SmogRank / Episodes / United States

North-eastern United States and Canada, July 2023

For 4 days, from 23 to 26 July 2023, 75 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.

No cause namedWe have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached75in 2 countries
Days423 to 26 July 2023
Worst day25 July53 cities counted
Furthest above usual6.2×Madison

Day by day

25 July 53 cities at twice their usual or more
PortageGaryLimaSault Ste. MarieMiddletownColumbusTerre HauteDublinLebanonMasonWhite OakWestervilleGahannaClevelandMedinaShaker HeightsSt. ThomasDecaturPainesvilleAkronMolineDavenportCantonSpringfieldWarrenLa CrosseBrantfordMuscatineYoungstownHermitageGreater SudburyErieWaterdownIowa CitySteubenvilleHamiltonWeirton HeightsWheelingMississaugaPittsburghSt. CatharinesWilkinsburgWest MifflinMcKeesportRochesterBuffaloKenmoreNorth BayCheektowagaJohnstownAltoonaDes MoinesRochesterState CollegeBellevilleHagerstownCarlisleKingstonHarrisburgLibertySyracuseYorkSaint JosephLebanonHunt ValleyBaltimoreLancasterEdgewoodBellevueReadingScrantonOttawaOmahaUticaElktonAllentownNewarkBethlehemBearWilmingtonSioux FallsNorristownChesterBrookingsLincolnPhiladelphiaPennsaukenBensalemWatertownEwingSouth VinelandTrentonNew BrunswickLindenPatersonElizabethNewburghPleasantvilleBayonneJersey CityNew CityAlbanyNew York CityToms RiverFort LeeDorvalWhite PlainsMontréalRivière-des-Prairies–Pointe-aux-TremblesHempsteadDanburyBrossardPittsfieldBurlingtonSaint-Jean-sur-RichelieuGrand IslandBridgeportRutlandAberdeenWaterburyHolbrookNew HavenSpringfieldDaytonToledoLondonRedfordTorontoAnkenyMiltonWindsorPeoriaSarniaChathamClintonIndianapolisCornwallBrooklinBramptonBloomingtonFishersWaterlooShakopeeBurnsvilleOakvilleKitchenerDetroitDearbornBay CityApple ValleyGuelphPort HuronOak LawnLincoln ParkWest FargoNewmarketBarrieYpsilantiTaylorFlintChicagoGreen BaySuperiorBlainePeterboroughLafayetteNapervilleSaint PaulSaint MichaelMinneapolisGrand RapidsHollandHammondRockfordMilwaukeeElkhartAndersonKalamazooJolietDuluthJenisonCaryKokomoNorthbrookFranklin ParkZionSouth MilwaukeeDes PlainesCalumet CityWaukeshaAppletonEau ClaireSouth BendEast ChicagoSaint CloudLansingMadison
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

Saint CloudSaint Cloud, 20 July: 10.4 µg/m³, 1.2× usualSaint Cloud, 21 July: 12.2 µg/m³, 1.4× usualSaint Cloud, 22 July: 14.3 µg/m³, 1.7× usualSaint Cloud, 23 July: 46.7 µg/m³, 5.4× usualSaint Cloud, 24 July: 38.2 µg/m³, 4.4× usualSaint Cloud, 25 July: 21.7 µg/m³, 2.5× usualSaint Cloud, 26 July: 7.7 µg/m³, 0.9× usualSaint Cloud, 27 July: 10.5 µg/m³, 1.2× usualSaint Cloud, 28 July: 7.5 µg/m³, 0.9× usualSaint Cloud, 29 July: 5.8 µg/m³, 0.7× usualEau ClaireEau Claire, 20 July: 5.5 µg/m³, 0.6× usualEau Claire, 21 July: 8.1 µg/m³, 0.9× usualEau Claire, 22 July: 10.9 µg/m³, 1.2× usualEau Claire, 23 July: 35.9 µg/m³, 3.9× usualEau Claire, 24 July: 46.6 µg/m³, 5.1× usualEau Claire, 25 July: 29.9 µg/m³, 3.3× usualEau Claire, 26 July: 8.0 µg/m³, 0.9× usualEau Claire, 27 July: 7.5 µg/m³, 0.8× usualEau Claire, 28 July: 5.6 µg/m³, 0.6× usualEau Claire, 29 July: 5.3 µg/m³, 0.6× usualDuluthDuluth, 20 July: 8.0 µg/m³, 0.8× usualDuluth, 21 July: 11.8 µg/m³, 1.2× usualDuluth, 22 July: 13.1 µg/m³, 1.3× usualDuluth, 23 July: 44.5 µg/m³, 4.4× usualDuluth, 24 July: 39.2 µg/m³, 3.9× usualDuluth, 25 July: 24.2 µg/m³, 2.4× usualDuluth, 26 July: 16.9 µg/m³, 1.7× usualDuluth, 27 July: 9.2 µg/m³, 0.9× usualDuluth, 28 July: 6.2 µg/m³, 0.6× usualDuluth, 29 July: 4.8 µg/m³, 0.5× usualSuperiorSuperior, 20 July: 8.3 µg/m³, 0.8× usualSuperior, 21 July: 11.5 µg/m³, 1.1× usualSuperior, 22 July: 12.6 µg/m³, 1.2× usualSuperior, 23 July: 41.2 µg/m³, 3.8× usualSuperior, 24 July: 35.4 µg/m³, 3.2× usualSuperior, 25 July: 22.6 µg/m³, 2.1× usualSuperior, 26 July: 16.4 µg/m³, 1.5× usualSuperior, 27 July: 8.9 µg/m³, 0.8× usualSuperior, 28 July: 6.3 µg/m³, 0.6× usualSuperior, 29 July: 4.7 