SmogRank / Episodes / United States

Northern United States and Canada, May and June 2025

For 10 days, from 31 May to 9 June 2025, 247 cities in the United States and Canada had PM2.5 at least twice their usual for the time of year. The worst reading was Nepean, Ontario, Canada: 116.0 µg/m³ on 6 June, about 16× its usual 7.4. Ended 9 June.

No cause namedWe have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached247in 2 countries
Days1031 May to 9 June 2025
Worst day7 June130 cities counted
Furthest above usual19×Duluth

Day by day

7 June 130 cities at twice their usual or more
LebanonFishersMcCordsvilleMasonMcKeesportJefferson HillsSharonvilleIndianapolisWhite OakMonessenDentGreensburgFort ThomasHighland HeightsColumbusJohnstownBloomingtonTerre HauteCharlestonFrostburgLexington-FayetteSaint MatthewsJeffersonvilleNew AlbanyJeffersontownNicholasvilleValley StationJasperPikevilleHalfwayElizabethtownHagerstownSchlusserCarlisleHazardHarrisonburgHarrisburgSomersetHersheyOwensboroEvansvilleYorkLebanonAshburnMiddlesboroRoanokeCharlottesvilleKingsportRockvilleLancasterHunt ValleyWyomissingScaggsvilleReadingNew HollandSpringfieldWashingtonSouth LaurelRose HillBaltimoreOxon Hill-GlassmanorEssexAllentownEdgewoodBethlehemKennett SquareElktonNewarkGlasgowOak GroveNorristownShort PumpBearWilmingtonUniversity CityClarksvilleClaymontLemayChesterPaducahRichmondPhiladelphiaPaulsboroArnoldRandolphMendhamPennsaukenBensalemSewellCambridgeEwingDoverTrentonHopewellNewburghNew BrunswickSouth VinelandPatersonMount IvySeafordLindenNew CityElizabethBayonneJersey CityFort LeeNew York CityRoanoke RapidsWhite PlainsPittsfieldToms RiverSmithvillePleasantvilleDanburyAtlantic CityPoquosonWaterburyBridgeportChesapeakeNew HavenHolbrookHartfordNew LondonLaconiaCoventryWest GreenwichProvidencePawtucketKearneyLibertyFall RiverSaint JosephBrocktonSpringfieldKansas CityRaymoreLeawoodBellevueLewistonLa VistaVermillionMiamiChanuteBeatriceBangorGrand IslandPonca CityFrederictonSaint JohnBathurstMiramichiDodge CityMonctonEstevanLamarSt. LouisMiddletownNorwoodWest MifflinLouisvilleCincinnatiGranite CityElkhartSpringfieldDaytonAnkenyMoundsvilleFlintWheelingClevelandScrantonEast Saint LouisKennedy TownshipLimaWichitaWyomingDes MoinesAndersonKokomoAshlandPittsburghSteubenvilleSpringfieldColumbiaMuscatineWilkinsburgKansas CityColumbia CityOmahaDublinHaysvilleDerbyWaterlooNatrona HeightsWeirton HeightsDecaturColumbusSavoyLincolnBuffaloWestervilleClintonJerseyvilleLafayetteUniontownAugustaHuntingtonOlatheFlatwoodsCleveland HeightsMuncieUpper AltonMedinaRockfordTopekaBay CityAberdeenWareBenningtonState CollegeWood RiverCantonUxbridgeMilfordNew AlbanyGahannaNorth AdamsBlairErieNew BrightonFort WayneSpringfieldHollandAkronBarrieKeeneGreenfieldPortlandBrookfieldNorth ChicopeeWorcesterWeirtonDavenportAlbanyWarrensville HeightsSouth BendRedfordPainesvilleLondonderryDerryWheelersburgPortsmouthGaryWarrenFraminghamPierreChampaignPortsmouthToledoRutlandMolineBostonBeaver FallsUticaLowellSt. CatharinesGrand RapidsKalamazooHermitageWaukeshaJenisonHudsonvilleYoungstownPeoriaPortagePerrysburgMaumeeMilwaukeeQuincyAltoonaHaverhillHartfordLynnIowa CityOregonSouth MilwaukeeGreendaleJolietNapervilleLansingDetroitCaryDearbornDrummondvilleOak LawnSherbrookeNorth BayBloomingtonNorthbrookSt. ThomasCalumet CityBridgeviewSyracuseNew BaltimoreHamiltonGreater SudburyFranklin ParkMarquetteAllistonParry SoundEast ChicagoChathamRochesterBraidwoodTecumsehLincoln ParkHammondChicagoDes PlainesGranbyZionWinthrop HarborTaylorDoltonTomahSioux FallsWatertownWindsorBrantfordSorel-TracySaint-Jean-sur-RichelieuWarrenvilleAuroraYpsilantiWaterdownPort HuronKitchenerNewmarketPresque IsleCedar RapidsBarabooElginMichigan CityRochesterElmwood ParkRouyn-NorandaMadisonBrossardSarniaTrois-RivièresLondonEastpointeEdmundstonBrainerdBrookingsBécancourShawiniganLincolnwoodBramptonTorontoSaint CloudGuelphSault Ste. MarieMississaugaOakvilleSouthfieldRivière-des-Prairies–Pointe-aux-TremblesMiltonSaguenayMontréalAppletonManisteeGreen BayDorvalKingstonQuébecEau ClaireAltoonaL'Ancienne-LorettePeterboroughCornwallMarshallBurnsvilleVirginiaSaint PaulApple ValleyShakopeeMinneapolisLabrador CityOconomowocBellevilleSaint MichaelMankatoCloquetSept-ÎlesNepeanWest FargoSuperiorOttawaBlaineDetroit LakesDuluth
28 May2930311 Jun23456789101112
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

