SmogRank / Episodes / United States

North-eastern United States and Canada, 30 July to 9 August 2025

For 11 days, from 30 July to 9 August 2025, 241 cities in the United States and Canada had PM2.5 at least twice their usual for the time of year. The worst reading was Marquette, Michigan, United States: 112.0 µg/m³ on 30 July, about 14× its usual 8.1.

No cause namedWe have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached241in 2 countries
Days1130 July to 9 August 2025
Worst day4 August119 cities counted
Furthest above usual14×Marquette

Day by day

4 August 119 cities at twice their usual or more
MedinaAkronCantonHermitageDublinGahannaColumbusWeirtonWeirton HeightsSpringfieldWilkinsburgDaytonMcKeesportLebanonMasonPortsmouthWhite OakCincinnatiFort ThomasJohnstownAshlandHuntingtonCharlestonAltoonaColumbusLexington-FayetteNicholasvilleJeffersontownSaint MatthewsHarrisonburgJeffersonvilleLouisvilleHagerstownNew AlbanyValley StationElizabethtownCharlottesvilleAshburnKingsportJasperRockvilleSpringfieldScaggsvilleWashingtonRose HillHunt ValleySouth LaurelOxon Hill-GlassmanorBaltimoreEssexOwensboroReadingEdgewoodKnoxvilleShort PumpEvansvilleAshevilleRichmondMaryvilleGreensboroAllentownElktonCookevilleNewarkBethlehemBearChesterDurhamCharlotteHendersonvilleDoverMorrisvilleSpartanburgRoanoke RapidsBensalemNashvilleGreenvilleRaleighClarksvilleEwingTrentonSouth VinelandClaytonChattanoogaEast RidgePaducahFayettevilleColumbiaBayonnePleasantvilleToms RiverAtlantic CityGreenvilleLemayHuntsvilleDecaturHolbrookJacksonDyersburgNew LondonBartlettCoventryWest MemphisHernandoProvidencePawtucketFall RiverBrocktonQuincySpringfieldLittle RockSpringdaleFort SmithTulsaJenksMcAlesterWichitaSaint JohnEdmondOklahoma CityMooreSept-ÎlesLawtonDartmouthCharlottetownMiddletownWestervilleWest MifflinWarrenFishersTerre HauteWake ForestLimaPhiladelphiaPittsburghCamdenElizabethAnn ArborLindenPennsaukenIndianapolisYoungstownNew BrunswickJersey CityWinston-SalemLancasterHarrisburgClevelandSewellWilmingtonBloomingtonSteubenvillePonca CityRoanokeHopewellAbingtonClemmonsYorkHickoryPatersonLexingtonLincolnAndersonKokomoNepeanBostonShaker HeightsLebanonDerbySt. LouisNorristownEast HamptonPortlandNew York CityFort WayneLynnBridgeportLafayetteMuncieLowellCarlisleToledoL'Ancienne-LorettePortsmouthDodge CityChesapeakeLexingtonGranite CityFort LeeRandolphNew HavenArnoldSorel-TracyWyomingQuébecEast Saint LouisPortageAugustaState CollegeCleveland HeightsUniversity CityShawiniganMiramichiGaryBrossardWaterlooDerrySouth BendWatertownSaint JosephFraminghamHaverhillRivière-des-Prairies–Pointe-aux-TremblesRutlandTrois-RivièresMontréalWaterburyScrantonElkhartRedfordAnkenyUpper AltonDearbornWorcesterLincoln ParkLewistonDrummondvilleGrand IslandLeawoodTaylorDetroitMonctonDanburySt. CatharinesCalumet CityGranbyChampaignDecaturFrederictonPainesvilleKansas CityHollandCornwallDes MoinesYpsilantiSpringfieldWinnipegKalamazooLaconiaSaint-Jean-sur-RichelieuSherbrookeHartfordJolietNapervilleBridgeviewBay CityPeoriaMilfordWindsorKeeneEdmundstonOttawaWaterdownOakvilleOak LawnMichigan CityKansas CityMiltonLansingHammondNorthbrookWhite PlainsDorvalHamiltonDoltonRaymoreRochesterTorontoElginBangorNorth ChicopeeSpringfieldBuffaloMississaugaOlatheColumbiaOmahaSouthfieldGuelphBarrieEast ChicagoTopekaGreenfieldLibertyBrookingsAlbanyBramptonKingstonKitchenerFranklin ParkSyracuseSaguenaySt. ThomasBloomingtonPort HuronBrantfordPittsfieldNewmarketWest FargoAuroraSaint CloudUticaNewburghNew CityIowa CityElmwood ParkGrand RapidsAberdeenChathamLondonJenisonShakopeeSaint PaulBellevilleBrookfieldPeterboroughSarniaBurnsvilleRochesterMuscatineErieDavenportSioux FallsSaint MichaelChicagoOconomowocNorth BayAllistonCedar RapidsEastpointeFort DodgeBellevueGreater SudburyApple ValleyMinneapolisClintonCaryLa VistaDes PlainesRockfordMolineBlaineGreen BayDuluthMankatoSault Ste. MarieMilwaukeeWaukeshaEau ClaireAppletonSuperiorZionSouth MilwaukeeMadisonRouyn-NorandaMarquette
27 Jul301 Aug2581112
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

MarquetteMarquette, 27 July: 8.6 µg/m³Marquette, 28 July: 11.0 µg/m³Marquette, 29 July: 42.7 µg/m³Marquette, 30 July: 112.0 µg/m³, 14× its usual 8.1Marquette, 31 July: 84.7 µg/m³, 10× its usual 8.3Marquette, 1 August: 58.8 µg/m³, 7.1× its usual 8.3Marquette, 2 August: 62.6 µg/m³, 7.8× its usual 8.0Marquette, 3 August: 38.8 µg/m³, 5.1× its usual 7.6Marquette, 4 August: 33.0 µg/m³, 4.5× its usual 7.3Marquette, 5 August: 40.1 µg/m³, 5.6× its usual 7.1Marquette, 6 August: 40.8 µg/m³, 5.9× its usual 6.9Marquette, 7 August: 19.8 µg/m³Marquette, 8 August: 12.3 µg/m³Marquette, 9 August: 7.1 µg/m³Marquette, 10 August: 6.1 µg/m³Marquette, 11 August: 9.1 µg/m³Marquette, 12 August: 14.2 µg/m³OconomowocOconomowoc, 27 July: 13.6 µg/m³Oconomowoc, 28 July: 8.7 µg/m³Oconomowoc, 29 July: 14.1 µg/m³Oconomowoc, 30 July: 39.3 µg/m³, 2.6× its usual 15.4Oconomowoc, 31 July: 111.0 µg/m³, 7.6× its usual 14.6Oconomowoc, 1 August: 46.4 µg/m³, 3.2× its usual 14.6Oconomowoc, 2 August: 65.0 µg/m³, 4.5× its usual 14.6Oconomowoc, 3 August: 77.6 µg/m³, 5.3× its usual 14.6Oconomowoc, 4 August: 49.9 µg/m³, 3.6× its usual 13.7Oconomowoc, 5 August: 48.8 µg/m³, 3.6× its usual 13.6Oconomowoc, 6 August: 40.2 µg/m³, 3.0× its usual 13.6Oconomowoc, 7 August: 25.6 µg/m³Oconomowoc, 8 August: 19.8 µg/m³Oconomowoc, 9 August: 19.5 µg/m³Oconomowoc, 10 August: 7.6 µg/m³Oconomowoc, 11 August: 9.7 µg/m³Oconomowoc, 12 August: 6.7 µg/m³SuperiorSuperior, 27 July: 9.5 µg/m³Superior, 28 July: 11.0 µg/m³Superior, 29 July: 41.1 µg/m³Superior, 30 July: 108.0 µg/m³, 10× its usual 10.8Superior, 31 July: 102.0 µg/m³, 10× its usual 10.2Superior, 1 August: 92.3 µg/m³, 9.0× its usual 10.2Superior, 2 August: 66.1 µg/m³, 6.7× its usual 9.9Superior, 3 August: 39.2 µg/m³, 4.0× its usual 9.9Superior, 4 August: 35.4 µg/m³, 3.8× its usual 9.3Superior, 5 August: 44.3 µg/m³Superior, 6 August: 46.8 µg/m³Superior, 7 August: 22.3 µg/m³Superior, 8 August: 18.6 µg/m³Superior, 9 August: 11.5 µg/m³Superior, 10 August: 12.6 µg/m³Superior, 11 August: 37.7 µg/m³Superior, 12 August: 20.2 µg/m³MankatoMankato, 27 July: 7.0 µg/m³Mankato, 28 July: 6.7 µg/m³Mankato, 29 July: 10.8 µg/m³Mankato, 30 July: 49.9 µg/m³, 4.6× its usual 10.8Mankato, 31 July: 96.9 µg/m³, 9.1× its usual 10.7Mankato, 1 August: 95.4 µg/m³, 9.2× its usual 10.4Mankato, 2 August: 64.9 µg/m³, 6.4× its usual 10.1Mankato, 3 August: 39.0 µg/m³, 3.9× its usual 10.0Mankato, 4 August: 37.2 µg/m³, 3.8× its usual 9.9Mankato, 5 August: 21.4 µg/m³Mankato, 6 August: 11.6 µg/m³Mankato, 7 August: 14.1 µg/m³Mankato, 8 August: 17.2 µg/m³Mankato, 9 August: 10.9 µg/m³Mankato, 10 August: 8.3 µg/m³Mankato, 11 August: 38.2 µg/m³Mankato, 12 August: 40.5 µg/m³DuluthDuluth, 27 July: 6.0 µg/m³Duluth, 28 July: 8.0 µg/m³Duluth, 29 July: 32.6 µg/m³Duluth, 30 July: 91.1 µg/m³, 9.1× its usual 10.0Duluth, 31 July: 85.4 µg/m³, 9.0× its usual 9.5Duluth, 1 August: 81.7 µg/m³, 8.3× its usual 9.8Duluth, 2 August: 57.8 µg/m³, 6.1× its usual 9.5Duluth, 3 August: 31.3 µg/m³, 3.3× its usual 9.5Duluth, 4 August: 