µg/m³, 0.4× usualMinneapolisMinneapolis, 20 July: 8.6 µg/m³, 0.9× usualMinneapolis, 21 July: 13.8 µg/m³, 1.4× usualMinneapolis, 22 July: 15.0 µg/m³, 1.5× usualMinneapolis, 23 July: 40.7 µg/m³, 4.0× usualMinneapolis, 24 July: 37.3 µg/m³, 3.7× usualMinneapolis, 25 July: 22.8 µg/m³, 2.3× usualMinneapolis, 26 July: 6.3 µg/m³, 0.6× usualMinneapolis, 27 July: 9.2 µg/m³, 0.9× usualMinneapolis, 28 July: 6.2 µg/m³, 0.6× usualMinneapolis, 29 July: 9.4 µg/m³, 0.9× usualSaint PaulSaint Paul, 20 July: 8.5 µg/m³, 0.8× usualSaint Paul, 21 July: 11.5 µg/m³, 1.1× usualSaint Paul, 22 July: 14.4 µg/m³, 1.4× usualSaint Paul, 23 July: 40.1 µg/m³, 4.0× usualSaint Paul, 24 July: 34.0 µg/m³, 3.4× usualSaint Paul, 25 July: 25.3 µg/m³, 2.5× usualSaint Paul, 26 July: 7.7 µg/m³, 0.8× usualSaint Paul, 27 July: 9.7 µg/m³, 1.0× usualSaint Paul, 28 July: 6.1 µg/m³, 0.6× usualSaint Paul, 29 July: 6.8 µg/m³, 0.7× usualWest FargoWest Fargo, 20 July: 14.8 µg/m³, 1.5× usualWest Fargo, 21 July: 16.9 µg/m³, 1.7× usualWest Fargo, 22 July: 19.5 µg/m³, 2.0× usualWest Fargo, 23 July: 27.7 µg/m³, 2.8× usualWest Fargo, 24 July: 35.6 µg/m³, 3.6× usualWest Fargo, 25 July: 18.5 µg/m³, 1.9× usualWest Fargo, 26 July: 7.8 µg/m³, 0.8× usualWest Fargo, 27 July: 7.6 µg/m³, 0.8× usualWest Fargo, 28 July: 6.0 µg/m³, 0.6× usualWest Fargo, 29 July: 3.6 µg/m³, 0.4× usualSaint MichaelSaint Michael, 20 July: 8.5 µg/m³, 1.0× usualSaint Michael, 21 July: 10.5 µg/m³, 1.2× usualSaint Michael, 22 July: 13.6 µg/m³, 1.5× usualSaint Michael, 23 July: 35.4 µg/m³, 4.0× usualSaint Michael, 24 July: 29.6 µg/m³, 3.4× usualSaint Michael, 25 July: 23.8 µg/m³, 2.7× usualSaint Michael, 26 July: 6.2 µg/m³, 0.7× usualSaint Michael, 27 July: 10.3 µg/m³, 1.2× usualSaint Michael, 28 July: 6.1 µg/m³, 0.7× usualSaint Michael, 29 July: 5.7 µg/m³, 0.6× usualBlaineBlaine, 20 July: 4.8 µg/m³, 0.5× usualBlaine, 21 July: 8.0 µg/m³, 0.9× usualBlaine, 22 July: 9.8 µg/m³, 1.1× usualBlaine, 23 July: 33.4 µg/m³, 3.8× usualBlaine, 24 July: 32.2 µg/m³, 3.7× usualBlaine, 25 July: 18.2 µg/m³, 2.1× usualBlaine, 26 July: 3.8 µg/m³, 0.4× usualBlaine, 27 July: 6.9 µg/m³, 0.8× usualBlaine, 28 July: 2.4 µg/m³, 0.3× usualBlaine, 29 July: 2.1 µg/m³, 0.2× usualBurnsvilleBurnsville, 20 July: 8.5 µg/m³, 0.9× usualBurnsville, 21 July: 11.6 µg/m³, 1.2× usualBurnsville, 22 July: 14.5 µg/m³, 1.5× usualBurnsville, 23 July: 32.1 µg/m³, 3.2× usualBurnsville, 24 July: 29.9 µg/m³, 3.0× usualBurnsville, 25 July: 25.5 µg/m³, 2.6× usualBurnsville, 26 July: 6.9 µg/m³, 0.7× usualBurnsville, 27 July: 10.6 µg/m³, 1.1× usualBurnsville, 28 July: 7.1 µg/m³, 0.7× usualBurnsville, 29 July: 6.6 µg/m³, 0.7× usualShakopeeShakopee, 20 July: 8.6 µg/m³, 0.9× usualShakopee, 21 July: 11.8 µg/m³, 1.2× usualShakopee, 22 July: 15.5 µg/m³, 1.6× usualShakopee, 23 July: 31.5 µg/m³, 3.2× usualShakopee, 24 July: 29.7 µg/m³, 3.0× usualShakopee, 25 July: 24.3 µg/m³, 2.5× usualShakopee, 26 July: 6.4 µg/m³, 0.7× usualShakopee, 27 July: 11.1 µg/m³, 1.1× usualShakopee, 28 July: 7.2 µg/m³, 0.7× usualShakopee, 29 July: 6.9 µg/m³, 0.7× usualLansingLansing, 20 July: 23.0 µg/m³, 2.3× usualLansing, 21 July: 15.4 µg/m³, 1.6× usualLansing, 22 July: 18.4 µg/m³, 1.9× usualLansing, 23 July: 17.1 µg/m³, 1.7× usualLansing, 24 July: 33.7 µg/m³, 3.4× usualLansing, 25 July: 58.2 µg/m³, 5.9× usualLansing, 26 July: 35.7 µg/m³, 3.6× usualLansing, 27 July: 14.8 µg/m³, 1.5× usualLansing, 28 July: 10.7 µg/m³, 1.1× usualLansing, 29 July: 5.0 µg/m³, 0.5× usualFranklin ParkFranklin Park, 20 July: 11.7 µg/m³, 1.0× usualFranklin Park, 21 July: 8.3 µg/m³, 0.7× usualFranklin Park, 22 July: 12.4 µg/m³, 1.1× usualFranklin Park, 23 July: 13.0 µg/m³, 1.1× usualFranklin Park, 24 July: 38.9 µg/m³, 3.3× usualFranklin Park, 25 July: 57.0 µg/m³, 4.8× usualFranklin Park, 26 July: 22.8 µg/m³, 1.9× usualFranklin Park, 27 July: 13.0 µg/m³, 1.1× usualFranklin Park, 28 July: 11.6 µg/m³, 1.0× usualFranklin Park, 29 July: 5.7 µg/m³, 