SmogRank / Episodes / United States

Northern United States and Canada, July 2023

For 4 days, from 23 to 26 July 2023, 91 cities in the United States and Canada had PM2.5 at least twice their usual for the time of year. The worst reading was Lansing, Michigan, United States: 58.2 µg/m³ on 25 July, about 5.9× its usual 9.9. Ended 26 July.

Likely smoke from firesSmoke was mapped over the city on 94% of the counted city-days NOAA's smoke maps cover. Satellites see crop, field and forest fires alike, so this doesn't say which burned.
Cities reached91in 2 countries
Days423 to 26 July 2023
Worst day25 July65 cities counted
Furthest above usual6.3×Brainerd

Day by day

25 July 65 cities at twice their usual or more
PortageGarySault Ste. MarieLimaSavoyMiddletownColumbusDublinTerre HauteLebanonBloomingtonMasonWestervilleWhite OakSharonvilleDentClevelandNew AlbanyGahannaMedinaNorwoodCincinnatiSt. ThomasWarrensville HeightsDecaturPainesvilleAkronMolineDavenportCantonSpringfieldLa CrosseWarrenBrantfordGreater SudburyMuscatineYoungstownHermitageErieWaterdownHamiltonIowa CitySteubenvilleMississaugaWeirton HeightsBeaver FallsWheelingNew BrightonMoundsvilleJerseyvilleKennedy TownshipSt. CatharinesPittsburghRochesterWilkinsburgJefferson HillsWest MifflinMcKeesportMonessenNorth BayBuffaloKenmoreCheektowagaJohnstownFrostburgAltoonaDes MoinesRochesterBellevilleState CollegeHalfwayHagerstownSchlusserCarlisleKingstonHarrisburgKearneyLibertySyracuseYorkSaint JosephLebanonScaggsvilleHunt ValleyLancasterBaltimoreOttawaNew HollandBellevueWyomissingScrantonOmahaEdgewoodReadingBlairUticaAllentownElktonKennett SquareNewarkGlasgowBethlehemSioux FallsBearWilmingtonBrookingsClaymontNorristownChesterVermillionLincolnDoverPhiladelphiaPennsaukenWatertownBensalemBeatriceEwingSouth VinelandTrentonNew BrunswickPatersonLindenElizabethNewburghMount IvyPleasantvilleBayonneNew CitySmithvilleJersey CityAlbanyNew York CityFort LeeToms RiverDorvalWhite PlainsMontréalRivière-des-Prairies–Pointe-aux-TremblesBrossardHempsteadDanburyPittsfieldBurlingtonBenningtonSaint-Jean-sur-RichelieuNorth AdamsAberdeenGrand IslandRutlandBridgeportWaterburyHolbrookNew HavenDaytonSpringfieldToledoLondonRedfordAnkenyTorontoChathamMiltonPeoriaBrooklinClintonSarniaNew BaltimoreIndianapolisWaterlooCornwallBloomingtonBramptonKitchenerMcCordsvilleFishersShakopeeBurnsvilleApple ValleyGuelphBay CityOakvilleWindsorDearbornDetroitPort HuronOak LawnLincoln ParkWest FargoBraidwoodYpsilantiTaylorNewmarketBarrieBlaineTecumsehGreen BayChicagoSuperiorMarshallPeterboroughSaint MichaelLafayetteSaint PaulMinneapolisNapervilleGrand RapidsHollandVirginiaHammondRockfordFlintMilwaukeeAndersonElkhartDuluthJolietKalamazooJenisonHudsonvilleColumbia CityCaryParry SoundKokomoNorthbrookFranklin ParkZionWinthrop HarborSouth MilwaukeeGreendaleDetroit LakesDes PlainesCalumet CityAppletonEau ClaireAltoonaWaukeshaCloquetSouth BendSaint CloudEast ChicagoBarabooLansingMadisonBrainerd
20 Jul212223242526272829
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

BrainerdBrainerd, 20 July: 9.5 µg/m³Brainerd, 21 July: 9.9 µg/m³Brainerd, 22 July: 13.6 µg/m³Brainerd, 23 July: 46.6 µg/m³, 5.5× its usual 8.4Brainerd, 24 July: 53.0 µg/m³, 6.3× its usual 8.4Brainerd, 25 July: 24.5 µg/m³Brainerd, 26 July: 7.7 µg/m³Brainerd, 27 July: 8.3 µg/m³Brainerd, 28 July: 6.6 µg/m³Brainerd, 29 July: 3.9 µg/m³Saint CloudSaint Cloud, 20 July: 10.4 µg/m³Saint Cloud, 21 July: 12.2 µg/m³Saint Cloud, 22 July: 14.3 µg/m³Saint Cloud, 23 July: 46.7 µg/m³, 5.4× its usual 8.6Saint Cloud, 24 July: 38.2 µg/m³, 4.3× its usual 8.8Saint Cloud, 25 July: 21.7 µg/m³Saint Cloud, 26 July: 7.7 