West FargoWest Fargo, 28 May: 4.6 µg/m³West Fargo, 29 May: 9.4 µg/m³West Fargo, 30 May: 7.5 µg/m³West Fargo, 31 May: 26.3 µg/m³, 3.7× its usual 7.1West Fargo, 1 June: 113.0 µg/m³, 16× its usual 7.1West Fargo, 2 June: 81.9 µg/m³, 12× its usual 6.7West Fargo, 3 June: 17.9 µg/m³West Fargo, 4 June: 13.4 µg/m³West Fargo, 5 June: 9.4 µg/m³West Fargo, 6 June: 6.1 µg/m³West Fargo, 7 June: 7.3 µg/m³West Fargo, 8 June: 22.8 µg/m³West Fargo, 9 June: 18.1 µg/m³West Fargo, 10 June: 28.2 µg/m³West Fargo, 11 June: 44.9 µg/m³West Fargo, 12 June: 21.5 µg/m³WatertownWatertown, 28 May: 5.4 µg/m³Watertown, 29 May: 6.0 µg/m³Watertown, 30 May: 5.8 µg/m³Watertown, 31 May: 49.0 µg/m³, 6.5× its usual 7.5Watertown, 1 June: 61.2 µg/m³, 8.2× its usual 7.5Watertown, 2 June: no readingWatertown, 3 June: no readingWatertown, 4 June: 14.4 µg/m³Watertown, 5 June: 10.3 µg/m³Watertown, 6 June: 5.9 µg/m³Watertown, 7 June: 9.2 µg/m³Watertown, 8 June: 21.5 µg/m³Watertown, 9 June: 13.3 µg/m³Watertown, 10 June: 19.6 µg/m³Watertown, 11 June: 29.5 µg/m³Watertown, 12 June: 24.7 µg/m³BrookingsBrookings, 28 May: 9.4 µg/m³Brookings, 29 May: 7.9 µg/m³Brookings, 30 May: 7.7 µg/m³Brookings, 31 May: 39.9 µg/m³, 6.1× its usual 6.5Brookings, 1 June: 60.4 µg/m³, 9.3× its usual 6.5Brookings, 2 June: 30.9 µg/m³, 4.8× its usual 6.4Brookings, 3 June: 21.6 µg/m³Brookings, 4 June: 14.8 µg/m³Brookings, 5 June: 17.9 µg/m³Brookings, 6 June: 15.9 µg/m³Brookings, 7 June: 14.6 µg/m³Brookings, 8 June: 21.4 µg/m³Brookings, 9 June: 16.6 µg/m³Brookings, 10 June: 22.5 µg/m³Brookings, 11 June: 28.7 µg/m³Brookings, 12 June: 36.1 µg/m³Detroit LakesDetroit Lakes, 28 May: 3.6 µg/m³Detroit Lakes, 29 May: 9.0 µg/m³Detroit Lakes, 30 May: 11.0 µg/m³Detroit Lakes, 31 May: 15.7 µg/m³Detroit Lakes, 1 June: 40.9 µg/m³, 6.8× its usual 6.0Detroit Lakes, 2 June: 105.0 µg/m³, 18× its usual 6.0Detroit Lakes, 3 June: 21.5 µg/m³Detroit Lakes, 4 June: 13.6 µg/m³Detroit Lakes, 5 June: 11.0 µg/m³Detroit Lakes, 6 June: 6.8 µg/m³Detroit Lakes, 7 June: 8.3 µg/m³Detroit Lakes, 8 June: 26.9 µg/m³, 5.0× its usual 5.4Detroit Lakes, 9 June: 23.1 µg/m³Detroit Lakes, 10 June: 28.9 µg/m³Detroit Lakes, 11 June: 37.5 µg/m³Detroit Lakes, 12 June: 16.9 µg/m³MarshallMarshall, 28 May: 5.3 µg/m³Marshall, 29 May: 5.4 µg/m³Marshall, 30 May: 3.9 µg/m³Marshall, 31 May: 15.3 µg/m³Marshall, 1 June: 70.1 µg/m³, 13× its usual 5.6Marshall, 2 June: 33.5 µg/m³, 6.0× its usual 5.6Marshall, 3 June: 26.8 µg/m³, 5.1× its usual 5.3Marshall, 4 June: 13.5 µg/m³Marshall, 5 June: 13.1 µg/m³Marshall, 6 June: 14.0 µg/m³Marshall, 7 June: 12.5 µg/m³Marshall, 8 June: 19.9 µg/m³Marshall, 9 June: 14.4 µg/m³Marshall, 10 June: 25.8 µg/m³Marshall, 11 June: 34.7 µg/m³Marshall, 12 June: 42.9 µg/m³VirginiaVirginia, 28 May: 4.0 µg/m³Virginia, 29 May: 17.1 µg/m³Virginia, 30 May: 28.4 µg/m³Virginia, 31 May: 7.8 µg/m³Virginia, 1 June: 17.6 µg/m³Virginia, 2 June: 56.6 µg/m³, 11× its usual 4.7Virginia, 3 June: 65.7 µg/m³, 13× its usual 4.7Virginia, 4 June: 17.6 µg/m³Virginia, 5 June: 10.7 µg/m³Virginia, 6 June: 12.9 µg/m³Virginia, 7 June: 14.7 µg/m³Virginia, 8 June: 26.6 µg/m³, 5.3× its usual 4.7Virginia, 9 June: 11.9 µg/m³Virginia, 10 June: 18.7 µg/m³Virginia, 11 June: 21.2 µg/m³Virginia, 12 June: 7.8 µg/m³DuluthDuluth, 28 May: 5.7 µg/m³Duluth, 29 May: 24.0 µg/m³Duluth, 30 May: 21.4 µg/m³Duluth, 31 May: 12.8 µg/m³Duluth, 1 June: 8.0 µg/m³Duluth, 2 June: 17.0 µg/m³Duluth, 3 June: 96.0 µg/m³, 19× its usual 4.7Duluth, 4 June: 19.1 µg/m³Duluth, 5 June: 16.0 µg/m³Duluth, 6 June: 14.6 µg/m³Duluth, 7 June: 24.2 µg/m³Duluth, 8 June: 36.4 µg/m³, 7.3× its usual 4.7Duluth, 9 June: 14.7 µg/m³Duluth, 10 June: 30.6 µg/m³Duluth, 11 June: 51.3 µg/m³Duluth, 12 June: 6.9 µg/m³BlaineBlaine, 28 May: 4.3 µg/m³Blaine, 29 May: 6.0 µg/m³Blaine, 30 May: 8.3 µg/m³Blaine, 31 May: 14.0 µg/m³Blaine, 1 June: 18.1 µg/m³Blaine, 2 June: 12.7 µg/m³Blaine, 3 June: 90.5 µg/m³, 17× its usual 5.2Blaine, 4 June: 25.6 µg/m³, 5.0× its usual 5.1Blaine, 5 June: 14.9 µg/m³Blaine, 6 June: 9.8 µg/m³Blaine, 7 June: 15.8 µg/m³Blaine, 8 June: 15.2 µg/m³Blaine, 9 June: 12.3 µg/m³Blaine, 10 June: 30.6 µg/m³Blaine, 11 June: 32.7 µg/m³Blaine, 12 June: 40.3 µg/m³MinneapolisMinneapolis, 28 May: 4.7 µg/m³Minneapolis, 29 May: 6.7 µg/m³Minneapolis, 30 May: 9.0 µg/m³Minneapolis, 31 May: 15.8 µg/m³Minneapolis, 1 June: 20.2 µg/m³Minneapolis, 2 June: 13.7 µg/m³Minneapolis, 3 June: 90.2 µg/m³, 14× its usual 6.4Minneapolis, 4 June: 28.9 µg/m³, 4.6× its usual 6.3Minneapolis, 5 June: 17.7 µg/m³Minneapolis, 6 June: 11.8 µg/m³Minneapolis, 7 June: 18.3 µg/m³Minneapolis, 8 June: 16.3 µg/m³Minneapolis, 9 June: 13.0 µg/m³Minneapolis, 10 June: 31.1 µg/m³Minneapolis, 11 June: 34.3 µg/m³Minneapolis, 12 June: 43.7 µg/m³SuperiorSuperior, 28 May: 5.4 µg/m³Superior, 29 May: 20.5 µg/m³Superior, 30 May: 20.2 µg/m³Superior, 31 May: 20.2 µg/m³Superior, 1 June: 8.2 µg/m³Superior, 2 June: 11.9 µg/m³Superior, 3 June: 88.7 µg/m³, 16× its usual 5.5Superior, 4 June: 19.2 µg/m³Superior, 5 June: 13.4 µg/m³Superior, 6 June: 12.2 µg/m³Superior, 7 June: 18.9 µg/m³Superior, 8 June: 27.9 µg/m³, 4.8× its usual 5.8Superior, 9 June: 11.2 µg/m³Superior, 10 June: 24.7 µg/m³Superior, 11 June: 40.6 µg/m³Superior, 12 June: 6.6 µg/m³MankatoMankato, 28 May: 4.8 µg/m³Mankato, 29 May: 5.9 µg/m³Mankato, 30 May: 5.9 µg/m³Mankato, 31 May: 14.3 µg/m³Mankato, 1 June: 21.0 µg/m³Mankato, 2 June: 11.3 µg/m³Mankato, 3 June: 85.0 µg/m³, 15× its usual 5.7Mankato, 4 June: 21.8 µg/m³Mankato, 5 June: 14.4 