SmogRank / Episodes / Canada
Eastern Canada and United States, August 2024
For 2 days, from 16 to 17 August 2024, 16 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. Ended 17 August.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 16 in 2 countries
Days 2 16 to 17 August 2024
Worst day 16 August 15 cities counted
Furthest above usual 6.6× Saguenay
Day by day
Play 16 August 15 cities at twice their usual or more
Saint-Jean-sur-Richelieu Hartford Brossard Montréal Rivière-des-Prairies–Pointe-aux-Trembles Dorval Lewiston Portland Keene Augusta Derry Londonderry Portsmouth Haverhill Lowell Bennington Greenfield North Adams Lexington Lynn Worcester Boston Ware Cornwall Quincy Pittsfield North Chicopee Springfield Bangor Brockton Providence Coventry West Greenwich Fall River Waterbury New London Ottawa Utica New Haven Danbury Newburgh Kingston Syracuse Fredericton Scranton Belleville Rochester Hartford Nepean Sorel-Tracy Rutland Granby Albany Trois-Rivières Drummondville Shawinigan Presque Isle Bécancour 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 Saguenay, 14 August: 30.2 µg/m³ Saguenay, 15 August: 29.9 µg/m³ Saguenay, 16 August: 44.3 µg/m³, 6.6× its usual 6.7 Saguenay, 17 August: 43.4 µg/m³, 6.7× its usual 6.5 Saguenay, 18 August: 25.6 µg/m³ Saguenay, 19 August: 6.3 µg/m³ Saguenay, 20 August: 4.3 µg/m³ Shawinigan Shawinigan, 13 August: 14.7 µg/m³ Shawinigan, 14 August: 13.0 µg/m³ Shawinigan, 15 August: 24.4 µg/m³ Shawinigan, 16 August: 34.2 µg/m³, 4.7× its usual 7.3 Shawinigan, 17 August: 28.5 µg/m³, 4.1× its usual 6.9 Shawinigan, 18 August: 17.4 µg/m³ Shawinigan, 19 August: 6.9 µg/m³ Shawinigan, 20 August: 3.2 µg/m³ Sherbrooke Sherbrooke, 13 August: 11.1 µg/m³ Sherbrooke, 14 August: 12.4 µg/m³ Sherbrooke, 15 August: 19.3 µg/m³ Sherbrooke, 16 August: 33.8 µg/m³, 5.8× its usual 5.8 Sherbrooke, 17 August: 25.0 µg/m³, 4.3× its usual 5.8 Sherbrooke, 18 August: 16.9 µg/m³ Sherbrooke, 19 August: 8.9 µg/m³ Sherbrooke, 20 August: 2.9 µg/m³ Québec Québec, 13 August: 15.8 µg/m³ Québec, 14 August: 23.5 µg/m³ Québec, 15 August: 20.9 µg/m³ Québec, 16 August: 33.8 µg/m³, 4.9× its usual 6.9 Québec, 17 August: 36.0 µg/m³, 5.4× its usual 6.7 Québec, 18 August: 23.7 µg/m³ Québec, 19 August: 8.8 µg/m³ Québec, 20 August: 3.4 µg/m³ L'Ancienne-Lorette L'Ancienne-Lorette, 13 August: 13.4 µg/m³ L'Ancienne-Lorette, 14 August: 24.0 µg/m³ L'Ancienne-Lorette, 15 August: 21.0 µg/m³ L'Ancienne-Lorette, 16 August: 31.8 µg/m³, 4.2× its usual 7.6 L'Ancienne-Lorette, 17 August: 36.3 µg/m³, 4.8× its usual 7.5 L'Ancienne-Lorette, 18 August: 22.5 µg/m³ L'Ancienne-Lorette, 19 August: 8.0 µg/m³ L'Ancienne-Lorette, 20 August: 3.3 µg/m³ Edmundston Edmundston, 13 August: 23.3 µg/m³ Edmundston, 14 August: 31.7 µg/m³ Edmundston, 15 August: 30.5 µg/m³ Edmundston, 16 August: 31.1 µg/m³, 5.2× its usual 6.0 Edmundston, 17 August: 28.8 µg/m³, 5.0× its usual 5.8 Edmundston, 18 August: 20.5 µg/m³ Edmundston, 19 August: 13.2 µg/m³ Edmundston, 20 August: 2.2 µg/m³ Nepean Nepean, 13 August: 21.8 µg/m³ Nepean, 14 August: 27.5 µg/m³ Nepean, 15 August: 30.7 µg/m³ Nepean, 16 August: 30.1 µg/m³, 2.8× its usual 10.6 Nepean, 17 August: 33.7 µg/m³, 3.5× its usual 9.5 Nepean, 18 August: 27.8 µg/m³ Nepean, 19 August: 3.9 µg/m³ Nepean, 20 August: 1.8 µg/m³ Sorel-Tracy Sorel-Tracy, 13 August: 11.8 µg/m³ Sorel-Tracy, 14 August: 15.8 µg/m³ Sorel-Tracy, 15 August: 21.4 µg/m³ Sorel-Tracy, 16 August: 29.0 µg/m³, 3.9× its usual 7.4 Sorel-Tracy, 17 August: 27.7 µg/m³, 3.8× its usual 7.3 Sorel-Tracy, 18 August: 17.6 µg/m³ Sorel-Tracy, 19 August: 7.9 µg/m³ Sorel-Tracy, 20 August: no reading Bécancour Bécancour, 13 August: 13.3 µg/m³ Bécancour, 14 August: 16.3 µg/m³ Bécancour, 15 August: 21.4 µg/m³ Bécancour, 16 August: 28.5 µg/m³, 4.7× its usual 6.1 Bécancour, 17 August: 28.8 µg/m³, 4.8× its usual 6.0 Bécancour, 18 August: 18.2 µg/m³ Bécancour, 19 August: 9.1 µg/m³ Bécancour, 20 August: 3.3 µg/m³ Granby Granby, 13 August: no reading Granby, 14 August: no reading Granby, 15 