SmogRank / Episodes / United States

Minnesota, Wisconsin and North Dakota, United States, August 2024

For 2 days, from 18 to 19 August 2024, 11 cities in the United States had PM2.5 at least twice their usual for the time of year. The worst reading was Saint Cloud, Minnesota, United States: 30.0 µg/m³ on 18 August, about 3.5× its usual 8.5.

No cause namedWe have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached11in 1 country
Days218 to 19 August 2024
Worst day18 August9 cities counted
Furthest above usual3.6×Superior

Day by day

18 August 9 cities at twice their usual or more
Apple ValleyMankatoRochesterBrookingsWatertownSioux FallsAberdeenAppletonShakopeeMinneapolisBurnsvilleSaint PaulEau ClaireWest FargoBlaineSaint MichaelDuluthSaint CloudSuperior
15 Aug16171819202122
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

Saint CloudSaint Cloud, 15 August: 4.5 µg/m³Saint Cloud, 16 August: 2.7 µg/m³Saint Cloud, 17 August: 10.6 µg/m³Saint Cloud, 18 August: 30.0 µg/m³, 3.5× its usual 8.5Saint Cloud, 19 August: 27.8 µg/m³, 3.3× its usual 8.3Saint Cloud, 20 August: 23.3 µg/m³Saint Cloud, 21 August: 16.6 µg/m³Saint Cloud, 22 August: 7.5 µg/m³SuperiorSuperior, 15 August: 10.5 µg/m³Superior, 16 August: 4.5 µg/m³Superior, 17 August: 11.6 µg/m³Superior, 18 August: 29.8 µg/m³, 3.6× its usual 8.2Superior, 19 August: 17.9 µg/m³Superior, 20 August: 4.4 µg/m³Superior, 21 August: 6.4 µg/m³Superior, 22 August: 7.2 µg/m³BurnsvilleBurnsville, 15 August: 4.8 µg/m³Burnsville, 16 August: 5.2 µg/m³Burnsville, 17 August: 6.8 µg/m³Burnsville, 18 August: 28.6 µg/m³, 2.9× its usual 9.9Burnsville, 19 August: 25.7 µg/m³, 2.7× its usual 9.5Burnsville, 20 August: 21.7 µg/m³Burnsville, 21 August: 12.9 µg/m³Burnsville, 22 August: 7.9 µg/m³DuluthDuluth, 15 August: 9.1 µg/m³Duluth, 16 August: 4.1 µg/m³Duluth, 17 August: 12.2 µg/m³Duluth, 18 August: 27.9 µg/m³, 3.5× its usual 7.9Duluth, 19 August: 17.0 µg/m³Duluth, 20 August: 4.0 µg/m³Duluth, 21 August: 6.8 µg/m³Duluth, 22 August: 7.2 µg/m³Saint PaulSaint Paul, 15 August: 4.5 µg/m³Saint Paul, 16 August: 5.1 µg/m³Saint Paul, 17 August: 7.3 µg/m³Saint Paul, 18 August: 27.9 µg/m³, 3.0× its usual 9.2Saint Paul, 19 August: 25.3 µg/m³, 2.8× its usual 9.1Saint Paul, 20 August: 18.3 µg/m³Saint Paul, 21 August: 10.1 µg/m³Saint Paul, 22 August: 7.3 µg/m³MinneapolisMinneapolis, 15 August: 4.6 µg/m³Minneapolis, 16 August: 4.9 µg/m³Minneapolis, 17 August: 6.7 µg/m³Minneapolis, 18 August: 27.3 µg/m³, 2.9× its usual 9.5Minneapolis, 19 August: 25.2 µg/m³, 2.7× its usual 9.5Minneapolis, 20 August: 19.7 µg/m³Minneapolis, 21 August: 11.8 µg/m³Minneapolis, 22 August: 7.3 µg/m³Saint MichaelSaint Michael, 15 August: 4.1 µg/m³Saint Michael, 16 August: 3.7 µg/m³Saint Michael, 17 August: 8.0 µg/m³Saint Michael, 18 August: 26.2 µg/m³, 3.0× its usual 8.6Saint Michael, 19 August: 27.2 µg/m³, 3.2× its usual 8.5Saint Michael, 20 August: 22.1 µg/m³Saint Michael, 21 August: 14.9 µg/m³Saint Michael, 22 August: 7.1 µg/m³BlaineBlaine, 15 August: 4.1 µg/m³Blaine, 16 August: 3.8 µg/m³Blaine, 17 August: 6.6 µg/m³Blaine, 18 August: 26.2 µg/m³, 3.2× its usual 8.1Blaine, 19 August: 24.5 µg/m³Blaine, 20 August: 17.4 µg/m³Blaine, 21 August: 11.5 µg/m³Blaine, 22 August: 7.3 µg/m³ShakopeeShakopee, 15 August: 4.7 µg/m³Shakopee, 16 August: 4.7 µg/m³Shakopee, 17 August: 8.2 µg/m³Shakopee, 18 August: 25.9 µg/m³, 2.8× its usual 9.3Shakopee, 19 August: 27.0 µg/m³, 2.8× its usual 9.6Shakopee, 20 August: 21.0 µg/m³Shakopee, 21 August: 14.0 µg/m³Shakopee, 22 August: 7.2 µg/m³West FargoWest Fargo, 15 August: 1.9 µg/m³West Fargo, 16 August: 6.8 µg/m³West Fargo, 17 August: 29.6 µg/m³West Fargo, 18 August: 22.8 µg/m³West Fargo, 19 August: 25.1 µg/m³, 3.2× its usual 7.9West Fargo, 20 August: 23.3 µg/m³West Fargo, 21 August: 17.4 µg/m³West Fargo, 22 August: 11.4 µg/m³Eau ClaireEau Claire, 15 August: 5.2 µg/m³Eau Claire, 16 August: 4.1 µg/m³Eau Claire, 17 August: 4.4 µg/m³Eau Claire, 18 August: 21.3 µg/m³Eau Claire, 19 August: 25.0 µg/m³, 3.2× its usual 7.8Eau Claire, 20 August: 8.2 µg/m³Eau Claire, 21 August: 5.5 µg/m³Eau Claire, 22 August: 5.9 µg/m³15 Aug16171819202122
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
SuperiorWisconsin, United States1 29.818 August8.23.6×
Saint CloudMinnesota, United States2 30.018 August8.53.5×
DuluthMinnesota, United States1 27.918 August7.93.5×
Saint MichaelMinnesota, United States2 27.219 August8.53.2×
BlaineMinnesota, United States1 26.218 August8.13.2×
West FargoNorth Dakota, United States1 25.119 August7.93.2×
Eau ClaireWisconsin, United States1 25.019 August7.83.2×
Saint PaulMinnesota, United States2 27.918 August9.23.0×
BurnsvilleMinnesota, United States2 28.618 August9.92.9×
MinneapolisMinnesota, United States2 27.318 August9.52.9×
ShakopeeMinnesota, United States2 27.019 August9.62.8×

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 92 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, Minnesota, Wisconsin and North Dakota, United States, August 2024: 11 cities with PM2.5 at twice their usual or more, 18 to 19 August 2024, smogrank.com/episodes/2024-08-minnesota-wisconsin-and-north-dakota-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.