SmogRank / Episodes / United States

Northern United States and Canada, July 2026

For 8 days, from 14 to 21 July 2026, 327 cities in the United States and Canada had PM2.5 at least twice their usual for the time of year. The worst reading was Superior, Wisconsin, United States: 548.0 µg/m³ on 16 July, about 54× its usual 10.1. Ended 21 July.

Likely smoke from firesFires were detected within 300 km of the city on 36% of the counted city-days and smoke was mapped over the city on 90%. Satellites see crop, field and forest fires alike, so this doesn't say which burned.
Cities reached327in 2 countries
Days814 to 21 July 2026
Worst day16 July234 cities counted
Furthest above usual54×Superior

Day by day

16 July 234 cities at twice their usual or more
Ann ArborWhite OakDentEvanstonSkokieBlue IslandEvergreen ParkNilesPark RidgeWheatonLexington-FayetteSaint MatthewsJeffersonvilleJeffersontownNew AlbanyLouisvilleNicholasvilleValley StationPikevilleElizabethtownHazardSomersetOwensboroEvansvilleMiddlesboroKingsportBristolKnoxvilleCookevilleHarrimanRouyn-NorandaMaryvilleLoudonHendersonvilleOak GroveClarksvilleAshevilleNashvilleAthensHickoryPaducahClemmonsGreensboroLexingtonColumbiaChattanoogaArnoldSpartanburgGreenvilleCharlotteOttawaDurhamMarvinUticaMorrisvilleRaleighJacksonDyersburgClaytonAbingtonCamdenCornwallFayettevilleTarboroColumbiaGreenvilleNewarkBartlettAnkenyDes MoinesMarionWest MemphisMontréalFort DodgeRivière-des-Prairies–Pointe-aux-TremblesBrossardBurlingtonSaint-Jean-sur-RichelieuSorel-TracySpringfieldKearneyLibertyHartfordRaymoreKansas CityShawiniganKansas CitySaint JosephDrummondvilleLeawoodTrois-RivièresBécancourOlatheSherbrookeMarshallLawrenceLaconiaBellevueOmahaSpringdaleLa VistaBlairTopekaMiamiChanuteL'Ancienne-LoretteSioux FallsQuébecFort SmithLincolnBrookingsVermillionBeatriceSaint-GeorgesLewistonWatertownSaguenayAugustaTulsaJenksGlenpoolMcAlesterDerbyWichitaHaysvillePonca CityGrand IslandAberdeenBangorEdmondOklahoma CityMooreEdmundstonNepeanWinston-SalemWake ForestGranbyCincinnatiJasperMankatoFlatwoodsNorwoodCharlestonSharonvilleMasonSt. LouisWheelersburgHighland HeightsFort ThomasPortsmouthAshlandLebanonColumbusPortlandEast Saint LouisRutlandMiddletownUniversity CityPortsmouthLemayMuncieMcCordsvilleFishersGranite CityMuscatineNorth AdamsAlbanyIndianapolisLexingtonKokomoLafayetteFall RiverPittsfieldJerseyvilleWood RiverTerre HauteProvidenceKeeneBloomingtonAndersonUpper AltonBenningtonLondonderryDerryBostonPawtucketQuincySalemGatineauLynnSpringfieldBrocktonRochesterWest GreenwichCoventryNewburghHaverhillWorcesterGreenfieldHartfordHarrisonburgRoanoke RapidsFraminghamLowellNew LondonSpringfieldNorth ChicopeeUxbridgeMilfordWareWaterlooJersey CityNew HavenDecaturRoanokeChampaignPeoriaElizabethBridgeportToms RiverBloomingtonChesapeakeSavoyWinnipegWaterburyPatersonCedar RapidsIowa CitySouth VinelandDanburyWhite PlainsNorth BayClintonLindenKingstonDavenportMolineNew CityMount IvyNew York CityScrantonFort LeeNew BrunswickTrentonHolbrookEwingPoquosonSewellPaulsboroSmithvillePleasantvilleHersheyEast HamptonAllentownDaytonAtlantic CityWest FargoRandolphMendhamSyracuseDetroit LakesBensalemWashingtonPalmyraSeafordScaggsvilleRochesterRichmondCharlottesvilleHopewellElmwood ParkPennsaukenCambridgeJolietBrandermillParry SoundBarrieSt. CatharinesWyomissingOxon Hill-GlassmanorReadingShort PumpNew HollandBuffaloWest MifflinBayonneBraidwoodSpringfieldPhiladelphiaPainesvillePeterboroughGreater SudburyYoungstownWarrenAltoonaTorontoMichigan CityBeaver FallsBellevilleEdgewoodSaint PaulWarrenvilleAuroraShakopeeBaltimoreAllistonDoverMinneapolisKennett SquareLimaNewarkBearSaint MichaelElktonGlasgowColumbia CityElkhartLebanonMcKeesportJefferson HillsRockvilleSouth LaurelChesterClaymontHarrisburgWilkinsburgGaryOconomowocNorristownEau ClaireNewmarketSouth BendWyomingAltoonaRockfordTomahCalumet CityApple ValleyPittsburghColumbusNapervilleWilmingtonLancasterWarrenMonessenNatrona HeightsFort WayneMoundsvilleSaint CloudNew BrightonOakvilleKennedy TownshipMississaugaRose HillHunt ValleyDublinKalamazooHermitagePortageClevelandState CollegeWestervilleBethlehemBurnsvilleHammondCantonNew AlbanyGahannaBramptonSpringfieldJohnstownMiltonHamiltonWaterdownGreensburgAkronBridgeviewUpper Saint ClairBridgevilleSchlusserCarlisleFrostburgWeirton HeightsDoltonOak LawnCleveland HeightsHollandGuelphRedfordEast ChicagoBrantfordMadisonMiddletonRoyal OakKitchenerAshburnFranklin ParkChambersburgBlaineSteubenvilleUniontownTecumsehBrookfieldYorkWarrensville HeightsWeirtonChicagoElginBrookfieldLincolnwoodErieCanonsburgShaker HeightsHalfwayHagerstownMedinaBeecherCaryGreen BayDes PlainesBrainerdDearbornAppletonMilwaukeeJenisonHudsonvilleBay CityDetroitLondonLansingBarabooNew BaltimoreSouth MilwaukeeGrand RapidsWaukeshaTaylorGreendaleSt. ThomasPerrysburgMaumeePort HuronLincoln ParkWindsorYpsilantiToledoNorthbrookChathamSouthfieldOregonVirginiaWinthrop HarborSarniaManisteeZionSault Ste. MarieEastpointeMarquetteCloquetDuluthSuperior
11 Jul12131415161718192021222324
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

Sault Ste. MarieSault Ste. Marie, 11 July: 11.9 µg/m³Sault Ste. Marie, 12 July: 13.3 µg/m³Sault Ste. Marie, 13 July: 10.3 µg/m³Sault Ste. Marie, 14 July: 27.3 µg/m³, 3.3× its usual 8.4Sault Ste. Marie, 15 July: 185.0 µg/m³, 22× its usual 8.5Sault Ste. Marie, 16 July: 309.0 µg/m³, 36× its usual 8.5Sault Ste. Marie, 17 July: 66.6 µg/m³, 7.8× its usual 8.5Sault Ste. Marie, 18 July: 72.2 µg/m³, 8.4× its usual 8.6Sault Ste. Marie, 19 July: 12.1 µg/m³Sault Ste. Marie, 20 July: 30.6 µg/m³, 3.6× its usual 8.5Sault Ste. Marie, 21 July: 8.3 µg/m³Sault Ste. Marie, 22 July: 4.1 µg/m³Sault Ste. Marie, 23 July: 6.0 µg/m³Sault Ste. Marie, 24 July: 5.7 µg/m³SuperiorSuperior, 11 July: 12.4 µg/m³Superior, 12 July: 8.8 µg/m³Superior, 13 July: 8.3 µg/m³Superior, 14 July: 10.2 µg/m³Superior, 15 July: 339.0 µg/m³, 34× its usual 10.0Superior, 16 July: 548.0 µg/m³, 54× its usual 10.1Superior, 17 July: 246.0 µg/m³, 24× its usual 10.4Superior, 18 July: 42.1 µg/m³, 3.9× its usual 10.8Superior, 19 July: 38.0 µg/m³, 3.5× its usual 10.8Superior, 20 July: 28.4 µg/m³, 2.8× its usual 10.1Superior, 21 July: 6.2 µg/m³Superior, 22 July: 3.6 µg/m³Superior, 23 July: 9.9 µg/m³Superior, 24 July: 10.8 µg/m³DuluthDuluth, 11 July: 10.3 µg/m³Duluth, 12 July: 7.0 µg/m³Duluth, 13 July: 7.2 µg/m³Duluth, 14 July: 9.3 µg/m³Duluth, 15 July: 277.0 µg/m³, 28× its usual 9.8Duluth, 16 July: 466.0 µg/m³, 47× its usual 9.9Duluth, 17 July: 216.0 µg/m³, 22× its usual 10.0Duluth, 18 July: 37.0 µg/m³, 3.7× its usual 10.0Duluth, 19 July: 32.0 µg/m³, 3.2× its usual 9.9Duluth, 20 July: 24.9 µg/m³Duluth, 21 July: 5.0 µg/m³Duluth, 22 July: 3.2 µg/m³Duluth, 23 July: 9.0 µg/m³Duluth, 24 July: 9.5 µg/m³MarquetteMarquette, 11 July: 12.6 µg/m³Marquette, 12 July: 9.4 µg/m³Marquette, 13 July: 