August: 19.2 µg/m³ Granby, 16 August: 28.3 µg/m³, 4.1× its usual 6.9 Granby, 17 August: 24.9 µg/m³ Granby, 18 August: 14.6 µg/m³ Granby, 19 August: 8.1 µg/m³ Granby, 20 August: 3.3 µg/m³ Trois-Rivières Trois-Rivières, 13 August: 12.7 µg/m³ Trois-Rivières, 14 August: 15.1 µg/m³ Trois-Rivières, 15 August: 20.5 µg/m³ Trois-Rivières, 16 August: 28.2 µg/m³, 4.3× its usual 6.5 Trois-Rivières, 17 August: 27.3 µg/m³, 4.3× its usual 6.4 Trois-Rivières, 18 August: 15.8 µg/m³ Trois-Rivières, 19 August: 7.6 µg/m³ Trois-Rivières, 20 August: 3.1 µg/m³ Rutland Rutland, 13 August: 8.7 µg/m³ Rutland, 14 August: 14.0 µg/m³ Rutland, 15 August: 15.7 µg/m³ Rutland, 16 August: 27.4 µg/m³, 4.1× its usual 6.7 Rutland, 17 August: 23.3 µg/m³ Rutland, 18 August: 13.8 µg/m³ Rutland, 19 August: 6.5 µg/m³ Rutland, 20 August: 3.8 µg/m³ Drummondville Drummondville, 13 August: 10.0 µg/m³ Drummondville, 14 August: 12.5 µg/m³ Drummondville, 15 August: 20.9 µg/m³ Drummondville, 16 August: 26.7 µg/m³, 4.4× its usual 6.1 Drummondville, 17 August: 25.8 µg/m³, 4.4× its usual 5.9 Drummondville, 18 August: 15.6 µg/m³ Drummondville, 19 August: 9.3 µg/m³ Drummondville, 20 August: 3.4 µg/m³ Presque Isle Presque Isle, 13 August: 19.4 µg/m³ Presque Isle, 14 August: 28.9 µg/m³ Presque Isle, 15 August: 23.5 µg/m³ Presque Isle, 16 August: 25.0 µg/m³, 4.8× its usual 5.2 Presque Isle, 17 August: 21.8 µg/m³ Presque Isle, 18 August: 18.4 µg/m³ Presque Isle, 19 August: 14.8 µg/m³ Presque Isle, 20 August: 2.0 µg/m³ Hartford Hartford, 13 August: 7.1 µg/m³ Hartford, 14 August: 16.1 µg/m³ Hartford, 15 August: 16.6 µg/m³ Hartford, 16 August: 25.0 µg/m³, 3.4× its usual 7.3 Hartford, 17 August: 22.3 µg/m³ Hartford, 18 August: 17.1 µg/m³ Hartford, 19 August: 7.0 µg/m³ Hartford, 20 August: 2.7 µg/m³ Albany Albany, 13 August: 11.9 µg/m³ Albany, 14 August: 19.2 µg/m³ Albany, 15 August: 17.7 µg/m³ Albany, 16 August: 24.3 µg/m³ Albany, 17 August: 28.8 µg/m³, 4.2× its usual 6.8 Albany, 18 August: 16.7 µg/m³ Albany, 19 August: 8.1 µg/m³ Albany, 20 August: 3.2 µg/m³ 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 16 August 6.0 5.2× L'Ancienne-Lorette Quebec, Canada 2 17 August 7.5 4.8× Bécancour Quebec, Canada 2 17 August 6.0 4.8× Presque Isle Maine, United States 1 16 August 5.2 4.8× Shawinigan Quebec, Canada 2 16 August 7.3 4.7× Drummondville Quebec, Canada 2 16 August 6.1 4.4× Trois-Rivières Quebec, Canada 2 16 August 6.5 4.3× 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, over the days each city counted in this episode. Highest: its highest of those days. Usual: the city's median for the time of year of that day (its days within 21 days of the date, every year, leaving out the week around it). Above usual: its highest day against that, with a usual under 5 µg/m³ taken as 5.
Against other episodes in Canada and the United States
Number 89 of 173 episodes in Canada and the United States since our records began, by cities reached.
Eastern United States and Canada, June and July 2023 343 Northern United States and Canada, July 2026 327 United States and Canada, July 2023 322 Eastern United States and Canada, May and June 2023 317 North-eastern United States and Canada, 29 July to 9 August 2025 292 Northern United States and Canada, May and June 2025 247 United States and Canada, June 2023 195 North-western United States and Canada, August 2023 176 North-western United States and Canada, 4 to 22 August 2026 151 Northern United States and Canada, July 2025 139 Northern United States and Canada, June 2025 134 North-western United States and Canada, July and August 2026 118 Eastern Canada and United States, August 2024 16 Bars: cities reached; colour: the level of the episode's highest daily reading. All 173 .
Use this page SmogRank, Eastern Canada and United States, August 2024: 16 cities with PM2.5 at twice their usual or more, 16 to 17 August 2024, smogrank.com/episodes/2024-08-eastern-canada-and-united-states (accessed 5 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.