0.5× usualCalumet CityCalumet City, 20 July: 12.0 µg/m³, 1.1× usualCalumet City, 21 July: 8.2 µg/m³, 0.8× usualCalumet City, 22 July: 13.6 µg/m³, 1.3× usualCalumet City, 23 July: 13.7 µg/m³, 1.3× usualCalumet City, 24 July: 32.1 µg/m³, 3.0× usualCalumet City, 25 July: 53.7 µg/m³, 5.0× usualCalumet City, 26 July: 22.6 µg/m³, 2.1× usualCalumet City, 27 July: 15.2 µg/m³, 1.4× usualCalumet City, 28 July: 12.3 µg/m³, 1.1× usualCalumet City, 29 July: 5.6 µg/m³, 0.5× usualMadisonMadison, 20 July: 7.8 µg/m³, 0.9× usualMadison, 21 July: 7.5 µg/m³, 0.9× usualMadison, 22 July: 9.6 µg/m³, 1.1× usualMadison, 23 July: 14.8 µg/m³, 1.8× usualMadison, 24 July: 52.0 µg/m³, 6.2× usualMadison, 25 July: 35.7 µg/m³, 4.3× usualMadison, 26 July: 15.5 µg/m³, 1.8× usualMadison, 27 July: 5.9 µg/m³, 0.7× usualMadison, 28 July: 4.7 µg/m³, 0.6× usualMadison, 29 July: 5.5 µg/m³, 0.7× usualDes PlainesDes Plaines, 20 July: 10.2 µg/m³, 1.0× usualDes Plaines, 21 July: 7.3 µg/m³, 0.7× usualDes Plaines, 22 July: 11.4 µg/m³, 1.1× usualDes Plaines, 23 July: 11.6 µg/m³, 1.1× usualDes Plaines, 24 July: 34.1 µg/m³, 3.4× usualDes Plaines, 25 July: 50.8 µg/m³, 5.0× usualDes Plaines, 26 July: 19.1 µg/m³, 1.9× usualDes Plaines, 27 July: 8.9 µg/m³, 0.9× usualDes Plaines, 28 July: 8.6 µg/m³, 0.9× usualDes Plaines, 29 July: 5.0 µg/m³, 0.5× usualKalamazooKalamazoo, 20 July: 16.7 µg/m³, 1.5× usualKalamazoo, 21 July: 15.2 µg/m³, 1.3× usualKalamazoo, 22 July: 15.0 µg/m³, 1.3× usualKalamazoo, 23 July: 15.3 µg/m³, 1.3× usualKalamazoo, 24 July: 25.9 µg/m³, 2.3× usualKalamazoo, 25 July: 50.3 µg/m³, 4.4× usualKalamazoo, 26 July: 28.7 µg/m³, 2.5× usualKalamazoo, 27 July: 11.8 µg/m³, 1.0× usualKalamazoo, 28 July: 9.1 µg/m³, 0.8× usualKalamazoo, 29 July: 5.7 µg/m³, 0.5× usualWaukeshaWaukesha, 20 July: 7.2 µg/m³, 0.7× usualWaukesha, 21 July: 7.9 µg/m³, 0.8× usualWaukesha, 22 July: 9.8 µg/m³, 1.0× usualWaukesha, 23 July: 13.6 µg/m³, 1.4× usualWaukesha, 24 July: 49.2 µg/m³, 5.1× usualWaukesha, 25 July: 43.0 µg/m³, 4.4× usualWaukesha, 26 July: 19.4 µg/m³, 2.0× usualWaukesha, 27 July: 8.5 µg/m³, 0.9× usualWaukesha, 28 July: 4.2 µg/m³, 0.4× usualWaukesha, 29 July: 4.5 µg/m³, 0.5× usualNorthbrookNorthbrook, 20 July: 10.0 µg/m³, 1.0× usualNorthbrook, 21 July: 6.7 µg/m³, 0.7× usualNorthbrook, 22 July: 10.9 µg/m³, 1.1× usualNorthbrook, 23 July: 10.0 µg/m³, 1.0× usualNorthbrook, 24 July: 29.7 µg/m³, 2.9× usualNorthbrook, 25 July: 48.5 µg/m³, 4.7× usualNorthbrook, 26 July: 22.7 µg/m³, 2.2× usualNorthbrook, 27 July: 10.6 µg/m³, 1.0× usualNorthbrook, 28 July: 9.2 µg/m³, 0.9× usualNorthbrook, 29 July: 5.2 µg/m³, 0.5× usualJolietJoliet, 20 July: 12.0 µg/m³, 1.1× usualJoliet, 21 July: 8.4 µg/m³, 0.8× usualJoliet, 22 July: 12.0 µg/m³, 1.1× usualJoliet, 23 July: 13.3 µg/m³, 1.2× usualJoliet, 24 July: 35.7 µg/m³, 3.2× usualJoliet, 25 July: 48.1 µg/m³, 4.4× usualJoliet, 26 July: 21.8 µg/m³, 2.0× usualJoliet, 27 July: 12.2 µg/m³, 1.1× usualJoliet, 28 July: 14.2 µg/m³, 1.3× usualJoliet, 29 July: 5.8 µg/m³, 0.5× usualAppletonAppleton, 20 July: 5.4 µg/m³, 0.6× usualAppleton, 21 July: 9.0 µg/m³, 1.0× usualAppleton, 22 July: 9.7 µg/m³, 1.1× usualAppleton, 23 July: 18.7 µg/m³, 2.1× usualAppleton, 24 July: 46.4 µg/m³, 5.1× usualAppleton, 25 July: 32.4 µg/m³, 3.6× usualAppleton, 26 July: 19.4 µg/m³, 2.1× usualAppleton, 27 July: 8.5 µg/m³, 0.9× usualAppleton, 28 July: 4.7 µg/m³, 0.5× usualAppleton, 29 July: 4.1 µg/m³, 0.5× usualNapervilleNaperville, 20 July: 10.6 µg/m³, 0.9× usualNaperville, 21 July: 8.3 µg/m³, 0.7× usualNaperville, 22 July: 11.7 µg/m³, 1.0× usualNaperville, 23 July: 12.7 µg/m³, 1.1× usualNaperville, 24 July: 35.8 µg/m³, 3.1× usualNaperville, 25 July: 45.8 µg/m³, 4.0× usualNaperville, 26 July: 20.9 µg/m³, 1.8× usualNaperville, 27 July: no readingNaperville, 28 July: no readingNaperville, 29 July: no readingMilwaukeeMilwaukee, 20 July: 7.6 µg/m³, 0.7× usualMilwaukee, 21 July: 8.2 µg/m³, 0.8× usualMilwaukee, 22 