µg/m³Saint Cloud, 27 July: 10.5 µg/m³Saint Cloud, 28 July: 7.5 µg/m³Saint Cloud, 29 July: 5.8 µg/m³AltoonaAltoona, 20 July: 5.5 µg/m³Altoona, 21 July: 8.1 µg/m³Altoona, 22 July: 10.9 µg/m³Altoona, 23 July: 35.9 µg/m³, 4.0× its usual 8.9Altoona, 24 July: 46.6 µg/m³, 5.1× its usual 9.1Altoona, 25 July: 29.9 µg/m³, 3.3× its usual 9.1Altoona, 26 July: 8.0 µg/m³Altoona, 27 July: 7.5 µg/m³Altoona, 28 July: 5.6 µg/m³Altoona, 29 July: 5.3 µg/m³Eau ClaireEau Claire, 20 July: 5.5 µg/m³Eau Claire, 21 July: 8.1 µg/m³Eau Claire, 22 July: 10.9 µg/m³Eau Claire, 23 July: 35.9 µg/m³, 4.0× its usual 8.9Eau Claire, 24 July: 46.6 µg/m³, 5.1× its usual 9.2Eau Claire, 25 July: 29.9 µg/m³, 3.3× its usual 9.2Eau Claire, 26 July: 8.0 µg/m³Eau Claire, 27 July: 7.5 µg/m³Eau Claire, 28 July: 5.6 µg/m³Eau Claire, 29 July: 5.3 µg/m³DuluthDuluth, 20 July: 8.0 µg/m³Duluth, 21 July: 11.8 µg/m³Duluth, 22 July: 13.1 µg/m³Duluth, 23 July: 44.5 µg/m³, 4.4× its usual 10.1Duluth, 24 July: 39.2 µg/m³, 3.9× its usual 10.0Duluth, 25 July: 24.2 µg/m³Duluth, 26 July: 16.9 µg/m³Duluth, 27 July: 9.2 µg/m³Duluth, 28 July: 6.2 µg/m³Duluth, 29 July: 4.8 µg/m³VirginiaVirginia, 20 July: 8.1 µg/m³Virginia, 21 July: 11.5 µg/m³Virginia, 22 July: 13.8 µg/m³Virginia, 23 July: 43.7 µg/m³, 4.2× its usual 10.3Virginia, 24 July: 20.6 µg/m³Virginia, 25 July: 28.4 µg/m³, 2.8× its usual 10.2Virginia, 26 July: 17.9 µg/m³Virginia, 27 July: 8.7 µg/m³Virginia, 28 July: 5.8 µg/m³Virginia, 29 July: 3.9 µg/m³Detroit LakesDetroit Lakes, 20 July: 11.4 µg/m³Detroit Lakes, 21 July: 13.8 µg/m³Detroit Lakes, 22 July: 16.8 µg/m³Detroit Lakes, 23 July: 43.4 µg/m³, 5.0× its usual 8.6Detroit Lakes, 24 July: 35.6 µg/m³, 4.1× its usual 8.6Detroit Lakes, 25 July: 22.1 µg/m³Detroit Lakes, 26 July: 9.1 µg/m³Detroit Lakes, 27 July: 7.4 µg/m³Detroit Lakes, 28 July: 5.7 µg/m³Detroit Lakes, 29 July: 4.1 µg/m³CloquetCloquet, 20 July: 7.0 µg/m³Cloquet, 21 July: 9.7 µg/m³Cloquet, 22 July: 11.8 µg/m³Cloquet, 23 July: 41.1 µg/m³, 5.1× its usual 8.1Cloquet, 24 July: 42.6 µg/m³, 5.3× its usual 8.1Cloquet, 25 July: 25.7 µg/m³, 3.3× its usual 7.8Cloquet, 26 July: 19.3 µg/m³Cloquet, 27 July: 7.6 µg/m³Cloquet, 28 July: 5.9 µg/m³Cloquet, 29 July: 4.2 µg/m³SuperiorSuperior, 20 July: 8.3 µg/m³Superior, 21 July: 11.5 µg/m³Superior, 22 July: 12.6 µg/m³Superior, 23 July: 41.2 µg/m³, 3.8× its usual 10.9Superior, 24 July: 35.4 µg/m³, 3.2× its usual 10.9Superior, 25 July: 22.6 µg/m³Superior, 26 July: 16.4 µg/m³Superior, 27 July: 8.9 µg/m³Superior, 28 July: 6.3 µg/m³Superior, 29 July: 4.7 µg/m³MinneapolisMinneapolis, 20 July: 8.6 µg/m³Minneapolis, 21 July: 13.8 µg/m³Minneapolis, 22 July: 15.0 µg/m³Minneapolis, 23 July: 40.7 µg/m³, 4.0× its usual 10.1Minneapolis, 24 July: 37.3 µg/m³, 3.7× its usual 10.2Minneapolis, 25 July: 22.8 µg/m³Minneapolis, 26 July: 6.3 µg/m³Minneapolis, 27 July: 9.2 µg/m³Minneapolis, 28 July: 6.2 µg/m³Minneapolis, 29 July: 9.4 µg/m³Saint PaulSaint Paul, 20 July: 8.5 µg/m³Saint Paul, 21 July: 11.5 µg/m³Saint Paul, 22 July: 14.4 µg/m³Saint Paul, 23 July: 40.1 µg/m³, 4.0× its usual 10.1Saint Paul, 24 July: 34.0 µg/m³, 3.4× its usual 10.1Saint Paul, 25 July: 25.3 µg/m³, 2.5× its usual 10.1Saint Paul, 26 July: 7.7 µg/m³Saint Paul, 27 July: 9.7 µg/m³Saint Paul, 28 July: 6.1 µg/m³Saint Paul, 29 July: 6.8 µg/m³West FargoWest Fargo, 20 July: 14.8 µg/m³West Fargo, 21 July: 16.9 µg/m³West Fargo, 22 July: 19.5 µg/m³West Fargo, 23 July: 27.7 µg/m³, 2.8× its usual 10.0West Fargo, 24 July: 35.6 µg/m³, 3.6× its usual 9.9West Fargo, 25 July: 18.5 µg/m³West Fargo, 26 July: 7.8 µg/m³West Fargo, 27 July: 7.6 µg/m³West Fargo, 28 July: 6.0 µg/m³West Fargo, 29 July: 3.6 