8.3 µg/m³Marquette, 14 July: 10.9 µg/m³Marquette, 15 July: 322.0 µg/m³, 37× its usual 8.6Marquette, 16 July: 398.0 µg/m³, 46× its usual 8.6Marquette, 17 July: 167.0 µg/m³, 19× its usual 8.8Marquette, 18 July: 174.0 µg/m³, 20× its usual 8.8Marquette, 19 July: 139.0 µg/m³, 16× its usual 8.6Marquette, 20 July: 77.1 µg/m³, 9.1× its usual 8.5Marquette, 21 July: 5.5 µg/m³Marquette, 22 July: 3.7 µg/m³Marquette, 23 July: 13.2 µg/m³Marquette, 24 July: 9.9 µg/m³CloquetCloquet, 11 July: 8.1 µg/m³Cloquet, 12 July: 6.0 µg/m³Cloquet, 13 July: 6.0 µg/m³Cloquet, 14 July: 7.2 µg/m³Cloquet, 15 July: 170.0 µg/m³, 22× its usual 7.7Cloquet, 16 July: 361.0 µg/m³, 47× its usual 7.7Cloquet, 17 July: 176.0 µg/m³, 23× its usual 7.8Cloquet, 18 July: 23.5 µg/m³Cloquet, 19 July: 22.9 µg/m³Cloquet, 20 July: 23.0 µg/m³Cloquet, 21 July: 5.8 µg/m³Cloquet, 22 July: 3.0 µg/m³Cloquet, 23 July: 8.3 µg/m³Cloquet, 24 July: 9.5 µg/m³VirginiaVirginia, 11 July: 10.2 µg/m³Virginia, 12 July: 6.5 µg/m³Virginia, 13 July: 6.1 µg/m³Virginia, 14 July: 8.7 µg/m³Virginia, 15 July: 111.0 µg/m³, 11× its usual 10.0Virginia, 16 July: 349.0 µg/m³, 35× its usual 10.0Virginia, 17 July: 246.0 µg/m³, 24× its usual 10.3Virginia, 18 July: 27.8 µg/m³, 2.7× its usual 10.3Virginia, 19 July: 17.6 µg/m³Virginia, 20 July: 16.0 µg/m³Virginia, 21 July: 3.9 µg/m³Virginia, 22 July: 3.6 µg/m³Virginia, 23 July: 11.4 µg/m³Virginia, 24 July: 10.3 µg/m³WindsorWindsor, 11 July: 9.4 µg/m³Windsor, 12 July: 16.2 µg/m³Windsor, 13 July: 18.3 µg/m³Windsor, 14 July: 13.5 µg/m³Windsor, 15 July: 76.3 µg/m³, 7.6× its usual 10.1Windsor, 16 July: 329.0 µg/m³, 32× its usual 10.2Windsor, 17 July: 204.5 µg/m³, 20× its usual 10.3Windsor, 18 July: 27.5 µg/m³, 2.6× its usual 10.4Windsor, 19 July: 43.0 µg/m³, 4.2× its usual 10.3Windsor, 20 July: 30.0 µg/m³, 2.8× its usual 10.6Windsor, 21 July: 24.8 µg/m³Windsor, 22 July: 3.5 µg/m³Windsor, 23 July: 5.5 µg/m³Windsor, 24 July: 5.9 µg/m³ManisteeManistee, 11 July: 11.1 µg/m³Manistee, 12 July: 13.0 µg/m³Manistee, 13 July: 12.0 µg/m³Manistee, 14 July: 11.4 µg/m³Manistee, 15 July: 99.5 µg/m³, 12× its usual 8.5Manistee, 16 July: 324.0 µg/m³, 36× its usual 9.0Manistee, 17 July: 192.0 µg/m³, 21× its usual 9.2Manistee, 18 July: 57.9 µg/m³, 6.3× its usual 9.2Manistee, 19 July: 92.3 µg/m³, 9.0× its usual 10.3Manistee, 20 July: 49.5 µg/m³, 4.8× its usual 10.3Manistee, 21 July: 9.5 µg/m³Manistee, 22 July: 3.6 µg/m³Manistee, 23 July: 4.3 µg/m³Manistee, 24 July: 5.2 µg/m³SarniaSarnia, 11 July: 11.5 µg/m³Sarnia, 12 July: 16.1 µg/m³Sarnia, 13 July: 16.3 µg/m³Sarnia, 14 July: 12.3 µg/m³Sarnia, 15 July: 106.0 µg/m³, 12× its usual 8.8Sarnia, 16 July: 323.0 µg/m³, 36× its usual 9.0Sarnia, 17 July: 196.0 µg/m³, 22× its usual 9.0Sarnia, 18 July: 50.4 µg/m³, 5.6× its usual 9.0Sarnia, 19 July: 34.0 µg/m³, 3.7× its usual 9.1Sarnia, 20 July: 27.8 µg/m³, 3.0× its usual 9.3Sarnia, 21 July: 21.7 µg/m³Sarnia, 22 July: 3.3 µg/m³Sarnia, 23 July: 5.7 µg/m³Sarnia, 24 July: 7.7 µg/m³Lincoln ParkLincoln Park, 11 July: 9.6 µg/m³Lincoln Park, 12 July: 16.4 µg/m³Lincoln Park, 13 July: 17.9 µg/m³Lincoln Park, 14 July: 12.7 µg/m³Lincoln Park, 15 July: 60.0 µg/m³, 6.2× its usual 9.7Lincoln Park, 16 July: 314.0 µg/m³, 32× its usual 9.8Lincoln Park, 17 July: 203.0 µg/m³, 21× its usual 9.8Lincoln Park, 18 July: 25.9 µg/m³, 2.6× its usual 9.9Lincoln Park, 19 July: 40.7 µg/m³, 4.2× its usual 9.8Lincoln Park, 20 July: 28.9 µg/m³, 2.9× its usual 10.1Lincoln Park, 21 July: 23.3 µg/m³Lincoln Park, 22 July: 3.4 µg/m³Lincoln Park, 23 July: 5.3 µg/m³Lincoln Park, 24 July: 6.6 µg/m³DetroitDetroit, 11 July: 9.5 µg/m³Detroit, 12 July: 15.9 µg/m³Detroit, 13 July: 19.2 µg/m³Detroit, 14 July: 13.6 µg/m³Detroit, 15 July: 66.4 µg/m³, 6.3× its usual 10.6Detroit, 16 July: 312.5 µg/m³, 29× its usual 10.7Detroit, 17 July: 201.0 µg/m³, 18× its usual 10.9Detroit, 18 July: 27.7 µg/m³, 2.5× its usual 11.0Detroit, 19 July: 41.2 µg/m³, 3.7× its usual 11.0Detroit, 20 July: 30.9 µg/m³, 2.8× its usual 11.1Detroit, 21 July: 25.3 µg/m³, 2.3× its usual 11.1Detroit, 22 July: 3.7 µg/m³Detroit, 23 July: 5.7 µg/m³Detroit, 24 July: 7.8 µg/m³DearbornDearborn, 11 July: 9.1 µg/m³Dearborn, 12 July: 15.2 µg/m³Dearborn, 13 July: 17.9 µg/m³Dearborn, 14 July: 12.4 µg/m³Dearborn, 15 July: 60.6 µg/m³, 5.5× its usual 11.0Dearborn, 16 July: 305.0 µg/m³, 27× its usual 11.1Dearborn, 17 July: 206.0 µg/m³, 19× its usual 11.1Dearborn, 18 July: 27.2 µg/m³, 2.4× its usual 11.2Dearborn, 19 July: 40.1 µg/m³, 3.6× its usual 11.2Dearborn, 20 July: 28.9 µg/m³, 2.6× its usual 11.2Dearborn, 21 July: 24.2 µg/m³Dearborn, 22 July: 3.7 µg/m³Dearborn, 23 July: 9.3 µg/m³Dearborn, 24 July: 7.7 µg/m³Port HuronPort Huron, 11 July: 11.1 µg/m³Port Huron, 12 July: 14.7 µg/m³Port Huron, 13 July: 15.2 µg/m³Port Huron, 14 July: 11.7 µg/m³Port Huron, 15 July: 131.0 µg/m³, 14× its usual 9.4Port Huron, 16 July: 301.0 µg/m³, 32× its usual 9.4Port Huron, 17 July: 189.0 µg/m³, 20× its usual 9.5Port Huron, 18 July: 49.7 µg/m³, 5.0× its usual 10.0Port Huron, 19 July: 33.7 µg/m³, 3.4× its usual 10.0Port Huron, 20 July: 26.5 µg/m³, 2.6× its usual 10.1Port Huron, 21 July: 21.2 µg/m³Port Huron, 22 July: 3.1 µg/m³Port Huron, 23 July: 5.8 µg/m³Port Huron, 24 July: 6.2 µg/m³SouthfieldSouthfield, 11 July: 10.0 µg/m³Southfield, 12 July: 15.4 µg/m³Southfield, 13 July: 15.1 µg/m³Southfield, 14 July: 12.6 µg/m³Southfield, 15 July: 56.5 µg/m³, 6.9× its usual 8.2Southfield, 16 July: 297.0 µg/m³, 34× its usual 8.7Southfield, 17 July: 212.0 µg/m³, 23× its usual 9.2Southfield, 18 July: 33.7 µg/m³, 3.5× its usual 9.5Southfield, 19 July: 39.0 µg/m³, 3.9× its usual 10.0Southfield, 20 July: 28.7 µg/m³, 2.8× its usual 10.4Southfield, 21 July: 23.8 µg/m³Southfield, 22 July: 3.1 µg/m³Southfield, 23 July: 5.1 µg/m³Southfield, 24 July: 6.8 µg/m³TaylorTaylor, 11 July: 8.8 µg/m³Taylor, 12 July: 14.9 µg/m³Taylor, 13 July: 15.7 µg/m³Taylor, 14 July: 11.8 µg/m³Taylor, 15 July: 52.3 µg/m³, 5.5× its usual 9.5Taylor, 16 July: 296.0 µg/m³, 31× its usual 9.6Taylor, 17 July: 197.0 µg/m³, 21× its usual 9.6Taylor, 18 July: 23.7 µg/m³Taylor, 19 July: 38.8 µg/m³, 4.0× its usual 9.6Taylor, 20 July: 28.8 µg/m³, 3.0× its usual 9.6Taylor, 21 July: 23.2 µg/m³Taylor, 22 July: 3.3 µg/m³Taylor, 23 July: 5.3 µg/m³Taylor, 24 July: 6.9 µg/m³New BaltimoreNew Baltimore, 11 July: 10.8 µg/m³New Baltimore, 12 July: 15.2 µg/m³New Baltimore, 13 July: 16.6 µg/m³New Baltimore, 14 July: 12.5 µg/m³New Baltimore, 15 July: 104.0 µg/m³, 11× its usual 9.5New Baltimore, 16 July: 290.0 µg/m³, 31× its usual 9.5New Baltimore, 17 July: 192.0 µg/m³, 19× its usual 9.9New Baltimore, 18 July: 42.6 µg/m³, 4.2× its usual 10.1New Baltimore, 19 July: 38.4 µg/m³, 3.8× its usual 10.1New Baltimore, 20 July: 25.2 µg/m³, 2.5× its usual 10.1New Baltimore, 21 July: 22.0 µg/m³New Baltimore, 22 July: 4.5 µg/m³New Baltimore, 23 July: 4.8 µg/m³New