Pollutant concentrations for May 21, 2026, 1:00 am EDT

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Pollutant concentrations for May 21, 2026, 1:00 am EDT
Station O3 (ppb) PM2.5 (µg/m3) NO2 (ppb) SO2 (ppb) CO (ppm)
Barrie 25Barrie graph for O3 1Barrie graph for PM2.5 0.7Barrie graph for NO2    
Belleville 16Belleville graph for O3 2Belleville graph for PM2.5 2Belleville graph for NO2    
Brampton 20Brampton graph for O3 1Brampton graph for PM2.5 1.7Brampton graph for NO2    
Brantford 26Brantford graph for O3 7Brantford graph for PM2.5 3Brantford graph for NO2    
Burlington 24Burlington graph for O3 1Burlington graph for PM2.5 4.5Burlington graph for NO2    
Chatham 27Chatham graph for O3 0Chatham graph for PM2.5 2Chatham graph for NO2    
Cornwall 34Cornwall graph for O3 3Cornwall graph for PM2.5 0.4Cornwall graph for NO2    
Dorset 19Dorset graph for O3 1Dorset graph for PM2.5      
Grand Bend 40Grand Bend graph for O3 1Grand Bend graph for PM2.5 0.9Grand Bend graph for NO2    
Guelph 20Guelph graph for O3 1Guelph graph for PM2.5 1.8Guelph graph for NO2    
Hamilton Downtown 23Hamilton Downtown graph for O3 1Hamilton Downtown graph for PM2.5 3.7Hamilton Downtown graph for NO2 0Hamilton Downtown graph for SO2 0.12Hamilton Downtown graph for CO
Hamilton Mountain 25Hamilton Mountain graph for O3 1Hamilton Mountain graph for PM2.5 3.3Hamilton Mountain graph for NO2 0Hamilton Mountain graph for SO2  
Hamilton West 25Hamilton West graph for O3 2Hamilton West graph for PM2.5 2.9Hamilton West graph for NO2    
Kingston 30Kingston graph for O3 1Kingston graph for PM2.5 1.4Kingston graph for NO2    
Kitchener 22Kitchener graph for O3 2Kitchener graph for PM2.5 2.7Kitchener graph for NO2    
London 25London graph for O3 3London graph for PM2.5 4London graph for NO2    
Milton 22Milton graph for O3 1Milton graph for PM2.5 1Milton graph for NO2 0.2Milton graph for SO2  
Mississauga 17Mississauga graph for O3 2Mississauga graph for PM2.5 5.1Mississauga graph for NO2    
Newmarket 25Newmarket graph for O3 1Newmarket graph for PM2.5 1.2Newmarket graph for NO2    
North Bay N/ANorth Bay graph for O3 N/ANorth Bay graph for PM2.5 N/ANorth Bay graph for NO2    
Oakville 20Oakville graph for O3 1Oakville graph for PM2.5 2.2Oakville graph for NO2    
Oshawa 19Oshawa graph for O3 1Oshawa graph for PM2.5 0.7Oshawa graph for NO2    
Ottawa Downtown 33Ottawa Downtown graph for O3 2Ottawa Downtown graph for PM2.5 1.3Ottawa Downtown graph for NO2    
Parry Sound 25Parry Sound graph for O3 1Parry Sound graph for PM2.5 2.1Parry Sound graph for NO2    
Peterborough 19Peterborough graph for O3 1Peterborough graph for PM2.5 0.4Peterborough graph for NO2    
Port Stanley 31Port Stanley graph for O3 2Port Stanley graph for PM2.5 3.7Port Stanley graph for NO2    
Sarnia 39Sarnia graph for O3 1Sarnia graph for PM2.5 1Sarnia graph for NO2 0Sarnia graph for SO2  
Sault Ste. Marie 28Sault Ste. Marie graph for O3 1Sault Ste. Marie graph for PM2.5 1.3Sault Ste. Marie graph for NO2 0Sault Ste. Marie graph for SO2  
St. Catharines 19St. Catharines graph for O3 1St. Catharines graph for PM2.5 3.7St. Catharines graph for NO2    
Sudbury 32Sudbury graph for O3 1Sudbury graph for PM2.5 1.1Sudbury graph for NO2 0Sudbury graph for SO2  
Thunder Bay 17Thunder Bay graph for O3 4Thunder Bay graph for PM2.5 9.7Thunder Bay graph for NO2    
Tiverton 38Tiverton graph for O3 1Tiverton graph for PM2.5      
Toronto Downtown 23Toronto Downtown graph for O3 3Toronto Downtown graph for PM2.5 2.5Toronto Downtown graph for NO2    
Toronto East 22Toronto East graph for O3 1Toronto East graph for PM2.5 2.2Toronto East graph for NO2    
Toronto North 23Toronto North graph for O3 1Toronto North graph for PM2.5 1.6Toronto North graph for NO2 0Toronto North graph for SO2  
Toronto West 20Toronto West graph for O3 1Toronto West graph for PM2.5 4.5Toronto West graph for NO2 0Toronto West graph for SO2 0.12Toronto West graph for CO
Windsor Downtown 36Windsor Downtown graph for O3 1Windsor Downtown graph for PM2.5 3.7Windsor Downtown graph for NO2 0.4Windsor Downtown graph for SO2 0.12Windsor Downtown graph for CO
Windsor West 35Windsor West graph for O3 1Windsor West graph for PM2.5 3.7Windsor West graph for NO2 0.4Windsor West graph for SO2  

Order by station location (east to west)

Note: 
Ontario 1-hour AAQC for O3 = 80 ppb
Ontario 1-hour AAQC for NO2 = 200 ppb
Ontario 1-hour AAQC for SO2 = 40 ppb
Ontario 1-hour AAQC for CO = 30 ppm

Note: The pollutant concentrations on this web page are based on automatically polled data and have not undergone final verification.

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