SmogRank / Episodes / Canada
South-eastern Canada and United States, August 2024
For 2 days, from 16 to 17 August 2024, 14 cities in Canada and the United States had PM2.5 at least twice their usual for the time of year. The worst reading was Saguenay, Quebec, Canada: 44.3 µg/m³ on 16 August, about 6.6× its usual 6.7.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 14 in 2 countries
Days 2 16 to 17 August 2024
Worst day 16 August 13 cities counted
Furthest above usual 6.6× Saguenay
Day by day
Play 16 August 13 cities at twice their usual or more
Saint-Jean-sur-Richelieu Brossard Montréal Rivière-des-Prairies–Pointe-aux-Trembles Dorval Lewiston Keene Portland Derry Augusta Portsmouth Haverhill Lowell Greenfield Cornwall Lexington Lynn Worcester Boston Pittsfield North Chicopee Quincy Springfield Brockton Bangor Providence Coventry Fall River Waterbury Ottawa New London Utica New Haven Danbury Newburgh Kingston Syracuse Scranton Fredericton Belleville Rochester Hartford Nepean Sorel-Tracy Granby Rutland Albany Drummondville Trois-Rivières Shawinigan L'Ancienne-Lorette Edmundston Québec Sherbrooke Saguenay 13 Aug 14 15 16 17 18 19 20 Every measured city in the area, coloured by its PM2.5 that day; a dark ring marks a city at twice its usual or more. Bars: cities counted each day, coloured by their median level. Choose a day or press play; without JavaScript, the days link to that day's world ranking.
How it spread
Saguenay Saguenay, 13 August: 25.0 µg/m³, 3.7× usual Saguenay, 14 August: 30.2 µg/m³, 4.5× usual Saguenay, 15 August: 29.9 µg/m³, 4.5× usual Saguenay, 16 August: 44.3 µg/m³, 6.6× usual Saguenay, 17 August: 43.4 µg/m³, 6.5× usual Saguenay, 18 August: 25.6 µg/m³, 3.8× usual Saguenay, 19 August: 6.3 µg/m³, 0.9× usual Saguenay, 20 August: 4.3 µg/m³, 0.6× usual Edmundston Edmundston, 13 August: 23.3 µg/m³, 3.9× usual Edmundston, 14 August: 31.7 µg/m³, 5.3× usual Edmundston, 15 August: 30.5 µg/m³, 5.1× usual Edmundston, 16 August: 31.1 µg/m³, 5.2× usual Edmundston, 17 August: 28.8 µg/m³, 4.8× usual Edmundston, 18 August: 20.5 µg/m³, 3.4× usual Edmundston, 19 August: 13.2 µg/m³, 2.2× usual Edmundston, 20 August: 2.2 µg/m³, 0.4× usual Nepean Nepean, 13 August: 21.8 µg/m³, 2.3× usual Nepean, 14 August: 27.5 µg/m³, 2.9× usual Nepean, 15 August: 30.7 µg/m³, 3.2× usual Nepean, 16 August: 30.1 µg/m³, 3.2× usual Nepean, 17 August: 33.7 µg/m³, 3.5× usual Nepean, 18 August: 27.8 µg/m³, 2.9× usual Nepean, 19 August: 3.9 µg/m³, 0.4× usual Nepean, 20 August: 1.8 µg/m³, 0.2× usual Shawinigan Shawinigan, 13 August: 14.7 µg/m³, 2.0× usual Shawinigan, 14 August: 13.0 µg/m³, 1.8× usual Shawinigan, 15 August: 24.4 µg/m³, 3.3× usual Shawinigan, 16 August: 34.2 µg/m³, 4.7× usual Shawinigan, 17 August: 28.5 µg/m³, 3.9× usual Shawinigan, 18 August: 17.4 µg/m³, 2.4× usual Shawinigan, 19 August: 6.9 µg/m³, 0.9× usual Shawinigan, 20 August: 3.2 µg/m³, 0.4× usual Sherbrooke Sherbrooke, 13 August: 11.1 µg/m³, 1.9× usual Sherbrooke, 14 August: 12.4 µg/m³, 2.1× usual Sherbrooke, 15 August: 19.3 µg/m³, 3.3× usual Sherbrooke, 16 August: 33.8 µg/m³, 5.8× usual Sherbrooke, 17 August: 25.0 µg/m³, 4.3× usual Sherbrooke, 18 August: 16.9 µg/m³, 2.9× usual Sherbrooke, 19 August: 8.9 µg/m³, 1.5× usual