Baltimore, 24 July: 5.9 µg/m³Royal OakRoyal Oak, 11 July: 17.5 µg/m³Royal Oak, 12 July: 26.7 µg/m³Royal Oak, 13 July: 27.0 µg/m³Royal Oak, 14 July: 24.1 µg/m³Royal Oak, 15 July: 75.4 µg/m³, 6.4× its usual 11.8Royal Oak, 16 July: 289.0 µg/m³, 22× its usual 13.4Royal Oak, 17 July: 225.5 µg/m³, 16× its usual 13.8Royal Oak, 18 July: 45.0 µg/m³, 3.2× its usual 14.2Royal Oak, 19 July: 49.4 µg/m³, 3.5× its usual 14.2Royal Oak, 20 July: 40.6 µg/m³, 2.9× its usual 14.2Royal Oak, 21 July: 33.3 µg/m³, 2.3× its usual 14.7Royal Oak, 22 July: 2.1 µg/m³Royal Oak, 23 July: 1.7 µg/m³Royal Oak, 24 July: 4.1 µg/m³MilwaukeeMilwaukee, 11 July: 12.5 µg/m³Milwaukee, 12 July: 14.2 µg/m³Milwaukee, 13 July: 12.4 µg/m³Milwaukee, 14 July: 10.4 µg/m³Milwaukee, 15 July: 42.3 µg/m³, 4.3× its usual 9.9Milwaukee, 16 July: 280.0 µg/m³, 28× its usual 10.1Milwaukee, 17 July: no readingMilwaukee, 18 July: no readingMilwaukee, 19 July: no readingMilwaukee, 20 July: no readingMilwaukee, 21 July: no readingMilwaukee, 22 July: no readingMilwaukee, 23 July: no readingMilwaukee, 24 July: no readingWaukeshaWaukesha, 11 July: 12.1 µg/m³Waukesha, 12 July: 13.6 µg/m³Waukesha, 13 July: 12.5 µg/m³Waukesha, 14 July: 9.6 µg/m³Waukesha, 15 July: 33.7 µg/m³, 3.9× its usual 8.7Waukesha, 16 July: 274.0 µg/m³, 31× its usual 8.9Waukesha, 17 July: 136.0 µg/m³, 15× its usual 8.9Waukesha, 18 July: 44.7 µg/m³, 4.9× its usual 9.1Waukesha, 19 July: 92.0 µg/m³, 10× its usual 9.1Waukesha, 20 July: 42.0 µg/m³, 4.5× its usual 9.3Waukesha, 21 July: 7.6 µg/m³Waukesha, 22 July: 4.2 µg/m³Waukesha, 23 July: 5.7 µg/m³Waukesha, 24 July: 7.3 µg/m³EastpointeEastpointe, 11 July: 7.8 µg/m³Eastpointe, 12 July: 13.2 µg/m³Eastpointe, 13 July: 15.2 µg/m³Eastpointe, 14 July: 9.5 µg/m³Eastpointe, 15 July: 64.9 µg/m³, 9.0× its usual 7.2Eastpointe, 16 July: 273.0 µg/m³, 37× its usual 7.3Eastpointe, 17 July: 183.0 µg/m³, 24× its usual 7.5Eastpointe, 18 July: 27.2 µg/m³, 3.5× its usual 7.7Eastpointe, 19 July: 37.7 µg/m³, 4.8× its usual 7.8Eastpointe, 20 July: 26.2 µg/m³, 3.4× its usual 7.8Eastpointe, 21 July: 20.2 µg/m³Eastpointe, 22 July: 3.0 µg/m³Eastpointe, 23 July: 4.6 µg/m³Eastpointe, 24 July: 5.5 µg/m³BrookfieldBrookfield, 11 July: 16.2 µg/m³Brookfield, 12 July: 20.6 µg/m³Brookfield, 13 July: 16.9 µg/m³Brookfield, 14 July: 10.5 µg/m³Brookfield, 15 July: 40.9 µg/m³, 4.5× its usual 9.1Brookfield, 16 July: 270.5 µg/m³, 25× its usual 11.0Brookfield, 17 July: 132.0 µg/m³, 11× its usual 11.5Brookfield, 18 July: 54.5 µg/m³, 4.7× its usual 11.5Brookfield, 19 July: 97.5 µg/m³, 9.2× its usual 10.6Brookfield, 20 July: 51.5 µg/m³, 4.5× its usual 11.5Brookfield, 21 July: 5.4 µg/m³Brookfield, 22 July: 0.5 µg/m³Brookfield, 23 July: 1.1 µg/m³Brookfield, 24 July: 6.1 µg/m³LondonLondon, 11 July: 11.8 µg/m³London, 12 July: 15.2 µg/m³London, 13 July: 16.9 µg/m³London, 14 July: 12.2 µg/m³London, 15 July: 80.6 µg/m³, 9.0× its usual 9.0London, 16 July: 267.0 µg/m³, 30× its usual 9.0London, 17 July: 210.0 µg/m³, 23× its usual 9.0London, 18 July: 43.0 µg/m³, 4.7× its usual 9.1London, 19 July: 28.2 µg/m³, 3.1× its usual 9.2London, 20 July: 28.1 µg/m³, 3.0× its usual 9.5London, 21 July: 21.1 µg/m³London, 22 July: 2.9 µg/m³London, 23 July: 4.7 µg/m³London, 24 July: 6.7 µg/m³Bay CityBay City, 11 July: 9.5 µg/m³Bay City, 12 July: 14.2 µg/m³Bay City, 13 July: 12.5 µg/m³Bay City, 14 July: 9.4 µg/m³Bay City, 15 July: 86.1 µg/m³, 9.5× its usual 9.1Bay City, 16 July: 266.0 µg/m³, 29× its usual 9.1Bay City, 17 July: 212.0 µg/m³, 23× its usual 9.2Bay City, 18 July: 34.3 µg/m³, 3.6× its usual 9.4Bay City, 19 July: 37.4 µg/m³, 4.0× its usual 9.4Bay City, 20 July: 29.0 µg/m³, 3.1× its usual 9.5Bay City, 21 July: 17.5 µg/m³Bay City, 22 July: 4.3 µg/m³Bay City, 23 July: 4.9 µg/m³Bay City, 24 July: 6.5 µg/m³St. ThomasSt. Thomas, 11 July: 12.9 µg/m³St. Thomas, 12 July: 17.9 µg/m³St. Thomas, 13 July: 17.8 µg/m³St. Thomas, 14 July: 14.1 µg/m³St. Thomas, 15 July: 71.1 µg/m³, 8.6× its usual 8.3St. Thomas, 16 July: 259.0 µg/m³, 31× its usual 8.3St. Thomas, 17 July: 247.0 µg/m³, 29× its usual 8.4St. Thomas, 18 July: 44.4 µg/m³, 5.2× its usual 8.5St. Thomas, 19 July: 31.0 µg/m³, 3.6× its usual 8.5St. Thomas, 20 July: 27.8 µg/m³, 3.2× its usual 8.6St. Thomas, 21 July: 19.3 µg/m³St. Thomas, 22 July: 2.8 µg/m³St. Thomas, 23 July: 4.2 µg/m³St. Thomas, 24 July: 4.9 µg/m³Green BayGreen Bay, 11 July: 15.7 µg/m³Green Bay, 12 July: 14.7 µg/m³Green Bay, 13 July: 12.2 µg/m³Green Bay, 14 July: 10.5 µg/m³Green Bay, 15 July: 75.8 µg/m³, 8.2× its usual 9.3Green Bay, 16 July: 255.0 µg/m³, 27× its usual 9.4Green Bay, 17 July: 157.0 µg/m³, 17× its usual 9.5Green Bay, 18 July: 83.3 µg/m³, 8.8× its usual 9.5Green Bay, 19 July: 128.0 µg/m³, 13× its usual 9.5Green Bay, 20 July: 36.4 µg/m³, 3.8× its usual 9.5Green Bay, 21 July: 8.1 µg/m³Green Bay, 22 July: 4.5 µg/m³Green Bay, 23 July: 5.4 µg/m³Green Bay, 24 July: 6.6 µg/m³BeecherBeecher, 11 July: 10.7 µg/m³Beecher, 12 July: 13.2 µg/m³Beecher, 13 July: 12.9 µg/m³Beecher, 14 July: 10.6 µg/m³Beecher, 15 July: 84.7 µg/m³, 9.6× its usual 8.8Beecher, 16 July: 251.0 µg/m³, 27× its usual 9.3Beecher, 17 July: 161.0 µg/m³, 18× its usual 9.2Beecher, 18 July: 35.3 µg/m³, 3.8× its usual 9.2Beecher, 19 July: 34.6 µg/m³, 3.8× its usual 9.2Beecher, 20 July: 27.0 µg/m³, 3.0× its usual 9.1Beecher, 21 July: 17.1 µg/m³Beecher, 22 July: 6.6 µg/m³Beecher, 23 July: 7.7 µg/m³Beecher, 24 July: 9.6 µg/m³GreendaleGreendale, 11 July: 11.6 µg/m³Greendale, 12 July: 11.8 µg/m³Greendale, 13 July: 11.6 µg/m³Greendale, 14 July: 9.2 µg/m³Greendale, 15 July: 36.7 µg/m³, 4.6× its usual 7.9Greendale, 16 July: 248.0 µg/m³, 31× its usual 8.0Greendale, 17 July: 128.0 µg/m³, 16× its usual 8.0Greendale, 18 July: 45.4 µg/m³, 5.7× its usual 8.0Greendale, 19 July: 62.2 µg/m³, 7.5× its usual 8.3Greendale, 20 July: 43.0 µg/m³, 5.2× its usual 8.3Greendale, 21 July: 7.1 µg/m³Greendale, 22 July: 4.4 µg/m³Greendale, 23 July: 6.2 µg/m³Greendale, 24 July: 7.5 µg/m³South MilwaukeeSouth Milwaukee, 11 July: 11.6 µg/m³South Milwaukee, 12 July: 11.8 µg/m³South Milwaukee, 13 July: 11.6 µg/m³South Milwaukee, 14 July: 9.2 µg/m³South Milwaukee, 15 July: 36.7 µg/m³, 4.6× its usual 7.9South Milwaukee, 16 July: 248.0 µg/m³, 31× its usual 8.1South Milwaukee, 17 July: 128.0 µg/m³, 16× its usual 8.0South Milwaukee, 18 July: 45.4 µg/m³, 5.5× its usual 8.2South Milwaukee, 19 July: 62.2 µg/m³, 7.4× its usual 8.4South Milwaukee, 20 July: 43.0 µg/m³, 5.1× its usual 8.4South Milwaukee, 21 July: 7.1 µg/m³South Milwaukee, 22 July: 4.4 µg/m³South Milwaukee, 23 July: 6.2 µg/m³South Milwaukee, 24 July: 7.5 µg/m³ChathamChatham, 11 July: 9.2 µg/m³Chatham, 12 July: 14.5 µg/m³Chatham, 13 July: 15.8 µg/m³Chatham, 14 July: 12.0 µg/m³Chatham, 15 July: 49.1 µg/m³, 6.7× its usual 7.3Chatham, 16 July: 245.0 µg/m³, 34× its usual 7.3Chatham, 17 July: 166.0 µg/m³, 23× its usual 