28.2 µg/m³, 3.0× its usual 9.3Duluth, 5 August: 32.6 µg/m³Duluth, 6 August: 34.0 µg/m³Duluth, 7 August: 13.3 µg/m³Duluth, 8 August: 11.6 µg/m³Duluth, 9 August: 7.3 µg/m³Duluth, 10 August: 7.9 µg/m³Duluth, 11 August: 25.6 µg/m³Duluth, 12 August: 13.8 µg/m³MilwaukeeMilwaukee, 27 July: 5.6 µg/m³Milwaukee, 28 July: 7.0 µg/m³Milwaukee, 29 July: 9.6 µg/m³Milwaukee, 30 July: 30.1 µg/m³, 3.1× its usual 9.8Milwaukee, 31 July: 91.1 µg/m³, 9.4× its usual 9.7Milwaukee, 1 August: 39.2 µg/m³, 4.0× its usual 9.7Milwaukee, 2 August: 51.0 µg/m³, 5.2× its usual 9.9Milwaukee, 3 August: 68.2 µg/m³, 6.8× its usual 10.0Milwaukee, 4 August: 39.1 µg/m³, 4.0× its usual 9.7Milwaukee, 5 August: 48.7 µg/m³, 5.1× its usual 9.5Milwaukee, 6 August: 28.7 µg/m³, 3.2× its usual 8.9Milwaukee, 7 August: 16.0 µg/m³Milwaukee, 8 August: 13.3 µg/m³Milwaukee, 9 August: 11.2 µg/m³Milwaukee, 10 August: 6.4 µg/m³Milwaukee, 11 August: 7.1 µg/m³Milwaukee, 12 August: 5.7 µg/m³Rouyn-NorandaRouyn-Noranda, 27 July: 28.9 µg/m³Rouyn-Noranda, 28 July: 21.7 µg/m³Rouyn-Noranda, 29 July: 47.3 µg/m³Rouyn-Noranda, 30 July: 42.2 µg/m³, 5.4× its usual 7.8Rouyn-Noranda, 31 July: 3.7 µg/m³Rouyn-Noranda, 1 August: 43.6 µg/m³Rouyn-Noranda, 2 August: 87.3 µg/m³, 12× its usual 7.5Rouyn-Noranda, 3 August: 55.5 µg/m³, 7.7× its usual 7.2Rouyn-Noranda, 4 August: 25.7 µg/m³Rouyn-Noranda, 5 August: no readingRouyn-Noranda, 6 August: no readingRouyn-Noranda, 7 August: no readingRouyn-Noranda, 8 August: no readingRouyn-Noranda, 9 August: no readingRouyn-Noranda, 10 August: no readingRouyn-Noranda, 11 August: no readingRouyn-Noranda, 12 August: no readingAppletonAppleton, 27 July: 5.5 µg/m³Appleton, 28 July: 5.3 µg/m³Appleton, 29 July: 8.4 µg/m³Appleton, 30 July: 79.1 µg/m³, 9.2× its usual 8.6Appleton, 31 July: 86.9 µg/m³, 10.0× its usual 8.7Appleton, 1 August: 42.6 µg/m³, 5.0× its usual 8.6Appleton, 2 August: 57.4 µg/m³, 6.6× its usual 8.7Appleton, 3 August: 61.4 µg/m³, 7.1× its usual 8.7Appleton, 4 August: 51.4 µg/m³, 6.0× its usual 8.6Appleton, 5 August: 43.5 µg/m³, 5.2× its usual 8.4Appleton, 6 August: 30.3 µg/m³, 3.7× its usual 8.3Appleton, 7 August: 14.9 µg/m³Appleton, 8 August: 10.7 µg/m³Appleton, 9 August: 8.2 µg/m³Appleton, 10 August: 4.2 µg/m³Appleton, 11 August: 9.1 µg/m³Appleton, 12 August: 12.4 µg/m³Eau ClaireEau Claire, 27 July: 4.8 µg/m³Eau Claire, 28 July: 5.6 µg/m³Eau Claire, 29 July: 11.1 µg/m³Eau Claire, 30 July: 59.2 µg/m³, 6.7× its usual 8.9Eau Claire, 31 July: 86.8 µg/m³, 9.8× its usual 8.9Eau Claire, 1 August: 72.9 µg/m³, 8.2× its usual 8.9Eau Claire, 2 August: 48.9 µg/m³, 5.4× its usual 9.0Eau Claire, 3 August: 37.2 µg/m³, 4.2× its usual 8.9Eau Claire, 4 August: 33.9 µg/m³, 3.9× its usual 8.7Eau Claire, 5 August: 21.8 µg/m³Eau Claire, 6 August: 24.3 µg/m³Eau Claire, 7 August: 10.4 µg/m³Eau Claire, 8 August: 10.5 µg/m³Eau Claire, 9 August: 6.3 µg/m³Eau Claire, 10 August: 5.1 µg/m³Eau Claire, 11 August: 14.7 µg/m³Eau Claire, 12 August: 21.0 µg/m³WaukeshaWaukesha, 27 July: 5.2 µg/m³Waukesha, 28 July: 6.4 µg/m³Waukesha, 29 July: 9.6 µg/m³Waukesha, 30 July: 28.0 µg/m³, 3.1× its usual 8.9Waukesha, 31 July: 86.0 µg/m³, 9.7× its usual 8.9Waukesha, 1 August: 36.5 µg/m³, 4.1× its usual 8.8Waukesha, 2 August: 55.4 µg/m³, 6.2× its usual 8.9Waukesha, 3 August: 66.8 µg/m³, 7.5× its usual 8.9Waukesha, 4 August: 39.8 µg/m³, 4.6× its usual 8.7Waukesha, 5 August: 36.6 µg/m³, 4.3× its usual 8.5Waukesha, 6 August: 30.6 µg/m³, 3.6× its usual 8.5Waukesha, 7 August: 14.5 µg/m³Waukesha, 8 August: 10.4 µg/m³Waukesha, 9 August: 10.0 µg/m³Waukesha, 10 August: 5.1 µg/m³Waukesha, 11 August: 5.6 µg/m³Waukesha, 12 August: 4.9 µg/m³Green BayGreen Bay, 27 July: 8.2 µg/m³Green Bay, 28 July: 7.7 µg/m³Green Bay, 29 July: 9.5 µg/m³Green Bay, 30 July: 85.9 µg/m³, 9.1× its usual 9.4Green Bay, 31 July: 85.6 µg/m³, 9.0× its usual 9.5Green Bay, 1 August: 47.1 µg/m³, 5.2× its usual 9.0Green Bay, 2 August: 58.1 µg/m³, 6.3× its usual 9.2Green Bay, 3 August: 61.3 µg/m³, 6.8× its usual 9.0Green Bay, 4 August: 58.1 µg/m³, 6.8× its usual 8.6Green Bay, 5 August: 49.2 µg/m³, 5.8× its usual 8.5Green Bay, 6 August: 29.9 µg/m³, 3.7× its usual 8.1Green Bay, 7 August: 15.1 µg/m³Green Bay, 8 August: 13.4 µg/m³Green Bay, 9 August: 10.0 µg/m³Green Bay, 10 August: 4.4 µg/m³Green Bay, 11 August: 12.3 µg/m³Green Bay, 12 August: 11.5 µg/m³MadisonMadison, 27 July: 4.3 µg/m³Madison, 28 July: 5.0 µg/m³Madison, 29 July: 9.7 µg/m³Madison, 30 July: 27.0 µg/m³, 3.4× its usual 8.0Madison, 31 July: 82.4 µg/m³, 10× its usual 8.0Madison, 1 August: 36.8 µg/m³, 4.7× its usual 7.8Madison, 2 August: 34.0 µg/m³, 4.4× its usual 7.8Madison, 3 August: 38.2 µg/m³, 4.9× its usual 7.8Madison, 4 August: 39.5 µg/m³, 5.2× its usual 7.6Madison, 5 August: 25.4 µg/m³, 3.4× its usual 7.5Madison, 6 August: 27.2 µg/m³, 3.6× its usual 7.5Madison, 7 August: 13.8 µg/m³Madison, 8 August: 10.7 µg/m³Madison, 9 August: 9.7 µg/m³Madison, 10 August: 6.7 µg/m³Madison, 11 August: 5.0 µg/m³Madison, 12 August: 8.8 µg/m³MinneapolisMinneapolis, 27 July: 5.6 µg/m³Minneapolis, 28 July: 7.2 µg/m³Minneapolis, 29 July: 9.5 µg/m³Minneapolis, 30 July: 54.0 µg/m³, 5.3× its usual 10.1Minneapolis, 31 July: 71.0 µg/m³, 7.0× its usual 10.1Minneapolis, 1 August: 80.7 µg/m³, 7.9× its usual 10.2Minneapolis, 2 August: 48.5 µg/m³, 4.7× its usual 10.3Minneapolis, 3 August: 27.6 µg/m³, 2.7× its usual 10.2Minneapolis, 4 August: 28.8 µg/m³, 2.9× its usual 10.1Minneapolis, 5 August: 17.4 µg/m³Minneapolis, 6 August: 13.7 µg/m³Minneapolis, 7 August: 12.8 µg/m³Minneapolis, 8 August: 12.8 µg/m³Minneapolis, 9 August: 7.6 µg/m³Minneapolis, 10 August: 8.0 µg/m³Minneapolis, 11 August: 27.3 µg/m³Minneapolis, 12 August: 22.6 µg/m³BlaineBlaine, 27 July: 5.2 µg/m³Blaine, 28 July: 6.4 µg/m³Blaine, 29 July: 8.4 µg/m³Blaine, 30 July: 49.7 µg/m³, 5.8× its usual 8.5Blaine, 31 July: 70.0 µg/m³, 8.2× its usual 8.5Blaine, 1 August: 79.3 µg/m³, 9.1× its usual 8.7Blaine, 2 August: 50.5 µg/m³, 5.7× its usual 8.8Blaine, 3 August: 27.3 µg/m³, 3.1× its usual 8.9Blaine, 4 August: 30.0 µg/m³, 3.4× its usual 8.7Blaine, 5 August: 17.7 µg/m³Blaine, 6 August: 12.9 µg/m³Blaine, 7 August: 10.7 µg/m³Blaine, 8 August: 10.4 µg/m³Blaine, 9 August: 6.7 µg/m³Blaine, 10 August: 7.6 µg/m³Blaine, 11 August: 26.3 µg/m³Blaine, 12 August: 17.3 µg/m³RochesterRochester, 27 July: 5.8 µg/m³Rochester, 28 July: 4.8 µg/m³Rochester, 29 July: 10.1 µg/m³Rochester, 30 July: 41.9 µg/m³, 4.1× its usual 10.3Rochester, 31 July: 76.2 µg/m³, 7.4× its usual 10.3Rochester, 1 August: 71.0 µg/m³, 6.9× its usual 10.3Rochester, 2 August: 39.7 µg/m³, 3.8× its usual 10.4Rochester, 3 August: 27.5 µg/m³, 2.6× its usual 10.4Rochester, 4 August: 32.5 µg/m³, 3.2× its usual 10.3Rochester, 5 August: 16.5 µg/m³Rochester, 6 August: 15.5 µg/m³Rochester, 7 August: 11.9 µg/m³Rochester, 8 August: 12.3 µg/m³Rochester, 9 August: 7.4 µg/m³Rochester, 10 August: 4.9 µg/m³Rochester, 11 August: 15.6 µg/m³Rochester, 12 August: 21.9 µg/m³BurnsvilleBurnsville, 27 July: 5.1 µg/m³Burnsville, 28 July: 6.0 µg/m³Burnsville, 29 July: no readingBurnsville, 30 July: 53.8 µg/m³, 5.3× its