Monitoring air quality

To support the Air Quality Health Index (AQHI), the Ministry monitors up to 6 common pollutants at each of the 38 stations across the provincial AQHI network, including:

Ontario Air Quality Health Index (AQHI) monitoring network

Pollutants are monitored at each station.
CITY/TOWN	O₃	PM_2.5	NO₂	SO₂	CO	TRS
Barrie	X	X	X	-	-	-
Belleville	X	X	X	-	-	-
Brampton	X	X	X	-	-	-
Brantford	X	X	X	-	-	-
Burlington	X	X	X	-	-	-
Chatham	X	X	X	-	-	-
Cornwall	X	X	X	-	-	-
Dorset	X	X	-	-	-	-
Grand Bend	X	X	X	-	-	-
Guelph	X	X	X	-	-	-
Hamilton Downtown	X	X	X	X	X	X
Hamilton Mountain	X	X	X	X	-	-
Hamilton West	X	X	X	-	-	-
Kingston	X	X	X	-	-	-
Kitchener	X	X	X	-	-	-
London	X	X	X	-	-	-
Milton	X	X	X	X	-	-
Mississauga	X	X	X	-	-	-
Newmarket	X	X	X	-	-	-
North Bay	X	X	X	-	-	-
Oakville	X	X	X	-	-	-
Oshawa	X	X	X	-	-	-
Ottawa Downtown	X	X	X	-	-	-
Parry Sound	X	X	X	-	-	-
Peterborough	X	X	X	-	-	-
Port Stanley	X	X	X	-	-	-
Sarnia	X	X	X	X	-	X
Sault Ste. Marie	X	X	X	X	-	-
St. Catharines	X	X	X	-	-	-
Sudbury	X	X	X	X	-	-
Thunder Bay	X	X	X	-	-	-
Tiverton	X	X	-	-	-	-
Toronto Downtown	X	X	X	-	-	-
Toronto East	X	X	X	-	-	-
Toronto North	X	X	X	X	X	-
Toronto West	X	X	X	X	X	-
Windsor Downtown	X	X	X	X	X	-
Windsor West	X	X	X	X	-	X

For current AQHI information, please visit Air Quality Ontario, Environment and Climate Change Canada, or call the AQHI Reporting System line at: 416-246-0411 in the Toronto area or toll-free at 1-800-387-7768.