7.3Chatham, 18 July: 25.2 µg/m³, 3.2× its usual 7.8Chatham, 19 July: 35.4 µg/m³, 4.5× its usual 7.9Chatham, 20 July: 28.3 µg/m³, 3.6× its usual 7.9Chatham, 21 July: 20.1 µg/m³Chatham, 22 July: 3.2 µg/m³Chatham, 23 July: 4.3 µg/m³Chatham, 24 July: 5.8 µg/m³OconomowocOconomowoc, 11 July: 18.0 µg/m³Oconomowoc, 12 July: 19.6 µg/m³Oconomowoc, 13 July: 18.1 µg/m³Oconomowoc, 14 July: 13.7 µg/m³Oconomowoc, 15 July: 34.8 µg/m³, 2.4× its usual 14.4Oconomowoc, 16 July: 243.0 µg/m³, 17× its usual 14.6Oconomowoc, 17 July: 121.0 µg/m³, 7.6× its usual 15.9Oconomowoc, 18 July: 47.5 µg/m³, 3.0× its usual 15.9Oconomowoc, 19 July: 99.5 µg/m³, 6.2× its usual 16.0Oconomowoc, 20 July: 44.6 µg/m³, 2.8× its usual 16.0Oconomowoc, 21 July: 10.1 µg/m³Oconomowoc, 22 July: 3.2 µg/m³Oconomowoc, 23 July: 5.6 µg/m³Oconomowoc, 24 July: 7.3 µg/m³AppletonAppleton, 11 July: 13.7 µg/m³Appleton, 12 July: 13.9 µg/m³Appleton, 13 July: 9.9 µg/m³Appleton, 14 July: 8.9 µg/m³Appleton, 15 July: 88.7 µg/m³, 11× its usual 8.4Appleton, 16 July: 235.0 µg/m³, 28× its usual 8.5Appleton, 17 July: 146.0 µg/m³, 17× its usual 8.6Appleton, 18 July: 70.3 µg/m³, 8.2× its usual 8.6Appleton, 19 July: 135.0 µg/m³, 16× its usual 8.6Appleton, 20 July: 38.1 µg/m³, 4.4× its usual 8.6Appleton, 21 July: 11.2 µg/m³Appleton, 22 July: 5.2 µg/m³Appleton, 23 July: 5.4 µg/m³Appleton, 24 July: 6.1 µg/m³BrainerdBrainerd, 11 July: 6.3 µg/m³Brainerd, 12 July: 5.9 µg/m³Brainerd, 13 July: 7.2 µg/m³Brainerd, 14 July: 8.3 µg/m³Brainerd, 15 July: 166.0 µg/m³, 20× its usual 8.1Brainerd, 16 July: 224.0 µg/m³, 27× its usual 8.2Brainerd, 17 July: 53.6 µg/m³, 6.5× its usual 8.2Brainerd, 18 July: 11.0 µg/m³Brainerd, 19 July: 13.3 µg/m³Brainerd, 20 July: 19.0 µg/m³Brainerd, 21 July: 9.5 µg/m³Brainerd, 22 July: 3.4 µg/m³Brainerd, 23 July: 8.8 µg/m³Brainerd, 24 July: 11.2 µg/m³RedfordRedford, 11 July: 5.5 µg/m³Redford, 12 July: 9.5 µg/m³Redford, 13 July: 11.1 µg/m³Redford, 14 July: 8.6 µg/m³Redford, 15 July: 40.7 µg/m³, 3.9× its usual 10.4Redford, 16 July: 224.0 µg/m³, 21× its usual 10.5Redford, 17 July: 160.0 µg/m³, 16× its usual 10.3Redford, 18 July: 23.3 µg/m³Redford, 19 July: 29.6 µg/m³, 2.8× its usual 10.5Redford, 20 July: 25.9 µg/m³, 2.5× its usual 10.5Redford, 21 July: 19.4 µg/m³Redford, 22 July: 2.1 µg/m³Redford, 23 July: 4.8 µg/m³Redford, 24 July: 8.1 µg/m³BarabooBaraboo, 11 July: 9.9 µg/m³Baraboo, 12 July: 9.4 µg/m³Baraboo, 13 July: 8.7 µg/m³Baraboo, 14 July: 7.0 µg/m³Baraboo, 15 July: 29.9 µg/m³, 4.3× its usual 6.9Baraboo, 16 July: 212.0 µg/m³, 30× its usual 7.0Baraboo, 17 July: 112.0 µg/m³, 16× its usual 7.1Baraboo, 18 July: 23.5 µg/m³Baraboo, 19 July: 113.0 µg/m³, 15× its usual 7.5Baraboo, 20 July: 28.6 µg/m³, 3.7× its usual 7.8Baraboo, 21 July: 8.8 µg/m³Baraboo, 22 July: 3.3 µg/m³Baraboo, 23 July: 3.7 µg/m³Baraboo, 24 July: 5.1 µg/m³OregonOregon, 11 July: 8.4 µg/m³Oregon, 12 July: 16.6 µg/m³Oregon, 13 July: 19.2 µg/m³Oregon, 14 July: 17.7 µg/m³Oregon, 15 July: 16.6 µg/m³Oregon, 16 July: 377.0 µg/m³, 34× its usual 11.0Oregon, 17 July: 207.0 µg/m³, 18× its usual 11.2Oregon, 18 July: 19.3 µg/m³Oregon, 19 July: 41.8 µg/m³, 3.8× its usual 11.0Oregon, 20 July: 39.4 µg/m³, 3.5× its usual 11.4Oregon, 21 July: 24.2 µg/m³Oregon, 22 July: 4.1 µg/m³Oregon, 23 July: 5.9 µg/m³Oregon, 24 July: 7.6 µg/m³MaumeeMaumee, 11 July: 10.6 µg/m³Maumee, 12 July: 18.9 µg/m³Maumee, 13 July: 20.4 µg/m³Maumee, 14 July: 18.3 µg/m³Maumee, 15 July: 17.3 µg/m³Maumee, 16 July: 355.0 µg/m³, 32× its usual 11.2Maumee, 17 July: 254.0 µg/m³, 22× its usual 11.4Maumee, 18 July: 24.4 µg/m³Maumee, 19 July: 46.3 µg/m³, 4.0× its usual 11.5Maumee, 20 July: 50.7 µg/m³, 4.4× its usual 11.5Maumee, 21 July: 33.0 µg/m³, 2.8× its usual 11.9Maumee, 22 July: 5.7 µg/m³Maumee, 23 July: 9.3 µg/m³Maumee, 24 July: 12.3 µg/m³PerrysburgPerrysburg, 11 July: 10.6 µg/m³Perrysburg, 12 July: 18.9 µg/m³Perrysburg, 13 July: 20.4 µg/m³Perrysburg, 14 July: 18.3 µg/m³Perrysburg, 15 July: 17.3 µg/m³Perrysburg, 16 July: 355.0 µg/m³, 32× its usual 11.2Perrysburg, 17 July: 254.0 µg/m³, 22× its usual 11.4Perrysburg, 18 July: 24.4 µg/m³Perrysburg, 19 July: 46.3 µg/m³, 4.0× its usual 11.5Perrysburg, 20 July: 50.7 µg/m³, 4.4× its usual 11.5Perrysburg, 21 July: 33.0 µg/m³, 2.8× its usual 11.9Perrysburg, 22 July: 5.7 µg/m³Perrysburg, 23 July: 9.3 µg/m³Perrysburg, 24 July: 12.3 µg/m³ToledoToledo, 11 July: 10.1 µg/m³Toledo, 12 July: 17.9 µg/m³Toledo, 13 July: 20.4 µg/m³Toledo, 14 July: 15.5 µg/m³Toledo, 15 July: 11.6 µg/m³Toledo, 16 July: 334.0 µg/m³, 33× its usual 10.0Toledo, 17 July: 212.0 µg/m³, 21× its usual 10.1Toledo, 18 July: 17.3 µg/m³Toledo, 19 July: 43.5 µg/m³, 4.3× its usual 10.1Toledo, 20 July: 40.3 µg/m³, 4.0× its usual 10.1Toledo, 21 July: 21.8 µg/m³Toledo, 22 July: 4.3 µg/m³Toledo, 23 July: 6.9 µg/m³Toledo, 24 July: 8.1 µg/m³NorthbrookNorthbrook, 11 July: 9.5 µg/m³Northbrook, 12 July: 13.3 µg/m³Northbrook, 13 July: 15.8 µg/m³Northbrook, 14 July: 14.3 µg/m³Northbrook, 15 July: 16.2 µg/m³Northbrook, 16 July: 322.0 µg/m³, 34× its usual 9.6Northbrook, 17 July: 157.0 µg/m³, 16× its usual 9.8Northbrook, 18 July: 39.1 µg/m³, 4.0× its usual 9.8Northbrook, 19 July: 54.2 µg/m³, 5.5× its usual 9.8Northbrook, 20 July: 48.9 µg/m³, 5.0× its usual 9.8Northbrook, 21 July: 9.9 µg/m³Northbrook, 22 July: 3.2 µg/m³Northbrook, 23 July: 5.5 µg/m³Northbrook, 24 July: 7.6 µg/m³Grand RapidsGrand Rapids, 11 July: 8.5 µg/m³Grand Rapids, 12 July: 13.8 µg/m³Grand Rapids, 13 July: 12.5 µg/m³Grand Rapids, 14 July: 11.6 µg/m³Grand Rapids, 15 July: 20.0 µg/m³Grand Rapids, 16 July: 313.0 µg/m³, 31× its usual 10.2Grand Rapids, 17 July: 220.0 µg/m³, 21× its usual 10.3Grand Rapids, 18 July: 39.2 µg/m³, 3.8× its usual 10.4Grand Rapids, 19 July: 52.0 µg/m³, 5.0× its usual 10.4Grand Rapids, 20 July: 54.8 µg/m³, 5.3× its usual 10.3Grand Rapids, 21 July: 16.1 µg/m³Grand Rapids, 22 July: 3.8 µg/m³Grand Rapids, 23 July: 6.0 µg/m³Grand Rapids, 24 July: 7.2 µg/m³YpsilantiYpsilanti, 11 July: 9.0 µg/m³Ypsilanti, 12 July: 15.8 µg/m³Ypsilanti, 13 July: 13.4 µg/m³Ypsilanti, 14 July: 11.9 µg/m³Ypsilanti, 15 July: 15.6 µg/m³Ypsilanti, 16 July: 286.0 µg/m³, 33× its usual 8.8Ypsilanti, 17 July: 216.0 µg/m³, 25× its usual 8.8Ypsilanti, 18 July: 27.6 µg/m³, 3.1× its usual 9.0Ypsilanti, 19 July: 37.8 µg/m³, 4.2× its usual 9.1Ypsilanti, 20 July: 32.2 µg/m³, 3.5× its usual 9.2Ypsilanti, 21 July: 23.5 µg/m³Ypsilanti, 22 July: 4.1 µg/m³Ypsilanti, 23 July: 4.8 µg/m³Ypsilanti, 24 July: 6.4 µg/m³LansingLansing, 11 July: no readingLansing, 12 July: no readingLansing, 13 July: 14.1 µg/m³Lansing, 14 July: 8.5 µg/m³Lansing, 15 July: 21.5 µg/m³Lansing, 16 July: 278.0 µg/m³, 30× its usual 9.2Lansing, 17 July: 223.0 µg/m³, 24× its usual 9.3Lansing, 18 July: 29.5 µg/m³, 3.0× its usual 9.8Lansing, 19 July: 36.0 µg/m³, 3.6× its usual 9.9Lansing, 20 July: 32.0 µg/m³, 3.2× its usual 9.9Lansing, 21 July: 20.1 