µg/m³Mankato, 6 June: 16.1 µg/m³Mankato, 7 June: 18.7 µg/m³Mankato, 8 June: 16.2 µg/m³Mankato, 9 June: 12.9 µg/m³Mankato, 10 June: 23.5 µg/m³Mankato, 11 June: 35.8 µg/m³Mankato, 12 June: 40.6 µg/m³ShakopeeShakopee, 28 May: 4.7 µg/m³Shakopee, 29 May: 5.3 µg/m³Shakopee, 30 May: 7.2 µg/m³Shakopee, 31 May: 14.1 µg/m³Shakopee, 1 June: 24.2 µg/m³Shakopee, 2 June: 11.3 µg/m³Shakopee, 3 June: 84.2 µg/m³, 14× its usual 6.0Shakopee, 4 June: 24.7 µg/m³Shakopee, 5 June: 13.5 µg/m³Shakopee, 6 June: 11.3 µg/m³Shakopee, 7 June: 17.0 µg/m³Shakopee, 8 June: 15.2 µg/m³Shakopee, 9 June: 11.4 µg/m³Shakopee, 10 June: 27.4 µg/m³Shakopee, 11 June: 33.5 µg/m³Shakopee, 12 June: 43.8 µg/m³Saint MichaelSaint Michael, 28 May: 4.1 µg/m³Saint Michael, 29 May: 5.6 µg/m³Saint Michael, 30 May: 7.5 µg/m³Saint Michael, 31 May: 13.6 µg/m³Saint Michael, 1 June: 23.2 µg/m³Saint Michael, 2 June: 12.5 µg/m³Saint Michael, 3 June: 81.2 µg/m³, 15× its usual 5.6Saint Michael, 4 June: 19.0 µg/m³Saint Michael, 5 June: 12.7 µg/m³Saint Michael, 6 June: 10.0 µg/m³Saint Michael, 7 June: 13.5 µg/m³Saint Michael, 8 June: 13.3 µg/m³Saint Michael, 9 June: 12.3 µg/m³Saint Michael, 10 June: 28.9 µg/m³Saint Michael, 11 June: 27.4 µg/m³Saint Michael, 12 June: 39.4 µg/m³Saint PaulSaint Paul, 28 May: 4.3 µg/m³Saint Paul, 29 May: 6.2 µg/m³Saint Paul, 30 May: 8.2 µg/m³Saint Paul, 31 May: 14.8 µg/m³Saint Paul, 1 June: 16.4 µg/m³Saint Paul, 2 June: 12.3 µg/m³Saint Paul, 3 June: 80.9 µg/m³, 13× its usual 6.1Saint Paul, 4 June: 28.9 µg/m³, 4.8× its usual 6.0Saint Paul, 5 June: 16.3 µg/m³Saint Paul, 6 June: 10.8 µg/m³Saint Paul, 7 June: 18.5 µg/m³Saint Paul, 8 June: 15.4 µg/m³Saint Paul, 9 June: 11.2 µg/m³Saint Paul, 10 June: 28.7 µg/m³Saint Paul, 11 June: 31.3 µg/m³Saint Paul, 12 June: 38.4 µg/m³BurnsvilleBurnsville, 28 May: 4.3 µg/m³Burnsville, 29 May: 5.7 µg/m³Burnsville, 30 May: 7.7 µg/m³Burnsville, 31 May: 14.1 µg/m³Burnsville, 1 June: 20.8 µg/m³Burnsville, 2 June: 11.4 µg/m³Burnsville, 3 June: 79.7 µg/m³, 12× its usual 6.4Burnsville, 4 June: 23.9 µg/m³Burnsville, 5 June: 12.9 µg/m³Burnsville, 6 June: 12.8 µg/m³Burnsville, 7 June: 20.4 µg/m³Burnsville, 8 June: 16.3 µg/m³Burnsville, 9 June: 11.1 µg/m³Burnsville, 10 June: 27.6 µg/m³Burnsville, 11 June: 35.2 µg/m³Burnsville, 12 June: 44.8 µg/m³Apple ValleyApple Valley, 28 May: 5.6 µg/m³Apple Valley, 29 May: 6.9 µg/m³Apple Valley, 30 May: 8.2 µg/m³Apple Valley, 31 May: 13.9 µg/m³Apple Valley, 1 June: 20.0 µg/m³Apple Valley, 2 June: 11.8 µg/m³Apple Valley, 3 June: 78.3 µg/m³, 14× its usual 5.7Apple Valley, 4 June: 25.7 µg/m³, 4.8× its usual 5.4Apple Valley, 5 June: 13.1 µg/m³Apple Valley, 6 June: 14.1 µg/m³Apple Valley, 7 June: 20.0 µg/m³Apple Valley, 8 June: 16.9 µg/m³Apple Valley, 9 June: 12.0 µg/m³Apple Valley, 10 June: 27.2 µg/m³Apple Valley, 11 June: 35.3 µg/m³Apple Valley, 12 June: 46.1 µg/m³CloquetCloquet, 28 May: 3.5 µg/m³Cloquet, 29 May: 9.7 µg/m³Cloquet, 30 May: 14.5 µg/m³Cloquet, 31 May: 13.2 µg/m³Cloquet, 1 June: 10.6 µg/m³Cloquet, 2 June: 18.0 µg/m³Cloquet, 3 June: 75.8 µg/m³, 15× its usual 4.2Cloquet, 4 June: 15.2 µg/m³Cloquet, 5 June: 9.2 µg/m³Cloquet, 6 June: 8.0 µg/m³Cloquet, 7 June: 14.5 µg/m³Cloquet, 8 June: 21.7 µg/m³Cloquet, 9 June: 9.4 µg/m³Cloquet, 10 June: 20.0 µg/m³Cloquet, 11 June: 37.3 µg/m³Cloquet, 12 June: 12.5 µg/m³AltoonaAltoona, 28 May: 5.1 µg/m³Altoona, 29 May: 5.6 µg/m³Altoona, 30 May: 8.5 µg/m³Altoona, 31 May: 11.7 µg/m³Altoona, 1 June: 8.1 µg/m³Altoona, 2 June: 14.7 µg/m³Altoona, 3 June: 63.2 µg/m³, 11× its usual 5.5Altoona, 4 June: 40.5 µg/m³, 7.4× its usual 5.5Altoona, 5 June: 14.0 µg/m³Altoona, 6 June: 14.3 µg/m³Altoona, 7 June: 19.5 µg/m³Altoona, 8 June: 22.5 µg/m³Altoona, 9 June: 9.6 µg/m³Altoona, 10 June: 30.8 µg/m³Altoona, 11 June: 34.8 µg/m³Altoona, 12 June: 41.5 µg/m³Eau ClaireEau Claire, 28 May: 5.1 µg/m³Eau Claire, 29 May: 5.6 µg/m³Eau Claire, 30 May: 8.5 µg/m³Eau Claire, 31 May: 11.7 µg/m³Eau Claire, 1 June: 8.1 µg/m³Eau Claire, 2 June: 14.7 µg/m³Eau Claire, 3 June: 63.2 µg/m³, 11× its usual 5.5Eau Claire, 4 June: 40.5 µg/m³, 7.4× its usual 5.5Eau Claire, 5 June: 14.0 µg/m³Eau Claire, 6 June: 14.3 µg/m³Eau Claire, 7 June: 19.5 µg/m³Eau Claire, 8 June: 22.5 µg/m³Eau Claire, 9 June: 9.6 µg/m³Eau Claire, 10 June: 30.8 µg/m³Eau Claire, 11 June: 34.8 µg/m³Eau Claire, 12 June: 41.5 µg/m³RochesterRochester, 28 May: 4.6 µg/m³Rochester, 29 May: 5.5 µg/m³Rochester, 30 May: 8.4 µg/m³Rochester, 31 May: 16.5 µg/m³Rochester, 1 June: 18.3 µg/m³Rochester, 2 June: 13.9 µg/m³Rochester, 3 June: 61.9 µg/m³, 8.8× its usual 7.0Rochester, 4 June: 36.7 µg/m³, 5.3× its usual 6.9Rochester, 5 June: 14.8 µg/m³Rochester, 6 June: 16.3 µg/m³Rochester, 7 June: 25.0 µg/m³, 3.8× its usual 6.6Rochester, 8 June: 21.6 µg/m³Rochester, 9 June: 10.5 µg/m³Rochester, 10 June: 25.3 µg/m³Rochester, 11 June: 34.2 µg/m³Rochester, 12 June: 42.0 µg/m³OconomowocOconomowoc, 28 May: 9.2 µg/m³Oconomowoc, 29 May: 10.2 µg/m³Oconomowoc, 30 