µg/m³Saint MichaelSaint Michael, 20 July: 8.5 µg/m³Saint Michael, 21 July: 10.5 µg/m³Saint Michael, 22 July: 13.6 µg/m³Saint Michael, 23 July: 35.4 µg/m³, 4.0× its usual 8.8Saint Michael, 24 July: 29.6 µg/m³, 3.3× its usual 9.0Saint Michael, 25 July: 23.8 µg/m³Saint Michael, 26 July: 6.2 µg/m³Saint Michael, 27 July: 10.3 µg/m³Saint Michael, 28 July: 6.1 µg/m³Saint Michael, 29 July: 5.7 µg/m³BlaineBlaine, 20 July: 4.8 µg/m³Blaine, 21 July: 8.0 µg/m³Blaine, 22 July: 9.8 µg/m³Blaine, 23 July: 33.4 µg/m³, 3.8× its usual 8.8Blaine, 24 July: 32.2 µg/m³, 3.6× its usual 8.9Blaine, 25 July: 18.2 µg/m³Blaine, 26 July: 3.8 µg/m³Blaine, 27 July: 6.9 µg/m³Blaine, 28 July: 2.4 µg/m³Blaine, 29 July: 2.1 µg/m³LansingLansing, 20 July: 23.0 µg/m³Lansing, 21 July: 15.4 µg/m³Lansing, 22 July: 18.4 µg/m³Lansing, 23 July: 17.1 µg/m³Lansing, 24 July: 33.7 µg/m³, 3.6× its usual 9.3Lansing, 25 July: 58.2 µg/m³, 5.9× its usual 9.9Lansing, 26 July: 35.7 µg/m³, 3.6× its usual 9.9Lansing, 27 July: 14.8 µg/m³Lansing, 28 July: 10.7 µg/m³Lansing, 29 July: 5.0 µg/m³Franklin ParkFranklin Park, 20 July: 11.7 µg/m³Franklin Park, 21 July: 8.3 µg/m³Franklin Park, 22 July: 12.4 µg/m³Franklin Park, 23 July: 13.0 µg/m³Franklin Park, 24 July: 38.9 µg/m³, 3.3× its usual 11.8Franklin Park, 25 July: 57.0 µg/m³, 4.8× its usual 11.8Franklin Park, 26 July: 22.8 µg/m³Franklin Park, 27 July: 13.0 µg/m³Franklin Park, 28 July: 11.6 µg/m³Franklin Park, 29 July: 5.7 µg/m³Calumet CityCalumet City, 20 July: 12.0 µg/m³Calumet City, 21 July: 8.2 µg/m³Calumet City, 22 July: 13.6 µg/m³Calumet City, 23 July: 13.7 µg/m³Calumet City, 24 July: 32.1 µg/m³, 3.0× its usual 10.7Calumet City, 25 July: 53.7 µg/m³, 5.0× its usual 10.7Calumet City, 26 July: 22.6 µg/m³Calumet City, 27 July: 15.2 µg/m³Calumet City, 28 July: 12.3 µg/m³Calumet City, 29 July: 5.6 µg/m³MadisonMadison, 20 July: 7.8 µg/m³Madison, 21 July: 7.5 µg/m³Madison, 22 July: 9.6 µg/m³Madison, 23 July: 14.8 µg/m³Madison, 24 July: 52.0 µg/m³, 6.2× its usual 8.4Madison, 25 July: 35.7 µg/m³, 4.2× its usual 8.5Madison, 26 July: 15.5 µg/m³Madison, 27 July: 5.9 µg/m³Madison, 28 July: 4.7 µg/m³Madison, 29 July: 5.5 µg/m³Des PlainesDes Plaines, 20 July: 10.2 µg/m³Des Plaines, 21 July: 7.3 µg/m³Des Plaines, 22 July: 11.4 µg/m³Des Plaines, 23 July: 11.6 µg/m³Des Plaines, 24 July: 34.1 µg/m³, 3.4× its usual 10.0Des Plaines, 25 July: 50.8 µg/m³, 5.0× its usual 10.1Des Plaines, 26 July: 19.1 µg/m³Des Plaines, 27 July: 8.9 µg/m³Des Plaines, 28 July: 8.6 µg/m³Des Plaines, 29 July: 5.0 µg/m³KalamazooKalamazoo, 20 July: 16.7 µg/m³Kalamazoo, 21 July: 15.2 µg/m³Kalamazoo, 22 July: 15.0 µg/m³Kalamazoo, 23 July: 15.3 µg/m³Kalamazoo, 24 July: 25.9 µg/m³, 2.3× its usual 11.2Kalamazoo, 25 July: 50.3 µg/m³, 4.4× its usual 11.4Kalamazoo, 26 July: 28.7 µg/m³, 2.6× its usual 11.2Kalamazoo, 27 July: 11.8 µg/m³Kalamazoo, 28 July: 9.1 µg/m³Kalamazoo, 29 July: 5.7 µg/m³WaukeshaWaukesha, 20 July: 7.2 µg/m³Waukesha, 21 July: 7.9 µg/m³Waukesha, 22 July: 9.8 µg/m³Waukesha, 23 July: 13.6 µg/m³Waukesha, 24 July: 49.2 µg/m³, 5.1× its usual 9.7Waukesha, 25 July: 43.0 µg/m³, 4.4× its usual 9.8Waukesha, 26 July: 19.4 µg/m³Waukesha, 27 July: 8.5 µg/m³Waukesha, 28 July: 4.2 µg/m³Waukesha, 29 July: 4.5 µg/m³NorthbrookNorthbrook, 20 July: 10.0 µg/m³Northbrook, 21 July: 6.7 µg/m³Northbrook, 22 July: 10.9 µg/m³Northbrook, 23 July: 10.0 µg/m³Northbrook, 24 July: 29.7 µg/m³, 3.0× its usual 9.9Northbrook, 25 July: 48.5 µg/m³, 4.7× its usual 10.3Northbrook, 26 July: 22.7 µg/m³Northbrook, 27 July: 10.6 µg/m³Northbrook, 28 July: 9.2 µg/m³Northbrook, 29 July: 5.2 µg/m³JolietJoliet, 20 July: 12.0 µg/m³Joliet, 21 July: 8.4 