SmogRank / Episodes / United States
Northern United States, September 2023
For 3 days, from 6 to 8 September 2023, 26 cities in the United States had PM2.5 at least twice their usual for the time of year. The worst reading was Topeka, Kansas, United States: 72.4 µg/m³ on 7 September, about 8.2× its usual 8.8.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 26 in 1 country
Days 3 6 to 8 September 2023
Worst day 6 September 25 cities counted
Furthest above usual 11× Grand Island
Day by day
Play 6 September 25 cities at twice their usual or more
Waterloo Shakopee Burnsville Apple Valley Rochester Saint Michael Minneapolis Saint Paul Blaine Springfield Muscatine La Crosse Springdale Eau Claire Edmond Oklahoma City Moore Fort Smith Superior Duluth Tulsa Saint Cloud Iowa City Jenks Des Moines Ankeny Saint Joseph Ponca City West Fargo Bismarck Wichita Kansas City Derby Aberdeen Olathe Kansas City Raymore Watertown Omaha Liberty Topeka Brookings Sioux Falls Bellevue Lincoln Grand Island 3 Sep 4 5 6 7 8 9 10 11 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
Bismarck Bismarck, 3 September: 31.4 µg/m³, 3.5× usual Bismarck, 4 September: 14.4 µg/m³, 1.6× usual Bismarck, 5 September: 87.3 µg/m³, 9.6× usual Bismarck, 6 September: 45.0 µg/m³, 4.9× usual Bismarck, 7 September: 49.8 µg/m³, 5.5× usual Bismarck, 8 September: 34.4 µg/m³, 3.8× usual Bismarck, 9 September: 16.5 µg/m³, 1.8× usual Bismarck, 10 September: 18.3 µg/m³, 2.0× usual Bismarck, 11 September: 13.3 µg/m³, 1.5× usual West Fargo West Fargo, 3 September: 23.7 µg/m³, 3.4× usual West Fargo, 4 September: 11.6 µg/m³, 1.7× usual West Fargo, 5 September: 51.7 µg/m³, 7.4× usual West Fargo, 6 September: 36.4 µg/m³, 5.2× usual West Fargo, 7 September: 32.2 µg/m³, 4.6× usual West Fargo, 8 September: 23.7 µg/m³, 3.4× usual West Fargo, 9 September: 18.7 µg/m³, 2.7× usual West Fargo, 10 September: 20.3 µg/m³, 2.9× usual West Fargo, 11 September: 11.0 µg/m³, 1.6× usual Aberdeen Aberdeen, 3 September: 6.3 µg/m³, 1.2× usual Aberdeen, 4 September: 5.2 µg/m³, 1.0× usual Aberdeen, 5 September: 40.8 µg/m³, 7.7× usual Aberdeen, 6 September: 35.3 µg/m³, 6.7× usual Aberdeen, 7 September: 28.1 µg/m³, 5.3× usual Aberdeen, 8 September: 27.4 µg/m³, 5.2× usual Aberdeen, 9 September: 14.5 µg/m³, 2.7× usual Aberdeen, 10 September: 11.7 µg/m³, 2.2× usual Aberdeen, 11 September: 8.4 µg/m³, 1.6× usual Topeka Topeka, 3 September: 13.0 µg/m³, 1.5× usual Topeka, 4 September: 14.3 µg/m³, 1.6× usual Topeka, 5 September: 12.6 µg/m³, 1.4× usual Topeka, 6 September: 71.8 µg/m³, 8.2× usual Topeka, 7 September: 72.4 µg/m³, 8.2× usual Topeka, 8 September: 29.5 µg/m³, 3.4× usual Topeka, 9 September: 17.6 µg/m³, 2.0× usual Topeka, 10 September: 12.6 µg/m³, 1.4× usual Topeka, 11 September: 8.9 µg/m³, 1.0× usual Grand Island Grand Island, 3 September: 12.3 µg/m³, 1.9× usual Grand Island, 4 September: 13.0 µg/m³, 2.0× usual Grand Island, 5 September: 17.5 µg/m³, 2.7× usual Grand Island, 6 September: 