May: 16.7 µg/m³Oconomowoc, 31 May: 8.1 µg/m³Oconomowoc, 1 June: no readingOconomowoc, 2 June: no readingOconomowoc, 3 June: 18.5 µg/m³Oconomowoc, 4 June: 71.9 µg/m³, 14× its usual 4.5Oconomowoc, 5 June: 44.2 µg/m³, 8.8× its usual 4.8Oconomowoc, 6 June: 35.7 µg/m³, 7.1× its usual 4.8Oconomowoc, 7 June: 36.8 µg/m³, 6.8× its usual 5.4Oconomowoc, 8 June: 36.5 µg/m³, 6.8× its usual 5.4Oconomowoc, 9 June: 24.4 µg/m³Oconomowoc, 10 June: 32.2 µg/m³Oconomowoc, 11 June: 38.2 µg/m³Oconomowoc, 12 June: 41.8 µg/m³Elmwood ParkElmwood Park, 28 May: 10.1 µg/m³Elmwood Park, 29 May: 21.8 µg/m³Elmwood Park, 30 May: 22.8 µg/m³Elmwood Park, 31 May: 12.1 µg/m³Elmwood Park, 1 June: no readingElmwood Park, 2 June: no readingElmwood Park, 3 June: 21.2 µg/m³Elmwood Park, 4 June: 34.2 µg/m³, 4.4× its usual 7.8Elmwood Park, 5 June: 70.6 µg/m³, 8.9× its usual 7.9Elmwood Park, 6 June: 44.2 µg/m³, 5.7× its usual 7.8Elmwood Park, 7 June: 36.7 µg/m³, 4.6× its usual 7.9Elmwood Park, 8 June: 38.6 µg/m³, 4.3× its usual 8.9Elmwood Park, 9 June: 26.5 µg/m³Elmwood Park, 10 June: 25.9 µg/m³Elmwood Park, 11 June: 32.7 µg/m³Elmwood Park, 12 June: 37.5 µg/m³WindsorWindsor, 28 May: 3.5 µg/m³Windsor, 29 May: 10.5 µg/m³Windsor, 30 May: 9.5 µg/m³Windsor, 31 May: 7.4 µg/m³Windsor, 1 June: 6.0 µg/m³Windsor, 2 June: 7.0 µg/m³Windsor, 3 June: 16.0 µg/m³Windsor, 4 June: 26.2 µg/m³, 3.6× its usual 7.3Windsor, 5 June: 45.5 µg/m³, 6.1× its usual 7.4Windsor, 6 June: 61.3 µg/m³, 8.2× its usual 7.5Windsor, 7 June: 24.3 µg/m³Windsor, 8 June: 43.1 µg/m³, 5.9× its usual 7.3Windsor, 9 June: 25.7 µg/m³Windsor, 10 June: 15.7 µg/m³Windsor, 11 June: 25.0 µg/m³Windsor, 12 June: 27.4 µg/m³Green BayGreen Bay, 28 May: 4.8 µg/m³Green Bay, 29 May: 5.3 µg/m³Green Bay, 30 May: 24.3 µg/m³Green Bay, 31 May: 5.1 µg/m³Green Bay, 1 June: 6.0 µg/m³Green Bay, 2 June: 10.1 µg/m³Green Bay, 3 June: 19.2 µg/m³Green Bay, 4 June: 60.8 µg/m³, 11× its usual 5.5Green Bay, 5 June: 34.5 µg/m³, 6.3× its usual 5.5Green Bay, 6 June: 23.6 µg/m³Green Bay, 7 June: 19.8 µg/m³Green Bay, 8 June: 20.8 µg/m³Green Bay, 9 June: 10.3 µg/m³Green Bay, 10 June: 18.3 µg/m³Green Bay, 11 June: 34.9 µg/m³Green Bay, 12 June: 24.4 µg/m³DoltonDolton, 28 May: 7.5 µg/m³Dolton, 29 May: 14.1 µg/m³Dolton, 30 May: 17.6 µg/m³Dolton, 31 May: 8.5 µg/m³Dolton, 1 June: 8.7 µg/m³Dolton, 2 June: 11.5 µg/m³Dolton, 3 June: 18.3 µg/m³Dolton, 4 June: 41.8 µg/m³, 5.5× its usual 7.6Dolton, 5 June: 60.1 µg/m³, 7.9× its usual 7.6Dolton, 6 June: 37.4 µg/m³, 4.9× its usual 7.7Dolton, 7 June: 24.4 µg/m³Dolton, 8 June: 26.1 µg/m³, 3.4× its usual 7.7Dolton, 9 June: 22.3 µg/m³Dolton, 10 June: 21.1 µg/m³Dolton, 11 June: 26.3 µg/m³Dolton, 12 June: 29.1 µg/m³LincolnwoodLincolnwood, 28 May: 6.2 µg/m³Lincolnwood, 29 May: 13.4 µg/m³Lincolnwood, 30 May: 16.0 µg/m³Lincolnwood, 31 May: 8.8 µg/m³Lincolnwood, 1 June: 7.1 µg/m³Lincolnwood, 2 June: 11.3 µg/m³Lincolnwood, 3 June: 16.2 µg/m³Lincolnwood, 4 June: 25.5 µg/m³, 4.0× its usual 6.3Lincolnwood, 5 June: 59.7 µg/m³, 9.6× its usual 6.2Lincolnwood, 6 June: 35.5 µg/m³, 5.8× its usual 6.1Lincolnwood, 7 June: 27.2 µg/m³, 4.7× its usual 5.8Lincolnwood, 8 June: 27.0 µg/m³, 4.4× its usual 6.1Lincolnwood, 9 June: 19.4 µg/m³Lincolnwood, 10 June: 19.7 µg/m³Lincolnwood, 11 June: 24.7 µg/m³Lincolnwood, 12 June: 26.8 µg/m³AppletonAppleton, 28 May: 5.7 µg/m³Appleton, 29 May: 5.3 µg/m³Appleton, 30 May: 22.3 µg/m³Appleton, 31 May: 6.0 µg/m³Appleton, 1 June: 6.5 µg/m³Appleton, 2 June: 10.5 µg/m³Appleton, 3 June: 20.4 µg/m³Appleton, 4 June: 59.0 µg/m³, 11× its usual 5.4Appleton, 5 June: 30.5 µg/m³, 5.5× its usual 5.5Appleton, 6 June: 23.8 µg/m³Appleton, 7 June: 18.8 µg/m³Appleton, 8 June: 24.8 µg/m³Appleton, 9 June: 10.1 µg/m³Appleton, 10 June: 21.3 µg/m³Appleton, 11 June: 31.9 µg/m³Appleton, 12 June: 31.3 µg/m³HammondHammond, 28 May: 8.6 µg/m³Hammond, 29 May: 12.8 µg/m³Hammond, 30 May: 16.1 µg/m³Hammond, 31 May: 9.0 µg/m³Hammond, 1 June: 9.2 µg/m³Hammond, 2 June: 9.8 µg/m³Hammond, 3 June: 15.5 µg/m³Hammond, 4 June: 35.0 µg/m³, 4.5× its usual 7.7Hammond, 5 June: 58.3 µg/m³, 7.7× its usual 7.6Hammond, 6 June: 40.5 µg/m³, 5.3× its usual 7.6Hammond, 7 June: 28.1 µg/m³, 3.7× its usual 7.5Hammond, 8 June: 25.5 µg/m³, 3.4× its usual 7.6Hammond, 9 June: 21.5 µg/m³Hammond, 10 June: 17.0 µg/m³Hammond, 11 June: 21.7 µg/m³Hammond, 12 June: 30.4 µg/m³SarniaSarnia, 28 May: 3.0 µg/m³Sarnia, 29 May: 6.7 µg/m³Sarnia, 30 May: 7.9 µg/m³Sarnia, 31 May: 3.7 µg/m³Sarnia, 1 June: 4.1 µg/m³Sarnia, 2 June: 5.8 µg/m³Sarnia, 3 June: 14.8 µg/m³Sarnia, 4 June: 33.3 µg/m³, 5.3× its usual 6.3Sarnia, 5 June: 57.6 µg/m³, 9.0× its usual 6.4Sarnia, 6 June: 29.4 µg/m³, 4.5× its usual 6.5Sarnia, 7 June: 28.4 µg/m³, 4.4× its usual 6.5Sarnia, 8 June: 35.4 µg/m³, 5.4× its usual 6.5Sarnia, 9 June: 25.8 µg/m³Sarnia, 10 June: 13.0 µg/m³Sarnia, 11 June: 24.1 µg/m³Sarnia, 12 June: 24.3 µg/m³DearbornDearborn, 28 May: 3.6 µg/m³Dearborn, 29 May: 9.3 µg/m³Dearborn, 30 May: 7.7 