µg/m³Lansing, 22 July: 3.7 µg/m³Lansing, 23 July: 5.2 µg/m³Lansing, 24 July: 7.3 µg/m³HudsonvilleHudsonville, 11 July: 8.6 µg/m³Hudsonville, 12 July: 13.9 µg/m³Hudsonville, 13 July: 13.0 µg/m³Hudsonville, 14 July: 12.6 µg/m³Hudsonville, 15 July: 18.4 µg/m³Hudsonville, 16 July: 275.0 µg/m³, 29× its usual 9.6Hudsonville, 17 July: 212.0 µg/m³, 22× its usual 9.8Hudsonville, 18 July: 38.9 µg/m³, 4.0× its usual 9.8Hudsonville, 19 July: 55.6 µg/m³, 5.7× its usual 9.8Hudsonville, 20 July: 54.1 µg/m³, 5.5× its usual 9.8Hudsonville, 21 July: 15.7 µg/m³Hudsonville, 22 July: 3.5 µg/m³Hudsonville, 23 July: 5.4 µg/m³Hudsonville, 24 July: 6.6 µg/m³JenisonJenison, 11 July: 8.6 µg/m³Jenison, 12 July: 13.9 µg/m³Jenison, 13 July: 13.0 µg/m³Jenison, 14 July: 12.6 µg/m³Jenison, 15 July: 18.4 µg/m³Jenison, 16 July: 275.0 µg/m³, 29× its usual 9.6Jenison, 17 July: 212.0 µg/m³, 22× its usual 9.8Jenison, 18 July: 38.9 µg/m³, 4.0× its usual 9.8Jenison, 19 July: 55.6 µg/m³, 5.7× its usual 9.8Jenison, 20 July: 54.1 µg/m³, 5.5× its usual 9.8Jenison, 21 July: 15.7 µg/m³Jenison, 22 July: 3.5 µg/m³Jenison, 23 July: 5.4 µg/m³Jenison, 24 July: 6.6 µg/m³ElginElgin, 11 July: 15.5 µg/m³Elgin, 12 July: 21.0 µg/m³Elgin, 13 July: 22.0 µg/m³Elgin, 14 July: 19.3 µg/m³Elgin, 15 July: 17.2 µg/m³Elgin, 16 July: 275.0 µg/m³, 24× its usual 11.3Elgin, 17 July: 142.0 µg/m³, 12× its usual 12.1Elgin, 18 July: 37.1 µg/m³, 3.1× its usual 12.1Elgin, 19 July: 77.3 µg/m³, 6.3× its usual 12.2Elgin, 20 July: 59.7 µg/m³, 4.9× its usual 12.3Elgin, 21 July: 13.1 µg/m³Elgin, 22 July: 5.1 µg/m³Elgin, 23 July: 10.1 µg/m³Elgin, 24 July: 11.7 µg/m³ZionZion, 11 July: 9.0 µg/m³Zion, 12 July: 11.8 µg/m³Zion, 13 July: 12.6 µg/m³Zion, 14 July: 11.0 µg/m³Zion, 15 July: 24.5 µg/m³Zion, 16 July: 274.0 µg/m³, 36× its usual 7.6Zion, 17 July: 127.0 µg/m³, 16× its usual 7.7Zion, 18 July: 36.8 µg/m³, 4.8× its usual 7.7Zion, 19 July: 49.4 µg/m³, 6.4× its usual 7.7Zion, 20 July: 43.5 µg/m³, 5.6× its usual 7.8Zion, 21 July: 7.2 µg/m³Zion, 22 July: 3.3 µg/m³Zion, 23 July: 4.7 µg/m³Zion, 24 July: 6.7 µg/m³Winthrop HarborWinthrop Harbor, 11 July: 9.0 µg/m³Winthrop Harbor, 12 July: 11.8 µg/m³Winthrop Harbor, 13 July: 12.6 µg/m³Winthrop Harbor, 14 July: 11.0 µg/m³Winthrop Harbor, 15 July: 24.5 µg/m³Winthrop Harbor, 16 July: 274.0 µg/m³, 36× its usual 7.7Winthrop Harbor, 17 July: 127.0 µg/m³, 16× its usual 7.7Winthrop Harbor, 18 July: 36.8 µg/m³, 4.8× its usual 7.7Winthrop Harbor, 19 July: 49.4 µg/m³, 6.3× its usual 7.8Winthrop Harbor, 20 July: 43.5 µg/m³, 5.6× its usual 7.8Winthrop Harbor, 21 July: 7.2 µg/m³Winthrop Harbor, 22 July: 3.3 µg/m³Winthrop Harbor, 23 July: 4.7 µg/m³Winthrop Harbor, 24 July: 6.7 µg/m³LincolnwoodLincolnwood, 11 July: 8.6 µg/m³Lincolnwood, 12 July: 13.2 µg/m³Lincolnwood, 13 July: 19.0 µg/m³Lincolnwood, 14 July: 16.2 µg/m³Lincolnwood, 15 July: 13.9 µg/m³Lincolnwood, 16 July: 267.0 µg/m³, 25× its usual 10.8Lincolnwood, 17 July: 128.0 µg/m³, 11× its usual 11.2Lincolnwood, 18 July: 33.9 µg/m³, 3.0× its usual 11.2Lincolnwood, 19 July: 52.3 µg/m³, 4.7× its usual 11.2Lincolnwood, 20 July: 47.2 µg/m³, 4.1× its usual 11.4Lincolnwood, 21 July: 10.9 µg/m³Lincolnwood, 22 July: 4.3 µg/m³Lincolnwood, 23 July: 7.2 µg/m³Lincolnwood, 24 July: 9.5 µg/m³Des PlainesDes Plaines, 11 July: 8.6 µg/m³Des Plaines, 12 July: 11.1 µg/m³Des Plaines, 13 July: 13.0 µg/m³Des Plaines, 14 July: 12.0 µg/m³Des Plaines, 15 July: 11.8 µg/m³Des Plaines, 16 July: 256.0 µg/m³, 27× its usual 9.4Des Plaines, 17 July: 119.0 µg/m³, 13× its usual 9.4Des Plaines, 18 July: 31.0 µg/m³, 3.3× its usual 9.4Des Plaines, 19 July: 47.9 µg/m³, 5.1× its usual 9.4Des Plaines, 20 July: 42.3 µg/m³, 4.4× its usual 9.6Des Plaines, 21 July: 8.6 µg/m³Des Plaines, 22 July: 3.0 µg/m³Des Plaines, 23 July: 5.7 µg/m³Des Plaines, 24 July: 7.7 µg/m³CaryCary, 11 July: 9.6 µg/m³Cary, 12 July: 12.4 µg/m³Cary, 13 July: 12.6 µg/m³Cary, 14 July: 11.8 µg/m³Cary, 15 July: 13.4 µg/m³Cary, 16 July: 252.0 µg/m³, 27× its usual 9.3Cary, 17 July: 110.0 µg/m³, 12× its usual 9.3Cary, 18 July: 28.9 µg/m³, 3.1× its usual 9.3Cary, 19 July: 55.9 µg/m³, 5.9× its usual 9.4Cary, 20 July: 42.5 µg/m³, 4.5× its usual 9.4Cary, 21 July: 7.8 µg/m³Cary, 22 July: 3.2 µg/m³Cary, 23 July: 5.5 µg/m³Cary, 24 July: 6.8 µg/m³Franklin ParkFranklin Park, 11 July: 9.6 µg/m³Franklin Park, 12 July: 13.5 µg/m³Franklin Park, 13 July: 17.6 µg/m³Franklin Park, 14 July: 15.9 µg/m³Franklin Park, 15 July: 14.0 µg/m³Franklin Park, 16 July: 249.0 µg/m³, 22× its usual 11.4Franklin Park, 17 July: 132.0 µg/m³, 11× its usual 11.7Franklin Park, 18 July: 33.9 µg/m³, 2.9× its usual 11.6Franklin Park, 19 July: 53.9 µg/m³, 4.6× its usual 11.6Franklin Park, 20 July: 49.3 µg/m³, 4.2× its usual 11.7Franklin Park, 21 July: 11.4 µg/m³Franklin Park, 22 July: 3.8 µg/m³Franklin Park, 23 July: 8.7 µg/m³Franklin Park, 24 July: 10.7 µg/m³DoltonDolton, 11 July: 7.8 µg/m³Dolton, 12 July: 13.3 µg/m³Dolton, 13 July: 19.4 µg/m³Dolton, 14 July: 17.8 µg/m³Dolton, 15 July: 14.1 µg/m³Dolton, 16 July: 239.0 µg/m³, 21× its usual 11.6Dolton, 17 July: 118.0 µg/m³, 9.8× its usual 12.1Dolton, 18 July: 31.1 µg/m³, 2.6× its usual 12.1Dolton, 19 July: 52.9 µg/m³, 4.4× its usual 12.0Dolton, 20 July: 46.3 µg/m³, 3.9× its usual 12.0Dolton, 21 July: 13.6 µg/m³Dolton, 22 July: 3.2 µg/m³Dolton, 23 July: 7.9 µg/m³Dolton, 24 July: 8.3 µg/m³SteubenvilleSteubenville, 11 July: 8.2 µg/m³Steubenville, 12 July: 11.6 µg/m³Steubenville, 13 July: 11.0 µg/m³Steubenville, 14 July: 14.4 µg/m³Steubenville, 15 July: 14.9 µg/m³Steubenville, 16 July: 106.0 µg/m³, 10× its usual 10.3Steubenville, 17 July: 236.0 µg/m³, 23× its usual 10.3Steubenville, 18 July: 70.8 µg/m³, 6.9× its usual 10.3Steubenville, 19 July: 41.5 µg/m³, 4.0× its usual 10.3Steubenville, 20 July: 31.6 µg/m³, 3.1× its usual 10.3Steubenville, 21 July: 22.1 µg/m³Steubenville, 22 July: 7.3 µg/m³Steubenville, 23 July: 7.3 µg/m³Steubenville, 24 July: 6.6 µg/m³ChicagoChicago, 11 July: 8.7 µg/m³Chicago, 12 July: 13.1 µg/m³Chicago, 13 July: 18.9 µg/m³Chicago, 14 July: 14.6 µg/m³Chicago, 15 July: 11.9 µg/m³Chicago, 16 July: 233.0 µg/m³, 24× its usual 9.6Chicago, 17 July: 111.0 µg/m³, 11× its usual 9.7Chicago, 18 July: 29.9 µg/m³, 3.1× its usual 9.8Chicago, 19 July: 51.3 µg/m³, 5.2× its usual 9.8Chicago, 20 July: 43.4 µg/m³, 4.4× its usual 9.9Chicago, 21 July: 10.6 µg/m³Chicago, 22 July: 3.9 µg/m³Chicago, 23 July: 7.0 µg/m³Chicago, 24 July: 9.2 µg/m³BridgeviewBridgeview, 11 July: 9.7 µg/m³Bridgeview, 12 July: 14.6 µg/m³Bridgeview, 13 July: 20.0 µg/m³Bridgeview, 14 July: 17.1 µg/m³Bridgeview, 15 July: 14.4 µg/m³Bridgeview, 16 July: 229.0 µg/m³, 20× its usual 11.7Bridgeview, 17 July: 122.0 µg/m³, 10× its usual 12.1Bridgeview, 18 July: 31.9 µg/m³, 2.6× its usual 12.1Bridgeview, 19 July: 54.3 µg/m³, 4.5× its usual 12.1Bridgeview, 20 July: 46.1 µg/m³, 3.7× its usual 12.5Bridgeview, 