71.0 µg/m³, 11× usual Grand Island, 7 September: 59.5 µg/m³, 9.3× usual Grand Island, 8 September: 34.0 µg/m³, 5.3× usual Grand Island, 9 September: 15.0 µg/m³, 2.3× usual Grand Island, 10 September: 13.1 µg/m³, 2.0× usual Grand Island, 11 September: 10.1 µg/m³, 1.6× usual Lincoln Lincoln, 3 September: 8.8 µg/m³, 1.3× usual Lincoln, 4 September: 10.0 µg/m³, 1.5× usual Lincoln, 5 September: 14.3 µg/m³, 2.1× usual Lincoln, 6 September: 70.1 µg/m³, 10× usual Lincoln, 7 September: 49.9 µg/m³, 7.4× usual Lincoln, 8 September: 19.0 µg/m³, 2.8× usual Lincoln, 9 September: no reading Lincoln, 10 September: no reading Lincoln, 11 September: no reading Wichita Wichita, 3 September: 16.6 µg/m³, 1.7× usual Wichita, 4 September: 15.3 µg/m³, 1.5× usual Wichita, 5 September: 13.3 µg/m³, 1.3× usual Wichita, 6 September: 61.9 µg/m³, 6.2× usual Wichita, 7 September: 48.2 µg/m³, 4.8× usual Wichita, 8 September: 33.1 µg/m³, 3.3× usual Wichita, 9 September: 15.5 µg/m³, 1.6× usual Wichita, 10 September: 14.6 µg/m³, 1.5× usual Wichita, 11 September: 10.4 µg/m³, 1.0× usual Omaha Omaha, 3 September: 9.3 µg/m³, 1.3× usual Omaha, 4 September: 10.5 µg/m³, 1.5× usual Omaha, 5 September: 11.5 µg/m³, 1.6× usual Omaha, 6 September: 58.0 µg/m³, 8.1× usual Omaha, 7 September: 40.1 µg/m³, 5.6× usual Omaha, 8 September: 22.0 µg/m³, 3.1× usual Omaha, 9 September: 16.5 µg/m³, 2.3× usual Omaha, 10 September: 11.0 µg/m³, 1.5× usual Omaha, 11 September: 10.9 µg/m³, 1.5× usual Bellevue Bellevue, 3 September: 8.3 µg/m³, 1.4× usual Bellevue, 4 September: 11.2 µg/m³, 1.9× usual Bellevue, 5 September: 10.6 µg/m³, 1.8× usual Bellevue, 6 September: 56.4 µg/m³, 9.4× usual Bellevue, 7 September: 39.9 µg/m³, 6.6× usual Bellevue, 8 September: 21.6 µg/m³, 3.6× usual Bellevue, 9 September: 12.8 µg/m³, 2.1× usual Bellevue, 10 September: 8.2 µg/m³, 1.4× usual Bellevue, 11 September: 8.0 µg/m³, 1.3× usual Derby Derby, 3 September: 17.0 µg/m³, 2.0× usual Derby, 4 September: 15.4 µg/m³, 1.8× usual Derby, 5 September: 12.7 µg/m³, 1.5× usual Derby, 6 September: 56.2 µg/m³, 6.5× usual Derby, 7 September: 44.5 µg/m³, 5.2× usual Derby, 8 September: 32.0 µg/m³, 3.7× usual Derby, 9 September: 15.1 µg/m³, 1.8× usual Derby, 10 September: 14.6 µg/m³, 1.7× usual Derby, 11 September: 11.1 µg/m³, 1.3× usual Sioux Falls Sioux Falls, 3 September: 8.0 µg/m³, 1.4× usual Sioux Falls, 4 September: 7.3 µg/m³, 1.3× usual Sioux Falls, 5 September: 9.0 µg/m³, 1.6× usual Sioux Falls, 6 September: 52.3 µg/m³, 9.0× usual Sioux Falls, 7 September: 30.6 µg/m³, 5.3× usual Sioux Falls, 8 September: 22.9 µg/m³, 3.9× usual Sioux Falls, 9 September: 20.6 µg/m³, 3.6× usual Sioux Falls, 10 September: 8.5 µg/m³, 1.5× usual Sioux Falls, 11 September: 8.9 µg/m³, 1.5× usual Brookings Brookings, 3 September: 9.1 µg/m³, 1.5× usual Brookings, 4 September: 11.2 µg/m³, 1.9× usual Brookings, 5 September: 15.1 µg/m³, 2.5× usual Brookings, 6 September: 51.6 µg/m³, 8.6× usual Brookings, 7 September: 25.5 µg/m³, 