SmogRank / Episodes / Canada
Alberta and British Columbia, Canada, July 2023
For 4 days, from 6 to 9 July 2023, 14 cities in Canada had PM2.5 at least twice their usual for the time of year. The worst reading was Fort McMurray, Alberta, Canada: 66.5 µg/m³ on 8 July, about 5.6× its usual 11.8. Ended 9 July.
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 1 country
Days 4 6 to 9 July 2023
Worst day 8 July 9 cities counted
Furthest above usual 10× Fort St. John
Day by day
Play 8 July 9 cities at twice their usual or more
Williams Lake Quesnel St. Albert Red Deer Sherwood Park Prince George Edson Drayton Valley Fort Saskatchewan Edmonton Grande Prairie Grand Centre Smithers Fort McMurray Fort St. John 3 Jul 4 5 6 7 8 9 10 11 12 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
Fort St. John Fort St. John, 3 July: 18.0 µg/m³ Fort St. John, 4 July: 14.9 µg/m³ Fort St. John, 5 July: 23.8 µg/m³ Fort St. John, 6 July: 58.8 µg/m³, 10× its usual 5.7 Fort St. John, 7 July: 59.4 µg/m³, 10× its usual 5.7 Fort St. John, 8 July: 29.8 µg/m³, 5.2× its usual 5.7 Fort St. John, 9 July: 84.9 µg/m³ Fort St. John, 10 July: 146.0 µg/m³ Fort St. John, 11 July: 68.6 µg/m³ Fort St. John, 12 July: 45.2 µg/m³ Grande Prairie Grande Prairie, 3 July: 16.1 µg/m³ Grande Prairie, 4 July: 12.6 µg/m³ Grande Prairie, 5 July: 24.3 µg/m³ Grande Prairie, 6 July: 32.7 µg/m³, 5.0× its usual 6.6 Grande Prairie, 7 July: 19.2 µg/m³ Grande Prairie, 8 July: 26.8 µg/m³, 4.1× its usual 6.5 Grande Prairie, 9 July: 29.5 µg/m³ Grande Prairie, 10 July: 72.2 µg/m³ Grande Prairie, 11 July: 66.2 µg/m³ Grande Prairie, 12 July: 123.0 µg/m³ Edmonton Edmonton, 3 July: 14.2 µg/m³ Edmonton, 4 July: 12.8 µg/m³ Edmonton, 5 July: 17.1 µg/m³ Edmonton, 6 July: 27.8 µg/m³, 2.7× its usual 10.4 Edmonton, 7 July: 34.2 µg/m³ Edmonton, 8 July: 41.4 µg/m³, 3.9× its usual 10.7 Edmonton, 9 July: 47.4 µg/m³, 4.4× its usual 10.7 Edmonton, 10 July: 30.0 µg/m³ Edmonton, 11 July: 10.4 µg/m³ Edmonton, 12 July: 35.1 µg/m³ Grand Centre Grand Centre, 3 July: 20.2 µg/m³ Grand Centre, 4 July: 3.5 µg/m³ Grand Centre, 5 July: 7.9 µg/m³ Grand Centre, 6 July: 27.6 µg/m³, 3.1× its usual 8.8 Grand Centre, 7 July: 16.3 µg/m³ Grand Centre, 8 July: 34.6 µg/m³, 3.6× its usual 9.5 Grand Centre, 9 July: 50.8 µg/m³, 5.3× its usual 9.5 Grand Centre, 10 July: 4.0 µg/m³ Grand Centre, 11 July: 4.2 µg/m³ Grand Centre, 12 July: 6.8 µg/m³ Edson Edson, 3 July: 7.5 µg/m³ Edson, 4 July: 10.9 µg/m³ Edson, 5 July: 15.5 µg/m³ Edson, 6 July: 25.2 µg/m³, 3.7× its usual 6.8 Edson, 7 July: 21.7 µg/m³ Edson, 8 July: 27.3 µg/m³, 3.9× its usual 7.0 Edson, 9 July: 23.1 µg/m³ Edson, 10 July: 15.7 µg/m³ Edson, 11 