usual 10.1Burnsville, 31 July: 73.2 µg/m³, 7.2× its usual 10.1Burnsville, 1 August: 75.1 µg/m³, 7.4× its usual 10.1Burnsville, 2 August: 47.4 µg/m³, 4.5× its usual 10.5Burnsville, 3 August: 27.4 µg/m³, 2.6× its usual 10.6Burnsville, 4 August: 31.6 µg/m³, 3.0× its usual 10.5Burnsville, 5 August: 17.5 µg/m³Burnsville, 6 August: 13.8 µg/m³Burnsville, 7 August: 11.9 µg/m³Burnsville, 8 August: 11.9 µg/m³Burnsville, 9 August: 6.6 µg/m³Burnsville, 10 August: 5.9 µg/m³Burnsville, 11 August: 25.8 µg/m³Burnsville, 12 August: 27.7 µg/m³Saint PaulSaint Paul, 27 July: 5.2 µg/m³Saint Paul, 28 July: 6.1 µg/m³Saint Paul, 29 July: 9.2 µg/m³Saint Paul, 30 July: 53.3 µg/m³, 5.3× its usual 10.1Saint Paul, 31 July: 65.1 µg/m³, 6.4× its usual 10.1Saint Paul, 1 August: 73.0 µg/m³, 7.2× its usual 10.1Saint Paul, 2 August: 45.6 µg/m³, 4.5× its usual 10.2Saint Paul, 3 August: 24.1 µg/m³Saint Paul, 4 August: 28.8 µg/m³, 2.9× its usual 10.1Saint Paul, 5 August: 16.3 µg/m³Saint Paul, 6 August: 13.9 µg/m³Saint Paul, 7 August: 11.5 µg/m³Saint Paul, 8 August: 11.6 µg/m³Saint Paul, 9 August: 6.8 µg/m³Saint Paul, 10 August: 7.4 µg/m³Saint Paul, 11 August: 24.2 µg/m³Saint Paul, 12 August: 22.5 µg/m³Sault Ste. MarieSault Ste. Marie, 27 July: 12.8 µg/m³Sault Ste. Marie, 28 July: 12.6 µg/m³Sault Ste. Marie, 29 July: 19.5 µg/m³Sault Ste. Marie, 30 July: 71.6 µg/m³, 9.3× its usual 7.7Sault Ste. Marie, 31 July: 32.2 µg/m³, 4.1× its usual 7.8Sault Ste. Marie, 1 August: 34.2 µg/m³, 4.7× its usual 7.3Sault Ste. Marie, 2 August: 60.0 µg/m³, 8.2× its usual 7.3Sault Ste. Marie, 3 August: 50.3 µg/m³, 6.9× its usual 7.3Sault Ste. Marie, 4 August: 34.7 µg/m³, 4.8× its usual 7.3Sault Ste. Marie, 5 August: 39.9 µg/m³, 5.7× its usual 7.0Sault Ste. Marie, 6 August: 35.3 µg/m³, 5.4× its usual 6.5Sault Ste. Marie, 7 August: 25.5 µg/m³, 4.0× its usual 6.3Sault Ste. Marie, 8 August: 11.9 µg/m³Sault Ste. Marie, 9 August: 9.5 µg/m³Sault Ste. Marie, 10 August: 6.4 µg/m³Sault Ste. Marie, 11 August: 6.4 µg/m³Sault Ste. Marie, 12 August: 7.3 µg/m³Saint MichaelSaint Michael, 27 July: 4.8 µg/m³Saint Michael, 28 July: 6.3 µg/m³Saint Michael, 29 July: 8.2 µg/m³Saint Michael, 30 July: 46.3 µg/m³, 5.1× its usual 9.0Saint Michael, 31 July: 61.6 µg/m³, 6.8× its usual 9.1Saint Michael, 1 August: 69.3 µg/m³, 7.6× its usual 9.1Saint Michael, 2 August: 46.9 µg/m³, 5.1× its usual 9.2Saint Michael, 3 August: 28.9 µg/m³, 3.1× its usual 9.2Saint Michael, 4 August: 26.0 µg/m³, 2.9× its usual 9.1Saint Michael, 5 August: 16.6 µg/m³Saint Michael, 6 August: 9.5 µg/m³Saint Michael, 7 August: 8.7 µg/m³Saint Michael, 8 August: 11.0 µg/m³Saint Michael, 9 August: 5.6 µg/m³Saint Michael, 10 August: 6.7 µg/m³Saint Michael, 11 August: no readingSaint Michael, 12 August: 11.4 µg/m³ShakopeeShakopee, 27 July: 5.0 µg/m³Shakopee, 28 July: 5.9 µg/m³Shakopee, 29 July: 8.5 µg/m³Shakopee, 30 July: 49.4 µg/m³, 5.1× its usual 9.6Shakopee, 31 July: 68.9 µg/m³, 7.2× its usual 9.6Shakopee, 1 August: 68.7 µg/m³, 7.2× its usual 9.6Shakopee, 2 August: 44.1 µg/m³, 4.5× its usual 9.8Shakopee, 3 August: 27.0 µg/m³, 2.8× its usual 9.8Shakopee, 4 August: 28.9 µg/m³, 3.0× its usual 9.6Shakopee, 5 August: 16.9 µg/m³Shakopee, 6 August: 10.5 µg/m³Shakopee, 7 August: 11.1 µg/m³Shakopee, 8 August: 11.3 µg/m³Shakopee, 9 August: 7.0 µg/m³Shakopee, 10 August: 6.6 µg/m³Shakopee, 11 August: 27.7 µg/m³Shakopee, 12 August: 25.2 µg/m³West FargoWest Fargo, 27 July: no readingWest Fargo, 28 July: no readingWest Fargo, 29 July: no readingWest Fargo, 30 July: 58.3 µg/m³, 6.1× its usual 9.6West Fargo, 31 July: 67.2 µg/m³, 6.9× its usual 9.7West Fargo, 1 August: 55.0 µg/m³, 5.6× its usual 9.9West Fargo, 2 August: 47.4 µg/m³, 4.8× its usual 9.9West Fargo, 3 August: 26.8 µg/m³, 2.8× its usual 9.7West Fargo, 4 August: 19.8 µg/m³West Fargo, 5 August: 11.9 µg/m³West Fargo, 6 August: 3.8 µg/m³West Fargo, 7 August: 4.6 µg/m³West Fargo, 8 August: 3.8 µg/m³West Fargo, 9 August: 3.4 µg/m³West Fargo, 10 August: 12.2 µg/m³West Fargo, 11 August: 58.0 µg/m³West Fargo, 12 August: 17.3 µg/m³Apple ValleyApple Valley, 27 July: 4.1 µg/m³Apple Valley, 28 July: 5.4 µg/m³Apple Valley, 29 July: 7.9 µg/m³Apple Valley, 30 July: 46.0 µg/m³, 5.5× its usual 8.4Apple Valley, 31 July: 65.5 µg/m³, 7.8× its usual 8.4Apple Valley, 1 August: 66.1 µg/m³, 7.9× its usual 8.4Apple Valley, 2 August: 40.4 µg/m³, 4.8× its usual 8.5Apple Valley, 3 August: 23.9 µg/m³Apple Valley, 4 August: 27.9 µg/m³, 3.3× its usual 8.4Apple Valley, 5 August: 14.9 µg/m³Apple Valley, 6 August: 11.5 µg/m³Apple Valley, 7 August: 9.9 µg/m³Apple Valley, 8 August: 9.3 µg/m³Apple Valley, 9 August: 5.8 µg/m³Apple Valley, 10 August: 4.7 µg/m³Apple Valley, 11 August: 21.2 µg/m³Apple Valley, 12 August: 23.6 µg/m³Saint CloudSaint Cloud, 27 July: 4.9 µg/m³Saint Cloud, 28 July: 6.1 µg/m³Saint Cloud, 29 July: 9.8 µg/m³Saint Cloud, 30 July: 53.4 µg/m³, 5.9× its usual 9.1Saint Cloud, 31 July: 57.1 µg/m³, 6.3× its usual 9.1Saint Cloud, 1 August: 63.7 µg/m³, 7.0× its usual 9.1Saint Cloud, 2 August: 51.5 µg/m³, 5.6× its usual 9.2Saint Cloud, 3 August: 30.8 µg/m³, 3.3× its usual 9.2Saint Cloud, 4 August: 23.4 µg/m³Saint Cloud, 5 August: 17.5 µg/m³Saint Cloud, 6 August: 8.1 µg/m³Saint Cloud, 7 August: 7.2 µg/m³Saint Cloud, 8 August: 10.2 µg/m³Saint Cloud, 9 August: 4.5 µg/m³Saint Cloud, 10 August: 9.1 µg/m³Saint Cloud, 11 August: 46.6 µg/m³Saint Cloud, 12 August: 9.0 µg/m³Greater SudburyGreater Sudbury, 27 July: 22.4 µg/m³Greater Sudbury, 28 July: 8.3 µg/m³Greater Sudbury, 29 July: 11.1 µg/m³Greater Sudbury, 30 July: 63.1 µg/m³, 7.9× its usual 8.0Greater Sudbury, 31 July: 11.8 µg/m³Greater Sudbury, 1 August: 7.4 µg/m³Greater Sudbury, 2 August: 46.3 µg/m³, 6.6× its usual 7.0Greater Sudbury, 3 August: 49.3 µg/m³, 7.1× its usual 6.9Greater Sudbury, 4 August: 21.8 µg/m³Greater Sudbury, 5 August: 6.6 µg/m³Greater Sudbury, 6 August: 17.7 µg/m³Greater Sudbury, 7 August: 25.8 µg/m³, 4.2× its usual 6.2Greater Sudbury, 8 August: 13.3 µg/m³Greater Sudbury, 9 August: 10.9 µg/m³Greater Sudbury, 10 August: 11.7 µg/m³Greater Sudbury, 11 August: 11.1 µg/m³Greater Sudbury, 12 August: 8.8 µg/m³NewmarketNewmarket, 27 July: 9.8 µg/m³Newmarket, 28 July: 13.0 µg/m³Newmarket, 29 July: 8.5 µg/m³Newmarket, 30 July: 25.3 µg/m³, 2.6× its usual 9.6Newmarket, 31 July: 46.8 µg/m³, 4.9× its usual 9.6Newmarket, 1 August: 6.3 µg/m³Newmarket, 2 August: 21.0 µg/m³Newmarket, 3 August: 60.2 µg/m³, 6.9× its usual 8.7Newmarket, 4 August: 48.5 µg/m³, 5.7× its usual 8.5Newmarket, 5 August: 38.6 µg/m³, 4.6× its usual 8.4Newmarket, 6 August: 34.1 µg/m³, 4.1× its usual 8.3Newmarket, 7 August: 37.2 µg/m³, 4.6× its usual 8.1Newmarket, 8 August: 30.3 µg/m³, 3.8× its usual 8.0Newmarket, 9 August: 21.9 µg/m³Newmarket, 10 August: 18.7 µg/m³Newmarket, 11 August: 18.2 µg/m³Newmarket, 12 August: 12.0 µg/m³South MilwaukeeSouth Milwaukee, 27 July: 4.4 µg/m³South Milwaukee, 28 July: 6.1 µg/m³South Milwaukee, 29 July: 7.9 µg/m³South Milwaukee, 30 July: 24.0 µg/m³South Milwaukee, 31 July: 82.9 µg/m³, 10× its usual 8.1South Milwaukee, 1 August: 36.4 µg/m³, 4.5× its usual 8.1South