SmogRank / Episodes / United States

Northern United States, 6 to 8 September 2023

For 3 days, from 6 to 8 September 2023, 25 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 namedWe have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached25in 1 country
Days36 to 8 September 2023
Worst day6 September24 cities counted
Furthest above usual11×Grand Island

Day by day

6 September 24 cities at twice their usual or more
WaterlooRochesterShakopeeApple ValleyBurnsvilleMinneapolisMuscatineSaint PaulSaint MichaelBlaineDavenportLa CrosseMolineSpringfieldClintonEau ClaireSpringdaleUniversity CityPeoriaArnoldLemaySt. LouisGranite CitySpringfieldEast Saint LouisSuperiorDuluthFort SmithEdmondOklahoma CityMooreWest MemphisBartlettTulsaSaint CloudIowa CityJenksDes MoinesAnkenySaint JosephPonca CityWest FargoWichitaKansas CityDerbyAberdeenOlatheKansas CityRaymoreWatertownLibertyOmahaTopekaBrookingsSioux FallsBellevueLincolnGrand Island
3 Sep4567891011
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

TopekaTopeka, 3 September: 13.0 µg/m³Topeka, 4 September: 14.3 µg/m³Topeka, 5 September: 12.6 µg/m³Topeka, 6 September: 71.8 µg/m³, 8.3× its usual 8.6Topeka, 7 September: 72.4 µg/m³, 8.2× its usual 8.8Topeka, 8 September: 29.5 µg/m³, 3.3× its usual 8.9Topeka, 9 September: 17.6 µg/m³Topeka, 10 September: 12.6 µg/m³Topeka, 11 September: 8.9 µg/m³Grand IslandGrand Island, 3 September: 12.3 µg/m³Grand Island, 4 September: 13.0 µg/m³Grand Island, 5 September: 17.5 µg/m³Grand Island, 6 September: 71.0 µg/m³, 11× its usual 6.4Grand Island, 7 September: 59.5 µg/m³, 9.0× its usual 6.6Grand Island, 8 September: 34.0 µg/m³, 4.9× its usual 6.9Grand Island, 9 September: 15.0 µg/m³Grand Island, 10 September: 13.1 µg/m³Grand Island, 11 September: 10.1 µg/m³LincolnLincoln, 3 September: 8.8 µg/m³Lincoln, 4 September: 10.0 µg/m³Lincoln, 5 September: 14.3 µg/m³Lincoln, 6 September: 70.1 µg/m³, 10× its usual 6.7Lincoln, 7 September: 49.9 µg/m³, 7.2× its usual 6.9Lincoln, 8 September: 19.0 µg/m³Lincoln, 9 September: no readingLincoln, 10 September: no readingLincoln, 11 September: no readingWichitaWichita, 3 September: 16.6 µg/m³Wichita, 4 September: 15.3 µg/m³Wichita, 5 September: 13.3 µg/m³Wichita, 6 September: 61.9 µg/m³, 6.2× its usual 10.0Wichita, 7 September: 48.2 µg/m³, 4.7× its usual 10.3Wichita, 8 September: 33.1 µg/m³, 3.2× its usual 10.3Wichita, 9 September: 15.5 µg/m³Wichita, 10 September: 14.6 µg/m³Wichita, 11 September: 10.4 µg/m³OmahaOmaha, 3 September: 9.3 µg/m³Omaha, 4 September: 10.5 µg/m³Omaha, 5 September: 11.5 µg/m³Omaha, 6 September: 58.0 µg/m³, 8.1× its usual 7.2Omaha, 7 September: 40.1 µg/m³, 5.5× its usual 7.3Omaha, 8 September: 22.0 µg/m³Omaha, 9 September: 16.5 µg/m³Omaha, 10 September: 11.0 µg/m³Omaha, 11 September: 10.9 µg/m³BellevueBellevue, 3 September: 8.3 µg/m³Bellevue, 4 September: 11.2 µg/m³Bellevue, 5 September: 10.6 µg/m³Bellevue, 6 September: 56.4 µg/m³, 9.4× its usual 