Pollutant concentrations for
October 25, 2025, 11:00 am EDT

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Pollutant concentrations for
October 25, 2025, 11:00 am EDT October 25, 2025, 11:00 am EDT
Station O3 (ppb) PM2.5 (µg/m3) NO2 (ppb) SO2 (ppb) CO (ppm)
Barrie 16Barrie graph for O3 5Barrie graph for PM2.5 3.2Barrie graph for NO2    
Belleville 16Belleville graph for O3 3Belleville graph for PM2.5 2.8Belleville graph for NO2    
Brampton 22Brampton graph for O3 1Brampton graph for PM2.5 2.5Brampton graph for NO2    
Brantford 21Brantford graph for O3 11Brantford graph for PM2.5 2.4Brantford graph for NO2    
Burlington 13Burlington graph for O3 4Burlington graph for PM2.5 6.7Burlington graph for NO2    
Chatham 21Chatham graph for O3 3Chatham graph for PM2.5 4.5Chatham graph for NO2    
Cornwall 15Cornwall graph for O3 2Cornwall graph for PM2.5 1.1Cornwall graph for NO2    
Dorset 12Dorset graph for O3 3Dorset graph for PM2.5      
Grand Bend 26Grand Bend graph for O3 1Grand Bend graph for PM2.5 0.1Grand Bend graph for NO2    
Guelph 18Guelph graph for O3 3Guelph graph for PM2.5 1.3Guelph graph for NO2    
Hamilton Downtown 12Hamilton Downtown graph for O3 4Hamilton Downtown graph for PM2.5 4.8Hamilton Downtown graph for NO2 0.3Hamilton Downtown graph for SO2 0.17Hamilton Downtown graph for CO
Hamilton Mountain 14Hamilton Mountain graph for O3 3Hamilton Mountain graph for PM2.5 2.5Hamilton Mountain graph for NO2 0Hamilton Mountain graph for SO2  
Hamilton West 13Hamilton West graph for O3 4Hamilton West graph for PM2.5 4.2Hamilton West graph for NO2    
Kingston 17Kingston graph for O3 2Kingston graph for PM2.5 3.1Kingston graph for NO2    
Kitchener 22Kitchener graph for O3 2Kitchener graph for PM2.5 1.5Kitchener graph for NO2    
London 15London graph for O3 4London graph for PM2.5 8.7London graph for NO2    
Milton 19Milton graph for O3 3Milton graph for PM2.5 4.2Milton graph for NO2 0.2Milton graph for SO2  
Mississauga 19Mississauga graph for O3 2Mississauga graph for PM2.5 5Mississauga graph for NO2    
Newmarket 21Newmarket graph for O3 1Newmarket graph for PM2.5 1.7Newmarket graph for NO2    
North Bay 13North Bay graph for O3 3North Bay graph for PM2.5 0.6North Bay graph for NO2    
Oakville 18Oakville graph for O3 3Oakville graph for PM2.5 3.9Oakville graph for NO2    
Oshawa 19Oshawa graph for O3 2Oshawa graph for PM2.5 2.8Oshawa graph for NO2    
Ottawa Downtown 15Ottawa Downtown graph for O3 2Ottawa Downtown graph for PM2.5 2.1Ottawa Downtown graph for NO2    
Parry Sound 13Parry Sound graph for O3 2Parry Sound graph for PM2.5 0.9Parry Sound graph for NO2    
Peterborough 11Peterborough graph for O3 3Peterborough graph for PM2.5 3.6Peterborough graph for NO2    
Port Stanley 14Port Stanley graph for O3 3Port Stanley graph for PM2.5 3.6Port Stanley graph for NO2    
Sarnia 20Sarnia graph for O3 2Sarnia graph for PM2.5 1.9Sarnia graph for NO2 0.2Sarnia graph for SO2  
Sault Ste. Marie 12Sault Ste. Marie graph for O3 2Sault Ste. Marie graph for PM2.5 1Sault Ste. Marie graph for NO2 0.1Sault Ste. Marie graph for SO2  
St. Catharines 19St. Catharines graph for O3 3St. Catharines graph for PM2.5 3.9St. Catharines graph for NO2    
Sudbury 20Sudbury graph for O3 1Sudbury graph for PM2.5 0Sudbury graph for NO2 0Sudbury graph for SO2  
Thunder Bay 4Thunder Bay graph for O3 5Thunder Bay graph for PM2.5 5.7Thunder Bay graph for NO2    
Tiverton 24Tiverton graph for O3 1Tiverton graph for PM2.5      
Toronto Downtown 3Toronto Downtown graph for O3 10Toronto Downtown graph for PM2.5 24.6Toronto Downtown graph for NO2    
Toronto East 13Toronto East graph for O3 3Toronto East graph for PM2.5 17.1Toronto East graph for NO2    
Toronto North 18Toronto North graph for O3 3Toronto North graph for PM2.5 10Toronto North graph for NO2 0.1Toronto North graph for SO2  
Toronto West 8Toronto West graph for O3 5Toronto West graph for PM2.5 13.2Toronto West graph for NO2 0.1Toronto West graph for SO2 0.22Toronto West graph for CO
Windsor Downtown 16Windsor Downtown graph for O3 5Windsor Downtown graph for PM2.5 11.9Windsor Downtown graph for NO2 0.1Windsor Downtown graph for SO2 0.22Windsor Downtown graph for CO
Windsor West 18Windsor West graph for O3 5Windsor West graph for PM2.5 9Windsor West graph for NO2 0.1Windsor 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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