21 July: 12.1 µg/m³Bridgeview, 22 July: 4.1 µg/m³Bridgeview, 23 July: 9.4 µg/m³Bridgeview, 24 July: 9.0 µg/m³MedinaMedina, 11 July: 9.6 µg/m³Medina, 12 July: 18.0 µg/m³Medina, 13 July: 16.7 µg/m³Medina, 14 July: 14.4 µg/m³Medina, 15 July: 13.0 µg/m³Medina, 16 July: 191.0 µg/m³, 22× its usual 8.5Medina, 17 July: 229.0 µg/m³, 27× its usual 8.5Medina, 18 July: 20.4 µg/m³Medina, 19 July: 47.8 µg/m³, 5.4× its usual 8.9Medina, 20 July: 38.4 µg/m³, 4.3× its usual 8.9Medina, 21 July: 25.3 µg/m³, 2.8× its usual 9.0Medina, 22 July: 3.4 µg/m³Medina, 23 July: 5.1 µg/m³Medina, 24 July: 6.9 µg/m³BrookfieldBrookfield, 11 July: 7.8 µg/m³Brookfield, 12 July: 12.5 µg/m³Brookfield, 13 July: 15.9 µg/m³Brookfield, 14 July: 12.9 µg/m³Brookfield, 15 July: 10.0 µg/m³Brookfield, 16 July: 223.0 µg/m³, 24× its usual 9.4Brookfield, 17 July: 116.0 µg/m³, 12× its usual 9.6Brookfield, 18 July: 29.4 µg/m³, 3.1× its usual 9.6Brookfield, 19 July: 52.6 µg/m³, 5.5× its usual 9.6Brookfield, 20 July: 47.5 µg/m³, 4.9× its usual 9.7Brookfield, 21 July: 10.3 µg/m³Brookfield, 22 July: 3.5 µg/m³Brookfield, 23 July: 7.8 µg/m³Brookfield, 24 July: 11.4 µg/m³TecumsehTecumseh, 11 July: 8.3 µg/m³Tecumseh, 12 July: 14.3 µg/m³Tecumseh, 13 July: 12.6 µg/m³Tecumseh, 14 July: 12.0 µg/m³Tecumseh, 15 July: 10.5 µg/m³Tecumseh, 16 July: 197.0 µg/m³, 21× its usual 9.5Tecumseh, 17 July: 219.0 µg/m³, 23× its usual 9.5Tecumseh, 18 July: 22.0 µg/m³Tecumseh, 19 July: 36.6 µg/m³, 3.9× its usual 9.5Tecumseh, 20 July: 32.1 µg/m³, 3.4× its usual 9.5Tecumseh, 21 July: 23.0 µg/m³Tecumseh, 22 July: 3.4 µg/m³Tecumseh, 23 July: 4.5 µg/m³Tecumseh, 24 July: 6.8 µg/m³HollandHolland, 11 July: 4.4 µg/m³Holland, 12 July: 7.7 µg/m³Holland, 13 July: 7.8 µg/m³Holland, 14 July: 8.2 µg/m³Holland, 15 July: 12.4 µg/m³Holland, 16 July: 213.0 µg/m³, 21× its usual 10.1Holland, 17 July: 157.0 µg/m³, 16× its usual 10.1Holland, 18 July: 30.1 µg/m³, 3.0× its usual 10.1Holland, 19 July: 46.1 µg/m³, 4.5× its usual 10.2Holland, 20 July: 41.4 µg/m³, 4.1× its usual 10.1Holland, 21 July: 9.9 µg/m³Holland, 22 July: 0.4 µg/m³Holland, 23 July: 1.6 µg/m³Holland, 24 July: 3.3 µg/m³WyomingWyoming, 11 July: 11.6 µg/m³Wyoming, 12 July: 15.4 µg/m³Wyoming, 13 July: 17.0 µg/m³Wyoming, 14 July: 16.1 µg/m³Wyoming, 15 July: 19.8 µg/m³Wyoming, 16 July: 210.0 µg/m³, 17× its usual 12.5Wyoming, 17 July: 168.0 µg/m³, 13× its usual 12.6Wyoming, 18 July: 35.6 µg/m³, 2.8× its usual 12.6Wyoming, 19 July: 46.0 µg/m³, 3.7× its usual 12.6Wyoming, 20 July: 47.0 µg/m³, 3.7× its usual 12.6Wyoming, 21 July: 18.7 µg/m³Wyoming, 22 July: 6.9 µg/m³Wyoming, 23 July: 11.6 µg/m³Wyoming, 24 July: 11.8 µg/m³11 Jul131517192123
The 60 cities with the highest readings of 327, 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 States6 548.016 July10.154×
DuluthMinnesota, United States5 466.016 July9.947×
CloquetMinnesota, United States3 361.016 July7.747×
MarquetteMichigan, United States6 398.016 July8.646×
EastpointeMichigan, United States6 273.016 July7.337×
Sault Ste. MarieOntario, Canada6 309.016 July8.536×
ZionIllinois, United States5 274.016 July7.636×
ManisteeMichigan, United States6 324.016 July9.036×
SarniaOntario, Canada6 323.016 July9.036×
Winthrop HarborIllinois, United States5 274.016 July7.736×
VirginiaMinnesota, United States4 349.016 July10.035×
OregonOhio, United States4 377.016 July11.034×
SouthfieldMichigan, United States6 297.016 July8.734×
ChathamOntario, Canada6 245.016 July7.334×
NorthbrookIllinois, United States5 322.016 July9.634×
ToledoOhio, United States4 334.016 July10.033×
YpsilantiMichigan, United States5 286.016 July8.833×
WindsorOntario, Canada6 329.016 July10.232×
Lincoln ParkMichigan, United States6 314.016 July9.832×
Port HuronMichigan, United States6 301.016 July9.432×
MaumeeOhio, United States5 355.016 July11.232×
PerrysburgOhio, United States5 355.016 July11.232×
St. ThomasOntario, Canada6 259.016 July8.331×
GreendaleWisconsin, United States6 248.016 July8.031×
TaylorMichigan, United States5 296.016 July9.631×
WaukeshaWisconsin, United States6 274.016 July8.931×
Grand RapidsMichigan, United States5 313.016 July10.231×
South MilwaukeeWisconsin, United States6 248.016 July8.131×
New BaltimoreMichigan, United States6 290.016 July9.531×
BarabooWisconsin, United States5 212.016 July7.030×
LansingMichigan, United States5 278.016 July9.230×
LondonOntario, Canada6 267.016 July9.030×
DetroitMichigan, United States7 312.516 July10.729×
Bay CityMichigan, United States6 266.016 July9.129×
HudsonvilleMichigan, United States5 275.016 July9.629×
JenisonMichigan, United States5 275.016 July9.629×
MilwaukeeWisconsin, United States2 280.016 July10.128×
AppletonWisconsin, United States6 235.016 July8.528×
DearbornMichigan, United States6 305.016 July11.128×
BrainerdMinnesota, United States3 224.016 July8.227×
Des PlainesIllinois, United States5 256.016 July9.427×
Green BayWisconsin, United States6 255.016 July9.427×
CaryIllinois, United States5 252.016 July9.327×
BeecherMichigan, United States6 251.016 July9.327×
MedinaOhio, United States5 229.017 July8.527×
HagerstownMaryland, United States3 149.017 July5.627×
HalfwayMaryland, United States3 149.017 July5.627×
Shaker HeightsOhio, United States5 177.016 July6.826×
CanonsburgPennsylvania, United States4 189.017 July7.625×
EriePennsylvania, United States4 181.017 July7.325×
LincolnwoodIllinois, United States5 267.016 July10.825×
BrookfieldWisconsin, United States6 270.516 July11.025×
ElginIllinois, United States5 275.016 July11.324×
ChicagoIllinois, United States5 233.016 July9.624×
WeirtonWest Virginia, United States5 197.517 July8.224×
Warrensville HeightsOhio, United States5 194.016 July8.124×
YorkPennsylvania, United States3 185.017 July7.724×
BrookfieldIllinois, United States5 223.016 July9.424×
TecumsehMichigan, United States4 219.017 July9.523×
UniontownPennsylvania, United States5 193.017 July8.423×
SteubenvilleOhio, United States5 236.017 July10.323×
BlaineMinnesota, United States3 186.016 July8.223×
ChambersburgPennsylvania, United States3 171.017 July7.822×
Franklin ParkIllinois, United States5 249.016 July11.422×
AshburnVirginia, United States2 172.017 July7.922×
KitchenerOntario, Canada4 200.016 July9.222×
Royal OakMichigan, United States7 289.016 July13.422×
MiddletonWisconsin, United States5 158.016 July7.322×
MadisonWisconsin, United States4 174.516 July8.122×
BrantfordOntario, Canada4 193.016 July9.021×
East ChicagoIndiana, United States5 193.016 July9.021×
RedfordMichigan, United States5 224.016 July10.521×
GuelphOntario, Canada4 181.016 July8.521×
HollandMichigan, United States5 213.016 July10.121×
Cleveland HeightsOhio, United States5 175.016 July8.321×
Oak LawnIllinois, United States5 202.016 July9.621×
DoltonIllinois, United States5 239.016 July11.621×
Weirton HeightsWest Virginia, United States4 161.017 July7.821×