6.0Bellevue, 7 September: 39.9 µg/m³, 6.6× its usual 6.0Bellevue, 8 September: 21.6 µg/m³Bellevue, 9 September: 12.8 µg/m³Bellevue, 10 September: 8.2 µg/m³Bellevue, 11 September: 8.0 µg/m³DerbyDerby, 3 September: 17.0 µg/m³Derby, 4 September: 15.4 µg/m³Derby, 5 September: 12.7 µg/m³Derby, 6 September: 56.2 µg/m³, 6.5× its usual 8.6Derby, 7 September: 44.5 µg/m³, 4.9× its usual 9.1Derby, 8 September: 32.0 µg/m³, 3.5× its usual 9.1Derby, 9 September: 15.1 µg/m³Derby, 10 September: 14.6 µg/m³Derby, 11 September: 11.1 µg/m³Sioux FallsSioux Falls, 3 September: 8.0 µg/m³Sioux Falls, 4 September: 7.3 µg/m³Sioux Falls, 5 September: 9.0 µg/m³Sioux Falls, 6 September: 52.3 µg/m³, 9.0× its usual 5.8Sioux Falls, 7 September: 30.6 µg/m³, 5.3× its usual 5.8Sioux Falls, 8 September: 22.9 µg/m³Sioux Falls, 9 September: 20.6 µg/m³Sioux Falls, 10 September: 8.5 µg/m³Sioux Falls, 11 September: 8.9 µg/m³BrookingsBrookings, 3 September: 9.1 µg/m³Brookings, 4 September: 11.2 µg/m³Brookings, 5 September: 15.1 µg/m³Brookings, 6 September: 51.6 µg/m³, 8.6× its usual 6.0Brookings, 7 September: 25.5 µg/m³, 4.2× its usual 6.1Brookings, 8 September: 24.1 µg/m³Brookings, 9 September: 18.5 µg/m³Brookings, 10 September: 11.5 µg/m³Brookings, 11 September: 10.8 µg/m³WatertownWatertown, 3 September: 12.3 µg/m³Watertown, 4 September: 11.3 µg/m³Watertown, 5 September: 20.9 µg/m³Watertown, 6 September: 50.3 µg/m³, 7.5× its usual 6.7Watertown, 7 September: 24.3 µg/m³Watertown, 8 September: 28.0 µg/m³Watertown, 9 September: 18.2 µg/m³Watertown, 10 September: 13.4 µg/m³Watertown, 11 September: 9.8 µg/m³Kansas CityKansas City, 3 September: 12.9 µg/m³Kansas City, 4 September: 12.4 µg/m³Kansas City, 5 September: 10.7 µg/m³Kansas City, 6 September: 44.5 µg/m³, 5.3× its usual 8.4Kansas City, 7 September: 57.5 µg/m³, 6.9× its usual 8.3Kansas City, 8 September: 26.5 µg/m³, 3.2× its usual 8.4Kansas City, 9 September: 14.9 µg/m³Kansas City, 10 September: 11.1 µg/m³Kansas City, 11 September: 9.0 µg/m³Ponca CityPonca City, 3 September: 16.9 µg/m³Ponca City, 4 September: 13.6 µg/m³Ponca City, 5 September: 11.0 µg/m³Ponca City, 6 September: 43.4 µg/m³, 5.0× its usual 8.6Ponca City, 7 September: 31.8 µg/m³, 3.7× its usual 8.6Ponca City, 8 September: 27.4 µg/m³, 3.1× its usual 8.7Ponca City, 9 September: 14.1 µg/m³Ponca City, 10 September: 11.4 µg/m³Ponca City, 11 September: 10.8 µg/m³OlatheOlathe, 3 September: 13.6 µg/m³Olathe, 4 September: 12.7 µg/m³Olathe, 5 September: 10.2 µg/m³Olathe, 6 September: 42.1 µg/m³, 5.3× its usual 8.0Olathe, 7 September: 56.0 µg/m³, 6.7× its usual 8.3Olathe, 8 September: 26.0 µg/m³, 3.1× its usual 8.3Olathe, 9 September: 13.5 µg/m³Olathe, 10 September: 10.3 µg/m³Olathe, 11 September: 9.8 µg/m³Saint JosephSaint Joseph, 3 September: 11.5 µg/m³Saint Joseph, 4 September: 11.9 µg/m³Saint Joseph, 5 September: 10.1 µg/m³Saint Joseph, 6 September: 39.7 µg/m³, 4.5× its usual 8.8Saint Joseph, 7 September: 43.8 µg/m³, 4.9× its