Sherbrooke, 20 August: 2.9 µg/m³, 0.5× usual Québec Québec, 13 August: 15.8 µg/m³, 2.4× usual Québec, 14 August: 23.5 µg/m³, 3.5× usual Québec, 15 August: 20.9 µg/m³, 3.1× usual Québec, 16 August: 33.8 µg/m³, 5.0× usual Québec, 17 August: 36.0 µg/m³, 5.4× usual Québec, 18 August: 23.7 µg/m³, 3.5× usual Québec, 19 August: 8.8 µg/m³, 1.3× usual Québec, 20 August: 3.4 µg/m³, 0.5× usual L'Ancienne-Lorette L'Ancienne-Lorette, 13 August: 13.4 µg/m³, 1.8× usual L'Ancienne-Lorette, 14 August: 24.0 µg/m³, 3.2× usual L'Ancienne-Lorette, 15 August: 21.0 µg/m³, 2.8× usual L'Ancienne-Lorette, 16 August: 31.8 µg/m³, 4.2× usual L'Ancienne-Lorette, 17 August: 36.3 µg/m³, 4.8× usual L'Ancienne-Lorette, 18 August: 22.5 µg/m³, 3.0× usual L'Ancienne-Lorette, 19 August: 8.0 µg/m³, 1.1× usual L'Ancienne-Lorette, 20 August: 3.3 µg/m³, 0.4× usual Sorel-Tracy Sorel-Tracy, 13 August: 11.8 µg/m³, 1.6× usual Sorel-Tracy, 14 August: 15.8 µg/m³, 2.1× usual Sorel-Tracy, 15 August: 21.4 µg/m³, 2.9× usual Sorel-Tracy, 16 August: 29.0 µg/m³, 3.9× usual Sorel-Tracy, 17 August: 27.7 µg/m³, 3.7× usual Sorel-Tracy, 18 August: 17.6 µg/m³, 2.4× usual Sorel-Tracy, 19 August: 7.9 µg/m³, 1.1× usual Sorel-Tracy, 20 August: no reading Trois-Rivières Trois-Rivières, 13 August: 13.0 µg/m³, 2.1× usual Trois-Rivières, 14 August: 15.7 µg/m³, 2.5× usual Trois-Rivières, 15 August: 21.0 µg/m³, 3.3× usual Trois-Rivières, 16 August: 28.4 µg/m³, 4.5× usual Trois-Rivières, 17 August: 28.1 µg/m³, 4.5× usual Trois-Rivières, 18 August: 17.0 µg/m³, 2.7× usual Trois-Rivières, 19 August: 8.4 µg/m³, 1.3× usual Trois-Rivières, 20 August: 3.2 µg/m³, 0.5× usual Granby Granby, 13 August: no reading Granby, 14 August: no reading Granby, 15 August: 19.2 µg/m³, 2.8× usual Granby, 16 August: 28.3 µg/m³, 4.1× usual Granby, 17 August: 24.9 µg/m³, 3.6× usual Granby, 18 August: 14.6 µg/m³, 2.1× usual Granby, 19 August: 8.1 µg/m³, 1.2× usual Granby, 20 August: 3.3 µg/m³, 0.5× usual Rutland Rutland, 13 August: 8.7 µg/m³, 1.3× usual Rutland, 14 August: 14.0 µg/m³, 2.1× usual Rutland, 15 August: 15.7 µg/m³, 2.3× usual Rutland, 16 August: 27.4 µg/m³, 4.1× usual Rutland, 17 August: 23.3 µg/m³, 3.5× usual Rutland, 18 August: 13.8 µg/m³, 2.1× usual Rutland, 19 August: 6.5 µg/m³, 1.0× usual Rutland, 20 August: 3.8 µg/m³, 0.6× usual Drummondville Drummondville, 13 August: 10.0 µg/m³, 1.6× usual Drummondville, 14 August: 12.5 µg/m³, 2.0× usual Drummondville, 15 August: 20.9 µg/m³, 3.4× usual Drummondville, 16 August: 26.7 µg/m³, 4.4× usual Drummondville, 17 August: 25.8 µg/m³, 4.2× usual Drummondville, 18 August: 15.6 µg/m³, 2.6× usual Drummondville, 19 August: 9.3 µg/m³, 1.5× usual Drummondville, 20 August: 3.4 µg/m³, 0.6× usual Hartford Hartford, 13 August: 7.1 µg/m³, 1.0× usual Hartford, 14 August: 16.1 µg/m³, 2.2× usual Hartford, 15 August: 16.6 µg/m³, 2.3× usual Hartford, 16 August: 25.0 µg/m³, 3.4× usual Hartford, 17 August: 22.3 µg/m³, 3.1× usual Hartford, 18 August: 17.1 µg/m³, 2.3× usual Hartford, 19 August: 7.0 µg/m³, 1.0× usual Hartford, 20 August: 2.7 µg/m³, 0.4× usual Albany Albany, 13 August: 11.9 µg/m³, 1.8× usual Albany, 14 August: 19.2 µg/m³, 2.8× usual Albany, 15 August: 17.7 µg/m³, 2.6× usual Albany, 16 August: 24.3 µg/m³, 3.6× usual Albany, 17 August: 28.8 µg/m³, 4.2× usual Albany, 18 August: 16.7 µg/m³, 2.5× usual Albany, 19 August: 8.1 µg/m³, 1.2× usual Albany, 20 August: 3.2 µg/m³, 0.5× usual 13 Aug 14 15 16 17 18 19 20 Every counted city, in the order the episode reached them, 3 days before to 3 after. Each square is a day, coloured by that day's PM2.5; outlined: at twice the city's usual or more. Good 0–50