Milwaukee, 2 August: 40.5 µg/m³, 5.0× its usual 8.1South Milwaukee, 3 August: 53.3 µg/m³, 6.6× its usual 8.1South Milwaukee, 4 August: 35.4 µg/m³, 4.4× its usual 8.0South Milwaukee, 5 August: 43.0 µg/m³, 5.5× its usual 7.8South Milwaukee, 6 August: 25.0 µg/m³, 3.2× its usual 7.8South Milwaukee, 7 August: 13.9 µg/m³South Milwaukee, 8 August: 11.3 µg/m³South Milwaukee, 9 August: 9.7 µg/m³South Milwaukee, 10 August: 5.1 µg/m³South Milwaukee, 11 August: 6.2 µg/m³South Milwaukee, 12 August: 5.2 µg/m³RockfordRockford, 27 July: 5.9 µg/m³Rockford, 28 July: 6.4 µg/m³Rockford, 29 July: 8.6 µg/m³Rockford, 30 July: 10.9 µg/m³Rockford, 31 July: 79.8 µg/m³, 8.3× its usual 9.6Rockford, 1 August: 42.6 µg/m³, 4.4× its usual 9.6Rockford, 2 August: 33.4 µg/m³, 3.4× its usual 9.7Rockford, 3 August: 41.3 µg/m³, 4.3× its usual 9.7Rockford, 4 August: 33.7 µg/m³, 3.5× its usual 9.5Rockford, 5 August: 25.6 µg/m³, 2.7× its usual 9.5Rockford, 6 August: 28.6 µg/m³, 3.0× its usual 9.4Rockford, 7 August: 13.4 µg/m³Rockford, 8 August: 12.9 µg/m³Rockford, 9 August: 12.9 µg/m³Rockford, 10 August: 8.6 µg/m³Rockford, 11 August: 6.4 µg/m³Rockford, 12 August: 5.8 µg/m³ZionZion, 27 July: 3.9 µg/m³Zion, 28 July: 5.8 µg/m³Zion, 29 July: 7.3 µg/m³Zion, 30 July: 14.7 µg/m³Zion, 31 July: 77.5 µg/m³, 10× its usual 7.6Zion, 1 August: 37.8 µg/m³, 5.0× its usual 7.6Zion, 2 August: 34.9 µg/m³, 4.6× its usual 7.6Zion, 3 August: 41.8 µg/m³, 5.4× its usual 7.7Zion, 4 August: 29.9 µg/m³, 3.9× its usual 7.6Zion, 5 August: 39.6 µg/m³, 5.2× its usual 7.6Zion, 6 August: 21.9 µg/m³Zion, 7 August: 12.9 µg/m³Zion, 8 August: 11.7 µg/m³Zion, 9 August: 9.9 µg/m³Zion, 10 August: 5.1 µg/m³Zion, 11 August: 6.2 µg/m³Zion, 12 August: 4.2 µg/m³Franklin ParkFranklin Park, 27 July: 9.1 µg/m³Franklin Park, 28 July: 10.6 µg/m³Franklin Park, 29 July: 11.8 µg/m³Franklin Park, 30 July: 12.8 µg/m³Franklin Park, 31 July: 76.9 µg/m³, 6.7× its usual 11.4Franklin Park, 1 August: 52.0 µg/m³, 4.5× its usual 11.5Franklin Park, 2 August: 31.6 µg/m³, 2.7× its usual 11.6Franklin Park, 3 August: 38.3 µg/m³, 3.3× its usual 11.6Franklin Park, 4 August: 31.1 µg/m³, 2.7× its usual 11.4Franklin Park, 5 August: 32.4 µg/m³, 2.8× its usual 11.4Franklin Park, 6 August: 37.1 µg/m³, 3.3× its usual 11.1Franklin Park, 7 August: 18.2 µg/m³Franklin Park, 8 August: 15.5 µg/m³Franklin Park, 9 August: 14.0 µg/m³Franklin Park, 10 August: 11.0 µg/m³Franklin Park, 11 August: 10.6 µg/m³Franklin Park, 12 August: 9.5 µg/m³MolineMoline, 27 July: 6.2 µg/m³Moline, 28 July: 5.2 µg/m³Moline, 29 July: 6.2 µg/m³Moline, 30 July: 5.5 µg/m³Moline, 31 July: 76.0 µg/m³, 8.6× its usual 8.8Moline, 1 August: 59.2 µg/m³, 6.7× its usual 8.8Moline, 2 August: 32.5 µg/m³, 3.7× its usual 8.7Moline, 3 August: 29.7 µg/m³, 3.4× its usual 8.7Moline, 4 August: 21.1 µg/m³Moline, 5 August: 18.4 µg/m³Moline, 6 August: 19.4 µg/m³Moline, 7 August: 13.0 µg/m³Moline, 8 August: 12.6 µg/m³Moline, 9 August: 11.9 µg/m³Moline, 10 August: 8.6 µg/m³Moline, 11 August: 7.1 µg/m³Moline, 12 August: 5.8 µg/m³Des PlainesDes Plaines, 27 July: 8.4 µg/m³Des Plaines, 28 July: 9.7 µg/m³Des Plaines, 29 July: 10.7 µg/m³Des Plaines, 30 July: 12.4 µg/m³Des Plaines, 31 July: 75.8 µg/m³, 8.2× its usual 9.2Des Plaines, 1 August: 47.7 µg/m³, 5.3× its usual 9.0Des Plaines, 2 August: 31.3 µg/m³, 3.4× its usual 9.2Des Plaines, 3 August: 38.1 µg/m³, 4.2× its usual 9.0Des Plaines, 4 August: 29.7 µg/m³, 3.3× its usual 8.9Des Plaines, 5 August: 32.0 µg/m³, 3.6× its usual 8.9Des Plaines, 6 August: 33.2 µg/m³, 3.8× its usual 8.8Des Plaines, 7 August: 18.0 µg/m³Des Plaines, 8 August: 15.2 µg/m³Des Plaines, 9 August: 14.0 µg/m³Des Plaines, 10 August: 10.2 µg/m³Des Plaines, 11 August: 9.2 µg/m³Des Plaines, 12 August: 8.1 µg/m³CaryCary, 27 July: 6.5 µg/m³Cary, 28 July: 8.1 µg/m³Cary, 29 July: 8.1 µg/m³Cary, 30 July: 11.0 µg/m³Cary, 31 July: 75.0 µg/m³, 8.1× its usual 9.3Cary, 1 August: 42.0 µg/m³, 4.5× its usual 9.3Cary, 2 August: 32.0 µg/m³, 3.4× its usual 9.3Cary, 3 August: 40.3 µg/m³, 4.3× its usual 9.3Cary, 4 August: 29.2 µg/m³, 3.1× its usual 9.3Cary, 5 August: 26.0 µg/m³, 2.8× its usual 9.3Cary, 6 August: 28.8 µg/m³, 3.3× its usual 8.8Cary, 7 August: 15.4 µg/m³Cary, 8 August: 12.8 µg/m³Cary, 9 August: 12.6 µg/m³Cary, 10 August: 8.4 µg/m³Cary, 11 August: 6.9 µg/m³Cary, 12 August: 5.3 µg/m³Fort DodgeFort Dodge, 27 July: 4.7 µg/m³Fort Dodge, 28 July: 5.0 µg/m³Fort Dodge, 29 July: 7.9 µg/m³Fort Dodge, 30 July: 12.2 µg/m³Fort Dodge, 31 July: 74.8 µg/m³, 7.8× its usual 9.6Fort Dodge, 1 August: 67.3 µg/m³, 6.9× its usual 9.8Fort Dodge, 2 August: 45.5 µg/m³, 4.6× its usual 10.0Fort Dodge, 3 August: 26.1 µg/m³, 2.7× its usual 9.8Fort Dodge, 4 August: 22.5 µg/m³Fort Dodge, 5 August: 11.8 µg/m³Fort Dodge, 6 August: 8.4 µg/m³Fort Dodge, 7 August: 9.2 µg/m³Fort Dodge, 8 August: 11.2 µg/m³Fort Dodge, 9 August: 8.0 µg/m³Fort Dodge, 10 August: 6.8 µg/m³Fort Dodge, 11 August: 21.2 µg/m³Fort Dodge, 12 August: 20.2 µg/m³ClintonClinton, 27 July: 5.1 µg/m³Clinton, 28 July: 4.9 µg/m³Clinton, 29 July: 5.6 µg/m³Clinton, 30 July: 5.7 µg/m³Clinton, 31 July: 73.9 µg/m³, 8.0× its usual 9.2Clinton, 1 August: 48.4 µg/m³, 5.3× its usual 9.1Clinton, 2 August: 29.8 µg/m³, 3.3× its usual 8.9Clinton, 3 August: 28.8 µg/m³, 3.2× its usual 8.9Clinton, 4 August: 23.6 µg/m³Clinton, 5 August: 18.3 µg/m³Clinton, 6 August: 18.2 µg/m³Clinton, 7 August: 9.9 µg/m³Clinton, 8 August: 10.5 µg/m³Clinton, 9 August: 11.0 µg/m³Clinton, 10 August: 7.1 µg/m³Clinton, 11 August: 6.4 µg/m³Clinton, 12 August: 5.2 µg/m³ElginElgin, 27 July: 6.7 µg/m³Elgin, 28 July: 7.7 µg/m³Elgin, 29 July: 9.2 µg/m³Elgin, 30 July: 10.1 µg/m³Elgin, 31 July: 73.7 µg/m³, 6.3× its usual 11.7Elgin, 1 August: 49.8 µg/m³, 4.9× its usual 10.1Elgin, 2 August: 33.3 µg/m³, 3.5× its usual 9.5Elgin, 3 August: 39.0 µg/m³, 4.1× its usual 9.5Elgin, 4 August: 29.6 µg/m³, 3.2× its usual 9.2Elgin, 5 August: 26.3 µg/m³, 2.9× its usual 9.1Elgin, 6 August: 29.7 µg/m³, 3.3× its usual 9.0Elgin, 7 August: 14.5 µg/m³Elgin, 8 August: 13.2 µg/m³Elgin, 9 August: 12.3 µg/m³Elgin, 10 August: 9.1 µg/m³Elgin, 11 August: 7.1 µg/m³Elgin, 12 August: 5.8 µg/m³Grand RapidsGrand Rapids, 27 July: 7.4 µg/m³Grand Rapids, 28 July: 8.3 µg/m³Grand Rapids, 29 July: 7.9 µg/m³Grand Rapids, 30 July: 23.1 µg/m³Grand Rapids, 31 July: 73.2 µg/m³, 7.1× its usual 10.3Grand Rapids, 1 August: 24.7 µg/m³Grand Rapids, 2 August: 43.2 µg/m³, 4.2× its usual 10.3Grand Rapids, 3 August: 56.0 µg/m³, 5.4× its usual 10.4Grand Rapids, 4 August: 39.3 µg/m³, 3.8× its usual 10.3Grand Rapids, 5 August: 42.8 µg/m³, 4.2× its usual 10.3Grand Rapids, 6 August: 24.4 µg/m³Grand Rapids, 7 August: 11.9 µg/m³Grand Rapids, 8 August: 11.0 µg/m³Grand Rapids, 9 August: 11.2 µg/m³Grand Rapids, 10 August: 7.1 µg/m³Grand Rapids, 11 August: 8.2 µg/m³Grand Rapids, 12 August: 5.7 µg/m³ColumbiaColumbia, 27 July: 13.5 µg/m³Columbia, 28 July: 13.5 µg/m³Columbia, 29 July: 9.2 µg/m³Columbia, 30 July: 5.9 µg/m³Columbia, 31 July: 29.6 µg/m³, 2.6× its usual 11.5Columbia, 1 August: 72.5 µg/m³, 6.4× its usual 11.4Columbia, 2 August: 46.3 µg/m³, 4.1× its usual 