July: 10.5 µg/m³, 1.0× usualMilwaukee, 23 July: 12.7 µg/m³, 1.2× usualMilwaukee, 24 July: 35.1 µg/m³, 3.3× usualMilwaukee, 25 July: 45.6 µg/m³, 4.3× usualMilwaukee, 26 July: 26.0 µg/m³, 2.5× usualMilwaukee, 27 July: 10.1 µg/m³, 1.0× usualMilwaukee, 28 July: 4.9 µg/m³, 0.5× usualMilwaukee, 29 July: 4.9 µg/m³, 0.5× usualCaryCary, 20 July: 8.8 µg/m³, 0.9× usualCary, 21 July: 7.0 µg/m³, 0.7× usualCary, 22 July: 9.7 µg/m³, 1.0× usualCary, 23 July: 11.6 µg/m³, 1.2× usualCary, 24 July: 39.2 µg/m³, 4.0× usualCary, 25 July: 45.4 µg/m³, 4.6× usualCary, 26 July: 17.9 µg/m³, 1.8× usualCary, 27 July: 8.5 µg/m³, 0.9× usualCary, 28 July: 7.8 µg/m³, 0.8× usualCary, 29 July: 4.9 µg/m³, 0.5× usualRockfordRockford, 20 July: 9.5 µg/m³, 0.9× usualRockford, 21 July: 7.1 µg/m³, 0.7× usualRockford, 22 July: 10.8 µg/m³, 1.0× usualRockford, 23 July: 12.7 µg/m³, 1.2× usualRockford, 24 July: 37.2 µg/m³, 3.4× usualRockford, 25 July: 45.2 µg/m³, 4.2× usualRockford, 26 July: 15.3 µg/m³, 1.4× usualRockford, 27 July: 6.9 µg/m³, 0.6× usualRockford, 28 July: 8.0 µg/m³, 0.7× usualRockford, 29 July: 5.7 µg/m³, 0.5× usualHammondHammond, 20 July: 9.6 µg/m³, 0.9× usualHammond, 21 July: 6.8 µg/m³, 0.6× usualHammond, 22 July: 11.2 µg/m³, 1.1× usualHammond, 23 July: 10.6 µg/m³, 1.0× usualHammond, 24 July: 25.4 µg/m³, 2.4× usualHammond, 25 July: 44.3 µg/m³, 4.2× usualHammond, 26 July: 19.3 µg/m³, 1.8× usualHammond, 27 July: 13.2 µg/m³, 1.2× usualHammond, 28 July: 9.1 µg/m³, 0.9× usualHammond, 29 July: 4.2 µg/m³, 0.4× usualSouth MilwaukeeSouth Milwaukee, 20 July: 7.3 µg/m³, 0.8× usualSouth Milwaukee, 21 July: 7.6 µg/m³, 0.9× usualSouth Milwaukee, 22 July: 9.9 µg/m³, 1.1× usualSouth Milwaukee, 23 July: 12.1 µg/m³, 1.4× usualSouth Milwaukee, 24 July: 34.6 µg/m³, 4.0× usualSouth Milwaukee, 25 July: 42.4 µg/m³, 4.9× usualSouth Milwaukee, 26 July: 22.9 µg/m³, 2.6× usualSouth Milwaukee, 27 July: 8.0 µg/m³, 0.9× usualSouth Milwaukee, 28 July: 4.4 µg/m³, 0.5× usualSouth Milwaukee, 29 July: 4.2 µg/m³, 0.5× usualGreen BayGreen Bay, 20 July: 5.1 µg/m³, 0.5× usualGreen Bay, 21 July: 8.9 µg/m³, 0.9× usualGreen Bay, 22 July: 10.2 µg/m³, 1.0× usualGreen Bay, 23 July: 15.3 µg/m³, 1.5× usualGreen Bay, 24 July: 37.9 µg/m³, 3.8× usualGreen Bay, 25 July: 26.0 µg/m³, 2.6× usualGreen Bay, 26 July: 21.7 µg/m³, 2.2× usualGreen Bay, 27 July: 10.5 µg/m³, 1.1× usualGreen Bay, 28 July: 4.5 µg/m³, 0.5× usualGreen Bay, 29 July: 3.6 µg/m³, 0.4× usualSouth BendSouth Bend, 20 July: 11.7 µg/m³, 1.2× usualSouth Bend, 21 July: 7.0 µg/m³, 0.7× usualSouth Bend, 22 July: 10.9 µg/m³, 1.1× usualSouth Bend, 23 July: 11.8 µg/m³, 1.2× usualSouth Bend, 24 July: 24.3 µg/m³, 2.4× usualSouth Bend, 25 July: 52.5 µg/m³, 5.3× usualSouth Bend, 26 July: 25.2 µg/m³, 2.5× usualSouth Bend, 27 July: 11.6 µg/m³, 1.2× usualSouth Bend, 28 July: 8.0 µg/m³, 0.8× usualSouth Bend, 29 July: 3.9 µg/m³, 0.4× usualEast ChicagoEast Chicago, 20 July: 11.3 µg/m³, 1.2× usualEast Chicago, 21 July: 6.6 µg/m³, 0.7× usualEast Chicago, 22 July: 11.3 µg/m³, 1.2× usualEast Chicago, 23 July: 10.1 µg/m³, 1.1× usualEast Chicago, 24 July: 23.8 µg/m³, 2.6× usualEast Chicago, 25 July: 50.1 µg/m³, 5.4× usualEast Chicago, 26 July: 20.2 µg/m³, 2.2× usualEast Chicago, 27 July: 10.8 µg/m³, 1.2× usualEast Chicago, 28 July: 8.5 µg/m³, 0.9× usualEast Chicago, 29 July: 4.1 µg/m³, 0.4× usualJenisonJenison, 20 July: 11.4 µg/m³, 1.1× usualJenison, 21 July: 9.5 µg/m³, 1.0× usualJenison, 22 July: 12.6 µg/m³, 1.3× usualJenison, 23 July: 12.2 µg/m³, 1.2× usualJenison, 24 July: 21.7 µg/m³, 2.2× usualJenison, 25 July: 45.1 µg/m³, 4.5× usualJenison, 26 July: 30.7 µg/m³, 3.1× usualJenison, 27 July: 14.1 µg/m³, 1.4× usualJenison, 28 July: 10.1 µg/m³, 1.0× usualJenison, 29 July: 5.5 µg/m³, 0.6× usualGrand RapidsGrand Rapids, 20 July: 11.9 µg/m³, 1.1× usualGrand Rapids, 21 July: 9.9 µg/m³, 0.9× usualGrand Rapids, 22 July: 13.9 µg/m³, 1.3× usualGrand Rapids, 23 July: 12.3 µg/m³, 