µg/m³Dearborn, 31 May: 6.9 µg/m³Dearborn, 1 June: 4.5 µg/m³Dearborn, 2 June: 6.9 µg/m³Dearborn, 3 June: 17.0 µg/m³Dearborn, 4 June: 25.0 µg/m³, 3.0× its usual 8.4Dearborn, 5 June: 44.2 µg/m³, 5.3× its usual 8.4Dearborn, 6 June: 56.0 µg/m³, 6.6× its usual 8.5Dearborn, 7 June: 21.3 µg/m³Dearborn, 8 June: 38.3 µg/m³, 4.6× its usual 8.4Dearborn, 9 June: 23.7 µg/m³Dearborn, 10 June: 15.1 µg/m³Dearborn, 11 June: 23.9 µg/m³Dearborn, 12 June: 23.6 µg/m³NepeanNepean, 28 May: 8.3 µg/m³Nepean, 29 May: 5.8 µg/m³Nepean, 30 May: 9.9 µg/m³Nepean, 31 May: 5.9 µg/m³Nepean, 1 June: no readingNepean, 2 June: no readingNepean, 3 June: 7.6 µg/m³Nepean, 4 June: 28.0 µg/m³Nepean, 5 June: 50.2 µg/m³, 6.8× its usual 7.4Nepean, 6 June: 116.0 µg/m³, 16× its usual 7.4Nepean, 7 June: 65.3 µg/m³, 8.5× its usual 7.7Nepean, 8 June: 34.7 µg/m³, 4.8× its usual 7.3Nepean, 9 June: 33.2 µg/m³, 4.5× its usual 7.4Nepean, 10 June: 12.9 µg/m³Nepean, 11 June: 28.1 µg/m³Nepean, 12 June: 22.8 µg/m³OttawaOttawa, 28 May: 6.4 µg/m³Ottawa, 29 May: 3.7 µg/m³Ottawa, 30 May: 4.9 µg/m³Ottawa, 31 May: 4.0 µg/m³Ottawa, 1 June: 1.4 µg/m³Ottawa, 2 June: 3.4 µg/m³Ottawa, 3 June: 6.4 µg/m³Ottawa, 4 June: 15.5 µg/m³Ottawa, 5 June: 32.1 µg/m³, 5.8× its usual 5.5Ottawa, 6 June: 89.6 µg/m³, 16× its usual 5.5Ottawa, 7 June: 46.8 µg/m³, 8.5× its usual 5.5Ottawa, 8 June: 20.1 µg/m³Ottawa, 9 June: 20.5 µg/m³Ottawa, 10 June: 7.4 µg/m³Ottawa, 11 June: 13.2 µg/m³Ottawa, 12 June: 11.0 µg/m³L'Ancienne-LoretteL'Ancienne-Lorette, 28 May: 8.3 µg/m³L'Ancienne-Lorette, 29 May: 8.5 µg/m³L'Ancienne-Lorette, 30 May: 7.4 µg/m³L'Ancienne-Lorette, 31 May: 5.4 µg/m³L'Ancienne-Lorette, 1 June: 1.7 µg/m³L'Ancienne-Lorette, 2 June: 3.8 µg/m³L'Ancienne-Lorette, 3 June: 5.8 µg/m³L'Ancienne-Lorette, 4 June: 14.5 µg/m³L'Ancienne-Lorette, 5 June: 26.2 µg/m³, 4.2× its usual 6.3L'Ancienne-Lorette, 6 June: 73.3 µg/m³, 12× its usual 6.1L'Ancienne-Lorette, 7 June: 50.2 µg/m³, 8.2× its usual 6.1L'Ancienne-Lorette, 8 June: 10.5 µg/m³L'Ancienne-Lorette, 9 June: 14.0 µg/m³L'Ancienne-Lorette, 10 June: 13.7 µg/m³L'Ancienne-Lorette, 11 June: 13.1 µg/m³L'Ancienne-Lorette, 12 June: 10.0 µg/m³CornwallCornwall, 28 May: 7.3 µg/m³Cornwall, 29 May: 4.1 µg/m³Cornwall, 30 May: 7.1 µg/m³Cornwall, 31 May: 4.7 µg/m³Cornwall, 1 June: 1.8 µg/m³Cornwall, 2 June: 3.7 µg/m³Cornwall, 3 June: 6.8 µg/m³Cornwall, 4 June: 16.8 µg/m³Cornwall, 5 June: 25.1 µg/m³, 4.4× its usual 5.7Cornwall, 6 June: 70.3 µg/m³, 12× its usual 5.7Cornwall, 7 June: 48.8 µg/m³, 8.6× its usual 5.7Cornwall, 8 June: 29.3 µg/m³, 5.1× its usual 5.7Cornwall, 9 June: 19.7 µg/m³Cornwall, 10 June: 7.2 µg/m³Cornwall, 11 June: 14.5 µg/m³Cornwall, 12 June: 16.7 µg/m³TorontoToronto, 28 May: 4.9 µg/m³Toronto, 29 May: 6.7 µg/m³Toronto, 30 May: 9.5 µg/m³Toronto, 31 May: 5.8 µg/m³Toronto, 1 June: 3.0 µg/m³Toronto, 2 June: 5.9 µg/m³Toronto, 3 June: 10.5 µg/m³Toronto, 4 June: 20.2 µg/m³Toronto, 5 June: 29.6 µg/m³, 4.4× its usual 6.8Toronto, 6 June: 67.9 µg/m³, 9.8× its usual 6.9Toronto, 7 June: 31.4 µg/m³, 4.6× its usual 6.8Toronto, 8 June: 37.8 µg/m³, 5.5× its usual 6.9Toronto, 9 June: 21.3 µg/m³Toronto, 10 June: 10.8 µg/m³Toronto, 11 June: 21.5 µg/m³Toronto, 12 June: 18.4 µg/m³SaguenaySaguenay, 28 May: 10.6 µg/m³Saguenay, 29 May: 11.4 µg/m³Saguenay, 30 May: 7.0 µg/m³Saguenay, 31 May: 7.0 µg/m³Saguenay, 1 June: 1.9 µg/m³Saguenay, 2 June: 2.8 µg/m³Saguenay, 3 June: 7.0 µg/m³Saguenay, 4 June: 15.8 µg/m³Saguenay, 5 June: 41.6 µg/m³, 7.1× its usual 5.9Saguenay, 6 June: 66.9 µg/m³, 11× its usual 6.2Saguenay, 7 June: 27.6 µg/m³, 4.4× its usual 6.3Saguenay, 8 June: 8.9 µg/m³Saguenay, 9 June: 15.2 µg/m³Saguenay, 10 June: 16.1 µg/m³Saguenay, 11 June: 11.8 µg/m³Saguenay, 12 June: 6.4 µg/m³PeterboroughPeterborough, 28 May: 4.0 µg/m³Peterborough, 29 May: 3.3 µg/m³Peterborough, 30 May: 5.0 µg/m³Peterborough, 31 May: 3.1 µg/m³Peterborough, 1 June: 2.1 µg/m³Peterborough, 2 June: 3.3 µg/m³Peterborough, 3 June: 8.0 µg/m³Peterborough, 4 June: 15.7 µg/m³Peterborough, 5 June: 30.8 µg/m³, 5.8× its usual 5.3Peterborough, 6 June: 66.2 µg/m³, 12× its usual 5.4Peterborough, 7 June: 39.5 µg/m³, 7.5× its usual 5.3Peterborough, 8 June: 32.1 µg/m³, 6.1× its usual 5.3Peterborough, 9 June: 11.8 µg/m³Peterborough, 10 June: 8.1 µg/m³Peterborough, 11 June: 15.9 µg/m³Peterborough, 12 June: 16.1 µg/m³KitchenerKitchener, 28 May: 4.3 µg/m³Kitchener, 29 May: 7.4 µg/m³Kitchener, 30 May: 8.8 µg/m³Kitchener, 31 May: 4.7 µg/m³Kitchener, 1 June: 3.0 µg/m³Kitchener, 2 June: 4.4 µg/m³Kitchener, 3 June: 10.1 µg/m³Kitchener, 4 June: 17.7 µg/m³Kitchener, 5 June: 44.7 µg/m³, 6.0× its usual 7.4Kitchener, 6 June: 63.9 µg/m³, 8.6× its usual 7.4Kitchener, 7 June: 24.4 µg/m³Kitchener, 8 June: 37.0 µg/m³, 5.0× its usual 7.4Kitchener, 9 June: 21.5 µg/m³Kitchener, 10 June: 10.8 µg/m³Kitchener, 11 June: 22.0 µg/m³Kitchener, 12 June: 18.2 µg/m³MiltonMilton, 28 May: 6.4 µg/m³Milton, 29 May: 6.5 µg/m³Milton, 30 May: 9.2 µg/m³Milton, 31 