11.4Columbia, 3 August: 23.5 µg/m³Columbia, 4 August: 15.5 µg/m³Columbia, 5 August: 17.9 µg/m³Columbia, 6 August: 22.1 µg/m³Columbia, 7 August: 22.5 µg/m³Columbia, 8 August: 18.7 µg/m³Columbia, 9 August: 21.0 µg/m³Columbia, 10 August: 13.8 µg/m³Columbia, 11 August: 13.1 µg/m³Columbia, 12 August: no readingElmwood ParkElmwood Park, 27 July: 7.4 µg/m³Elmwood Park, 28 July: 9.2 µg/m³Elmwood Park, 29 July: 11.3 µg/m³Elmwood Park, 30 July: 11.7 µg/m³Elmwood Park, 31 July: 72.0 µg/m³, 7.1× its usual 10.2Elmwood Park, 1 August: 48.6 µg/m³, 4.8× its usual 10.2Elmwood Park, 2 August: 28.6 µg/m³, 2.8× its usual 10.2Elmwood Park, 3 August: 34.0 µg/m³, 3.4× its usual 9.9Elmwood Park, 4 August: 27.7 µg/m³, 2.9× its usual 9.5Elmwood Park, 5 August: 32.9 µg/m³, 3.5× its usual 9.4Elmwood Park, 6 August: 33.3 µg/m³, 3.7× its usual 9.0Elmwood Park, 7 August: 18.9 µg/m³Elmwood Park, 8 August: 15.3 µg/m³Elmwood Park, 9 August: 14.3 µg/m³Elmwood Park, 10 August: 10.6 µg/m³Elmwood Park, 11 August: 9.1 µg/m³Elmwood Park, 12 August: 8.0 µg/m³ChicagoChicago, 27 July: 7.9 µg/m³Chicago, 28 July: 9.3 µg/m³Chicago, 29 July: 11.1 µg/m³Chicago, 30 July: 12.4 µg/m³Chicago, 31 July: 69.7 µg/m³, 7.6× its usual 9.2Chicago, 1 August: 47.9 µg/m³, 5.2× its usual 9.3Chicago, 2 August: 26.2 µg/m³, 2.8× its usual 9.4Chicago, 3 August: 33.6 µg/m³, 3.6× its usual 9.4Chicago, 4 August: 22.2 µg/m³Chicago, 5 August: 32.4 µg/m³, 3.5× its usual 9.3Chicago, 6 August: 35.0 µg/m³, 3.8× its usual 9.2Chicago, 7 August: 17.6 µg/m³Chicago, 8 August: 14.3 µg/m³Chicago, 9 August: 13.2 µg/m³Chicago, 10 August: 10.4 µg/m³Chicago, 11 August: 8.7 µg/m³Chicago, 12 August: 8.3 µg/m³BridgeviewBridgeview, 27 July: 8.5 µg/m³Bridgeview, 28 July: 9.2 µg/m³Bridgeview, 29 July: 11.7 µg/m³Bridgeview, 30 July: 13.9 µg/m³Bridgeview, 31 July: 68.0 µg/m³, 5.8× its usual 11.7Bridgeview, 1 August: 52.2 µg/m³, 4.5× its usual 11.5Bridgeview, 2 August: 26.8 µg/m³, 2.3× its usual 11.5Bridgeview, 3 August: 32.2 µg/m³, 2.9× its usual 11.2Bridgeview, 4 August: 22.6 µg/m³Bridgeview, 5 August: 30.8 µg/m³, 2.9× its usual 10.5Bridgeview, 6 August: 33.4 µg/m³, 3.2× its usual 10.5Bridgeview, 7 August: 14.9 µg/m³Bridgeview, 8 August: 13.8 µg/m³Bridgeview, 9 August: 12.7 µg/m³Bridgeview, 10 August: 10.0 µg/m³Bridgeview, 11 August: 8.7 µg/m³Bridgeview, 12 August: 8.6 µg/m³JenisonJenison, 27 July: 6.3 µg/m³Jenison, 28 July: 6.8 µg/m³Jenison, 29 July: 7.3 µg/m³Jenison, 30 July: 21.1 µg/m³Jenison, 31 July: 67.1 µg/m³, 7.2× its usual 9.3Jenison, 1 August: 28.5 µg/m³, 3.1× its usual 9.3Jenison, 2 August: 38.6 µg/m³, 4.2× its usual 9.3Jenison, 3 August: 47.3 µg/m³, 5.0× its usual 9.4Jenison, 4 August: 33.0 µg/m³, 3.5× its usual 9.3Jenison, 5 August: 38.9 µg/m³, 4.2× its usual 9.3Jenison, 6 August: 25.3 µg/m³, 2.8× its usual 9.2Jenison, 7 August: 11.3 µg/m³Jenison, 8 August: 10.6 µg/m³Jenison, 9 August: 10.8 µg/m³Jenison, 10 August: 7.0 µg/m³Jenison, 11 August: 7.5 µg/m³Jenison, 12 August: 5.2 µg/m³Cedar RapidsCedar Rapids, 27 July: 5.4 µg/m³Cedar Rapids, 28 July: 4.7 µg/m³Cedar Rapids, 29 July: 6.8 µg/m³Cedar Rapids, 30 July: 6.2 µg/m³Cedar Rapids, 31 July: 66.5 µg/m³, 7.7× its usual 8.6Cedar Rapids, 1 August: 42.5 µg/m³, 5.0× its usual 8.5Cedar Rapids, 2 August: 36.0 µg/m³, 4.2× its usual 8.5Cedar Rapids, 3 August: 24.8 µg/m³Cedar Rapids, 4 August: 19.2 µg/m³Cedar Rapids, 5 August: 14.2 µg/m³Cedar Rapids, 6 August: 15.4 µg/m³Cedar Rapids, 7 August: 8.9 µg/m³Cedar Rapids, 8 August: 10.2 µg/m³Cedar Rapids, 9 August: 10.2 µg/m³Cedar Rapids, 10 August: 6.1 µg/m³Cedar Rapids, 11 August: 4.8 µg/m³Cedar Rapids, 12 August: 7.2 µg/m³BrookfieldBrookfield, 27 July: 6.2 µg/m³Brookfield, 28 July: 6.8 µg/m³Brookfield, 29 July: 11.1 µg/m³Brookfield, 30 July: 11.1 µg/m³Brookfield, 31 July: 66.3 µg/m³, 7.3× its usual 9.1Brookfield, 1 August: 51.0 µg/m³, 5.5× its usual 9.2Brookfield, 2 August: 27.8 µg/m³, 3.0× its usual 9.4Brookfield, 3 August: 33.8 µg/m³, 3.6× its usual 9.4Brookfield, 4 August: 25.2 µg/m³, 2.7× its usual 9.2Brookfield, 5 August: 28.0 µg/m³, 3.0× its usual 9.2Brookfield, 6 August: 32.7 µg/m³, 3.6× its usual 9.2Brookfield, 7 August: 13.9 µg/m³Brookfield, 8 August: 13.6 µg/m³Brookfield, 9 August: 10.5 µg/m³Brookfield, 10 August: 7.5 µg/m³Brookfield, 11 August: 7.9 µg/m³Brookfield, 12 August: 7.7 µg/m³Iowa CityIowa City, 27 July: 4.1 µg/m³Iowa City, 28 July: 4.7 µg/m³Iowa City, 29 July: 5.0 µg/m³Iowa City, 30 July: 4.2 µg/m³Iowa City, 31 July: 64.9 µg/m³, 7.1× its usual 9.1Iowa City, 1 August: 48.1 µg/m³, 5.3× its usual 9.1Iowa City, 2 August: 36.4 µg/m³, 4.0× its usual 9.1Iowa City, 3 August: 23.6 µg/m³Iowa City, 4 August: 19.7 µg/m³Iowa City, 5 August: 14.3 µg/m³Iowa City, 6 August: 14.4 µg/m³Iowa City, 7 August: 8.6 µg/m³Iowa City, 8 August: 9.5 µg/m³Iowa City, 9 August: 9.6 µg/m³Iowa City, 10 August: 6.9 µg/m³Iowa City, 11 August: 5.3 µg/m³Iowa City, 12 August: 4.9 µg/m³DoltonDolton, 27 July: 7.6 µg/m³Dolton, 28 July: 9.7 µg/m³Dolton, 29 July: 11.0 µg/m³Dolton, 30 July: 13.4 µg/m³Dolton, 31 July: 64.8 µg/m³, 6.2× its usual 10.5Dolton, 1 August: 48.0 µg/m³, 4.6× its usual 10.5Dolton, 2 August: 25.3 µg/m³, 2.4× its usual 10.5Dolton, 3 August: 28.9 µg/m³, 2.8× its usual 10.3Dolton, 4 August: 18.2 µg/m³Dolton, 5 August: 32.7 µg/m³, 3.3× its usual 9.8Dolton, 6 August: 32.3 µg/m³, 3.3× its usual 9.7Dolton, 7 August: 15.8 µg/m³Dolton, 8 August: 15.1 µg/m³Dolton, 9 August: 13.0 µg/m³Dolton, 10 August: 10.5 µg/m³Dolton, 11 August: 10.2 µg/m³Dolton, 12 August: 9.4 µg/m³DavenportDavenport, 27 July: 4.6 µg/m³Davenport, 28 July: 4.2 µg/m³Davenport, 29 July: 5.1 µg/m³Davenport, 30 July: 4.8 µg/m³Davenport, 31 July: 64.4 µg/m³, 7.5× its usual 8.6Davenport, 1 August: 50.7 µg/m³, 5.9× its usual 8.6Davenport, 2 August: 28.5 µg/m³, 3.4× its usual 8.5Davenport, 3 August: 30.1 µg/m³, 3.5× its usual 8.5Davenport, 4 August: 19.6 µg/m³Davenport, 5 August: 16.1 µg/m³Davenport, 6 August: 14.8 µg/m³Davenport, 7 August: 9.2 µg/m³Davenport, 8 August: 9.1 µg/m³Davenport, 9 August: 8.5 µg/m³Davenport, 10 August: 6.0 µg/m³Davenport, 11 August: 6.3 µg/m³Davenport, 12 August: 4.7 µg/m³AuroraAurora, 27 July: 6.3 µg/m³Aurora, 28 July: 7.4 µg/m³Aurora, 29 July: 7.5 µg/m³Aurora, 30 July: 9.7 µg/m³Aurora, 31 July: 63.4 µg/m³, 7.0× its usual 9.1Aurora, 1 August: 48.2 µg/m³, 5.3× its usual 9.1Aurora, 2 August: 29.0 µg/m³, 3.2× its usual 9.0Aurora, 3 August: 31.5 µg/m³, 3.8× its usual 8.4Aurora, 4 August: 24.4 µg/m³Aurora, 5 August: 23.1 µg/m³Aurora, 6 August: 26.7 µg/m³, 3.4× its usual 7.9Aurora, 7 August: 12.6 µg/m³Aurora, 8 August: 12.1 µg/m³Aurora, 9 August: 11.3 µg/m³Aurora, 10 August: 9.1 µg/m³Aurora, 11 August: 6.6 µg/m³Aurora, 12 August: 6.4 µg/m³LondonLondon, 27 July: 5.9 µg/m³London, 28 July: 9.9 µg/m³London, 29 July: 8.8 µg/m³London, 30 July: 18.8 µg/m³London, 31 July: 44.9 µg/m³, 4.7× its usual 9.5London, 1 August: 19.6 µg/m³London, 2 August: 11.5 µg/m³London, 3 August: 45.8 µg/m³, 5.1× its usual 9.0London, 4 August: 63.1 µg/m³, 7.2× its usual 8.8London, 5 August: 33.4 µg/m³, 3.9× its usual 8.6London, 6 August: 37.8 µg/m³, 4.4× its