1.1× usualGrand Rapids, 24 July: 22.8 µg/m³, 2.1× usualGrand Rapids, 25 July: 44.3 µg/m³, 4.1× usualGrand Rapids, 26 July: 31.6 µg/m³, 3.0× usualGrand Rapids, 27 July: 17.4 µg/m³, 1.6× usualGrand Rapids, 28 July: 12.3 µg/m³, 1.1× usualGrand Rapids, 29 July: 6.0 µg/m³, 0.6× usualElkhartElkhart, 20 July: no readingElkhart, 21 July: no readingElkhart, 22 July: 11.3 µg/m³, 1.1× usualElkhart, 23 July: 11.4 µg/m³, 1.2× usualElkhart, 24 July: 19.9 µg/m³, 2.0× usualElkhart, 25 July: 43.4 µg/m³, 4.4× usualElkhart, 26 July: 24.9 µg/m³, 2.5× usualElkhart, 27 July: 11.0 µg/m³, 1.1× usualElkhart, 28 July: 8.4 µg/m³, 0.8× usualElkhart, 29 July: 4.0 µg/m³, 0.4× usualZionZion, 20 July: 6.8 µg/m³, 0.8× usualZion, 21 July: 5.3 µg/m³, 0.6× usualZion, 22 July: 7.9 µg/m³, 0.9× usualZion, 23 July: 7.3 µg/m³, 0.9× usualZion, 24 July: 23.1 µg/m³, 2.8× usualZion, 25 July: 41.5 µg/m³, 4.9× usualZion, 26 July: 19.2 µg/m³, 2.3× usualZion, 27 July: 6.7 µg/m³, 0.8× usualZion, 28 July: 5.3 µg/m³, 0.6× usualZion, 29 July: no readingKokomoKokomo, 20 July: no readingKokomo, 21 July: 6.3 µg/m³, 0.7× usualKokomo, 22 July: 10.1 µg/m³, 1.1× usualKokomo, 23 July: 11.0 µg/m³, 1.2× usualKokomo, 24 July: 14.8 µg/m³, 1.7× usualKokomo, 25 July: 41.4 µg/m³, 4.7× usualKokomo, 26 July: 19.1 µg/m³, 2.1× usualKokomo, 27 July: 18.7 µg/m³, 2.1× usualKokomo, 28 July: 13.2 µg/m³, 1.5× usualKokomo, 29 July: 4.0 µg/m³, 0.4× usualHollandHolland, 20 July: no readingHolland, 21 July: no readingHolland, 22 July: 15.2 µg/m³, 1.6× usualHolland, 23 July: 13.2 µg/m³, 1.4× usualHolland, 24 July: 21.1 µg/m³, 2.2× usualHolland, 25 July: 40.4 µg/m³, 4.2× usualHolland, 26 July: 34.3 µg/m³, 3.5× usualHolland, 27 July: 17.7 µg/m³, 1.8× usualHolland, 28 July: 14.8 µg/m³, 1.5× usualHolland, 29 July: 11.3 µg/m³, 1.2× usualChicagoChicago, 20 July: 8.9 µg/m³, 0.9× usualChicago, 21 July: 6.4 µg/m³, 0.6× usualChicago, 22 July: 10.6 µg/m³, 1.0× usualChicago, 23 July: 10.3 µg/m³, 1.0× usualChicago, 24 July: 24.8 µg/m³, 2.5× usualChicago, 25 July: 38.7 µg/m³, 3.8× usualChicago, 26 July: 20.0 µg/m³, 2.0× usualChicago, 27 July: 11.8 µg/m³, 1.2× usualChicago, 28 July: 11.7 µg/m³, 1.2× usualChicago, 29 July: 5.1 µg/m³, 0.5× usualAndersonAnderson, 20 July: 11.6 µg/m³, 1.3× usualAnderson, 21 July: 5.9 µg/m³, 0.7× usualAnderson, 22 July: 8.6 µg/m³, 1.0× usualAnderson, 23 July: 11.6 µg/m³, 1.3× usualAnderson, 24 July: 12.9 µg/m³, 1.5× usualAnderson, 25 July: 37.7 µg/m³, 4.4× usualAnderson, 26 July: 19.4 µg/m³, 2.3× usualAnderson, 27 July: 19.5 µg/m³, 2.3× usualAnderson, 28 July: 11.1 µg/m³, 1.3× usualAnderson, 29 July: 5.2 µg/m³, 0.6× usualDearbornDearborn, 20 July: 14.1 µg/m³, 1.2× usualDearborn, 21 July: 9.5 µg/m³, 0.8× usualDearborn, 22 July: 15.4 µg/m³, 1.4× usualDearborn, 23 July: 16.8 µg/m³, 1.5× usualDearborn, 24 July: 16.2 µg/m³, 1.4× usualDearborn, 25 July: 36.8 µg/m³, 3.3× usualDearborn, 26 July: 28.0 µg/m³, 2.5× usualDearborn, 27 July: 12.6 µg/m³, 1.1× usualDearborn, 28 July: 15.3 µg/m³, 1.4× usualDearborn, 29 July: 7.3 µg/m³, 0.6× usualDetroitDetroit, 20 July: 12.6 µg/m³, 1.2× usualDetroit, 21 July: 8.9 µg/m³, 0.8× usualDetroit, 22 July: 14.1 µg/m³, 1.3× usualDetroit, 23 July: 13.1 µg/m³, 1.2× usualDetroit, 24 July: 15.4 µg/m³, 1.4× usualDetroit, 25 July: 35.9 µg/m³, 3.3× usualDetroit, 26 July: 27.6 µg/m³, 2.5× usualDetroit, 27 July: 11.5 µg/m³, 1.1× usualDetroit, 28 July: 12.4 µg/m³, 1.1× usualDetroit, 29 July: 6.5 µg/m³, 0.6× usualLafayetteLafayette, 20 July: no readingLafayette, 21 July: 7.6 µg/m³, 0.9× usualLafayette, 22 July: 11.1 µg/m³, 1.2× usualLafayette, 23 July: 11.6 µg/m³, 1.3× usualLafayette, 24 July: 15.8 µg/m³, 1.8× usualLafayette, 25 July: 35.8 µg/m³, 4.0× usualLafayette, 26 July: 14.9 µg/m³, 1.7× usualLafayette, 27 July: 17.8 µg/m³, 2.0× usualLafayette, 28 July: 14.4 µg/m³, 1.6× usualLafayette, 29 July: 6.2 µg/m³, 0.7× usualWindsorWindsor, 20 July: 11.3 µg/m³, 1.0× usualWindsor, 21 July: 8.7 µg/m³, 