µg/m³Joliet, 22 July: 12.0 µg/m³Joliet, 23 July: 13.3 µg/m³Joliet, 24 July: 35.7 µg/m³, 3.3× its usual 10.9Joliet, 25 July: 48.1 µg/m³, 4.4× its usual 11.0Joliet, 26 July: 21.8 µg/m³Joliet, 27 July: 12.2 µg/m³Joliet, 28 July: 14.2 µg/m³Joliet, 29 July: 5.8 µg/m³AppletonAppleton, 20 July: 5.4 µg/m³Appleton, 21 July: 9.0 µg/m³Appleton, 22 July: 9.7 µg/m³Appleton, 23 July: 18.7 µg/m³Appleton, 24 July: 46.4 µg/m³, 5.1× its usual 9.1Appleton, 25 July: 32.4 µg/m³, 3.6× its usual 9.1Appleton, 26 July: 19.4 µg/m³Appleton, 27 July: 8.5 µg/m³Appleton, 28 July: 4.7 µg/m³Appleton, 29 July: 4.1 µg/m³NapervilleNaperville, 20 July: 10.6 µg/m³Naperville, 21 July: 8.3 µg/m³Naperville, 22 July: 11.7 µg/m³Naperville, 23 July: 12.7 µg/m³Naperville, 24 July: 35.8 µg/m³, 3.2× its usual 11.2Naperville, 25 July: 45.8 µg/m³, 4.0× its usual 11.4Naperville, 26 July: 20.9 µg/m³Naperville, 27 July: no readingNaperville, 28 July: no readingNaperville, 29 July: no readingMilwaukeeMilwaukee, 20 July: 7.6 µg/m³Milwaukee, 21 July: 8.2 µg/m³Milwaukee, 22 July: 10.5 µg/m³Milwaukee, 23 July: 12.7 µg/m³Milwaukee, 24 July: 35.1 µg/m³, 3.3× its usual 10.5Milwaukee, 25 July: 45.6 µg/m³, 4.3× its usual 10.6Milwaukee, 26 July: 26.0 µg/m³, 2.5× its usual 10.5Milwaukee, 27 July: 10.1 µg/m³Milwaukee, 28 July: 4.9 µg/m³Milwaukee, 29 July: 4.9 µg/m³CaryCary, 20 July: 8.8 µg/m³Cary, 21 July: 7.0 µg/m³Cary, 22 July: 9.7 µg/m³Cary, 23 July: 11.6 µg/m³Cary, 24 July: 39.2 µg/m³, 4.1× its usual 9.6Cary, 25 July: 45.4 µg/m³, 4.5× its usual 10.0Cary, 26 July: 17.9 µg/m³Cary, 27 July: 8.5 µg/m³Cary, 28 July: 7.8 µg/m³Cary, 29 July: 4.9 µg/m³RockfordRockford, 20 July: 9.5 µg/m³Rockford, 21 July: 7.1 µg/m³Rockford, 22 July: 10.8 µg/m³Rockford, 23 July: 12.7 µg/m³Rockford, 24 July: 37.2 µg/m³, 3.7× its usual 10.0Rockford, 25 July: 45.2 µg/m³, 4.2× its usual 10.8Rockford, 26 July: 15.3 µg/m³Rockford, 27 July: 6.9 µg/m³Rockford, 28 July: 8.0 µg/m³Rockford, 29 July: 5.7 µg/m³HammondHammond, 20 July: 9.6 µg/m³Hammond, 21 July: 6.8 µg/m³Hammond, 22 July: 11.2 µg/m³Hammond, 23 July: 10.6 µg/m³Hammond, 24 July: 25.4 µg/m³, 2.4× its usual 10.5Hammond, 25 July: 44.3 µg/m³, 4.2× its usual 10.6Hammond, 26 July: 19.3 µg/m³Hammond, 27 July: 13.2 µg/m³Hammond, 28 July: 9.1 µg/m³Hammond, 29 July: 4.2 µg/m³BarabooBaraboo, 20 July: no readingBaraboo, 21 July: 7.7 µg/m³Baraboo, 22 July: 8.5 µg/m³Baraboo, 23 July: 16.2 µg/m³Baraboo, 24 July: 43.5 µg/m³, 5.5× its usual 7.9Baraboo, 25 July: 30.0 µg/m³, 3.8× its usual 7.9Baraboo, 26 July: 10.2 µg/m³Baraboo, 27 July: 3.8 µg/m³Baraboo, 28 July: 3.7 µg/m³Baraboo, 29 July: no readingGreendaleGreendale, 20 July: 7.3 µg/m³Greendale, 21 July: 7.6 µg/m³Greendale, 22 July: 9.9 µg/m³Greendale, 23 July: 12.1 µg/m³Greendale, 24 July: 34.6 µg/m³, 4.0× its usual 8.7Greendale, 25 July: 42.4 µg/m³, 4.9× its usual 8.7Greendale, 26 July: 22.9 µg/m³Greendale, 27 July: 8.0 µg/m³Greendale, 28 July: 4.4 µg/m³Greendale, 29 July: 4.2 µg/m³South MilwaukeeSouth Milwaukee, 20 July: 7.3 µg/m³South Milwaukee, 21 July: 7.6 µg/m³South Milwaukee, 22 July: 9.9 µg/m³South Milwaukee, 23 July: 12.1 µg/m³South Milwaukee, 24 July: 34.6 µg/m³, 4.0× its usual 8.7South Milwaukee, 25 July: 42.4 µg/m³, 4.9× its usual 8.7South Milwaukee, 26 July: 22.9 µg/m³South Milwaukee, 27 July: 8.0 µg/m³South Milwaukee, 28 July: 4.4 µg/m³South Milwaukee, 29 July: 4.2 µg/m³Green BayGreen Bay, 20 July: 5.1 µg/m³Green Bay, 21 July: 8.9 µg/m³Green Bay, 22 July: 10.2 µg/m³Green Bay, 23 July: 15.3 µg/m³Green Bay, 24 July: 37.9 µg/m³, 3.8× its usual 10.0Green Bay, 25 July: 26.0 µg/m³, 2.6× its usual 10.0Green Bay, 26 July: 21.7 µg/m³Green Bay, 27 July: 