4.3× usual Brookings, 8 September: 24.1 µg/m³, 4.0× usual Brookings, 9 September: 18.5 µg/m³, 3.1× usual Brookings, 10 September: 11.5 µg/m³, 1.9× usual Brookings, 11 September: 10.8 µg/m³, 1.8× usual Watertown Watertown, 3 September: 12.3 µg/m³, 1.8× usual Watertown, 4 September: 11.3 µg/m³, 1.7× usual Watertown, 5 September: 20.9 µg/m³, 3.1× usual Watertown, 6 September: 50.3 µg/m³, 7.5× usual Watertown, 7 September: 24.3 µg/m³, 3.6× usual Watertown, 8 September: 28.0 µg/m³, 4.2× usual Watertown, 9 September: 18.2 µg/m³, 2.7× usual Watertown, 10 September: 13.4 µg/m³, 2.0× usual Watertown, 11 September: 9.8 µg/m³, 1.5× usual Kansas City Kansas City, 3 September: 12.9 µg/m³, 1.6× usual Kansas City, 4 September: 12.4 µg/m³, 1.5× usual Kansas City, 5 September: 10.7 µg/m³, 1.3× usual Kansas City, 6 September: 44.5 µg/m³, 5.4× usual Kansas City, 7 September: 57.5 µg/m³, 6.9× usual Kansas City, 8 September: 26.5 µg/m³, 3.2× usual Kansas City, 9 September: 14.9 µg/m³, 1.8× usual Kansas City, 10 September: 11.1 µg/m³, 1.3× usual Kansas City, 11 September: 9.0 µg/m³, 1.1× usual Ponca City Ponca City, 3 September: 16.9 µg/m³, 2.0× usual Ponca City, 4 September: 13.6 µg/m³, 1.6× usual Ponca City, 5 September: 11.0 µg/m³, 1.3× usual Ponca City, 6 September: 43.4 µg/m³, 5.0× usual Ponca City, 7 September: 31.8 µg/m³, 3.7× usual Ponca City, 8 September: 27.4 µg/m³, 3.2× usual Ponca City, 9 September: 14.1 µg/m³, 1.6× usual Ponca City, 10 September: 11.4 µg/m³, 1.3× usual Ponca City, 11 September: 10.8 µg/m³, 1.3× usual Olathe Olathe, 3 September: 13.6 µg/m³, 1.6× usual Olathe, 4 September: 12.7 µg/m³, 1.5× usual Olathe, 5 September: 10.2 µg/m³, 1.2× usual Olathe, 6 September: 42.1 µg/m³, 5.1× usual Olathe, 7 September: 56.0 µg/m³, 6.7× usual Olathe, 8 September: 26.0 µg/m³, 3.1× usual Olathe, 9 September: 13.5 µg/m³, 1.6× usual Olathe, 10 September: 10.3 µg/m³, 1.2× usual Olathe, 11 September: 9.8 µg/m³, 1.2× usual Saint Joseph Saint Joseph, 3 September: 11.5 µg/m³, 1.3× usual Saint Joseph, 4 September: 11.9 µg/m³, 1.3× usual Saint Joseph, 5 September: 10.1 µg/m³, 1.1× usual Saint Joseph, 6 September: 39.7 µg/m³, 4.5× usual Saint Joseph, 7 September: 43.8 µg/m³, 4.9× usual Saint Joseph, 8 September: 22.7 µg/m³, 2.6× usual Saint Joseph, 9 September: 15.7 µg/m³, 1.8× usual Saint Joseph, 10 September: 10.3 µg/m³, 1.2× usual Saint Joseph, 11 September: 8.2 µg/m³, 0.9× usual Liberty Liberty, 3 September: 15.0 µg/m³, 2.6× usual Liberty, 4 September: 13.2 µg/m³, 2.3× usual Liberty, 5 September: 12.9 µg/m³, 2.3× usual Liberty, 6 September: 38.9 µg/m³, 6.8× usual Liberty, 7 September: 45.9 µg/m³, 8.1× usual Liberty, 8 September: 25.5 µg/m³, 4.5× usual Liberty, 9 September: 17.6 µg/m³, 3.1× usual Liberty, 10 September: 16.7 µg/m³, 2.9× usual Liberty, 11 September: 14.2 µg/m³, 2.5× usual Ankeny Ankeny, 3 September: 11.5 µg/m³, 1.6× usual Ankeny, 4 September: 14.1 µg/m³, 1.9× usual Ankeny, 5 September: 12.3 µg/m³, 1.7× usual