usual 8.6London, 7 August: 21.5 µg/m³London, 8 August: 19.7 µg/m³London, 9 August: 14.5 µg/m³London, 10 August: 16.7 µg/m³London, 11 August: 14.7 µg/m³London, 12 August: 10.2 µg/m³NapervilleNaperville, 27 July: 8.0 µg/m³Naperville, 28 July: 8.7 µg/m³Naperville, 29 July: 8.6 µg/m³Naperville, 30 July: 11.2 µg/m³Naperville, 31 July: 63.0 µg/m³, 5.8× its usual 10.9Naperville, 1 August: 49.4 µg/m³, 4.6× its usual 10.8Naperville, 2 August: 28.5 µg/m³, 2.7× its usual 10.6Naperville, 3 August: 31.5 µg/m³, 3.0× its usual 10.6Naperville, 4 August: 24.6 µg/m³Naperville, 5 August: 24.9 µg/m³Naperville, 6 August: 26.9 µg/m³, 2.7× its usual 10.1Naperville, 7 August: 13.3 µg/m³Naperville, 8 August: 13.3 µg/m³Naperville, 9 August: 12.1 µg/m³Naperville, 10 August: 9.7 µg/m³Naperville, 11 August: 7.5 µg/m³Naperville, 12 August: 7.2 µg/m³SarniaSarnia, 27 July: 7.4 µg/m³Sarnia, 28 July: 9.0 µg/m³Sarnia, 29 July: 8.9 µg/m³Sarnia, 30 July: 24.0 µg/m³Sarnia, 31 July: 50.9 µg/m³, 5.8× its usual 8.8Sarnia, 1 August: 9.5 µg/m³Sarnia, 2 August: 12.2 µg/m³Sarnia, 3 August: 45.7 µg/m³, 5.4× its usual 8.5Sarnia, 4 August: 62.5 µg/m³, 7.4× its usual 8.4Sarnia, 5 August: 37.5 µg/m³, 4.5× its usual 8.3Sarnia, 6 August: 36.2 µg/m³, 4.3× its usual 8.4Sarnia, 7 August: 20.0 µg/m³Sarnia, 8 August: 16.0 µg/m³Sarnia, 9 August: 12.2 µg/m³Sarnia, 10 August: 15.1 µg/m³Sarnia, 11 August: 13.3 µg/m³Sarnia, 12 August: 7.7 µg/m³KalamazooKalamazoo, 27 July: 5.9 µg/m³Kalamazoo, 28 July: 7.4 µg/m³Kalamazoo, 29 July: 8.2 µg/m³Kalamazoo, 30 July: 16.9 µg/m³Kalamazoo, 31 July: 61.6 µg/m³, 5.7× its usual 10.9Kalamazoo, 1 August: 28.1 µg/m³, 2.6× its usual 10.8Kalamazoo, 2 August: 28.6 µg/m³, 2.6× its usual 10.8Kalamazoo, 3 August: 41.0 µg/m³, 3.8× its usual 10.9Kalamazoo, 4 August: 31.6 µg/m³, 3.0× its usual 10.7Kalamazoo, 5 August: 41.9 µg/m³, 4.0× its usual 10.6Kalamazoo, 6 August: 25.7 µg/m³, 2.5× its usual 10.4Kalamazoo, 7 August: 11.5 µg/m³Kalamazoo, 8 August: 11.9 µg/m³Kalamazoo, 9 August: 11.1 µg/m³Kalamazoo, 10 August: 10.7 µg/m³Kalamazoo, 11 August: 9.1 µg/m³Kalamazoo, 12 August: 7.7 µg/m³PeoriaPeoria, 27 July: 9.0 µg/m³Peoria, 28 July: 6.5 µg/m³Peoria, 29 July: 8.9 µg/m³Peoria, 30 July: 6.6 µg/m³Peoria, 31 July: 57.1 µg/m³, 5.5× its usual 10.4Peoria, 1 August: 61.5 µg/m³, 5.9× its usual 10.4Peoria, 2 August: 27.2 µg/m³, 2.6× its usual 10.3Peoria, 3 August: 16.7 µg/m³Peoria, 4 August: 12.0 µg/m³Peoria, 5 August: 13.5 µg/m³Peoria, 6 August: 13.2 µg/m³Peoria, 7 August: 12.7 µg/m³Peoria, 8 August: 13.4 µg/m³Peoria, 9 August: 13.6 µg/m³Peoria, 10 August: 9.9 µg/m³Peoria, 11 August: 12.3 µg/m³Peoria, 12 August: 10.0 µg/m³NorthbrookNorthbrook, 27 July: 5.3 µg/m³Northbrook, 28 July: 7.8 µg/m³Northbrook, 29 July: 8.4 µg/m³Northbrook, 30 July: 12.4 µg/m³Northbrook, 31 July: 60.7 µg/m³, 6.1× its usual 9.9Northbrook, 1 August: 37.6 µg/m³, 3.8× its usual 9.9Northbrook, 2 August: no readingNorthbrook, 3 August: no readingNorthbrook, 4 August: no readingNorthbrook, 5 August: no readingNorthbrook, 6 August: 26.6 µg/m³, 2.7× its usual 9.8Northbrook, 7 August: 15.3 µg/m³Northbrook, 8 August: 13.2 µg/m³Northbrook, 9 August: 12.3 µg/m³Northbrook, 10 August: 7.5 µg/m³Northbrook, 11 August: 7.8 µg/m³Northbrook, 12 August: 6.8 µg/m³HammondHammond, 27 July: 8.0 µg/m³Hammond, 28 July: 10.0 µg/m³Hammond, 29 July: 9.8 µg/m³Hammond, 30 July: 14.2 µg/m³Hammond, 31 July: 60.4 µg/m³, 6.1× its usual 9.9Hammond, 1 August: 48.5 µg/m³, 4.9× its usual 9.9Hammond, 2 August: 26.4 µg/m³, 2.6× its usual 10.0Hammond, 3 August: 28.6 µg/m³, 2.9× its usual 10.0Hammond, 4 August: 16.9 µg/m³Hammond, 5 August: 30.8 µg/m³, 3.1× its usual 9.9Hammond, 6 August: 30.2 µg/m³, 3.1× its usual 9.8Hammond, 7 August: 13.8 µg/m³Hammond, 8 August: 14.3 µg/m³Hammond, 9 August: 12.6 µg/m³Hammond, 10 August: 10.2 µg/m³Hammond, 11 August: 8.2 µg/m³Hammond, 12 August: 7.8 µg/m³JolietJoliet, 27 July: 7.0 µg/m³Joliet, 28 July: 6.5 µg/m³Joliet, 29 July: 8.9 µg/m³Joliet, 30 July: 11.0 µg/m³Joliet, 31 July: 60.4 µg/m³, 5.8× its usual 10.5Joliet, 1 August: 51.4 µg/m³, 4.9× its usual 10.5Joliet, 2 August: 25.0 µg/m³, 2.4× its usual 10.3Joliet, 3 August: 26.2 µg/m³, 2.5× its usual 10.3Joliet, 4 August: 17.4 µg/m³Joliet, 5 August: 25.4 µg/m³, 2.5× its usual 10.2Joliet, 6 August: 24.5 µg/m³Joliet, 7 August: 12.2 µg/m³Joliet, 8 August: 13.3 µg/m³Joliet, 9 August: 11.7 µg/m³Joliet, 10 August: 9.1 µg/m³Joliet, 11 August: 9.4 µg/m³Joliet, 12 August: 7.4 µg/m³KitchenerKitchener, 27 July: 8.8 µg/m³Kitchener, 28 July: 11.0 µg/m³Kitchener, 29 July: 7.9 µg/m³Kitchener, 30 July: 20.6 µg/m³Kitchener, 31 July: 42.7 µg/m³, 4.6× its usual 9.3Kitchener, 1 August: 9.5 µg/m³Kitchener, 2 August: 16.1 µg/m³Kitchener, 3 August: 49.0 µg/m³, 5.4× its usual 9.0Kitchener, 4 August: 59.9 µg/m³, 6.7× its usual 9.0Kitchener, 5 August: 37.8 µg/m³, 4.3× its usual 8.7Kitchener, 6 August: 29.2 µg/m³, 3.7× its usual 8.0Kitchener, 7 August: 27.6 µg/m³, 3.5× its usual 7.9Kitchener, 8 August: 21.6 µg/m³Kitchener, 9 August: 14.2 µg/m³Kitchener, 10 August: 16.8 µg/m³Kitchener, 11 August: 14.6 µg/m³Kitchener, 12 August: 10.4 µg/m³WindsorWindsor, 27 July: 8.8 µg/m³Windsor, 28 July: 8.0 µg/m³Windsor, 29 July: 11.5 µg/m³Windsor, 30 July: 22.0 µg/m³Windsor, 31 July: 52.1 µg/m³, 4.9× its usual 10.7Windsor, 1 August: 18.1 µg/m³Windsor, 2 August: 9.0 µg/m³Windsor, 3 August: 26.5 µg/m³, 2.5× its usual 10.5Windsor, 4 August: 59.8 µg/m³, 6.0× its usual 10.0Windsor, 5 August: 38.1 µg/m³, 3.8× its usual 9.9Windsor, 6 August: 26.9 µg/m³, 2.7× its usual 9.8Windsor, 7 August: 19.5 µg/m³Windsor, 8 August: 12.9 µg/m³Windsor, 9 August: 15.0 µg/m³Windsor, 10 August: 15.8 µg/m³Windsor, 11 August: 14.8 µg/m³Windsor, 12 August: 14.2 µg/m³LansingLansing, 27 July: 7.7 µg/m³Lansing, 28 July: 7.2 µg/m³Lansing, 29 July: 6.7 µg/m³Lansing, 30 July: 19.7 µg/m³Lansing, 31 July: 59.7 µg/m³, 6.1× its usual 9.8Lansing, 1 August: 17.3 µg/m³Lansing, 2 August: 25.6 µg/m³, 2.7× its usual 9.5Lansing, 3 August: 52.7 µg/m³, 5.7× its usual 9.3Lansing, 4 August: 39.3 µg/m³, 4.3× its usual 9.1Lansing, 5 August: 42.5 µg/m³, 4.7× its usual 9.1Lansing, 6 August: 22.9 µg/m³Lansing, 7 August: 15.5 µg/m³Lansing, 8 August: 12.1 µg/m³Lansing, 9 August: 9.6 µg/m³Lansing, 10 August: 9.9 µg/m³Lansing, 11 August: 9.2 µg/m³Lansing, 12 August: 7.6 µg/m³OlatheOlathe, 27 July: 9.1 µg/m³Olathe, 28 July: 9.2 µg/m³Olathe, 29 July: 8.6 µg/m³Olathe, 30 July: 4.8 µg/m³Olathe, 31 July: 12.6 µg/m³Olathe, 1 August: 64.0 µg/m³, 6.4× its usual 10.0Olathe, 2 August: 41.8 µg/m³, 4.2× its usual 9.9Olathe, 3 August: 20.3 µg/m³Olathe, 4 August: 12.2 µg/m³Olathe, 5 August: 10.9 µg/m³Olathe, 6 August: 14.0 µg/m³Olathe, 7 August: 14.3 µg/m³Olathe, 8 August: 12.1 µg/m³Olathe, 9 August: 11.4 µg/m³Olathe, 10 August: 7.5 µg/m³Olathe, 11 August: 5.8 µg/m³Olathe, 12 August: 6.5 µg/m³TopekaTopeka, 27 July: 8.2 µg/m³Topeka, 28 July: 8.3 µg/m³Topeka, 29 July: 8.2 µg/m³Topeka, 30 July: 4.1 µg/m³Topeka, 31 July: 8.9 µg/m³Topeka, 1 August: 62.0 µg/m³, 6.5× its usual 9.6Topeka, 2 August: 41.5 µg/m³, 4.3× its usual 9.7Topeka, 3 August: 23.0 µg/m³Topeka, 4 August: 13.8 µg/m³Topeka, 5 August: 11.2 µg/m³Topeka, 6 August: 13.7 µg/m³Topeka, 7 August: 12.9 µg/m³Topeka, 8 August: 9.6 µg/m³Topeka, 9 August: 8.8 µg/m³Topeka, 10 August: 6.7 µg/m³Topeka, 11 August: 5.0 µg/m³Topeka, 12 August: 5.6 µg/m³27 Jul29311 Aug24681012
