioning (HVAC) systems to recirculate indoor air during poor outdoor air quality periods.
  • Use high-quality air filters in forced air systems based on manufacturers’ recommendations.
  • Reduce or eliminate indoor air pollutants such as tobacco smoke, incense, candle smoke, indoor grilling, and chemical-based products.
  • Consider portable air purifiers if you don’t have a forced air system. DIY options include the Corsi-Rosenthal box.
  • DIY Resources:
    • BCCDC: Do it Yourself Air Cleaner
    • Do it Yourself Ecology: Breathe Better by Easily Making a Clean Air Fan
    • Box Fan Filter: A Do it Yourself User Guide
    • Making a Corsi-Rosenthal box (Do it Yourself Air Cleaner)
• Stay Cool During Heat Events: If it’s hot outside and you don’t have air conditioning, prioritize cooling when air quality is poor. Seek cooler, cleaner air if needed.
• Use Respirators Outdoors: A well-fitted respirator type mask (such as a NIOSH certified N95 or equivalent respirator) that does not allow air to pass through small openings between the mask and face, may help reduce exposure to fine particles but not gases in smoke.
  • Avoid use by children under 2 years, individuals with breathing difficulties, or those who struggle to remove the respirator.
• Stay hydrated: Drink plenty of liquids, especially water, before feeling thirsty to decrease the risk of dehydration.
• If you are unable to maintain cool, clean air at home, consider visiting a participating location in the Cleaner Air Spaces Network to get a break from the smoke or the heat and smoke.

Cleaner Air Spaces Network

Launched in 2024, the Cleaner Air Spaces Network provides places to go for people who face barriers accessing cleaner air and air filtration at home.

Participating locations operate as Cleaner Air Spaces during their regular operating hours and are equipped with MERV13 filtration systems. Cleaner Air Spaces include Toronto’s Civic Centres in Scarborough, North York, East York, and York, Metro Hall, and Toronto City Hall downtown. Residents may consider visiting these sites if they are experiencing symptoms when air quality is poor due to wildfire smoke and/or are having difficulty accessing clean air.

Cleaner Air Spaces

The Cleaner Air Spaces locations and hours of operations are:

• City Hall – 100 Queen St. W.
  • Monday to Friday: 8:00 a.m. to 8:00 p.m.
  • Saturday: 10:00 a.m. to 6:00 p.m.
  • Sunday and Holidays: 8 a.m. to 6 p.m.
• Metro Hall – 55 John St.
  • Monday to Friday: 8:00 a.m. to 6:00 p.m.
  • Saturday, Sunday and Holidays: Closed
• East York Civic Centre – 850 Coxwell Ave.
  • Monday to Friday: 8:00 a.m. to 6:00 p.m.
  • Saturday: 10 a.m. to 6 p.m.
  • Sunday and Holidays: Closed
• North York Civic Centre – 5100 Yonge St.
  • Monday to Friday: 7:30 a.m. to 9:30 p.m.
  • Saturday, Sunday and Holidays: 8 a.m. to 6 p.m.
• Scarborough Civic Centre – 150 Borough Dr.
  • Monday to Friday: 8:00 a.m. to 6:00 p.m.
  • Saturday: 10 a.m. to 6 p.m.
  • Sunday and Holidays: Closed
• York Civic Centre – 2700 Eglinton Ave. W.
  • Monday to Friday: 8:00 a.m. to 6:00 p.m.
  • Saturday, Sunday and Holidays: Closed

Pre-season Preparedness Plan

TPH will monitor, evaluate, and update the Wildfire Smoke Response Strategy on an annual basis or as needed.

Prior to the wildfire season, TPH will identify and review changes to respond to wildfire smoke by:

• Scanning other jurisdictions’ wildfire smoke responses
• Reviewing scientific research
• Evaluating the previous year’s response plan
• Engaging with key stakeholders