July: 18.0 µg/m³ Edson, 12 July: 42.0 µg/m³ Smithers Smithers, 3 July: 8.5 µg/m³ Smithers, 4 July: 7.5 µg/m³ Smithers, 5 July: 4.7 µg/m³ Smithers, 6 July: 11.5 µg/m³ Smithers, 7 July: 27.3 µg/m³, 5.5× its usual 4.3 Smithers, 8 July: 39.2 µg/m³ Smithers, 9 July: 16.8 µg/m³ Smithers, 10 July: 10.8 µg/m³ Smithers, 11 July: 5.5 µg/m³ Smithers, 12 July: 6.2 µg/m³ Prince George Prince George, 3 July: 8.5 µg/m³ Prince George, 4 July: 15.8 µg/m³ Prince George, 5 July: 15.0 µg/m³ Prince George, 6 July: 23.0 µg/m³ Prince George, 7 July: 26.1 µg/m³, 3.9× its usual 6.7 Prince George, 8 July: 23.1 µg/m³ Prince George, 9 July: 36.9 µg/m³ Prince George, 10 July: 40.3 µg/m³ Prince George, 11 July: 82.6 µg/m³ Prince George, 12 July: 170.0 µg/m³ Quesnel Quesnel, 3 July: 10.6 µg/m³ Quesnel, 4 July: 11.9 µg/m³ Quesnel, 5 July: 20.0 µg/m³ Quesnel, 6 July: 23.9 µg/m³ Quesnel, 7 July: 25.0 µg/m³, 3.2× its usual 7.9 Quesnel, 8 July: 15.6 µg/m³ Quesnel, 9 July: 37.2 µg/m³ Quesnel, 10 July: 63.8 µg/m³ Quesnel, 11 July: 68.8 µg/m³ Quesnel, 12 July: 177.0 µg/m³ Fort McMurray Fort McMurray, 3 July: 11.3 µg/m³ Fort McMurray, 4 July: 5.0 µg/m³ Fort McMurray, 5 July: 12.5 µg/m³ Fort McMurray, 6 July: 16.6 µg/m³ Fort McMurray, 7 July: 20.4 µg/m³ Fort McMurray, 8 July: 66.5 µg/m³, 5.6× its usual 11.8 Fort McMurray, 9 July: 58.1 µg/m³, 5.1× its usual 11.4 Fort McMurray, 10 July: 2.4 µg/m³ Fort McMurray, 11 July: 5.1 µg/m³ Fort McMurray, 12 July: 28.8 µg/m³ Fort Saskatchewan Fort Saskatchewan, 3 July: 11.7 µg/m³ Fort Saskatchewan, 4 July: 8.0 µg/m³ Fort Saskatchewan, 5 July: 11.6 µg/m³ Fort Saskatchewan, 6 July: 19.0 µg/m³ Fort Saskatchewan, 7 July: 27.3 µg/m³ Fort Saskatchewan, 8 July: 32.5 µg/m³, 3.6× its usual 9.1 Fort Saskatchewan, 9 July: 40.1 µg/m³, 4.4× its usual 9.1 Fort Saskatchewan, 10 July: 32.9 µg/m³ Fort Saskatchewan, 11 July: 6.7 µg/m³ Fort Saskatchewan, 12 July: 23.7 µg/m³ Drayton Valley Drayton Valley, 3 July: 8.7 µg/m³ Drayton Valley, 4 July: 7.8 µg/m³ Drayton Valley, 5 July: 10.9 µg/m³ Drayton Valley, 6 July: 21.9 µg/m³ Drayton Valley, 7 July: 21.5 µg/m³ Drayton Valley, 8 July: 31.8 µg/m³, 4.2× its usual 7.6 Drayton Valley, 9 July: 21.7 µg/m³ Drayton Valley, 10 July: 16.4 µg/m³ Drayton Valley, 11 July: 9.4 µg/m³ Drayton Valley, 12 July: 36.9 µg/m³ St. Albert St. Albert, 3 July: 7.0 µg/m³ St. Albert, 4 July: 6.3 µg/m³ St. Albert, 5 July: 9.6 µg/m³ St. Albert, 6 July: 14.3 µg/m³ St. Albert, 7 July: 17.0 µg/m³ St. Albert, 8 July: 25.8 µg/m³, 3.2× its usual 8.1 St. Albert, 9 July: 26.9 µg/m³, 3.3× its usual 8.1 St. Albert, 10 July: 15.2 µg/m³ St. Albert, 11 July: 4.8 µg/m³ St. Albert, 12 July: 21.9 µg/m³ Red Deer Red Deer, 3 