usual 8.9Saint Joseph, 8 September: 22.7 µg/m³Saint Joseph, 9 September: 15.7 µg/m³Saint Joseph, 10 September: 10.3 µg/m³Saint Joseph, 11 September: 8.2 µg/m³LibertyLiberty, 3 September: 15.0 µg/m³Liberty, 4 September: 13.2 µg/m³Liberty, 5 September: 12.9 µg/m³Liberty, 6 September: 38.9 µg/m³, 6.9× its usual 5.6Liberty, 7 September: 45.9 µg/m³, 8.1× its usual 5.7Liberty, 8 September: 25.5 µg/m³, 4.5× its usual 5.7Liberty, 9 September: 17.6 µg/m³Liberty, 10 September: 16.7 µg/m³Liberty, 11 September: 14.2 µg/m³West FargoWest Fargo, 3 September: 23.7 µg/m³West Fargo, 4 September: 11.6 µg/m³West Fargo, 5 September: 51.7 µg/m³West Fargo, 6 September: 36.4 µg/m³, 5.2× its usual 7.0West Fargo, 7 September: 32.2 µg/m³, 4.5× its usual 7.1West Fargo, 8 September: 23.7 µg/m³West Fargo, 9 September: 18.7 µg/m³West Fargo, 10 September: 20.3 µg/m³West Fargo, 11 September: 11.0 µg/m³AnkenyAnkeny, 3 September: 11.5 µg/m³Ankeny, 4 September: 14.1 µg/m³Ankeny, 5 September: 12.3 µg/m³Ankeny, 6 September: 35.5 µg/m³, 4.8× its usual 7.4Ankeny, 7 September: 21.6 µg/m³Ankeny, 8 September: 10.3 µg/m³Ankeny, 9 September: 10.8 µg/m³Ankeny, 10 September: 16.6 µg/m³Ankeny, 11 September: 9.7 µg/m³AberdeenAberdeen, 3 September: 6.3 µg/m³Aberdeen, 4 September: 5.2 µg/m³Aberdeen, 5 September: 40.8 µg/m³Aberdeen, 6 September: 35.3 µg/m³, 6.7× its usual 5.3Aberdeen, 7 September: 28.1 µg/m³, 5.2× its usual 5.4Aberdeen, 8 September: 27.4 µg/m³Aberdeen, 9 September: 14.5 µg/m³Aberdeen, 10 September: 11.7 µg/m³Aberdeen, 11 September: 8.4 µg/m³Des MoinesDes Moines, 3 September: 9.7 µg/m³Des Moines, 4 September: 11.8 µg/m³Des Moines, 5 September: 10.6 µg/m³Des Moines, 6 September: 34.7 µg/m³, 4.7× its usual 7.4Des Moines, 7 September: 21.5 µg/m³Des Moines, 8 September: 9.2 µg/m³Des Moines, 9 September: 11.0 µg/m³Des Moines, 10 September: 13.9 µg/m³Des Moines, 11 September: 8.6 µg/m³JenksJenks, 3 September: 20.4 µg/m³Jenks, 4 September: 14.0 µg/m³Jenks, 5 September: 9.2 µg/m³Jenks, 6 September: 32.5 µg/m³, 3.8× its usual 8.5Jenks, 7 September: 35.4 µg/m³, 4.1× its usual 8.6Jenks, 8 September: 20.9 µg/m³Jenks, 9 September: 19.1 µg/m³Jenks, 10 September: 12.2 µg/m³Jenks, 11 September: 12.4 µg/m³Kansas CityKansas City, 3 September: 9.7 µg/m³Kansas City, 4 September: 9.4 µg/m³Kansas City, 5 September: 8.1 µg/m³Kansas City, 6 September: 31.4 µg/m³, 4.6× its usual 6.9Kansas City, 7 September: 43.5 µg/m³, 6.3× its usual 6.9Kansas City, 8 September: 18.2 µg/m³Kansas City, 9 September: 10.0 µg/m³Kansas City, 10 September: 8.0 µg/m³Kansas City, 11 September: 7.2 µg/m³Iowa CityIowa City, 3 September: 10.7 µg/m³Iowa City, 4 September: 13.5 µg/m³Iowa City, 5 September: 7.8 µg/m³Iowa City, 6 September: 27.5 µg/m³, 3.8× its usual 7.3Iowa City, 7 September: 10.8 µg/m³Iowa City, 8 September: 6.7 µg/m³Iowa City, 9 September: 6.7 µg/m³Iowa City, 10 September: 14.1 µg/m³Iowa City, 11 September: 9.9 µg/m³Saint CloudSaint Cloud, 3 September: 15.4 