The 60 cities with the highest readings of 241, 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
MarquetteMichigan, United States8 112.030 July8.114×
Rouyn-NorandaQuebec, Canada3 87.32 August7.512×
MadisonWisconsin, United States8 82.431 July8.010×
South MilwaukeeWisconsin, United States7 82.931 July8.110×
ZionIllinois, United States6 77.531 July7.610×
SuperiorWisconsin, United States6 108.030 July10.810×
AppletonWisconsin, United States8 86.931 July8.710×
Eau ClaireWisconsin, United States6 86.831 July8.99.8×
WaukeshaWisconsin, United States8 86.031 July8.99.7×
MilwaukeeWisconsin, United States8 91.131 July9.79.4×
Sault Ste. MarieOntario, Canada9 71.630 July7.79.3×
MankatoMinnesota, United States6 96.931 July10.79.1×
DuluthMinnesota, United States6 91.130 July10.09.1×
Green BayWisconsin, United States8 85.930 July9.49.1×
BlaineMinnesota, United States6 79.31 August8.79.1×
MolineIllinois, United States4 76.031 July8.88.6×
RockfordIllinois, United States7 79.831 July9.68.3×
Des PlainesIllinois, United States7 75.831 July9.28.2×
La VistaNebraska, United States2 48.51 August5.98.2×
CaryIllinois, United States7 75.031 July9.38.1×
ClintonIowa, United States4 73.931 July9.28.0×
MinneapolisMinnesota, United States6 80.71 August10.27.9×
Apple ValleyMinnesota, United States5 66.11 August8.47.9×
Greater SudburyOntario, Canada4 63.130 July8.07.9×
BellevueNebraska, United States2 49.51 August6.37.9×
Fort DodgeIowa, United States4 74.831 July9.67.8×
EastpointeMichigan, United States4 51.74 August6.67.8×
Cedar RapidsIowa, United States3 66.531 July8.67.7×
AllistonOntario, Canada7 53.83 August7.07.7×
North BayOntario, Canada4 53.030 July6.97.7×
OconomowocWisconsin, United States8 111.031 July14.67.6×
ChicagoIllinois, United States6 69.731 July9.27.6×
Saint MichaelMinnesota, United States6 69.31 August9.17.6×
Sioux FallsSouth Dakota, United States3 45.11 August5.97.6×
DavenportIowa, United States4 64.431 July8.67.5×
EriePennsylvania, United States5 53.34 August7.17.5×
MuscatineIowa, United States3 50.131 July6.77.5×
RochesterMinnesota, United States6 76.231 July10.37.4×
BurnsvilleMinnesota, United States6 75.11 August10.17.4×
SarniaOntario, Canada5 62.54 August8.47.4×
PeterboroughOntario, Canada6 52.53 August7.17.4×
BrookfieldIllinois, United States7 66.331 July9.17.3×
BellevilleOntario, Canada5 51.14 August7.07.3×
Saint PaulMinnesota, United States5 73.01 August10.17.2×
ShakopeeMinnesota, United States6 68.931 July9.67.2×
JenisonMichigan, United States7 67.131 July9.37.2×
LondonOntario, Canada5 63.14 August8.87.2×
ChathamOntario, Canada3 53.14 August7.47.2×
AberdeenSouth Dakota, United States4 41.11 August5.77.2×
Grand RapidsMichigan, United States5 73.231 July10.37.1×
Elmwood ParkIllinois, United States7 72.031 July10.27.1×
Iowa CityIowa, United States3 64.931 July9.17.1×
New CityNew York, United States1 35.55 August4.97.1×
NewburghNew York, United States2 35.45 August5.07.1×
UticaNew York, United States4 35.47 August4.97.1×
Saint CloudMinnesota, United States5 63.71 August9.17.0×
AuroraIllinois, United States5 63.431 July9.17.0×
West FargoNorth Dakota, United States5 67.231 July9.76.9×
NewmarketOntario, Canada8 60.23 August8.76.9×
PittsfieldMassachusetts, United States3 44.75 August6.56.9×
BrantfordOntario, Canada6 59.54 August8.86.8×
Port HuronMichigan, United States5 58.84 August8.66.8×
BloomingtonIllinois, United States2 57.51 August8.56.8×
St. ThomasOntario, Canada5 55.64 August8.26.8×
SaguenayQuebec, Canada2 53.73 August7.96.8×
SyracuseNew York, United States7 45.44 August6.76.8×
Franklin ParkIllinois, United States7 76.931 July11.46.7×
KitchenerOntario, Canada6 59.94 August9.06.7×
KingstonOntario, Canada4 47.24 August7.06.7×
BramptonOntario, Canada6 54.73 August8.36.6×
AlbanyNew York, United States5 49.85 August7.66.6×
BrookingsSouth Dakota, United States5 45.71 August6.96.6×
LibertyMissouri, United States2 44.61 August6.86.6×
GreenfieldMassachusetts, United States2 40.45 August6.16.6×
TopekaKansas, United States2 62.01 August9.66.5×
East ChicagoIndiana, United States4 59.431 July9.16.5×
BarrieOntario, Canada8 57.93 August8.96.5×
GuelphOntario, Canada5 57.54 August8.86.5×
SouthfieldMichigan, United States5 56.14 August8.66.5×
OmahaNebraska, United States3 50.91 August7.86.5×
ColumbiaMissouri, United States3 72.51 August11.46.4×
OlatheKansas, United States2 64.01 August10.06.4×
MississaugaOntario, Canada5 51.73 August8.16.4×
BuffaloNew York, United States7 50.24 August7.96.4×
SpringfieldMassachusetts, United States2 45.25 August7.16.4×
North ChicopeeMassachusetts, United States2 39.35 August6.16.4×
BangorMaine, United States1 35.14 August5.56.4×
ElginIllinois, United States7 73.731 July11.76.3×
TorontoOntario, Canada7 57.93 August9.26.3×
RochesterNew York, United States7 46.04 August7.36.3×
RaymoreMissouri, United States2 45.01 August7.16.3×
DoltonIllinois, United States6 64.831 July10.56.2×
HamiltonOntario, Canada6 55.44 August8.96.2×
DorvalQuebec, Canada4 44.24 August7.16.2×
White PlainsNew York, United States1 31.05 August4.76.2×
NorthbrookIllinois, United States3 60.731 July9.96.1×
HammondIndiana, United States6 60.431 July9.96.1×
LansingMichigan, United States5 59.731 July9.86.1×
MiltonOntario, Canada6 58.63 August9.66.1×
Kansas CityKansas, United States2 58.61 August9.66.1×
Michigan CityIndiana, United States5 56.931 July9.36.1×
Oak LawnIllinois, United States5 56.731 July9.36.1×
OakvilleOntario, Canada5 55.83 August9.16.1×
WaterdownOntario, Canada5 51.14 August8.46.1×
OttawaOntario, Canada5 45.23 August7.46.1×
EdmundstonNew Brunswick, Canada2 41.53 August6.86.1×
KeeneNew Hampshire, United States2 39.25 August6.46.1×
WindsorOntario, Canada5 59.84 August10.06.0×
MilfordMassachusetts, United States2 34.75 August5.86.0×
PeoriaIllinois, United States3 61.51 August10.45.9×
Bay CityMichigan, United States6 51.44 August8.75.9×
BridgeviewIllinois, United States6 68.031 July11.75.8×
NapervilleIllinois, United States5 63.031 July10.95.8×
JolietIllinois, United States5 60.431 July10.55.8×
HartfordConnecticut, United States2 45.15 August7.85.8×
SherbrookeQuebec, Canada2 39.03 August6.75.8×
Saint-Jean-sur-RichelieuQuebec, Canada3 35.13 August6.15.8×
LaconiaNew Hampshire, United States2 29.04 August4.55.8×
KalamazooMichigan, United States7 61.631 July10.95.7×
WinnipegManitoba, Canada2 54.32 August9.65.7×
SpringfieldIllinois, United States2 53.31 August9.45.7×
YpsilantiMichigan, United States3 49.231 July8.75.7×
Des MoinesIowa, United States3 48.331 July8.45.7×
CornwallOntario, Canada4 41.44 August7.35.7×
HollandMichigan, United States6 55.331 July9.85.6×
Kansas CityMissouri, United States2 47.01 August8.45.6×
PainesvilleOhio, United States2 36.24 August6.55.6×
FrederictonNew Brunswick, Canada1 30.24 August5.45.6×
DecaturIllinois, United States2 52.31 August9.55.5×