FrostburgMaryland, United States3 149.017 July7.320×
CarlislePennsylvania, United States3 155.017 July7.720×
SchlusserPennsylvania, United States3 155.017 July7.720×
BridgevillePennsylvania, United States4 167.017 July8.420×
Upper Saint ClairPennsylvania, United States4 167.017 July8.420×
BridgeviewIllinois, United States5 229.016 July11.720×
AkronOhio, United States5 163.017 July8.419×
GreensburgPennsylvania, United States4 164.017 July8.519×
WaterdownOntario, Canada4 160.016 July8.319×
HamiltonOntario, Canada4 174.516 July9.119×
MiltonOntario, Canada4 179.016 July9.419×
JohnstownPennsylvania, United States5 160.017 July8.419×
SpringfieldVirginia, United States2 160.017 July8.419×
BramptonOntario, Canada4 153.016 July8.119×
GahannaOhio, United States4 144.017 July7.619×
New AlbanyOhio, United States4 144.017 July7.619×
CantonOhio, United States5 203.517 July10.819×
HammondIndiana, United States5 188.016 July10.019×
BurnsvilleMinnesota, United States3 172.016 July9.219×
BethlehemPennsylvania, United States3 128.016 July7.018×
WestervilleOhio, United States4 202.017 July11.118×
State CollegePennsylvania, United States3 133.016 July7.318×
ClevelandOhio, United States5 204.016 July11.318×
PortageIndiana, United States5 177.016 July9.818×
HermitagePennsylvania, United States4 141.017 July7.818×
KalamazooMichigan, United States5 203.016 July11.318×
DublinOhio, United States4 162.017 July9.018×
Hunt ValleyMaryland, United States3 117.017 July6.518×
Rose HillVirginia, United States2 145.017 July8.118×
MississaugaOntario, Canada4 138.016 July7.718×
Kennedy TownshipPennsylvania, United States5 178.017 July10.018×
OakvilleOntario, Canada4 157.016 July8.818×
New BrightonPennsylvania, United States4 151.017 July8.518×
Saint CloudMinnesota, United States2 146.015 July8.218×
MoundsvilleWest Virginia, United States5 170.017 July9.618×
Fort WayneIndiana, United States4 173.017 July9.918×
Natrona HeightsPennsylvania, United States4 168.017 July9.618×
MonessenPennsylvania, United States5 163.017 July9.318×
WarrenPennsylvania, United States4 124.016 July7.118×
LancasterPennsylvania, United States3 146.017 July8.417×
WilmingtonDelaware, United States3 135.517 July7.817×
NapervilleIllinois, United States5 190.016 July11.017×
ColumbusOhio, United States4 183.517 July10.617×
PittsburghPennsylvania, United States5 175.017 July10.117×
Apple ValleyMinnesota, United States3 140.016 July8.117×
Calumet CityIllinois, United States5 175.016 July10.217×
TomahWisconsin, United States6 170.016 July9.917×
RockfordIllinois, United States4 158.016 July9.317×
AltoonaWisconsin, United States5 142.016 July8.417×
WyomingMichigan, United States5 210.016 July12.517×
South BendIndiana, United States5 161.017 July9.617×
NewmarketOntario, Canada4 147.016 July8.817×
Eau ClaireWisconsin, United States5 142.016 July8.517×
NorristownPennsylvania, United States3 127.017 July7.617×
OconomowocWisconsin, United States6 243.016 July14.617×
GaryIndiana, United States4 161.016 July9.717×
WilkinsburgPennsylvania, United States4 161.017 July9.717×
HarrisburgPennsylvania, United States3 153.017 July9.217×
ClaymontDelaware, United States3 126.017 July7.617×
ChesterPennsylvania, United States3 126.017 July7.617×
South LaurelMaryland, United States2 123.017 July7.417×
RockvilleMaryland, United States2 113.017 July6.817×
Jefferson HillsPennsylvania, United States4 155.017 July9.417×
McKeesportPennsylvania, United States4 155.017 July9.417×
LebanonPennsylvania, United States3 142.017 July8.617×
ElkhartIndiana, United States4 162.017 July10.016×
Columbia CityIndiana, United States4 160.017 July9.916×
GlasgowDelaware, United States3 123.017 July7.716×
ElktonMaryland, United States3 123.017 July7.716×
Saint MichaelMinnesota, United States3 137.016 July8.616×
BearDelaware, United States3 126.017 July7.916×
NewarkDelaware, United States3 130.517 July8.316×
LimaOhio, United States4 147.017 July9.416×
Kennett SquarePennsylvania, United States3 123.017 July7.916×
MinneapolisMinnesota, United States3 155.016 July10.016×
DoverDelaware, United States3 135.017 July8.716×
AllistonOntario, Canada4 118.016 July7.616×
BaltimoreMaryland, United States3 118.017 July7.616×
ShakopeeMinnesota, United States3 142.016 July9.215×
AuroraIllinois, United States4 148.017 July9.715×
WarrenvilleIllinois, United States4 148.017 July9.715×
Saint PaulMinnesota, United States3 154.016 July10.115×
EdgewoodMaryland, United States3 116.017 July7.715×
BellevilleOntario, Canada3 112.016 July7.415×
Beaver FallsPennsylvania, United States4 150.017 July10.115×
Michigan CityIndiana, United States4 150.017 July10.115×
TorontoOntario, Canada4 136.016 July9.115×
AltoonaPennsylvania, United States3 127.017 July8.515×
WarrenOhio, United States5 160.017 July10.915×
YoungstownOhio, United States4 138.017 July9.415×
Greater SudburyOntario, Canada4 122.015 July8.315×
PeterboroughOntario, Canada3 115.016 July7.915×
PainesvilleOhio, United States3 100.016 July6.915×
PhiladelphiaPennsylvania, United States4 144.017 July10.114×
SpringfieldOhio, United States3 143.017 July10.114×
BraidwoodIllinois, United States4 115.017 July8.114×
BayonneNew Jersey, United States4 86.916 July6.114×
West MifflinPennsylvania, United States5 166.517 July11.814×
BuffaloNew York, United States4 131.016 July9.314×
New HollandPennsylvania, United States3 124.017 July9.014×
Short PumpVirginia, United States2 106.017 July7.714×
ReadingPennsylvania, United States3 105.016 July7.614×
Oxon Hill-GlassmanorMaryland, United States2 106.017 July7.814×
WyomissingPennsylvania, United States3 105.016 July7.714×
St. CatharinesOntario, Canada4 107.017 July8.013×
BarrieOntario, Canada4 127.016 July9.613×
Parry SoundOntario, Canada3 104.016 July7.913×
BrandermillVirginia, United States2 102.017 July8.013×
JolietIllinois, United States4 130.017 July10.213×
CambridgeMaryland, United States2 91.517 July7.213×
PennsaukenNew Jersey, United States3 114.017 July9.113×
Elmwood ParkIllinois, United States4 196.016 July15.812×
HopewellVirginia, United States2 91.017 July7.412×
CharlottesvilleVirginia, United States2 101.017 July8.312×
RichmondVirginia, United States2 99.517 July8.212×
RochesterNew York, United States3 95.516 July8.012×
ScaggsvilleMaryland, United States2 114.017 July9.712×
SeafordDelaware, United States3 88.317 July7.612×
PalmyraNew Jersey, United States4 127.017 July11.012×
WashingtonDistrict of Columbia, United States2 107.517 July9.411×
BensalemPennsylvania, United States3 104.017 July9.111×
Detroit LakesMinnesota, United States2 100.016 July8.911×
SyracuseNew York, United States4 77.016 July7.011×
MendhamNew Jersey, United States4 82.416 July7.910×
RandolphNew Jersey, United States4 82.416 July7.910×
West FargoNorth Dakota, United States3 112.016 July10.910×
Atlantic CityNew Jersey, United States3 84.717 July8.410×
DaytonOhio, United States3 100.017 July10.010×