Ankeny, 6 September: 35.5 µg/m³, 4.8× usual Ankeny, 7 September: 21.6 µg/m³, 2.9× usual Ankeny, 8 September: 10.3 µg/m³, 1.4× usual Ankeny, 9 September: 10.8 µg/m³, 1.5× usual Ankeny, 10 September: 16.6 µg/m³, 2.2× usual Ankeny, 11 September: 9.7 µg/m³, 1.3× usual Des Moines Des Moines, 3 September: 9.7 µg/m³, 1.3× usual Des Moines, 4 September: 11.8 µg/m³, 1.6× usual Des Moines, 5 September: 10.6 µg/m³, 1.4× usual Des Moines, 6 September: 34.7 µg/m³, 4.7× usual Des Moines, 7 September: 21.5 µg/m³, 2.9× usual Des Moines, 8 September: 9.2 µg/m³, 1.2× usual Des Moines, 9 September: 11.0 µg/m³, 1.5× usual Des Moines, 10 September: 13.9 µg/m³, 1.9× usual Des Moines, 11 September: 8.6 µg/m³, 1.2× usual Jenks Jenks, 3 September: 20.4 µg/m³, 2.4× usual Jenks, 4 September: 14.0 µg/m³, 1.6× usual Jenks, 5 September: 9.2 µg/m³, 1.1× usual Jenks, 6 September: 32.5 µg/m³, 3.8× usual Jenks, 7 September: 35.4 µg/m³, 4.1× usual Jenks, 8 September: 20.9 µg/m³, 2.4× usual Jenks, 9 September: 19.1 µg/m³, 2.2× usual Jenks, 10 September: 12.2 µg/m³, 1.4× usual Jenks, 11 September: 12.4 µg/m³, 1.4× usual Kansas City Kansas City, 3 September: 9.7 µg/m³, 1.4× usual Kansas City, 4 September: 9.4 µg/m³, 1.4× usual Kansas City, 5 September: 8.1 µg/m³, 1.2× usual Kansas City, 6 September: 31.4 µg/m³, 4.6× usual Kansas City, 7 September: 43.5 µg/m³, 6.3× usual Kansas City, 8 September: 18.2 µg/m³, 2.6× usual Kansas City, 9 September: 10.0 µg/m³, 1.4× usual Kansas City, 10 September: 8.0 µg/m³, 1.2× usual Kansas City, 11 September: 7.2 µg/m³, 1.0× usual Iowa City Iowa City, 3 September: 10.7 µg/m³, 1.5× usual Iowa City, 4 September: 13.5 µg/m³, 1.8× usual Iowa City, 5 September: 7.8 µg/m³, 1.1× usual Iowa City, 6 September: 27.5 µg/m³, 3.8× usual Iowa City, 7 September: 10.8 µg/m³, 1.5× usual Iowa City, 8 September: 6.7 µg/m³, 0.9× usual Iowa City, 9 September: 6.7 µg/m³, 0.9× usual Iowa City, 10 September: 14.1 µg/m³, 1.9× usual Iowa City, 11 September: 9.9 µg/m³, 1.4× usual Saint Cloud Saint Cloud, 3 September: 15.4 µg/m³, 2.2× usual Saint Cloud, 4 September: 15.0 µg/m³, 2.1× usual Saint Cloud, 5 September: 13.7 µg/m³, 2.0× usual Saint Cloud, 6 September: 26.6 µg/m³, 3.8× usual Saint Cloud, 7 September: 14.9 µg/m³, 2.1× usual Saint Cloud, 8 September: 9.2 µg/m³, 1.3× usual Saint Cloud, 9 September: 11.9 µg/m³, 1.7× usual Saint Cloud, 10 September: 15.1 µg/m³, 2.2× usual Saint Cloud, 11 September: 15.9 µg/m³, 2.3× usual Raymore Raymore, 3 September: 9.4 µg/m³, 1.6× usual Raymore, 4 September: 8.9 µg/m³, 1.5× usual Raymore, 5 September: 7.1 µg/m³, 1.2× usual Raymore, 6 September: 26.1 µg/m³, 4.5× usual Raymore, 7 September: 41.3 µg/m³, 7.1× usual Raymore, 8 September: 16.6 µg/m³, 2.9× usual Raymore, 9 September: 7.2 µg/m³, 1.2× usual Raymore, 10 September: 6.9 µg/m³, 1.2× usual Raymore, 11 September: 7.6 µg/m³, 1.3× usual Tulsa Tulsa, 3 September: 18.4 µg/m³, 1.9× usual Tulsa, 4 September: 12.9 µg/m³, 1.3× usual Tulsa, 5 September: 8.1 µg/m³, 0.8× usual Tulsa, 6 September: no reading Tulsa, 7 September: 34.8 µg/m³, 3.6× usual Tulsa, 8 September: 20.2 µg/m³, 2.1× usual Tulsa, 9 September: 16.5 µg/m³, 1.7× usual Tulsa, 10 September: 13.1 µg/m³, 1.3× usual Tulsa, 11 September: 13.6 µg/m³, 1.4× usual 3 Sep 4 5 6 7 8 9 10 11 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