Moderate 51–100
Sensitive groups 101–150
Unhealthy 151–200
Very unhealthy 201–300
Hazardous 301+
Every city it reached
City Days Highest Usual Above usual
Saguenay Quebec, Canada 2 16 August 6.7 6.6× Sherbrooke Quebec, Canada 2 16 August 5.8 5.8× Québec Quebec, Canada 2 17 August 6.7 5.4× Edmundston New Brunswick, Canada 2 14 August 6.0 5.3× L'Ancienne-Lorette Quebec, Canada 2 17 August 7.5 4.8× Shawinigan Quebec, Canada 2 16 August 7.3 4.7× Trois-Rivières Quebec, Canada 2 16 August 6.3 4.5× Drummondville Quebec, Canada 2 16 August 6.1 4.4× Albany New York, United States 1 17 August 6.8 4.2× Granby Quebec, Canada 1 16 August 6.9 4.1× Rutland Vermont, United States 1 16 August 6.7 4.1× Sorel-Tracy Quebec, Canada 2 16 August 7.4 3.9× Nepean Ontario, Canada 2 17 August 9.5 3.5× Hartford Connecticut, United States 1 16 August 7.3 3.4×
Daily means in µg/m³. Usual: the city's median for this time of year (its days within 21 days of the date, every year, leaving out the week around it). Above usual: its highest day against that.
Against other episodes in Canada and the United States
Number 77 of 142 episodes in Canada and the United States since our records began, by cities reached.
North-eastern United States and Canada, June and July 2023 280 North-eastern United States and Canada, July 2026 264 North-eastern United States and Canada, May and June 2023 261 North-eastern United States and Canada, July and August 2025 241 North-eastern United States and Canada, July 2023 240 North-eastern United States and Canada, June 2025 196 North-eastern United States and Canada, June 2023 161 North-eastern United States and Canada, July 2025 119 North-western United States and Canada, August 2023 110 North-eastern United States, June 2025 104 North-western United States and Canada, August 2026 99 North-eastern United States and Canada, February 2026 96 South-eastern Canada and United States, August 2024 14 Bars: cities reached; colour: the level of the episode's highest daily reading. All 142 .
Use this page SmogRank, South-eastern Canada and United States, August 2024: 14 cities with PM2.5 at twice their usual or more, 16 to 17 August 2024, smogrank.com/episodes/2024-08-south-eastern-canada-and-united-states (accessed 3 October 2026).
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You're welcome to reuse a single chart, image or figure with this citation and a link. Terms .
An episode is a run of days when many cities close to each other (four or more within 350 km on a day, 8 or more in all) each had a daily PM2.5 mean of at least 25 µg/m³ and at least 2 times their usual for that time of year. Found in our own measurements, not picked by hand. How we find episodes . Values are each city's daily mean of its own monitors; causes are the usual kinds for a pattern like this, not a confirmed source.
