Ontario - Air Quality Health Index - Summary

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Forecast Regions

This table is a summary of air quality health messages by category
Health Risk	Air Quality Health Index	Health Messages
Health Risk	Air Quality Health Index	At Risk Population*	General Population
Low Risk	1-3	Enjoy your usual outdoor activities.	Ideal air quality for outdoor activities.
Moderate Risk	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 Risk	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 Risk	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.

This table shows a summary of current Air Quality Health Index values and forecast maximums¹
Location and sub-locations	Observed Conditions	Forecast Maximums
Location and sub-locations	Observed Conditions	Tuesday	Tuesday night	Wednesday	Wednesday night
Barrie	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Belleville	3 Low Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Brampton	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Brantford	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Burlington	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Chatham	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Cornwall	2 Low Risk	4 Moderate Risk	3 Low Risk	2 Low Risk	2 Low Risk
Dorset	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Grand Bend	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Guelph	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Hamilton	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Hamilton Downtown	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Hamilton Mountain	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Hamilton West	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Kingston	2 Low Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Kitchener	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
London	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Milton	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Mississauga	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Newmarket	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
North Bay	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Oakville	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Oshawa	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Ottawa	3 Low Risk	4 Moderate Risk	3 Low Risk	2 Low Risk	2 Low Risk
Parry Sound	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Peterborough	2 Low Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Port Stanley	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Sarnia	5 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Sault Ste. Marie	3 Low Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
St. Catharines	3 Low Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Sudbury	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Thunder Bay	2 Low Risk	3 Low Risk	4 Moderate Risk	4 Moderate Risk	3 Low Risk
Tiverton	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Toronto	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Toronto Downtown	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Toronto East	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Toronto North	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Toronto West	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Windsor	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Windsor Downtown	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk
Windsor West	4 Moderate Risk	4 Moderate Risk	3 Low Risk	3 Low Risk	3 Low Risk

1. Forecast issued at: 6:00 AM EDT Tuesday 21 July 2026

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