0.7× usualWindsor, 22 July: 13.9 µg/m³, 1.2× usualWindsor, 23 July: 12.6 µg/m³, 1.1× usualWindsor, 24 July: 15.5 µg/m³, 1.3× usualWindsor, 25 July: 35.8 µg/m³, 3.0× usualWindsor, 26 July: 25.7 µg/m³, 2.2× usualWindsor, 27 July: 11.8 µg/m³, 1.0× usualWindsor, 28 July: 11.6 µg/m³, 1.0× usualWindsor, 29 July: 6.0 µg/m³, 0.5× usualLincoln ParkLincoln Park, 20 July: 9.8 µg/m³, 1.0× usualLincoln Park, 21 July: 8.4 µg/m³, 0.8× usualLincoln Park, 22 July: 14.1 µg/m³, 1.4× usualLincoln Park, 23 July: 13.3 µg/m³, 1.3× usualLincoln Park, 24 July: 14.7 µg/m³, 1.5× usualLincoln Park, 25 July: 35.5 µg/m³, 3.5× usualLincoln 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/m³, 0.8× usualOak Lawn, 21 July: 4.8 µg/m³, 0.5× usualOak Lawn, 22 July: 7.8 µg/m³, 0.8× usualOak Lawn, 23 July: 8.8 µg/m³, 0.9× usualOak Lawn, 24 July: 20.0 µg/m³, 1.9× usualOak Lawn, 25 July: 35.2 µg/m³, 3.4× usualOak Lawn, 26 July: 18.4 µg/m³, 1.8× usualOak Lawn, 27 July: 18.3 µg/m³, 1.8× usualOak Lawn, 28 July: 13.2 µg/m³, 1.3× usualOak Lawn, 29 July: 4.3 µg/m³, 0.4× usualTaylorTaylor, 20 July: 10.4 µg/m³, 1.1× usualTaylor, 21 July: 8.3 µg/m³, 0.9× usualTaylor, 22 July: 13.7 µg/m³, 1.4× usualTaylor, 23 July: 13.0 µg/m³, 1.4× usualTaylor, 24 July: 14.7 µg/m³, 1.5× usualTaylor, 25 July: 35.1 µg/m³, 3.7× usualTaylor, 26 July: 26.9 µg/m³, 2.8× usualTaylor, 27 July: 10.5 µg/m³, 1.1× usualTaylor, 28 July: 11.6 µg/m³, 1.2× usualTaylor, 29 July: 5.6 µg/m³, 0.6× usualYpsilantiYpsilanti, 20 July: 10.5 µg/m³, 1.1× usualYpsilanti, 21 July: 9.5 µg/m³, 1.0× usualYpsilanti, 22 July: 13.8 µg/m³, 1.5× usualYpsilanti, 23 July: 11.1 µg/m³, 1.2× usualYpsilanti, 24 July: 15.0 µg/m³, 1.6× usualYpsilanti, 25 July: 33.7 µg/m³, 3.7× usualYpsilanti, 26 July: 25.1 µg/m³, 2.7× usualYpsilanti, 27 July: 10.5 µg/m³, 1.1× usualYpsilanti, 28 July: 10.5 µg/m³, 1.1× usualYpsilanti, 29 July: 5.8 µg/m³, 0.6× usualIndianapolisIndianapolis, 20 July: 11.0 µg/m³, 1.0× usualIndianapolis, 21 July: 6.9 µg/m³, 0.6× usualIndianapolis, 22 July: 12.5 µg/m³, 1.2× usualIndianapolis, 23 July: 18.1 µg/m³, 1.7× usualIndianapolis, 24 July: 15.6 µg/m³, 1.5× usualIndianapolis, 25 July: 33.3 µg/m³, 3.1× usualIndianapolis, 26 July: 15.3 µg/m³, 1.4× usualIndianapolis, 27 July: 18.8 µg/m³, 1.8× usualIndianapolis, 28 July: 14.0 µg/m³, 1.3× usualIndianapolis, 29 July: 5.4 µg/m³, 0.5× usualPort HuronPort Huron, 20 July: 9.1 µg/m³, 1.0× usualPort Huron, 21 July: 9.3 µg/m³, 1.0× usualPort Huron, 22 July: 15.4 µg/m³, 1.6× usualPort Huron, 23 July: 13.3 µg/m³, 1.4× usualPort Huron, 24 July: 14.2 µg/m³, 1.5× usualPort Huron, 25 July: 32.6 µg/m³, 3.4× usualPort Huron, 26 July: 30.2 µg/m³, 3.2× usualPort Huron, 27 July: 19.6 µg/m³, 2.1× usualPort Huron, 28 July: 12.4 µg/m³, 1.3× usualPort Huron, 29 July: 6.4 µg/m³, 0.7× usualPeoriaPeoria, 20 July: no readingPeoria, 21 July: no readingPeoria, 22 July: no readingPeoria, 23 July: no readingPeoria, 24 July: no readingPeoria, 25 July: 31.6 µg/m³, 3.0× usualPeoria, 26 July: 18.2 µg/m³, 1.7× usualPeoria, 27 July: 14.7 µg/m³, 1.4× usualPeoria, 28 July: 18.6 µg/m³, 1.8× usualPeoria, 29 July: 5.7 µg/m³, 0.5× usualBay CityBay City, 20 July: 7.3 µg/m³, 0.8× usualBay City, 21 July: 6.7 µg/m³, 0.7× usualBay City, 22 July: 9.9 µg/m³, 1.1× usualBay City, 23 July: 8.8 µg/m³, 0.9× usualBay City, 24 July: 15.0 µg/m³, 1.6× usualBay City, 25 July: 29.1 µg/m³, 3.1× usualBay City, 26 July: 31.3 µg/m³, 3.3× usualBay City, 27 July: 15.4 µg/m³, 1.6× usualBay City, 28 July: 9.5 µg/m³, 1.0× usualBay City, 29 July: 2.6 µg/m³, 0.3× usualFishersFishers, 20 July: 11.7 µg/m³, 1.2× usualFishers, 21 July: 6.0 µg/m³, 0.6× usualFishers, 22 July: 8.6 µg/m³, 0.9× usualFishers, 23 July: 11.9 µg/m³, 1.2× usualFishers, 24 July: 13.6 µg/m³, 1.4× usualFishers, 25 July: 30.4 µg/m³, 3.2× usualFishers, 26 July: 18.8 µg/m³, 2.0× usualFishers, 27 July: 22.6 µg/m³, 2.4× usualFishers, 28 July: 14.8 µg/m³, 1.5× usualFishers, 29 July: 5.3 µg/m³, 