Air quality alert issued for Mississauga, Brampton and Caledon

Residents across Mississauga, Brampton and Caledon are being warned to take precautions as wildfire smoke from forest fires burning in Northwestern Ontario pushes into the region, prompting an Orange Air Quality Alert from Peel Public Health.

The alert, issued Wednesday, July 15, means the Air Quality Health Index (AQHI) is expected to reach — or has already reached — the very high risk category, with a reading of 10 or higher.

But what does that actually mean?

The AQHI is a scale developed by Environment and Climate Change Canada that measures how air pollution can affect human health. Rather than simply measuring how much pollution is in the air, the index estimates the health risk people may experience from breathing that air.

The scale runs from 1 to 10+:

• 1 to 3 — Low risk: Enjoy outdoor activities as usual.
• 4 to 6 — Moderate risk: At-risk individuals should consider reducing prolonged outdoor exertion.
• 7 to 10 — High risk: People at greater risk should reduce or reschedule strenuous outdoor activities.
• 10+ — Very high risk: Everyone should consider reducing exposure, especially during strenuous outdoor activities.

An Orange Air Quality Alert is the highest warning level issued under Ontario’s air quality alert program.

The program uses two warning categories:

• Yellow Air Quality Warning: Issued when the AQHI is forecast to reach the high-risk category (7 or higher).
• Orange Air Quality Warning: Issued when the AQHI is forecast to reach, or has reached, the very high-risk category (10+).

Peel’s Medical Officer of Health issues Orange warnings when Environment and Climate Change Canada forecasts very poor air quality conditions, including during wildfire smoke events.

Why wildfire smoke is a health concern

Wildfire smoke contains fine particles that can travel deep into the lungs and enter the bloodstream. Even people who are normally healthy can experience symptoms when smoke levels are elevated.

Health effects can include:

• Eye, nose and throat irritation
• Headaches
• Runny nose
• Coughing
• Wheezing, including asthma attacks
• Dizziness
• Difficulty breathing
• Chest pain

Peel Public Health says wildfire smoke can affect everyone, even when concentrations are relatively low.

However, some residents face a higher risk of experiencing health effects, including:

• People with respiratory or heart conditions
• Older adults
• Infants and young children
• Pregnant people
• Indigenous Peoples
• People who work outdoors

What residents should do during an Orange alert

Public health officials recommend residents adjust their activities based on their own health needs and check air quality levels regularly.

People at higher risk should:

• Avoid or reschedule strenuous outdoor activities whenever possible.
• Limit time outdoors when smoke levels are elevated.
• Monitor the AQHI throughout the day at Air Quality Ontario AQHI updates.

Residents can also reduce their exposure indoors by:

• Keeping windows and doors closed if indoor temperatures are comfortable and below 26 C.
• Using community spaces such as libraries or recreation centres that offer clean, cool air.
• Avoiding activities that add indoor pollution, including smoking or vaping, burning candles or incense, frying foods, using wood stoves and vacuuming.
• Ensuring heating, ventilation and air conditioning filters are clean and using the highest-rated filter appropriate for the system.

Health officials note that if a heat event occurs at the same time as poor air quality, residents should prioritize staying cool. Closing windows to keep out smoke may not be advisable if it creates unsafe indoor temperatures.

The Orange Air Quality Alert remains in place while conditions are expected to pose a very high health risk. Residents are encouraged to check forecasts regularly as wildfire smoke conditions can change quickly depending on wind direction and fire activity.