May: 5.1 µg/m³Milton, 1 June: 3.0 µg/m³Milton, 2 June: 4.3 µg/m³Milton, 3 June: 10.5 µg/m³Milton, 4 June: 20.0 µg/m³Milton, 5 June: 38.0 µg/m³, 6.6× its usual 5.8Milton, 6 June: 62.8 µg/m³, 11× its usual 5.9Milton, 7 June: 28.7 µg/m³, 4.9× its usual 5.9Milton, 8 June: 37.1 µg/m³, 6.3× its usual 5.9Milton, 9 June: 23.2 µg/m³Milton, 10 June: 10.6 µg/m³Milton, 11 June: 22.0 µg/m³Milton, 12 June: 17.5 µg/m³Franklin ParkFranklin Park, 28 May: 7.1 µg/m³Franklin Park, 29 May: 12.5 µg/m³Franklin Park, 30 May: 16.0 µg/m³Franklin Park, 31 May: 9.4 µg/m³Franklin Park, 1 June: 8.6 µg/m³Franklin Park, 2 June: 10.6 µg/m³Franklin Park, 3 June: 16.2 µg/m³Franklin Park, 4 June: 23.7 µg/m³Franklin Park, 5 June: 59.5 µg/m³, 7.3× its usual 8.1Franklin Park, 6 June: 35.6 µg/m³, 4.2× its usual 8.4Franklin Park, 7 June: 32.3 µg/m³, 3.9× its usual 8.3Franklin Park, 8 June: 27.6 µg/m³, 3.3× its usual 8.4Franklin Park, 9 June: 20.4 µg/m³Franklin Park, 10 June: 20.9 µg/m³Franklin Park, 11 June: 26.3 µg/m³Franklin Park, 12 June: 30.3 µg/m³ChicagoChicago, 28 May: 7.5 µg/m³Chicago, 29 May: 12.3 µg/m³Chicago, 30 May: 16.0 µg/m³Chicago, 31 May: 8.1 µg/m³Chicago, 1 June: 7.7 µg/m³Chicago, 2 June: 9.7 µg/m³Chicago, 3 June: 15.8 µg/m³Chicago, 4 June: 20.8 µg/m³Chicago, 5 June: 58.4 µg/m³, 7.7× its usual 7.6Chicago, 6 June: 35.2 µg/m³, 4.5× its usual 7.9Chicago, 7 June: 26.3 µg/m³, 3.3× its usual 7.9Chicago, 8 June: 27.2 µg/m³, 3.4× its usual 8.0Chicago, 9 June: 18.7 µg/m³Chicago, 10 June: 18.1 µg/m³Chicago, 11 June: 24.2 µg/m³Chicago, 12 June: 27.8 µg/m³Lincoln ParkLincoln Park, 28 May: 3.2 µg/m³Lincoln Park, 29 May: 7.0 µg/m³Lincoln Park, 30 May: 6.7 µg/m³Lincoln Park, 31 May: 6.9 µg/m³Lincoln Park, 1 June: 5.3 µg/m³Lincoln Park, 2 June: 6.5 µg/m³Lincoln Park, 3 June: 14.0 µg/m³Lincoln Park, 4 June: 21.7 µg/m³Lincoln Park, 5 June: 41.4 µg/m³, 5.5× its usual 7.5Lincoln Park, 6 June: 56.8 µg/m³, 7.6× its usual 7.5Lincoln Park, 7 June: 21.0 µg/m³Lincoln Park, 8 June: 38.6 µg/m³, 5.3× its usual 7.3Lincoln Park, 9 June: 20.7 µg/m³Lincoln Park, 10 June: 12.9 µg/m³Lincoln Park, 11 June: 20.0 µg/m³Lincoln Park, 12 June: 24.2 µg/m³SouthfieldSouthfield, 28 May: 3.5 µg/m³Southfield, 29 May: 7.0 µg/m³Southfield, 30 May: 6.7 µg/m³Southfield, 31 May: 6.5 µg/m³Southfield, 1 June: 4.4 µg/m³Southfield, 2 June: 6.4 µg/m³Southfield, 3 June: 16.0 µg/m³Southfield, 4 June: 20.0 µg/m³Southfield, 5 June: 48.7 µg/m³, 9.4× its usual 5.2Southfield, 6 June: 56.1 µg/m³, 11× its usual 5.3Southfield, 7 June: 20.7 µg/m³Southfield, 8 June: 38.5 µg/m³, 7.3× its usual 5.3Southfield, 9 June: 24.1 µg/m³Southfield, 10 June: 13.5 µg/m³Southfield, 11 June: 23.8 µg/m³Southfield, 12 June: 24.0 µg/m³YpsilantiYpsilanti, 28 May: 4.2 µg/m³Ypsilanti, 29 May: 6.1 µg/m³Ypsilanti, 30 May: 6.1 µg/m³Ypsilanti, 31 May: 7.2 µg/m³Ypsilanti, 1 June: 4.5 µg/m³Ypsilanti, 2 June: 6.7 µg/m³Ypsilanti, 3 June: 15.5 µg/m³Ypsilanti, 4 June: 14.9 µg/m³Ypsilanti, 5 June: 39.6 µg/m³, 6.0× its usual 6.6Ypsilanti, 6 June: 56.0 µg/m³, 8.5× its usual 6.6Ypsilanti, 7 June: 26.4 µg/m³, 4.1× its usual 6.5Ypsilanti, 8 June: 37.8 µg/m³, 5.8× its usual 6.5Ypsilanti, 9 June: 20.8 µg/m³Ypsilanti, 10 June: 12.8 µg/m³Ypsilanti, 11 June: 19.3 µg/m³Ypsilanti, 12 June: 23.9 µg/m³BellevilleBelleville, 28 May: 6.0 µg/m³Belleville, 29 May: 4.3 µg/m³Belleville, 30 May: 8.5 µg/m³Belleville, 31 May: 3.9 µg/m³Belleville, 1 June: 1.7 µg/m³Belleville, 2 June: 3.5 µg/m³Belleville, 3 June: 5.8 µg/m³Belleville, 4 June: 17.4 µg/m³Belleville, 5 June: 21.4 µg/m³Belleville, 6 June: 79.5 µg/m³, 14× its usual 5.5Belleville, 7 June: 47.4 µg/m³, 8.6× its usual 5.5Belleville, 8 June: 34.0 µg/m³, 6.2× its usual 5.5Belleville, 9 June: 9.5 µg/m³Belleville, 10 June: 6.6 µg/m³Belleville, 11 June: 15.3 µg/m³Belleville, 12 June: 18.8 µg/m³Sept-ÎlesSept-Îles, 28 May: 7.9 µg/m³Sept-Îles, 29 May: 8.3 µg/m³Sept-Îles, 30 May: 9.8 µg/m³Sept-Îles, 31 May: 5.9 µg/m³Sept-Îles, 1 June: 4.5 µg/m³Sept-Îles, 2 June: 5.6 µg/m³Sept-Îles, 3 June: 2.3 µg/m³Sept-Îles, 4 June: 4.9 µg/m³Sept-Îles, 5 June: 8.5 µg/m³Sept-Îles, 6 June: 78.0 µg/m³, 16× its usual 3.5Sept-Îles, 7 June: 37.2 µg/m³, 7.4× its usual 3.6Sept-Îles, 8 June: 5.3 µg/m³Sept-Îles, 9 June: 10.6 µg/m³Sept-Îles, 10 June: 13.7 µg/m³Sept-Îles, 11 June: 4.6 µg/m³Sept-Îles, 12 June: 4.8 µg/m³Labrador CityLabrador City, 28 May: 7.3 µg/m³Labrador City, 29 May: 11.4 µg/m³Labrador City, 30 May: 21.3 µg/m³Labrador City, 31 May: 2.6 µg/m³Labrador City, 1 June: 1.1 µg/m³Labrador City, 2 June: 1.5 µg/m³Labrador City, 3 June: 3.0 µg/m³Labrador City, 4 June: 11.9 µg/m³Labrador City, 5 June: 55.5 µg/m³Labrador City, 6 June: 71.0 µg/m³, 14× its usual 4.0Labrador City, 7 June: 13.1 µg/m³Labrador City, 8 June: 8.3 µg/m³Labrador City, 9 June: 27.9 µg/m³Labrador City, 10 June: 19.7 µg/m³Labrador City, 11 June: 8.7 µg/m³Labrador City, 12 June: 2.8 µg/m³DorvalDorval, 28 May: 6.2 µg/m³Dorval, 29 May: 5.5 µg/m³Dorval, 30 May: 5.3 µg/m³Dorval, 