0.6× usualFlintFlint, 20 July: 5.5 µg/m³, 0.7× usualFlint, 21 July: 3.6 µg/m³, 0.4× usualFlint, 22 July: 6.8 µg/m³, 0.8× usualFlint, 23 July: 5.5 µg/m³, 0.7× usualFlint, 24 July: 9.2 µg/m³, 1.1× usualFlint, 25 July: 28.9 µg/m³, 3.6× usualFlint, 26 July: 30.4 µg/m³, 3.8× usualFlint, 27 July: 8.9 µg/m³, 1.1× usualFlint, 28 July: 7.2 µg/m³, 0.9× usualFlint, 29 July: 1.7 µg/m³, 0.2× usualSarniaSarnia, 20 July: 8.1 µg/m³, 0.9× usualSarnia, 21 July: 8.4 µg/m³, 0.9× usualSarnia, 22 July: 17.0 µg/m³, 1.8× usualSarnia, 23 July: 13.1 µg/m³, 1.4× usualSarnia, 24 July: 13.3 µg/m³, 1.4× usualSarnia, 25 July: 29.7 µg/m³, 3.1× usualSarnia, 26 July: 28.8 µg/m³, 3.0× usualSarnia, 27 July: 19.7 µg/m³, 2.1× usualSarnia, 28 July: 12.4 µg/m³, 1.3× usualSarnia, 29 July: 5.6 µg/m³, 0.6× usualBarrieBarrie, 20 July: 11.3 µg/m³, 1.2× usualBarrie, 21 July: 9.4 µg/m³, 1.0× usualBarrie, 22 July: 10.9 µg/m³, 1.1× usualBarrie, 23 July: 12.6 µg/m³, 1.3× usualBarrie, 24 July: 10.3 µg/m³, 1.1× usualBarrie, 25 July: 19.8 µg/m³, 2.0× usualBarrie, 26 July: 36.7 µg/m³, 3.7× usualBarrie, 27 July: 15.2 µg/m³, 1.6× usualBarrie, 28 July: 20.0 µg/m³, 2.0× usualBarrie, 29 July: 7.3 µg/m³, 0.7× usualNewmarketNewmarket, 20 July: 8.0 µg/m³, 0.8× usualNewmarket, 21 July: 8.3 µg/m³, 0.8× usualNewmarket, 22 July: 10.5 µg/m³, 1.1× usualNewmarket, 23 July: 11.3 µg/m³, 1.2× usualNewmarket, 24 July: 11.1 µg/m³, 1.1× usualNewmarket, 25 July: 19.2 µg/m³, 2.0× usualNewmarket, 26 July: 36.7 µg/m³, 3.7× usualNewmarket, 27 July: 14.6 µg/m³, 1.5× usualNewmarket, 28 July: no readingNewmarket, 29 July: no readingPeterboroughPeterborough, 20 July: 7.3 µg/m³, 0.9× usualPeterborough, 21 July: 6.4 µg/m³, 0.8× usualPeterborough, 22 July: 9.6 µg/m³, 1.2× usualPeterborough, 23 July: 10.9 µg/m³, 1.4× usualPeterborough, 24 July: 9.7 µg/m³, 1.2× usualPeterborough, 25 July: 16.0 µg/m³, 2.0× usualPeterborough, 26 July: 32.0 µg/m³, 4.0× usualPeterborough, 27 July: 8.9 µg/m³, 1.1× usualPeterborough, 28 July: 24.4 µg/m³, 3.1× usualPeterborough, 29 July: 6.0 µg/m³, 0.8× usualOakvilleOakville, 20 July: 9.6 µg/m³, 1.0× usualOakville, 21 July: 9.1 µg/m³, 0.9× usualOakville, 22 July: 13.0 µg/m³, 1.4× usualOakville, 23 July: 12.9 µg/m³, 1.3× usualOakville, 24 July: 10.6 µg/m³, 1.1× usualOakville, 25 July: 19.2 µg/m³, 2.0× usualOakville, 26 July: 31.8 µg/m³, 3.3× usualOakville, 27 July: 10.3 µg/m³, 1.1× usualOakville, 28 July: 23.7 µg/m³, 2.5× usualOakville, 29 July: 10.3 µg/m³, 1.1× usualMiltonMilton, 20 July: 10.4 µg/m³, 1.0× usualMilton, 21 July: 8.7 µg/m³, 0.8× usualMilton, 22 July: 12.0 µg/m³, 1.2× usualMilton, 23 July: 12.1 µg/m³, 1.2× usualMilton, 24 July: 11.3 µg/m³, 1.1× usualMilton, 25 July: 18.8 µg/m³, 1.8× usualMilton, 26 July: 30.9 µg/m³, 3.0× usualMilton, 27 July: 10.9 µg/m³, 1.1× usualMilton, 28 July: 21.6 µg/m³, 2.1× usualMilton, 29 July: 9.3 µg/m³, 0.9× usualGuelphGuelph, 20 July: 9.7 µg/m³, 1.1× usualGuelph, 21 July: 9.1 µg/m³, 1.0× usualGuelph, 22 July: 11.4 µg/m³, 1.3× usualGuelph, 23 July: 11.8 µg/m³, 1.3× usualGuelph, 24 July: 10.5 µg/m³, 1.2× usualGuelph, 25 July: 20.5 µg/m³, 2.3× usualGuelph, 26 July: 30.5 µg/m³, 3.4× usualGuelph, 27 July: 13.3 µg/m³, 1.5× usualGuelph, 28 July: 20.2 µg/m³, 2.2× usualGuelph, 29 July: 8.5 µg/m³, 0.9× usualKitchenerKitchener, 20 July: 8.7 µg/m³, 0.9× usualKitchener, 21 July: 9.3 µg/m³, 1.0× usualKitchener, 22 July: 13.4 µg/m³, 1.4× usualKitchener, 23 July: 15.9 µg/m³, 1.7× usualKitchener, 24 July: 11.8 µg/m³, 1.3× usualKitchener, 25 July: 22.1 µg/m³, 2.4× usualKitchener, 26 July: 30.4 µg/m³, 3.3× usualKitchener, 27 July: 13.3 µg/m³, 1.4× usualKitchener, 28 July: 19.0 µg/m³, 2.0× usualKitchener, 29 July: 7.8 µg/m³, 0.8× usual20 Jul212223242526272829
The 60 cities with the highest readings of 75, 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
MadisonWisconsin, United States2 52.024 July8.46.2×
LansingMichigan, United States3 58.225 July9.95.9×