µg/m³Saint Cloud, 4 September: 15.0 µg/m³Saint Cloud, 5 September: 13.7 µg/m³Saint Cloud, 6 September: 26.6 µg/m³, 3.8× its usual 7.0Saint Cloud, 7 September: 14.9 µg/m³Saint Cloud, 8 September: 9.2 µg/m³Saint Cloud, 9 September: 11.9 µg/m³Saint Cloud, 10 September: 15.1 µg/m³Saint Cloud, 11 September: 15.9 µg/m³RaymoreRaymore, 3 September: 9.4 µg/m³Raymore, 4 September: 8.9 µg/m³Raymore, 5 September: 7.1 µg/m³Raymore, 6 September: 26.1 µg/m³, 4.4× its usual 5.9Raymore, 7 September: 41.3 µg/m³, 7.1× its usual 5.8Raymore, 8 September: 16.6 µg/m³Raymore, 9 September: 7.2 µg/m³Raymore, 10 September: 6.9 µg/m³Raymore, 11 September: 7.6 µg/m³TulsaTulsa, 3 September: 18.4 µg/m³Tulsa, 4 September: 12.9 µg/m³Tulsa, 5 September: 8.1 µg/m³Tulsa, 6 September: no readingTulsa, 7 September: 34.8 µg/m³, 3.6× its usual 9.8Tulsa, 8 September: 20.2 µg/m³Tulsa, 9 September: 16.5 µg/m³Tulsa, 10 September: 13.1 µg/m³Tulsa, 11 September: 13.6 µg/m³3 Sep4567891011
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
Grand IslandNebraska, United States3 71.06 September6.411×
LincolnNebraska, United States2 70.16 September6.711×
BellevueNebraska, United States2 56.46 September6.09.4×
Sioux FallsSouth Dakota, United States2 52.36 September5.89.0×
BrookingsSouth Dakota, United States2 51.66 September6.08.6×
TopekaKansas, United States3 72.47 September8.88.2×
OmahaNebraska, United States2 58.06 September7.28.1×
LibertyMissouri, United States3 45.97 September5.78.1×
WatertownSouth Dakota, United States1 50.36 September6.77.5×
RaymoreMissouri, United States2 41.37 September5.87.1×
Kansas CityKansas, United States3 57.57 September8.36.9×
OlatheKansas, United States3 56.07 September8.36.7×
AberdeenSouth Dakota, United States2 35.36 September5.36.7×
DerbyKansas, United States3 56.26 September8.66.5×
Kansas CityMissouri, United States2 43.57 September6.96.3×
WichitaKansas, United States3 61.96 September10.06.2×
West FargoNorth Dakota, United States2 36.46 September7.05.2×
Ponca CityOklahoma, United States3 43.46 September8.65.0×
Saint JosephMissouri, United States2 43.87 September8.94.9×
AnkenyIowa, United States1 35.56 September7.44.8×
Des MoinesIowa, United States1 34.76 September7.44.7×
JenksOklahoma, United States2 35.47 September8.64.1×
Iowa CityIowa, United States1 27.56 September7.33.8×
Saint CloudMinnesota, United States1 26.66 September7.03.8×
TulsaOklahoma, United States1 34.87 September9.83.6×

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 the United States

Number 41 of 130 episodes in the United States since our records began, by cities reached.

Bars: cities reached; colour: the level of the episode's highest daily reading. All 130.

Use this page

SmogRank, Northern United States, 6 to 8 September 2023: 25 cities with PM2.5 at twice their usual or more, 6 to 8 September 2023, smogrank.com/episodes/2023-09-06-northern-united-states (accessed 4 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.