Outdoor Air Quality

The Air Quality Health Index (AQHI) is a tool to help people understand how the quality of the air can affect their health.

The AQHI provides real-time measurement of air-pollution levels for York Region and recommendations on how people can limit their exposure and adjust their activity level during times of high air pollution.

The AQHI is especially helpful to those who are at-risk or sensitive to air pollution and provides them with suggestions on how they can protect their health when poor air quality levels may pose low, moderate, high and very high health risks.

What does the Air Quality Health Index measure?

The AQHI measures three common air pollutants known to impact human health:

• Ground level ozone (O₃)
• Fine particulate matter (PM_2.5)
• Nitrogen dioxide (NO₂)

How does the AQHI work?

The AQHI uses a number scale from one to 10+ to communicate the level of risk associated with the local air quality. The higher the number is, the higher the health risk and the greater the need for people to take precautions.

The AQHI also provides health messaging tailored towards both high risk individuals and the general public and provides recommendations on how people can improve the quality of the air they breathe.

Air Quality Health Index categories

1 to 3 = ‘Low’ health risk
4 to 6 = ‘Moderate’ health risk
7 to 10 = ‘High’ health risk
Above 10 = ‘Very high’ health risk

How often should I check the AQHI?

You can check the Air Quality Health Index daily to receive real-time air quality levels and forecasts to help plan your outdoor activities.

Sign up for air quality alerts by visiting airqualityontario.com and check out the national AQHI website to learn more about this important tool. You can also get AQHI readings by calling 1-800-387-7768 (toll-free) or 416-246-0411 in Toronto. To obtain AQHI readings in French, dial 1-800-221-8852.

Download the Environment and Climate Change Canada (ECCC) WeatherCAN app on your phone and check the AQHI before your next outdoor activity. WeatherCAN is available for Android and Apple Devices.

What do the Numbers Mean?

Health Risk	Air Quality Health Index	Health Messages for At Risk Population	Health Messages for General Population
Low Risk	1-3	Enjoy your usual outdoor activities.	Ideal air quality for outdoor activities.
Moderate Risk	4-6	Consider reducing or re-scheduling outdoor activities, if you experience symptoms.	No need to modify your usual outdoor activities unless you experience symptoms such as coughing and throat irritation.
High Risk	7-10	Reduce or re-schedule outdoor activities. Children and the elderly should also take it easy.	Consider reducing or re-scheduling strenuous activities outdoors if you experience symptoms such as coughing and throat irritation.
Very High Risk	10+	Avoid outdoor activities. Children and the elderly should also avoid outdoor physical exertion.	Reduce or re-schedule strenuous activities outdoors, especially if you experience symptoms such as coughing and throat irritation.

Air Quality Health Index Videos

• When you’re active outdoors
• Air Quality and Young Children
• Air Quality and Senior Canadians

Environment and Climate Change Canada and the Ontario Ministry of Environment, Conservation and Parks (MECP) jointly issue two types of air quality alerts when Air Quality Health Index levels are expected to be high:

• Special Air Quality Statements (SAQS) are issued when high risk AQHI is forecasted to last for one to two hours
• Smog and Health Advisories (SAHA) are issued when high risk AQHI is forecasted to be persistent, for at least three hours or longer

The purpose of the air quality alerts is to advise people when they should take precautions to avoid unnecessary exposure to air pollution. They also help guide industries and the public on what steps they can take to reduce their emissions.

To sign up for emails when an air quality alert (Special Air Quality Statement or Smog and Air Health Advisory) is issued, visit: airqualityontario.com/alerts/signup.php

What You Need to Know

• Wildfire smoke is made up of a mixture of gases and very small particles that are produced when wood and other organic matter burn and may lead to poor air quality. The plume from wildfire smoke is influenced by many factors including weather conditions. It can change over short distances and can vary from hour to hour.
• The small particles in wildfire smoke can be harmful to everyone’s health even at low levels. Wildfire exposure symptoms can range from milder symptoms like headaches, nose and throat irritation to more serious symptoms like shortness of breath, wheezing, severe cough, dizziness or chest pain.
• Children, seniors, pregnant women, people who work outdoors and those who have underlying medical conditions, such as heart or lung disease, are at a higher risk to the health effects caused by wildfire smoke. If you have any serious symptoms, talk to a healthcare professional or seek urgent medical attention. For any health-related concerns about smoke, please call Ontario Health at 811 or 1-866-797-0007. Residents with asthma or other chronic illness should activate their asthma or personal care plan.
• Residents are encouraged to check in on people in your care and those around you who may be more at risk of negative effects from outdoor air pollution.
• Pay attention to local air quality reports; air quality may be poor even though smoke may not be visible. Air Quality Health Index levels and forecasts are posted at airhealth.ca - readings are updated hourly and forecasts are updated twice a day.
• During wildfire smoke events and poor air quality episodes, York Region Public Health (YRPH) monitors the wildfire smoke conditions, the Air Quality Health Index and Air Alert notifications (e.g., Special Air Quality Statements) from Environment and Climate Change Canada and the Ontario Ministry of Environment, Conservation and Parks.

To protect your health from wildfire smoke, consider the following:

• Limiting or rescheduling strenuous outdoor activities if experiencing symptoms such as coughing and throat irritation.
• Drinking plenty of cool liquids, especially water, decreases your risk of dehydration and helps your body cope with the smoke.
• Prevent wildfire smoke from entering your home by keeping doors, windows and fire dampers closed as a precaution if the temperature in your home is comfortable.
• Use exhaust fans only when needed and minimize activities that generate pollutants in your home like cooking, smoking, and the use of candles or strong cleaning products.
• If you have an HVAC system in your home, consider installing high quality air filters and setting the fan to recirculate the air.
• Consider purchasing a portable air purifier with a HEPA (high efficiency particulate air) filter that is suitable for the size of the room.
• If you must spend time outdoors, consider wearing a well-fitted mask like an N95 respirator that does not allow air to pass through small openings between the mask and your face. Be sure to practice proper hand hygiene when putting on and removing a mask, either by washing hands with soap and water or using an alcohol-based hand rub.
• If you don’t have air conditioning, consider taking a break from the smoke by temporarily relocating or finding a place in your community with clean, cool air such as a library, shopping mall or community centre.
• When in your car and driving through areas with poor air quality, consider keeping the windows closed and recirculating the air.