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×
AppletonWisconsin, United States2 46.424 July9.15.1×
WaukeshaWisconsin, United States2 49.224 July9.75.1×
Eau ClaireWisconsin, United States3 46.624 July9.25.1×
Des PlainesIllinois, United States2 50.825 July10.15.0×
Calumet CityIllinois, United States2 53.725 July10.75.0×
ZionIllinois, United States1 41.525 July8.44.9×
South MilwaukeeWisconsin, United States2 42.425 July8.74.9×
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×
CaryIllinois, United States2 45.425 July9.94.6×
JenisonMichigan, United States2 45.125 July10.04.5×
KalamazooMichigan, United States3 50.325 July11.44.4×
DuluthMinnesota, United States2 44.523 July10.14.4×
ElkhartIndiana, United States1 43.425 July9.94.4×
AndersonIndiana, United States1 37.725 July8.64.4×
JolietIllinois, United States2 48.125 July11.04.4×
MilwaukeeWisconsin, United States3 45.625 July10.64.3×
RockfordIllinois, United States2 45.225 July10.84.2×
HammondIndiana, United States2 44.325 July10.64.2×
HollandMichigan, United States2 40.425 July9.74.2×
Grand RapidsMichigan, United States2 44.325 July10.74.1×
MinneapolisMinnesota, United States2 40.723 July10.14.0×
Saint MichaelMinnesota, United States2 35.423 July8.84.0×
LafayetteIndiana, United States1 35.825 July8.94.0×
NapervilleIllinois, United States2 45.825 July11.44.0×
PeterboroughOntario, Canada1 32.026 July8.04.0×
Saint PaulMinnesota, United States3 40.123 July10.14.0×
ChicagoIllinois, United States1 38.725 July10.13.8×
BlaineMinnesota, United States2 33.423 July8.83.8×
Green BayWisconsin, United States2 37.924 July10.03.8×
SuperiorWisconsin, United States2 41.223 July10.93.8×
FlintMichigan, United States2 30.426 July8.13.8×
BarrieOntario, Canada1 36.726 July9.83.7×
NewmarketOntario, Canada1 36.726 July9.83.7×
YpsilantiMichigan, United States2 33.725 July9.23.7×
TaylorMichigan, United States2 35.125 July9.63.7×
West FargoNorth Dakota, United States2 35.624 July9.93.6×
Lincoln ParkMichigan, United States1 35.525 July10.13.5×
Port HuronMichigan, United States2 32.625 July9.53.4×
Oak LawnIllinois, United States1 35.225 July10.33.4×
GuelphOntario, Canada1 30.526 July9.13.4×
Bay CityMichigan, United States2 31.326 July9.43.3×
OakvilleOntario, Canada1 31.826 July9.63.3×
DetroitMichigan, United States2 35.925 July10.93.3×
KitchenerOntario, Canada1 30.426 July9.33.3×
Apple ValleyMinnesota, United States2 26.823 July8.23.3×
DearbornMichigan, United States2 36.825 July11.33.3×
BrooklinOntario, Canada1 25.026 July7.73.2×
BloomingtonIllinois, United States1 27.425 July8.53.2×
ShakopeeMinnesota, United States2 31.523 July9.83.2×
BurnsvilleMinnesota, United States3 32.123 July10.03.2×
WaterlooIowa, United States1 25.524 July8.03.2×
CornwallOntario, Canada1 26.326 July8.33.2×
FishersIndiana, United States1 30.425 July9.63.2×
BramptonOntario, Canada1 29.026 July9.23.2×
SarniaOntario, Canada2 29.725 July9.53.1×
IndianapolisIndiana, United States1 33.325 July10.73.1×
ChathamOntario, Canada1 25.525 July8.23.1×
ClintonIowa, United States1 28.625 July9.33.1×
WindsorOntario, Canada2 35.825 July11.83.0×
MiltonOntario, Canada1 30.926 July10.33.0×
PeoriaIllinois, United States1 31.625 July10.63.0×
AnkenyIowa, United States1 25.124 July9.02.8×
TorontoOntario, Canada1 28.126 July10.12.8×
LondonOntario, Canada2 25.926 July9.72.7×
RedfordMichigan, United States2 27.126 July10.22.7×
ToledoOhio, United States1 28.725 July11.02.6×
DaytonOhio, United States1 25.325 July10.02.5×
SpringfieldOhio, United States1 25.425 July10.12.5×

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 and Canada

Number 6 of 45 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 45.

Use this page

SmogRank, North-eastern United States and Canada, July 2023: 75 cities with PM2.5 at twice their usual or more, 23 to 26 July 2023, smogrank.com/episodes/2023-07-north-eastern-united-states-and-canada-2 (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.