AllentownPennsylvania, United States2 72.418 July7.39.9×
East HamptonVirginia, United States4 95.817 July9.99.7×
HersheyPennsylvania, United States1 88.018 July9.49.4×
PleasantvilleNew Jersey, United States3 80.617 July8.89.2×
SmithvilleNew Jersey, United States3 80.617 July8.89.2×
PaulsboroNew Jersey, United States3 90.117 July9.99.1×
SewellNew Jersey, United States3 90.117 July9.99.1×
PoquosonVirginia, United States2 68.817 July7.69.1×
EwingNew Jersey, United States4 83.616 July9.39.0×
HolbrookNew York, United States4 65.816 July7.39.0×
TrentonNew Jersey, United States3 84.616 July9.58.9×
New BrunswickNew Jersey, United States3 75.616 July8.58.9×
Fort LeeNew Jersey, United States4 70.916 July8.08.9×
ScrantonPennsylvania, United States4 78.816 July9.08.8×
New York CityNew York, United States4 84.616 July9.78.7×
Mount IvyNew York, United States4 51.216 July5.98.7×
New CityNew York, United States4 51.216 July5.98.7×
MolineIllinois, United States2 75.019 July8.78.6×
DavenportIowa, United States2 73.719 July8.78.5×
KingstonOntario, Canada3 67.016 July7.98.5×
LindenNew Jersey, United States4 81.316 July9.88.3×
ClintonIowa, United States2 75.819 July9.48.1×
North BayOntario, Canada4 63.016 July7.88.1×
White PlainsNew York, United States4 51.716 July6.48.1×
DanburyConnecticut, United States4 67.316 July8.57.9×
South VinelandNew Jersey, United States3 62.317 July8.07.8×
Iowa CityIowa, United States2 67.719 July8.87.7×
Cedar RapidsIowa, United States2 65.319 July8.57.7×
PatersonNew Jersey, United States4 66.616 July8.97.5×
WaterburyConnecticut, United States4 62.216 July8.37.5×
WinnipegManitoba, Canada2 82.116 July11.17.4×
SavoyIllinois, United States2 62.219 July8.47.4×
ChesapeakeVirginia, United States1 59.117 July8.07.4×
BloomingtonIllinois, United States2 63.119 July8.67.3×
Toms RiverNew Jersey, United States3 63.317 July8.87.2×
BridgeportConnecticut, United States4 65.616 July9.27.1×
ElizabethNew Jersey, United States4 74.316 July10.67.0×
PeoriaIllinois, United States2 73.319 July10.47.0×
ChampaignIllinois, United States2 63.919 July9.17.0×
RoanokeVirginia, United States2 54.817 July8.06.9×
DecaturIllinois, United States2 64.119 July9.46.8×
New HavenConnecticut, United States3 56.716 July8.46.8×
Jersey CityNew Jersey, United States4 64.816 July9.76.7×
WaterlooIowa, United States1 52.419 July8.06.6×
WareMassachusetts, United States3 43.818 July6.66.6×
MilfordMassachusetts, United States2 41.818 July6.36.6×
UxbridgeMassachusetts, United States2 41.818 July6.36.6×
North ChicopeeMassachusetts, United States3 40.718 July6.36.5×
SpringfieldMassachusetts, United States3 47.618 July7.66.3×
New LondonConnecticut, United States4 51.016 July8.26.2×
LowellMassachusetts, United States2 42.618 July7.06.1×
FraminghamMassachusetts, United States2 40.418 July6.66.1×
Roanoke RapidsNorth Carolina, United States1 58.017 July9.66.0×
HarrisonburgVirginia, United States3 43.417 July7.26.0×
HartfordConnecticut, United States3 50.918 July8.75.9×
GreenfieldMassachusetts, United States3 41.818 July7.15.9×
WorcesterMassachusetts, United States2 41.318 July7.05.9×
HaverhillMassachusetts, United States1 39.918 July7.05.7×
NewburghNew York, United States4 34.616 July6.15.7×
CoventryRhode Island, United States2 29.716 July5.25.7×
West GreenwichRhode Island, United States2 29.716 July5.25.7×
RochesterMinnesota, United States1 56.119 July10.15.6×
BrocktonMassachusetts, United States2 43.418 July7.75.6×
SpringfieldIllinois, United States2 51.419 July9.35.5×
LynnMassachusetts, United States2 38.318 July7.05.5×
GatineauQuebec, Canada1 32.714 July5.95.5×
SalemVirginia, United States1 45.117 July8.65.2×
QuincyMassachusetts, United States2 35.818 July6.95.2×
PawtucketRhode Island, United States1 32.118 July6.25.2×
BostonMassachusetts, United States2 39.318 July7.75.1×
DerryNew Hampshire, United States2 36.518 July7.15.1×
LondonderryNew Hampshire, United States2 36.518 July7.15.1×
BenningtonVermont, United States3 34.616 July6.85.1×
Upper AltonIllinois, United States1 52.720 July10.65.0×
AndersonIndiana, United States2 43.619 July8.85.0×
BloomingtonIndiana, United States2 40.120 July8.24.9×
KeeneNew Hampshire, United States2 34.618 July7.14.9×
ProvidenceRhode Island, United States1 33.718 July6.94.9×
Terre HauteIndiana, United States2 47.419 July10.14.7×
Wood RiverIllinois, United States1 45.120 July9.64.7×
JerseyvilleIllinois, United States1 37.020 July7.94.7×
PittsfieldMassachusetts, United States3 36.616 July7.84.7×
Fall RiverMassachusetts, United States3 33.118 July7.14.7×
LafayetteIndiana, United States2 41.519 July9.14.6×
KokomoIndiana, United States3 40.119 July8.84.6×
LexingtonMassachusetts, United States3 55.118 July12.24.5×
IndianapolisIndiana, United States2 48.019 July11.04.4×
AlbanyNew York, United States3 42.116 July9.74.3×
North AdamsMassachusetts, United States3 33.116 July7.74.3×
MuscatineIowa, United States1 29.520 July6.84.3×
Granite CityIllinois, United States1 42.320 July10.24.1×
FishersIndiana, United States2 41.719 July10.14.1×
McCordsvilleIndiana, United States2 41.719 July10.14.1×
MuncieIndiana, United States3 39.219 July9.54.1×
LemayMissouri, United States1 31.720 July7.94.0×
PortsmouthNew Hampshire, United States1 30.518 July7.64.0×
University CityMissouri, United States1 29.620 July7.53.9×
MiddletownOhio, United States3 43.419 July11.63.7×
RutlandVermont, United States1 30.018 July8.23.7×
East Saint LouisIllinois, United States1 36.620 July10.13.6×
PortlandMaine, United States1 32.618 July9.03.6×
ColumbusIndiana, United States2 31.119 July8.63.6×
LebanonOhio, United States2 28.919 July8.03.6×
AshlandKentucky, United States1 28.820 July8.13.6×
PortsmouthOhio, United States2 34.220 July9.93.5×
Fort ThomasKentucky, United States2 28.119 July8.03.5×
Highland HeightsKentucky, United States2 28.119 July8.03.5×
WheelersburgOhio, United States2 34.220 July10.03.4×
St. LouisMissouri, United States1 33.420 July9.73.4×
MasonOhio, United States2 29.319 July8.53.4×
SharonvilleOhio, United States2 29.319 July8.53.4×
CharlestonWest Virginia, United States1 26.620 July8.33.2×
NorwoodOhio, United States2 35.319 July11.33.1×
FlatwoodsKentucky, United States2 33.020 July10.53.1×
MankatoMinnesota, United States1 29.919 July9.63.1×
JasperIndiana, United States1 28.020 July9.13.1×
CincinnatiOhio, United States2 33.019 July11.52.9×
GranbyQuebec, Canada1 25.518 July8.82.9×
Wake ForestNorth Carolina, United States3 35.117 July12.62.8×
Winston-SalemNorth Carolina, United States1 25.318 July9.22.8×
NepeanOntario, Canada2 39.914 July14.82.7×

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 2 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 2026: 327 cities with PM2.5 at twice their usual or more, 14 to 21 July 2026, smogrank.com/episodes/2026-07-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.