31 May: 5.9 µg/m³Dorval, 1 June: 1.5 µg/m³Dorval, 2 June: 2.9 µg/m³Dorval, 3 June: 5.6 µg/m³Dorval, 4 June: 16.8 µg/m³Dorval, 5 June: 17.9 µg/m³Dorval, 6 June: 68.9 µg/m³, 11× its usual 6.2Dorval, 7 June: 52.7 µg/m³, 8.5× its usual 6.2Dorval, 8 June: 25.5 µg/m³, 4.2× its usual 6.1Dorval, 9 June: 27.7 µg/m³, 4.5× its usual 6.1Dorval, 10 June: 8.2 µg/m³Dorval, 11 June: 15.0 µg/m³Dorval, 12 June: 15.4 µg/m³MontréalMontréal, 28 May: 8.0 µg/m³Montréal, 29 May: 6.3 µg/m³Montréal, 30 May: 6.0 µg/m³Montréal, 31 May: 6.3 µg/m³Montréal, 1 June: 1.9 µg/m³Montréal, 2 June: 3.6 µg/m³Montréal, 3 June: 6.1 µg/m³Montréal, 4 June: 17.2 µg/m³Montréal, 5 June: 18.7 µg/m³Montréal, 6 June: 68.1 µg/m³, 11× its usual 6.3Montréal, 7 June: 52.1 µg/m³, 8.3× its usual 6.3Montréal, 8 June: 23.9 µg/m³Montréal, 9 June: 26.7 µg/m³, 4.2× its usual 6.3Montréal, 10 June: 8.0 µg/m³Montréal, 11 June: 15.2 µg/m³Montréal, 12 June: 16.0 µg/m³BrantfordBrantford, 28 May: 4.6 µg/m³Brantford, 29 May: 6.0 µg/m³Brantford, 30 May: 7.8 µg/m³Brantford, 31 May: 9.4 µg/m³Brantford, 1 June: 2.6 µg/m³Brantford, 2 June: 3.9 µg/m³Brantford, 3 June: 9.1 µg/m³Brantford, 4 June: 18.6 µg/m³Brantford, 5 June: 17.3 µg/m³Brantford, 6 June: 67.5 µg/m³, 8.3× its usual 8.1Brantford, 7 June: 28.8 µg/m³, 3.6× its usual 8.0Brantford, 8 June: 39.7 µg/m³, 4.7× its usual 8.4Brantford, 9 June: 20.4 µg/m³Brantford, 10 June: 8.6 µg/m³Brantford, 11 June: 19.5 µg/m³Brantford, 12 June: 21.6 µg/m³OakvilleOakville, 28 May: 6.8 µg/m³Oakville, 29 May: 5.5 µg/m³Oakville, 30 May: 8.0 µg/m³Oakville, 31 May: 5.7 µg/m³Oakville, 1 June: 2.7 µg/m³Oakville, 2 June: 3.9 µg/m³Oakville, 3 June: 9.0 µg/m³Oakville, 4 June: 18.5 µg/m³Oakville, 5 June: 19.2 µg/m³Oakville, 6 June: 63.8 µg/m³, 10× its usual 6.1Oakville, 7 June: 29.3 µg/m³, 4.9× its usual 6.0Oakville, 8 June: 36.9 µg/m³, 6.1× its usual 6.0Oakville, 9 June: 21.2 µg/m³Oakville, 10 June: 8.8 µg/m³Oakville, 11 June: 19.7 µg/m³Oakville, 12 June: 16.7 µg/m³LondonLondon, 28 May: 3.2 µg/m³London, 29 May: 7.7 µg/m³London, 30 May: 8.3 µg/m³London, 31 May: 5.6 µg/m³London, 1 June: 3.1 µg/m³London, 2 June: 5.9 µg/m³London, 3 June: no readingLondon, 4 June: 18.2 µg/m³London, 5 June: 20.3 µg/m³London, 6 June: 63.4 µg/m³, 9.1× its usual 7.0London, 7 June: 29.0 µg/m³, 4.1× its usual 7.0London, 8 June: 37.1 µg/m³, 5.3× its usual 7.0London, 9 June: 18.1 µg/m³London, 10 June: 10.2 µg/m³London, 11 June: 21.0 µg/m³London, 12 June: 20.8 µg/m³QuébecQuébec, 28 May: 7.8 µg/m³Québec, 29 May: 8.0 µg/m³Québec, 30 May: 6.3 µg/m³Québec, 31 May: 4.7 µg/m³Québec, 1 June: 1.6 µg/m³Québec, 2 June: 3.3 µg/m³Québec, 3 June: 5.8 µg/m³Québec, 4 June: 13.8 µg/m³Québec, 5 June: 19.7 µg/m³Québec, 6 June: 60.6 µg/m³, 11× its usual 5.4Québec, 7 June: 47.9 µg/m³, 8.9× its usual 5.4Québec, 8 June: 11.8 µg/m³Québec, 9 June: 13.1 µg/m³Québec, 10 June: 12.5 µg/m³Québec, 11 June: 12.4 µg/m³Québec, 12 June: 9.6 µg/m³Rivière-des-Prairie…Rivière-des-Prairies–Pointe-aux-Trembles, 28 May: 8.4 µg/m³Rivière-des-Prairies–Pointe-aux-Trembles, 29 May: 6.2 µg/m³Rivière-des-Prairies–Pointe-aux-Trembles, 30 May: 5.4 µg/m³Rivière-des-Prairies–Pointe-aux-Trembles, 31 May: 5.3 µg/m³Rivière-des-Prairies–Pointe-aux-Trembles, 1 June: 1.6 µg/m³Rivière-des-Prairies–Pointe-aux-Trembles, 2 June: 3.4 µg/m³Rivière-des-Prairies–Pointe-aux-Trembles, 3 June: 5.8 µg/m³Rivière-des-Prairies–Pointe-aux-Trembles, 4 June: 15.4 µg/m³Rivière-des-Prairies–Pointe-aux-Trembles, 5 June: 16.4 µg/m³Rivière-des-Prairies–Pointe-aux-Trembles, 6 June: 60.6 µg/m³, 11× its usual 5.7Rivière-des-Prairies–Pointe-aux-Trembles, 7 June: 43.5 µg/m³, 7.8× its usual 5.6Rivière-des-Prairies–Pointe-aux-Trembles, 8 June: 19.9 µg/m³Rivière-des-Prairies–Pointe-aux-Trembles, 9 June: 23.4 µg/m³Rivière-des-Prairies–Pointe-aux-Trembles, 10 June: 7.6 µg/m³Rivière-des-Prairies–Pointe-aux-Trembles, 11 June: 13.9 µg/m³Rivière-des-Prairies–Pointe-aux-Trembles, 12 June: 13.7 µg/m³KingstonKingston, 28 May: 6.9 µg/m³Kingston, 29 May: 3.5 µg/m³Kingston, 30 May: 8.8 µg/m³Kingston, 31 May: 4.0 µg/m³Kingston, 1 June: 1.3 µg/m³Kingston, 2 June: 3.3 µg/m³Kingston, 3 June: 5.0 µg/m³Kingston, 4 June: 13.5 µg/m³Kingston, 5 June: 14.0 µg/m³Kingston, 6 June: 59.5 µg/m³, 11× its usual 5.3Kingston, 7 June: 45.4 µg/m³, 8.4× its usual 5.4Kingston, 8 June: 30.3 µg/m³, 5.7× its usual 5.3Kingston, 9 June: 9.4 µg/m³Kingston, 10 June: 6.0 µg/m³Kingston, 11 June: 14.9 µg/m³Kingston, 12 June: 18.9 µg/m³HamiltonHamilton, 28 May: 10.7 µg/m³Hamilton, 29 May: 5.6 µg/m³Hamilton, 30 May: 8.5 µg/m³Hamilton, 31 May: 5.6 µg/m³Hamilton, 1 June: 2.8 µg/m³Hamilton, 2 June: 3.9 µg/m³Hamilton, 3 June: 8.6 µg/m³Hamilton, 4 June: 19.4 µg/m³Hamilton, 5 June: 17.1 µg/m³Hamilton, 6 June: 59.1 µg/m³, 7.2× its usual 8.2Hamilton, 7 June: 32.9 µg/m³, 4.0× its usual 8.2Hamilton, 8 June: 40.8 µg/m³, 5.1× its usual 8.0Hamilton, 9 June: 21.7 µg/m³Hamilton, 10 June: 8.3 µg/m³Hamilton, 11 June: 19.1 µg/m³Hamilton, 