SmogRank / Episodes / Canada

South-eastern Canada, February 2026

For 2 days, from 3 to 4 February 2026, 8 cities in Canada and the United States had PM2.5 at least twice their usual for the time of year. The worst reading was Nepean, Ontario, Canada: 39.6 µg/m³ on 3 February, about 7.9× its usual 4.5.

No cause namedWe have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached8in 2 countries
Days23 to 4 February 2026
Worst day4 February5 cities counted
Furthest above usual7.9×Nepean

Day by day

4 February 5 cities at twice their usual or more
Saint-Jean-sur-RichelieuBrossardDorvalMontréalRivière-des-Prairies–Pointe-aux-TremblesGranbyRutlandCornwallDrummondvilleSherbrookeKeenePittsfieldGreenfieldOttawaLaconiaUticaDerryLowellKingstonHaverhillSyracusePortsmouthFraminghamLexingtonNewtonLewistonBostonPortlandLynnAugustaBellevilleRochesterBangorPeterboroughBuffaloSorel-TracyL'Ancienne-LoretteQuébecAlbanyTrois-RivièresShawiniganGatineauNepean
31 Jan1 Feb234567
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

NepeanNepean, 31 January: 1.1 µg/m³, 0.2× usualNepean, 1 February: 1.2 µg/m³, 0.2× usualNepean, 2 February: 2.4 µg/m³, 0.5× usualNepean, 3 February: 39.6 µg/m³, 7.9× usualNepean, 4 February: 6.2 µg/m³, 1.2× usualNepean, 5 February: 3.7 µg/m³, 0.7× usualNepean, 6 February: 26.6 µg/m³, 5.3× usualNepean, 7 February: 4.0 µg/m³, 0.8× usualGatineauGatineau, 31 January: 1.5 µg/m³, 0.3× usualGatineau, 1 February: 2.3 µg/m³, 0.5× usualGatineau, 2 February: 3.4 µg/m³, 0.7× usualGatineau, 3 February: 36.7 µg/m³, 7.2× usualGatineau, 4 February: 8.3 µg/m³, 1.6× usualGatineau, 5 February: 2.9 µg/m³, 0.6× usualGatineau, 6 February: 23.2 µg/m³, 4.5× usualGatineau, 7 February: 1.2 µg/m³, 0.2× usualAlbanyAlbany, 31 January: 4.7 µg/m³, 0.7× usualAlbany, 1 February: 5.7 µg/m³, 0.9× usualAlbany, 2 February: 10.2 µg/m³, 1.5× usualAlbany, 3 February: 26.1 µg/m³, 4.0× usualAlbany, 4 February: 9.5 µg/m³, 1.4× usualAlbany, 5 February: 14.3 µg/m³, 2.2× usualAlbany, 6 February: 21.4 µg/m³, 3.2× usualAlbany, 7 February: 9.4 µg/m³, 1.4× usualTrois-RivièresTrois-Rivières, 31 January: 3.5 µg/m³, 0.5× usualTrois-Rivières, 1 February: 5.8 µg/m³, 0.8× usualTrois-Rivières, 2 February: 11.5 µg/m³, 1.7× usualTrois-Rivières, 3 February: 25.9 µg/m³, 3.8× usualTrois-Rivières, 4 February: 28.7 µg/m³, 4.2× usualTrois-Rivières, 5 February: 6.8 µg/m³, 1.0× usualTrois-Rivières, 6 February: 9.4 µg/m³, 1.4× usualTrois-Rivières, 7 February: 4.9 µg/m³, 0.7× usualL'Ancienne-LoretteL'Ancienne-Lorette, 31 January: 3.8 µg/m³, 0.4× usualL'Ancienne-Lorette, 1 February: 16.3 µg/m³, 1.7× usualL'Ancienne-Lorette, 2 February: 12.6 µg/m³, 1.3× usualL'Ancienne-Lorette, 3 February: 24.4 µg/m³, 2.6× usualL'Ancienne-Lorette, 4 February: 34.6 µg/m³, 3.6× usualL'Ancienne-Lorette, 5 February: 9.2 µg/m³, 1.0× usualL'Ancienne-Lorette, 6 February: 13.7 µg/m³, 1.4× usualL'Ancienne-Lorette, 7 February: 6.1 µg/m³, 0.6× usualShawiniganShawinigan, 31 January: 2.5 µg/m³, 0.4× usualShawinigan, 1 February: 4.7 µg/m³, 0.7× usualShawinigan, 2 February: 6.0 µg/m³, 0.9× usualShawinigan, 3 February: 21.1 µg/m³, 3.1× usualShawinigan, 4 February: 29.0 µg/m³, 4.3× usualShawinigan, 5 February: 6.5 µg/m³, 1.0× usualShawinigan, 6 February: 11.1 µg/m³, 1.7× usualShawinigan, 7 February: 5.5 µg/m³, 0.8× usualQuébecQuébec, 31 January: 3.2 µg/m³, 0.5× usualQuébec, 1 February: 12.8 µg/m³, 1.9× usualQuébec, 2 February: 10.9 µg/m³, 1.6× usualQuébec, 3 February: 19.8 µg/m³, 2.9× usualQuébec, 4 February: 27.3 µg/m³, 4.0× usualQuébec, 5 February: 6.1 µg/m³, 0.9× usualQuébec, 6 February: 7.7 µg/m³, 1.1× usualQuébec, 7 February: 4.2 µg/m³, 0.6× usualSorel-TracySorel-Tracy, 31 January: 4.2 µg/m³, 0.6× usualSorel-Tracy, 1 February: 4.9 µg/m³, 0.7× usualSorel-Tracy, 2 February: 14.2 µg/m³, 1.9× usualSorel-Tracy, 3 February: 22.2 µg/m³, 3.0× usualSorel-Tracy, 4 February: 25.5 µg/m³, 3.4× usualSorel-Tracy, 5 February: 5.1 µg/m³, 0.7× usualSorel-Tracy, 6 February: 8.9 µg/m³, 1.2× usualSorel-Tracy, 7 February: 5.4 µg/m³, 0.7× usual31 Jan1 Feb234567
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.
Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

Every city it reached

CityDaysHighestUsualAbove usual
NepeanOntario, Canada1 39.63 February4.57.9×
GatineauQuebec, Canada1 36.73 February5.17.2×
ShawiniganQuebec, Canada1 29.04 February6.74.3×
Trois-RivièresQuebec, Canada2 28.74 February6.94.2×
QuébecQuebec, Canada1 27.34 February6.84.0×
AlbanyNew York, United States1 26.13 February6.64.0×
L'Ancienne-LoretteQuebec, Canada1 34.64 February9.53.6×
Sorel-TracyQuebec, Canada1 25.54 February7.53.4×

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 95 of 106 episodes in Canada and the United States since our records began, by cities reached.

Bars: cities reached; colour: the level of the episode's highest daily reading. All 106.

Use this page

SmogRank, South-eastern Canada, February 2026: 8 cities with PM2.5 at twice their usual or more, 3 to 4 February 2026, smogrank.com/episodes/2026-02-south-eastern-canada (accessed 2 October 2026).

Download top 10 (PNG)

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.