10.5 µg/m³Green Bay, 28 July: 4.5 µg/m³Green Bay, 29 July: 3.6 µg/m³South BendSouth Bend, 20 July: 11.7 µg/m³South Bend, 21 July: 7.0 µg/m³South Bend, 22 July: 10.9 µg/m³South Bend, 23 July: 11.8 µg/m³South Bend, 24 July: 24.3 µg/m³South Bend, 25 July: 52.5 µg/m³, 5.3× its usual 10.0South Bend, 26 July: 25.2 µg/m³, 2.6× its usual 9.8South Bend, 27 July: 11.6 µg/m³South Bend, 28 July: 8.0 µg/m³South Bend, 29 July: 3.9 µg/m³East ChicagoEast Chicago, 20 July: 11.3 µg/m³East Chicago, 21 July: 6.6 µg/m³East Chicago, 22 July: 11.3 µg/m³East Chicago, 23 July: 10.1 µg/m³East Chicago, 24 July: 23.8 µg/m³East Chicago, 25 July: 50.1 µg/m³, 5.4× its usual 9.2East Chicago, 26 July: 20.2 µg/m³East Chicago, 27 July: 10.8 µg/m³East Chicago, 28 July: 8.5 µg/m³East Chicago, 29 July: 4.1 µg/m³Columbia CityColumbia City, 20 July: 12.7 µg/m³Columbia City, 21 July: 6.8 µg/m³Columbia City, 22 July: 10.6 µg/m³Columbia City, 23 July: 11.8 µg/m³Columbia City, 24 July: 18.7 µg/m³Columbia City, 25 July: 45.2 µg/m³, 4.5× its usual 10.1Columbia City, 26 July: 26.6 µg/m³, 2.6× its usual 10.1Columbia City, 27 July: 9.0 µg/m³Columbia City, 28 July: 8.4 µg/m³Columbia City, 29 July: 3.8 µg/m³HudsonvilleHudsonville, 20 July: 11.4 µg/m³Hudsonville, 21 July: 9.5 µg/m³Hudsonville, 22 July: 12.6 µg/m³Hudsonville, 23 July: 12.2 µg/m³Hudsonville, 24 July: 21.7 µg/m³Hudsonville, 25 July: 45.1 µg/m³, 4.5× its usual 10.0Hudsonville, 26 July: 30.7 µg/m³, 3.1× its usual 9.8Hudsonville, 27 July: 14.1 µg/m³Hudsonville, 28 July: 10.1 µg/m³Hudsonville, 29 July: 5.5 µg/m³JenisonJenison, 20 July: 11.4 µg/m³Jenison, 21 July: 9.5 µg/m³Jenison, 22 July: 12.6 µg/m³Jenison, 23 July: 12.2 µg/m³Jenison, 24 July: 21.7 µg/m³Jenison, 25 July: 45.1 µg/m³, 4.5× its usual 10.0Jenison, 26 July: 30.7 µg/m³, 3.1× its usual 9.8Jenison, 27 July: 14.1 µg/m³Jenison, 28 July: 10.1 µg/m³Jenison, 29 July: 5.5 µg/m³Grand RapidsGrand Rapids, 20 July: 11.9 µg/m³Grand Rapids, 21 July: 9.9 µg/m³Grand Rapids, 22 July: 13.9 µg/m³Grand Rapids, 23 July: 12.3 µg/m³Grand Rapids, 24 July: 22.8 µg/m³Grand Rapids, 25 July: 44.3 µg/m³, 4.1× its usual 10.7Grand Rapids, 26 July: 31.6 µg/m³, 3.0× its usual 10.4Grand Rapids, 27 July: 17.4 µg/m³Grand Rapids, 28 July: 12.3 µg/m³Grand Rapids, 29 July: 6.0 µg/m³ElkhartElkhart, 20 July: no readingElkhart, 21 July: no readingElkhart, 22 July: 11.3 µg/m³Elkhart, 23 July: 11.4 µg/m³Elkhart, 24 July: 19.9 µg/m³Elkhart, 25 July: 43.4 µg/m³, 4.4× its usual 9.9Elkhart, 26 July: 24.9 µg/m³Elkhart, 27 July: 11.0 µg/m³Elkhart, 28 July: 8.4 µg/m³Elkhart, 29 July: 4.0 µg/m³Winthrop HarborWinthrop Harbor, 20 July: 6.8 µg/m³Winthrop Harbor, 21 July: 5.3 µg/m³Winthrop Harbor, 22 July: 7.9 µg/m³Winthrop Harbor, 23 July: 7.3 µg/m³Winthrop Harbor, 24 July: 23.1 µg/m³Winthrop Harbor, 25 July: 41.5 µg/m³, 4.9× its usual 8.5Winthrop Harbor, 26 July: 19.2 µg/m³Winthrop Harbor, 27 July: 6.7 µg/m³Winthrop Harbor, 28 July: 5.3 µg/m³Winthrop Harbor, 29 July: no readingZionZion, 20 July: 6.8 µg/m³Zion, 21 July: 5.3 µg/m³Zion, 22 July: 7.9 µg/m³Zion, 23 July: 7.3 µg/m³Zion, 24 July: 23.1 µg/m³Zion, 25 July: 41.5 µg/m³, 4.9× its usual 8.4Zion, 26 July: 19.2 µg/m³Zion, 27 July: 6.7 µg/m³Zion, 28 July: 5.3 µg/m³Zion, 29 July: no readingKokomoKokomo, 20 July: no readingKokomo, 21 July: 6.3 µg/m³Kokomo, 22 July: 10.1 µg/m³Kokomo, 23 July: 11.0 µg/m³Kokomo, 24 July: 14.8 µg/m³Kokomo, 25 July: 41.4 µg/m³, 4.7× its usual 8.9Kokomo, 26 July: 19.1 µg/m³Kokomo, 27 July: 18.7 µg/m³Kokomo, 28 July: 13.2 µg/m³Kokomo, 29 July: 4.0 µg/m³HollandHolland, 20 July: no readingHolland, 21 July: no readingHolland, 22 July: 15.2 µg/m³Holland, 23 July: 13.2 