July: 16.4 µg/m³ Red Deer, 4 July: 10.0 µg/m³ Red Deer, 5 July: 11.6 µg/m³ Red Deer, 6 July: 22.5 µg/m³ Red Deer, 7 July: 22.1 µg/m³ Red Deer, 8 July: 21.3 µg/m³ Red Deer, 9 July: 26.6 µg/m³, 3.4× its usual 7.8 Red Deer, 10 July: 22.7 µg/m³ Red Deer, 11 July: 7.6 µg/m³ Red Deer, 12 July: 32.2 µg/m³ Sherwood Park Sherwood Park, 3 July: 7.8 µg/m³ Sherwood Park, 4 July: no reading Sherwood Park, 5 July: no reading Sherwood Park, 6 July: 14.7 µg/m³ Sherwood Park, 7 July: 17.3 µg/m³ Sherwood Park, 8 July: 24.9 µg/m³ Sherwood Park, 9 July: 26.2 µg/m³, 3.5× its usual 7.5 Sherwood Park, 10 July: 17.2 µg/m³ Sherwood Park, 11 July: 3.4 µg/m³ Sherwood Park, 12 July: 18.4 µg/m³ 3 Jul 4 5 6 7 8 9 10 11 12 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
Fort St. John British Columbia, Canada 3 7 July 5.7 10× Fort McMurray Alberta, Canada 2 8 July 11.8 5.6× Smithers British Columbia, Canada 1 7 July 4.3 5.5× Grand Centre Alberta, Canada 3 9 July 9.5 5.3× Grande Prairie Alberta, Canada 2 6 July 6.6 5.0× Edmonton Alberta, Canada 3 9 July 10.7 4.4× Fort Saskatchewan Alberta, Canada 2 9 July 9.1 4.4× Drayton Valley Alberta, Canada 1 8 July 7.6 4.2× Edson Alberta, Canada 2 8 July 7.0 3.9× Prince George British Columbia, Canada 1 7 July 6.7 3.9× Sherwood Park Alberta, Canada 1 9 July 7.5 3.5× Red Deer Alberta, Canada 1 9 July 7.8 3.4× St. Albert Alberta, Canada 2 9 July 8.1 3.3× Quesnel British Columbia, Canada 1 7 July 7.9 3.2×
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
Number 26 of 43 episodes in Canada since our records began, by cities reached.
North-western United States and Canada, August 2023 176 Northern United States and Canada, July 2025 139 North-western United States and Canada, July and August 2026 118 North-western United States and Canada, August and September 2025 94 North-western United States and Canada, July 2024 92 Northern United States and Canada, May 2023 83 Northern United States and Canada, August and September 2023 82 North-western United States and Canada, May 2023 63 North-western Canada and United States, September 2025 57 North-eastern United States and Canada, March 2026 40 North-western Canada and United States, June 2025 28 South-eastern Canada and United States, December 2024 27 Alberta and British Columbia, Canada, July 2023 14 Bars: cities reached; colour: the level of the episode's highest daily reading. All 43 .
Use this page SmogRank, Alberta and British Columbia, Canada, July 2023: 14 cities with PM2.5 at twice their usual or more, 6 to 9 July 2023, smogrank.com/episodes/2023-07-alberta-and-british-columbia-canada (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.
