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Air Quality Ontario

AQHI categories and health messages

Air Quality Health Index categories, values and associated colours
Air Quality Health Index categories and values
1
2
3
4
5
6
7
8
9
10
+
Low risk
(1 - 3)		 Moderate risk
(4 - 6)		 High risk
(7 - 10)		 Very high risk
 
The table below provides the health messages for each category of the Air Quality Health Index for the "at risk" population and the general population.
Health risk Air Quality Health Index Health messages
At risk population* General population
Low 1 - 3 Enjoy your usual outdoor activities. Ideal air quality for outdoor activities.
Moderate 4 - 6 Consider reducing or rescheduling strenuous activities outdoors if you are experiencing symptoms. No need to modify your usual outdoor activities unless you experience symptoms such as coughing and throat irritation.
High 7 - 10 Reduce or reschedule strenuous activities outdoors. Children and the elderly should also take it easy. Consider reducing or rescheduling strenuous activities outdoors if you experience symptoms such as coughing and throat irritation.
Very high Above 10 Avoid strenuous activities outdoors. Children and the elderly should also avoid outdoor physical exertion. Reduce or reschedule strenuous activities outdoors, especially if you experience symptoms such as coughing and throat irritation.

* People with heart or breathing problems are at greater risk. Follow your doctor's usual advice about exercising and managing your condition.

Health messages and advice during Air Quality Warnings

  1. Everyone’s health may be affected regardless of age or health status. Limit time outdoors and consider reducing, rescheduling, or cancelling outdoor sports, activities, and events.
  2. You may experience mild and common symptoms such as eye, nose and throat irritation, headaches or a mild cough. More serious, but less common symptoms include wheezing, chest pains or severe cough. If you think you are having a medical emergency, seek immediate medical assistance.
  3. People more likely to be impacted by outdoor air pollution, including people aged 65 and older, pregnant people, infants and young children, people with an existing illness or chronic health condition, and people who work outdoors should reduce or reschedule strenuous activities outdoors and seek medical attention if experiencing symptoms.
  4. When indoors, keep windows and doors closed as much as possible. When there is an extreme heat event occurring with poor air quality, prioritize keeping cool.
  5. Protect your indoor air from outdoor air pollution. Actions can include using the highest-quality air filter that your ventilation system can handle and/or a certified portable air cleaner.
  6. If you must spend time outdoors during a wildfire smoke event, limit the time as much as possible. A well-constructed, well-fitting and properly worn respirator type mask (such as a NIOSH-certified N95 or equivalent respirator) can reduce your exposure to the fine particles in the smoke. Even though exposure may be reduced, there can still be risks to health.
  7. Check in on others who are in your care or live nearby who may be more likely to be impacted by outdoor air pollution.
  8. Follow guidance from local authorities.