ChampaignIllinois, United States2 49.61 August9.05.5×
GranbyQuebec, Canada4 44.33 August8.05.5×
Calumet CityIllinois, United States5 56.031 July10.45.4×
St. CatharinesOntario, Canada7 41.54 August7.75.4×
DanburyConnecticut, United States2 40.25 August7.55.4×
MonctonNew Brunswick, Canada1 28.64 August5.35.4×
DetroitMichigan, United States5 56.04 August10.65.3×
TaylorMichigan, United States4 48.04 August9.05.3×
LeawoodKansas, United States2 44.11 August8.45.3×
Grand IslandNebraska, United States2 42.51 August8.05.3×
DrummondvilleQuebec, Canada3 36.43 August6.95.3×
LewistonMaine, United States1 32.24 August6.15.3×
Lincoln ParkMichigan, United States3 49.84 August9.65.2×
WorcesterMassachusetts, United States2 34.05 August6.55.2×
DearbornMichigan, United States5 53.64 August10.65.1×
Upper AltonIllinois, United States1 50.21 August9.95.1×
AnkenyIowa, United States3 48.331 July9.55.1×
RedfordMichigan, United States4 46.44 August9.15.1×
ElkhartIndiana, United States5 46.131 July9.15.1×
ScrantonPennsylvania, United States4 41.25 August8.15.1×
WaterburyConnecticut, United States2 38.55 August7.55.1×
MontréalQuebec, Canada4 38.33 August7.55.1×
Trois-RivièresQuebec, Canada3 36.03 August7.05.1×
RutlandVermont, United States3 34.74 August6.85.1×
Rivière-des-Prairies–Pointe-aux-TremblesQuebec, Canada4 36.33 August7.25.0×
HaverhillMassachusetts, United States1 29.74 August6.05.0×
FraminghamMassachusetts, United States2 26.85 August5.45.0×
Saint JosephMissouri, United States2 48.61 August10.04.9×
WatertownSouth Dakota, United States4 45.21 August9.34.9×
South BendIndiana, United States3 44.731 July9.24.9×
DerryNew Hampshire, United States2 32.04 August6.54.9×
WaterlooIowa, United States2 41.61 August8.64.8×
BrossardQuebec, Canada4 37.73 August7.84.8×
GaryIndiana, United States4 45.931 July9.84.7×
MiramichiNew Brunswick, Canada2 25.74 August5.54.7×
ShawiniganQuebec, Canada3 36.93 August8.14.6×
University CityMissouri, United States1 36.21 August7.84.6×
Cleveland HeightsOhio, United States2 34.34 August7.44.6×
State CollegePennsylvania, United States2 33.66 August7.34.6×
AugustaMaine, United States2 31.24 August6.84.6×
PortageIndiana, United States5 46.131 July10.24.5×
East Saint LouisIllinois, United States1 46.01 August10.34.5×
QuébecQuebec, Canada3 37.03 August8.24.5×
WyomingMichigan, United States5 54.731 July12.44.4×
Sorel-TracyQuebec, Canada5 39.93 August9.14.4×
ArnoldMissouri, United States1 35.11 August7.94.4×
New HavenConnecticut, United States1 33.75 August7.64.4×
RandolphNew Jersey, United States1 32.55 August7.44.4×
Fort LeeNew Jersey, United States1 31.45 August7.24.4×
Granite CityIllinois, United States1 47.61 August11.04.3×
LexingtonMassachusetts, United States3 38.65 August9.04.3×
ChesapeakeVirginia, United States1 34.97 August8.14.3×
Dodge CityKansas, United States1 30.72 August7.24.3×
PortsmouthNew Hampshire, United States1 28.54 August6.64.3×
L'Ancienne-LoretteQuebec, Canada2 38.93 August9.34.2×
ToledoOhio, United States4 38.44 August9.14.2×
CarlislePennsylvania, United States3 32.76 August7.74.2×
LowellMassachusetts, United States2 27.44 August6.54.2×
MuncieIndiana, United States1 34.61 August8.64.0×
LafayetteIndiana, United States1 31.81 August8.04.0×
BridgeportConnecticut, United States1 31.35 August7.94.0×
LynnMassachusetts, United States1 25.74 August6.54.0×
Fort WayneIndiana, United States3 35.91 August9.33.9×
New York CityNew York, United States1 32.85 August8.43.9×
PortlandMaine, United States1 31.54 August8.03.9×
East HamptonVirginia, United States1 28.97 August7.53.9×
NorristownPennsylvania, United States1 27.95 August7.23.9×
St. LouisMissouri, United States1 37.71 August9.83.8×
DerbyKansas, United States2 36.91 August9.63.8×
LebanonPennsylvania, United States2 32.36 August8.43.8×
Shaker HeightsOhio, United States1 31.44 August8.33.8×
BostonMassachusetts, United States1 26.84 August7.03.8×
NepeanOntario, Canada7 57.630 July15.63.7×
KokomoIndiana, United States1 30.51 August8.33.7×
AndersonIndiana, United States1 30.41 August8.23.7×
LincolnNebraska, United States1 27.32 August7.43.7×
LexingtonNorth Carolina, United States1 29.88 August8.33.6×
PatersonNew Jersey, United States1 28.55 August7.93.6×
HickoryNorth Carolina, United States1 28.48 August7.83.6×
YorkPennsylvania, United States1 29.26 August8.33.5×
ClemmonsNorth Carolina, United States1 27.48 August7.93.5×
AbingtonPennsylvania, United States1 25.75 August7.43.5×
HopewellVirginia, United States1 25.37 August7.23.5×
RoanokeVirginia, United States1 25.38 August7.33.5×
Ponca CityOklahoma, United States2 34.42 August10.13.4×
SteubenvilleOhio, United States2 31.08 August9.13.4×
BloomingtonIndiana, United States1 26.61 August7.93.4×
WilmingtonDelaware, United States1 26.05 August7.73.4×
SewellNew Jersey, United States1 25.66 August7.63.4×
ClevelandOhio, United States3 34.54 August10.43.3×
HarrisburgPennsylvania, United States2 30.56 August9.33.3×
LancasterPennsylvania, United States2 28.66 August8.83.3×
Winston-SalemNorth Carolina, United States1 28.08 August8.53.3×
Jersey CityNew Jersey, United States1 27.45 August8.23.3×
New BrunswickNew Jersey, United States1 25.15 August7.63.3×
YoungstownOhio, United States2 26.88 August8.33.2×
IndianapolisIndiana, United States1 33.11 August10.73.1×
PennsaukenNew Jersey, United States1 26.65 August8.63.1×
LindenNew Jersey, United States1 26.15 August8.43.1×
Ann ArborMichigan, United States3 38.931 July13.42.9×
ElizabethNew Jersey, United States1 27.85 August9.62.9×
CamdenNew Jersey, United States1 27.35 August9.32.9×
PittsburghPennsylvania, United States1 27.18 August9.22.9×
PhiladelphiaPennsylvania, United States1 27.55 August10.02.8×
LimaOhio, United States1 26.51 August9.52.8×
Wake ForestNorth Carolina, United States2 33.08 August12.42.7×
Terre HauteIndiana, United States1 28.01 August10.22.7×
FishersIndiana, United States1 26.51 August10.02.7×
WarrenOhio, United States1 25.66 August9.92.6×
West MifflinPennsylvania, United States1 26.18 August10.62.5×
WestervilleOhio, United States1 25.91 August10.42.5×
MiddletownOhio, United States1 26.01 August11.62.2×

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 4 of 141 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 141.

Use this page

SmogRank, North-eastern United States and Canada, 30 July to 9 August 2025: 241 cities with PM2.5 at twice their usual or more, 30 July to 9 August 2025, smogrank.com/episodes/2025-07-30-north-eastern-united-states-and-canada (accessed 4 October 2026).

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You're welcome to reuse a single chart, image or figure with this citation and a link. Terms.

An episode is a run of days when many cities close to each other (four or more within 350 km on a day, 8 or more in all) each had a daily PM2.5 mean of at least 25 µg/m³ and at least 2 times their usual for that time of year. Found in our own measurements, not picked by hand. How we find episodes. Values are each city's daily mean of its own monitors; causes are the usual kinds for a pattern like this, not a confirmed source.