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Air quality in Ontario
Air quality index (AQI) and PM2.5 air pollution in Ontario
LIVE AQI CITY RANKING
Real-time Ontario
Most polluted city ranking
| # | city | US AQI |
|---|---|---|
| 1 |  Niagara on the Lake | 79 |
| 2 | Fort Erie | 77 |
| 3 | Brockville | 75 |
| 4 | Vaughan | 73 |
| 5 | London | 72 |
| 6 | Niagara Falls | 71 |
| 7 | Kitchener | 70 |
| 8 | Blyth | 69 |
| 9 | Coldwater | 68 |
| 10 | Cornwall | 66 |
(local time)
SEE WORLD AQI RANKINGAIR QUALITY DATA CONTRIBUTORS
96 Contributors
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LIVE AQI CITY RANKING
Real-time Ontario
Cleanest city ranking
| # | city | US AQI |
|---|---|---|
| 1 | St. Catharines | 11 |
| 2 | Parry Sound | 22 |
| 3 | Port Stanley | 23 |
| 4 | Kirkland Lake | 24 |
| 5 | Thunder Bay | 24 |
| 6 | Sault Ste Marie | 27 |
| 7 | Sudbury | 27 |
| 8 | Sioux Narrows | 31 |
| 9 | Timmins | 33 |
| 10 | North Bay | 34 |
(local time)
SEE WORLD AQI RANKING
3D animated air pollution map
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The latest air quality news and resources.
Ontario air quality data attribution
96Contributors
- Hamilton Air Monitoring Network - HAMN
9 stations
- Township of SNNF
1 station
4 Government Contributors
- Blyth Festival
1 station
- DGEC - Greensville
1 station
Electric Vehicle Council of Ottawa1 station
- EVCO
1 station
National Air Pollution Surveillance Program2 stations
5 Non-profit organization Contributors
- Kevin Damen
1 station
- Anonymous
1 station
- Jim Guillet
1 station
- bsumm
1 station
A Hamiltonian1 station
Chris Fournier1 station
Slyyy1 station
JackB1 station
Christopher Trevors1 station
- Anonymous
1 station
Nichols Family1 station
- Bruce Buckley
1 station
Graydon1 station
- IQAir Lab
1 station
Anonymous1 station
- VB
1 station
- randalljhoward
1 station
CS2 stations
- **
1 station
- Bijan
1 station
- Libby
1 station
- Mark Douglas Wessel
1 station
- JayDee
1 station
Me1 station
- Keevabay
1 station
25 Individual Contributors
62 Anonymous contributors62 stations
62 Anonymous Contributors
Which is the most polluted city in Ontario?
- Niagara on the Lake 79
- Fort Erie 77
- Brockville 75
- Vaughan 73
- London 72
- Niagara Falls 71
- Kitchener 70
- Blyth 69
- Coldwater 68
- Cornwall 66
- Hamilton 66
- Markham 65
- Simcoe 64
- Wellington County 64
- Aylmer 63
- Binbrook 63
- Norfolk County 63
- Toronto 63
- Uxbridge 63
- Ajax 62
- Brant 62
- Mississauga 62
- Woodstock 62
- Ancaster 61
- Bluewater 61
- Cambridge 61
- Dorchester 61
- Ingersoll 61
- Oakville 61
- Paris 61
- Port Colborne 61
- St. Thomas 61
- Thorold 61
- Waterloo 61
- Welland 61
- Innisfil 60
- Richmond Hill 60
- Scarborough 60
- Gananoque 59
- Morrisburg 59
- Ottawa 59
- Prescott 59
- Brantford 58
- Delaware 58
- Dorset 58
- Milton 58
- Newmarket 58
- Picton 58
- Prince Edward 58
- Smiths Falls 58
- Burlington 57
- Casselman 57
- Deseronto 57
- Greater Napanee 57
- Napanee Downtown 57
- Skatepark 57
- Belleville 56
- Guelph 56
- Perth 56
- Stratford 56
- Almonte 55
- Brampton 55
- Kingston 55
- Quinte West 55
- Bourget 54
- East York 54
- Etobicoke 54
- Orillia 54
- Bells Corners 53
- Carleton Place 53
- Cobourg 53
- Nepean 53
- North York 53
- Renfrew 53
- Willowdale 53
- Amherstburg 52
- Concord 52
- Hawkesbury 52
- Owen Sound 52
- Peterborough 52
- South Huron 52
- Windsor 52
- Clarence-Rockland 51
- Pickering 51
- Wendover 51
- North Perth 48
- Oshawa 48
- Huron East 47
- Chatham 44
- Grand Bend 44
- Orangeville 44
- Petrolia 41
- Lambton Shores 40
- Walpole Island 40
- Arnprior 39
- Shelburne 39
- Keswick 38
- Omemee 38
- Sarnia 38
- Wingham 38
- Camlachie 37
- Egbert 37
- Experimental Lakes 37
- Lindsay 37
- Nestor Falls 37
- Angus 36
- Bancroft 36
- Barrie 36
- Pembroke 36
- Tiverton 36
- Deep River 35
- Fort Frances 35
- Petawawa 35
- Collingwood 34
- Goderich 34
- Hanover 34
- North Bay 34
- Dryden 33
- Minden Hills 33
- Timmins 33
- Wasaga Beach 33
- Bracebridge 32
- Gravenhurst 32
- Huntsville 32
- Mattawa 32
- Midland 32
- Powassan 32
- South River 32
- Ear Falls 31
- Red Lake 31
- Sioux Narrows 31
- Kincardine 29
- Pickle Lake 28
- Sault Ste Marie 27
- Sudbury 27
- Rayside-Balfour 26
- Espanola 24
- Kirkland Lake 24
- Little Current 24
- Thunder Bay 24
- Port Stanley 23
- Tobermory 23
- Parry Sound 22
- Temiskaming Shores 22
- Elliot Lake 21
- Atikokan 20
- Englehart 19
- Neebing 18
- Greenstone 17
- Thessalon 17
- Algoma 14
- Bonner Lake 14
- Hornepayne 12
- Iroquois Falls 12
- Marathon 12
- St. Catharines 11
- Hearst 10
- Kapuskasing 9
AQI US, Metric