µg/m³Holland, 24 July: 21.1 µg/m³Holland, 25 July: 40.4 µg/m³, 4.2× its usual 9.7Holland, 26 July: 34.3 µg/m³, 3.6× its usual 9.6Holland, 27 July: 17.7 µg/m³Holland, 28 July: 14.8 µg/m³Holland, 29 July: 11.3 µg/m³ChicagoChicago, 20 July: 8.9 µg/m³Chicago, 21 July: 6.4 µg/m³Chicago, 22 July: 10.6 µg/m³Chicago, 23 July: 10.3 µg/m³Chicago, 24 July: 24.8 µg/m³Chicago, 25 July: 38.7 µg/m³, 3.8× its usual 10.1Chicago, 26 July: 20.0 µg/m³Chicago, 27 July: 11.8 µg/m³Chicago, 28 July: 11.7 µg/m³Chicago, 29 July: 5.1 µg/m³AndersonAnderson, 20 July: 11.6 µg/m³Anderson, 21 July: 5.9 µg/m³Anderson, 22 July: 8.6 µg/m³Anderson, 23 July: 11.6 µg/m³Anderson, 24 July: 12.9 µg/m³Anderson, 25 July: 37.7 µg/m³, 4.4× its usual 8.6Anderson, 26 July: 19.4 µg/m³Anderson, 27 July: 19.5 µg/m³Anderson, 28 July: 11.1 µg/m³Anderson, 29 July: 5.2 µg/m³DetroitDetroit, 20 July: 14.1 µg/m³Detroit, 21 July: 10.0 µg/m³Detroit, 22 July: 16.1 µg/m³Detroit, 23 July: 15.0 µg/m³Detroit, 24 July: 17.8 µg/m³Detroit, 25 July: 37.1 µg/m³, 3.3× its usual 11.3Detroit, 26 July: 28.1 µg/m³, 2.5× its usual 11.1Detroit, 27 July: 12.6 µg/m³Detroit, 28 July: 14.8 µg/m³Detroit, 29 July: 7.4 µg/m³DearbornDearborn, 20 July: 14.1 µg/m³Dearborn, 21 July: 9.5 µg/m³Dearborn, 22 July: 15.4 µg/m³Dearborn, 23 July: 16.8 µg/m³Dearborn, 24 July: 16.2 µg/m³Dearborn, 25 July: 36.8 µg/m³, 3.3× its usual 11.3Dearborn, 26 July: 28.0 µg/m³, 2.5× its usual 11.1Dearborn, 27 July: 12.6 µg/m³Dearborn, 28 July: 15.3 µg/m³Dearborn, 29 July: 7.3 µg/m³TecumsehTecumseh, 20 July: 15.2 µg/m³Tecumseh, 21 July: 11.1 µg/m³Tecumseh, 22 July: 15.9 µg/m³Tecumseh, 23 July: 14.2 µg/m³Tecumseh, 24 July: 16.9 µg/m³Tecumseh, 25 July: 35.9 µg/m³, 3.8× its usual 9.5Tecumseh, 26 July: 23.7 µg/m³Tecumseh, 27 July: 10.2 µg/m³Tecumseh, 28 July: 9.7 µg/m³Tecumseh, 29 July: 4.7 µg/m³LafayetteLafayette, 20 July: no readingLafayette, 21 July: 7.6 µg/m³Lafayette, 22 July: 11.1 µg/m³Lafayette, 23 July: 11.6 µg/m³Lafayette, 24 July: 15.8 µg/m³Lafayette, 25 July: 35.8 µg/m³, 4.0× its usual 8.9Lafayette, 26 July: 14.9 µg/m³Lafayette, 27 July: 17.8 µg/m³Lafayette, 28 July: 14.4 µg/m³Lafayette, 29 July: 6.2 µg/m³WindsorWindsor, 20 July: 11.1 µg/m³Windsor, 21 July: 8.6 µg/m³Windsor, 22 July: 14.0 µg/m³Windsor, 23 July: 12.5 µg/m³Windsor, 24 July: 15.3 µg/m³Windsor, 25 July: 35.8 µg/m³, 3.3× its usual 11.0Windsor, 26 July: 25.9 µg/m³, 2.4× its usual 10.8Windsor, 27 July: 11.7 µg/m³Windsor, 28 July: 11.5 µg/m³Windsor, 29 July: 5.8 µg/m³Lincoln ParkLincoln Park, 20 July: 9.8 µg/m³Lincoln Park, 21 July: 8.4 µg/m³Lincoln Park, 22 July: 14.1 µg/m³Lincoln Park, 23 July: 13.3 µg/m³Lincoln Park, 24 July: 14.7 µg/m³Lincoln Park, 25 July: 35.5 µg/m³, 3.5× its usual 10.1Lincoln Park, 26 July: no readingLincoln Park, 27 July: no readingLincoln Park, 28 July: no readingLincoln Park, 29 July: no readingOak LawnOak Lawn, 20 July: 8.1 µg/m³Oak Lawn, 21 July: 4.8 µg/m³Oak Lawn, 22 July: 7.8 µg/m³Oak Lawn, 23 July: 8.8 µg/m³Oak Lawn, 24 July: 20.0 µg/m³Oak Lawn, 25 July: 35.2 µg/m³, 3.4× its usual 10.3Oak Lawn, 26 July: 18.4 µg/m³Oak Lawn, 27 July: 18.3 µg/m³Oak Lawn, 28 July: 13.2 µg/m³Oak Lawn, 29 July: 4.3 µg/m³TaylorTaylor, 20 July: 10.4 µg/m³Taylor, 21 July: 8.3 µg/m³Taylor, 22 July: 13.7 µg/m³Taylor, 23 July: 13.0 µg/m³Taylor, 24 July: 14.7 µg/m³Taylor, 25 July: 35.1 µg/m³, 3.7× its usual 9.6Taylor, 26 July: 26.9 µg/m³, 2.9× its usual 9.4Taylor, 27 July: 10.5 µg/m³Taylor, 28 July: 11.6 µg/m³Taylor, 29 July: 5.6 µg/m³YpsilantiYpsilanti, 20 July: 10.5 µg/m³Ypsilanti, 21 July: 9.5 µg/m³Ypsilanti, 22 July: 13.8 µg/m³Ypsilanti, 23 July: 11.1 µg/m³Ypsilanti, 24 July: 15.0 µg/m³Ypsilanti, 25 