Grand Island Nebraska, United States 3 6 September 6.4 11× Lincoln Nebraska, United States 2 6 September 6.7 10× Bismarck North Dakota, United States 2 5 September 9.1 9.6× Bellevue Nebraska, United States 2 6 September 6.0 9.4× Sioux Falls South Dakota, United States 2 6 September 5.8 9.0× Brookings South Dakota, United States 2 6 September 6.0 8.6× Topeka Kansas, United States 3 7 September 8.8 8.2× Omaha Nebraska, United States 2 6 September 7.2 8.1× Liberty Missouri, United States 3 7 September 5.7 8.1× Aberdeen South Dakota, United States 2 5 September 5.3 7.7× Watertown South Dakota, United States 1 6 September 6.7 7.5× West Fargo North Dakota, United States 2 5 September 7.0 7.4× Raymore Missouri, United States 2 7 September 5.8 7.1× Kansas City Kansas, United States 3 7 September 8.3 6.9× Olathe Kansas, United States 3 7 September 8.3 6.7× Derby Kansas, United States 3 6 September 8.6 6.5× Kansas City Missouri, United States 2 7 September 6.9 6.3× Wichita Kansas, United States 3 6 September 10.0 6.2× Ponca City Oklahoma, United States 3 6 September 8.6 5.0× Saint Joseph Missouri, United States 2 7 September 8.9 4.9× Ankeny Iowa, United States 1 6 September 7.4 4.8× Des Moines Iowa, United States 1 6 September 7.4 4.7× Jenks Oklahoma, United States 2 7 September 8.6 4.1× Saint Cloud Minnesota, United States 1 6 September 7.0 3.8× Iowa City Iowa, United States 1 6 September 7.3 3.8× Tulsa Oklahoma, United States 1 7 September 9.8 3.6×
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 the United States
Number 15 of 41 episodes in the United States since our records began, by cities reached.
North-eastern United States and Canada, June and July 2023 279 North-eastern United States and Canada, May and June 2023 260 North-eastern United States and Canada, July 2023 241 North-eastern United States and Canada, June 2023 161 North-western United States and Canada, August 2023 110 North-eastern United States and Canada, July 2023 75 Western United States, September 2023 61 South-eastern United States, October 2023 47 North-eastern United States, July 2023 46 North-western United States and Canada, May 2023 42 Western United States, December 2023 32 Northern United States, January 2023 32 Northern United States, September 2023 26 Bars: cities reached; colour: the level of the episode's highest daily reading. All 41 .
Use this page SmogRank, Northern United States, September 2023: 26 cities with PM2.5 at twice their usual or more, 6 to 8 September 2023, smogrank.com/episodes/2023-09-northern-united-states (accessed 2 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.