July: 33.7 µg/m³, 3.7× its usual 9.2Ypsilanti, 26 July: 25.1 µg/m³, 2.8× its usual 9.0Ypsilanti, 27 July: 10.5 µg/m³Ypsilanti, 28 July: 10.5 µg/m³Ypsilanti, 29 July: 5.8 µg/m³IndianapolisIndianapolis, 20 July: 11.0 µg/m³Indianapolis, 21 July: 6.9 µg/m³Indianapolis, 22 July: 12.5 µg/m³Indianapolis, 23 July: 18.1 µg/m³Indianapolis, 24 July: 15.6 µg/m³Indianapolis, 25 July: 33.3 µg/m³, 3.1× its usual 10.7Indianapolis, 26 July: 15.3 µg/m³Indianapolis, 27 July: 18.8 µg/m³Indianapolis, 28 July: 14.0 µg/m³Indianapolis, 29 July: 5.4 µg/m³Port HuronPort Huron, 20 July: 9.1 µg/m³Port Huron, 21 July: 9.3 µg/m³Port Huron, 22 July: 15.4 µg/m³Port Huron, 23 July: 13.3 µg/m³Port Huron, 24 July: 14.2 µg/m³Port Huron, 25 July: 32.6 µg/m³, 3.4× its usual 9.5Port Huron, 26 July: 30.2 µg/m³, 3.2× its usual 9.5Port Huron, 27 July: 19.6 µg/m³Port Huron, 28 July: 12.4 µg/m³Port Huron, 29 July: 6.4 µg/m³Parry SoundParry Sound, 20 July: 7.5 µg/m³Parry Sound, 21 July: 8.5 µg/m³Parry Sound, 22 July: 9.3 µg/m³Parry Sound, 23 July: 9.9 µg/m³Parry Sound, 24 July: 9.2 µg/m³Parry Sound, 25 July: 18.1 µg/m³Parry Sound, 26 July: 39.4 µg/m³, 4.7× its usual 8.3Parry Sound, 27 July: 23.2 µg/m³Parry Sound, 28 July: 20.2 µg/m³Parry Sound, 29 July: 5.6 µg/m³BarrieBarrie, 20 July: 11.3 µg/m³Barrie, 21 July: 9.4 µg/m³Barrie, 22 July: 10.9 µg/m³Barrie, 23 July: 12.6 µg/m³Barrie, 24 July: 10.3 µg/m³Barrie, 25 July: 19.8 µg/m³Barrie, 26 July: 36.7 µg/m³, 3.7× its usual 9.9Barrie, 27 July: 15.2 µg/m³Barrie, 28 July: 20.0 µg/m³Barrie, 29 July: 7.3 µg/m³NewmarketNewmarket, 20 July: 8.0 µg/m³Newmarket, 21 July: 8.3 µg/m³Newmarket, 22 July: 10.5 µg/m³Newmarket, 23 July: 11.3 µg/m³Newmarket, 24 July: 11.1 µg/m³Newmarket, 25 July: 19.2 µg/m³Newmarket, 26 July: 36.7 µg/m³, 3.7× its usual 9.9Newmarket, 27 July: 14.6 µg/m³Newmarket, 28 July: no readingNewmarket, 29 July: no reading20 Jul212223242526272829
The 60 cities with the highest readings of 91, 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
BrainerdMinnesota, United States2 53.024 July8.46.3×
MadisonWisconsin, United States2 52.024 July8.46.2×
LansingMichigan, United States3 58.225 July9.95.9×
BarabooWisconsin, United States2 43.524 July7.95.5×
East ChicagoIndiana, United States1 50.125 July9.25.4×
Saint CloudMinnesota, United States2 46.723 July8.65.4×
South BendIndiana, United States2 52.525 July10.05.3×
CloquetMinnesota, United States3 42.624 July8.15.3×
WaukeshaWisconsin, United States2 49.224 July9.75.1×
AltoonaWisconsin, United States3 46.624 July9.15.1×
Eau ClaireWisconsin, United States3 46.624 July9.25.1×
AppletonWisconsin, United States2 46.424 July9.15.1×
Calumet CityIllinois, United States2 53.725 July10.75.0×
Des PlainesIllinois, United States2 50.825 July10.15.0×
Detroit LakesMinnesota, United States2 43.423 July8.65.0×
GreendaleWisconsin, United States2 42.425 July8.74.9×
South MilwaukeeWisconsin, United States2 42.425 July8.74.9×
Winthrop HarborIllinois, United States1 41.525 July8.54.9×
ZionIllinois, United States1 41.525 July8.44.9×
Franklin ParkIllinois, United States2 57.025 July11.84.8×
NorthbrookIllinois, United States2 48.525 July10.34.7×
KokomoIndiana, United States1 41.425 July8.94.7×
Parry SoundOntario, Canada1 39.426 July8.34.7×
CaryIllinois, United States2 45.425 July10.04.5×
Columbia CityIndiana, United States2 45.225 July10.14.5×
HudsonvilleMichigan, United States2 45.125 July10.04.5×
JenisonMichigan, United States2 45.125 July10.04.5×
KalamazooMichigan, United States3 50.325 July11.44.4×
JolietIllinois, United States2 48.125 July11.04.4×
DuluthMinnesota, United States2 44.523 July10.14.4×
ElkhartIndiana, United States1 43.425 July9.94.4×
AndersonIndiana, United States1 37.725 July8.64.4×
MilwaukeeWisconsin, United States3 45.625 July10.64.3×
FlintMichigan, United States2 30.426 July7.14.3×
RockfordIllinois, United States2 45.225 July10.84.2×
HammondIndiana, United States2 44.325 July10.64.2×
VirginiaMinnesota, United States2 43.723 July10.34.2×
HollandMichigan, United States2 40.425 July9.74.2×
Grand RapidsMichigan, United States2 44.325 July10.74.1×
NapervilleIllinois, United States2 45.825 July11.44.0×
MinneapolisMinnesota, United States2 40.723 July10.14.0×
Saint PaulMinnesota, United States3 40.123 July10.14.0×
LafayetteIndiana, United States1 35.825 July8.94.0×
Saint MichaelMinnesota, United States2 35.423 July8.84.0×
PeterboroughOntario, Canada1 32.026 July8.04.0×
MarshallMinnesota, United States2 31.624 July8.13.9×
SuperiorWisconsin, United States2 41.223 July10.93.8×
ChicagoIllinois, United States1 38.725 July10.13.8×
Green BayWisconsin, United States2 37.924 July10.03.8×
TecumsehMichigan, United States1 35.925 July9.53.8×
BlaineMinnesota, United States2 33.423 July8.83.8×
BarrieOntario, Canada1 36.726 July9.93.7×
NewmarketOntario, Canada1 36.726 July9.93.7×
TaylorMichigan, United States2 35.125 July9.63.7×
YpsilantiMichigan, United States2 33.725 July9.23.7×
BraidwoodIllinois, United States1 31.925 July8.63.7×
West FargoNorth Dakota, United States2 35.624 July9.93.6×
Lincoln ParkMichigan, United States1 35.525 July10.13.5×
Oak LawnIllinois, United States1 35.225 July10.33.4×
Port HuronMichigan, United States2 32.625 July9.53.4×
DetroitMichigan, United States2 37.125 July11.33.3×
DearbornMichigan, United States2 36.825 July11.33.3×
WindsorOntario, Canada2 35.825 July11.03.3×
OakvilleOntario, Canada1 31.826 July9.73.3×
Bay CityMichigan, United States2 31.326 July9.43.3×
GuelphOntario, Canada1 30.526 July9.33.3×
Apple ValleyMinnesota, United States2 26.823 July8.23.3×
BurnsvilleMinnesota, United States3 32.123 July10.03.2×
ShakopeeMinnesota, United States2 31.523 July9.83.2×
FishersIndiana, United States1 30.425 July9.63.2×
McCordsvilleIndiana, United States1 30.425 July9.63.2×
KitchenerOntario, Canada1 30.426 July9.43.2×
BramptonOntario, Canada1 29.026 July9.23.2×
BloomingtonIllinois, United States1 27.425 July8.53.2×
CornwallOntario, Canada1 26.326 July8.33.2×
WaterlooIowa, United States1 25.524 July8.03.2×
IndianapolisIndiana, United States1 33.325 July10.73.1×
New BaltimoreMichigan, United States2 30.925 July10.13.1×
SarniaOntario, Canada2 29.725 July9.53.1×
ClintonIowa, United States1 28.625 July9.33.1×
BrooklinOntario, Canada1 25.026 July8.13.1×
PeoriaIllinois, United States1 31.625 July10.63.0×
MiltonOntario, Canada1 30.926 July10.43.0×
ChathamOntario, Canada1 25.525 July8.43.0×
TorontoOntario, Canada1 28.126 July10.12.8×
AnkenyIowa, United States1 25.124 July9.02.8×
RedfordMichigan, United States2 27.126 July10.22.7×
LondonOntario, Canada2 25.926 July9.72.7×
ToledoOhio, United States1 28.725 July11.02.6×
SpringfieldOhio, United States1 25.425 July10.12.5×
DaytonOhio, United States1 25.325 July10.02.5×

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 and Canada

Number 17 of 173 episodes in the United States and Canada since our records began, by cities reached.

Bars: cities reached; colour: the level of the episode's highest daily reading. All 173.

Use this page

SmogRank, Northern United States and Canada, July 2023: 91 cities with PM2.5 at twice their usual or more, 23 to 26 July 2023, smogrank.com/episodes/2023-07-northern-united-states-and-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. Fire detections from NASA FIRMS; smoke maps from NOAA HMS.