12 June: 20.4 µg/m³Sorel-TracySorel-Tracy, 28 May: 10.1 µg/m³Sorel-Tracy, 29 May: 7.1 µg/m³Sorel-Tracy, 30 May: 5.1 µg/m³Sorel-Tracy, 31 May: 5.7 µg/m³Sorel-Tracy, 1 June: 13.2 µg/m³Sorel-Tracy, 2 June: 5.4 µg/m³Sorel-Tracy, 3 June: 5.9 µg/m³Sorel-Tracy, 4 June: 14.7 µg/m³Sorel-Tracy, 5 June: 23.8 µg/m³Sorel-Tracy, 6 June: 58.9 µg/m³, 8.4× its usual 7.0Sorel-Tracy, 7 June: 40.3 µg/m³, 5.8× its usual 7.0Sorel-Tracy, 8 June: 13.0 µg/m³Sorel-Tracy, 9 June: 17.8 µg/m³Sorel-Tracy, 10 June: 8.2 µg/m³Sorel-Tracy, 11 June: 14.5 µg/m³Sorel-Tracy, 12 June: 15.3 µg/m³ShawiniganShawinigan, 28 May: 6.2 µg/m³Shawinigan, 29 May: 6.8 µg/m³Shawinigan, 30 May: 5.1 µg/m³Shawinigan, 31 May: 5.8 µg/m³Shawinigan, 1 June: 1.0 µg/m³Shawinigan, 2 June: 3.1 µg/m³Shawinigan, 3 June: 5.7 µg/m³Shawinigan, 4 June: 13.9 µg/m³Shawinigan, 5 June: 19.2 µg/m³Shawinigan, 6 June: 57.1 µg/m³, 9.5× its usual 6.0Shawinigan, 7 June: 37.5 µg/m³, 6.3× its usual 6.0Shawinigan, 8 June: 8.7 µg/m³Shawinigan, 9 June: 16.8 µg/m³Shawinigan, 10 June: 9.4 µg/m³Shawinigan, 11 June: 11.6 µg/m³Shawinigan, 12 June: 8.8 µg/m³MississaugaMississauga, 28 May: 4.8 µg/m³Mississauga, 29 May: 5.2 µg/m³Mississauga, 30 May: 7.3 µg/m³Mississauga, 31 May: 5.0 µg/m³Mississauga, 1 June: 2.2 µg/m³Mississauga, 2 June: 3.5 µg/m³Mississauga, 3 June: 8.6 µg/m³Mississauga, 4 June: 16.5 µg/m³Mississauga, 5 June: 20.0 µg/m³Mississauga, 6 June: 56.4 µg/m³, 10× its usual 5.5Mississauga, 7 June: 27.2 µg/m³, 4.9× its usual 5.5Mississauga, 8 June: 33.9 µg/m³, 6.2× its usual 5.5Mississauga, 9 June: 21.3 µg/m³Mississauga, 10 June: 8.5 µg/m³Mississauga, 11 June: 18.6 µg/m³Mississauga, 12 June: 15.8 µg/m³Trois-RivièresTrois-Rivières, 28 May: 7.9 µg/m³Trois-Rivières, 29 May: no readingTrois-Rivières, 30 May: no readingTrois-Rivières, 31 May: 6.8 µg/m³Trois-Rivières, 1 June: 1.9 µg/m³Trois-Rivières, 2 June: 4.2 µg/m³Trois-Rivières, 3 June: 8.2 µg/m³Trois-Rivières, 4 June: 14.4 µg/m³Trois-Rivières, 5 June: 19.0 µg/m³Trois-Rivières, 6 June: 56.3 µg/m³, 9.1× its usual 6.2Trois-Rivières, 7 June: 41.9 µg/m³, 6.8× its usual 6.2Trois-Rivières, 8 June: 14.9 µg/m³Trois-Rivières, 9 June: 20.7 µg/m³Trois-Rivières, 10 June: 8.5 µg/m³Trois-Rivières, 11 June: 14.7 µg/m³Trois-Rivières, 12 June: 12.3 µg/m³28 May301 Jun357911
The 60 cities with the highest readings of 247, 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
DuluthMinnesota, United States2 96.03 June4.719×
Detroit LakesMinnesota, United States3 105.02 June6.018×
BlaineMinnesota, United States2 90.53 June5.217×
OttawaOntario, Canada3 89.66 June5.516×
SuperiorWisconsin, United States2 88.73 June5.516×
West FargoNorth Dakota, United States3 113.01 June7.116×
NepeanOntario, Canada5 116.06 June7.416×
Sept-ÎlesQuebec, Canada2 78.06 June3.516×
CloquetMinnesota, United States1 75.83 June4.215×
MankatoMinnesota, United States1 85.03 June5.715×
Saint MichaelMinnesota, United States1 81.23 June5.615×
BellevilleOntario, Canada3 79.56 June5.515×
OconomowocWisconsin, United States5 71.94 June4.514×
Labrador CityNewfoundland and Labrador, Canada1 71.06 June4.014×
MinneapolisMinnesota, United States2 90.23 June6.414×
ShakopeeMinnesota, United States1 84.23 June6.014×
Apple ValleyMinnesota, United States2 78.33 June5.714×
Saint PaulMinnesota, United States2 80.93 June6.113×
VirginiaMinnesota, United States3 65.73 June4.713×
BurnsvilleMinnesota, United States1 79.73 June6.413×
MarshallMinnesota, United States3 70.11 June5.613×
CornwallOntario, Canada4 70.36 June5.712×
PeterboroughOntario, Canada4 66.26 June5.412×
L'Ancienne-LoretteQuebec, Canada3 73.36 June6.112×
AltoonaWisconsin, United States2 63.23 June5.512×
Eau ClaireWisconsin, United States2 63.23 June5.512×
QuébecQuebec, Canada2 60.66 June5.411×
KingstonOntario, Canada3 59.56 June5.311×
DorvalQuebec, Canada4 68.96 June6.211×
Green BayWisconsin, United States2 60.84 June5.511×
ManisteeMichigan, United States3 55.04 June3.711×
AppletonWisconsin, United States2 59.04 June5.411×
MontréalQuebec, Canada3 68.16 June6.311×
SaguenayQuebec, Canada3 66.96 June6.211×
MiltonOntario, Canada4 62.86 June5.911×
Rivière-des-Prairies–Pointe-aux-TremblesQuebec, Canada2 60.66 June5.711×
SouthfieldMichigan, United States3 56.16 June5.311×
OakvilleOntario, Canada3 63.86 June6.111×
MississaugaOntario, Canada3 56.46 June5.510×
Sault Ste. MarieOntario, Canada4 54.57 June5.410×
GuelphOntario, Canada3 54.96 June5.510×
Saint CloudMinnesota, United States1 54.73 June5.59.9×
TorontoOntario, Canada4 67.96 June6.99.8×
BramptonOntario, Canada4 54.66 June5.69.8×
LincolnwoodIllinois, United States5 59.75 June6.29.6×
ShawiniganQuebec, Canada2 57.16 June6.09.5×
BécancourQuebec, Canada2 54.06 June5.79.5×
BrookingsSouth Dakota, United States3 60.41 June6.59.3×
BrainerdMinnesota, United States2 46.33 June4.79.3×
EdmundstonNew Brunswick, Canada2 46.37 June5.09.3×
EastpointeMichigan, United States3 52.66 June5.79.2×
LondonOntario, Canada3 63.46 June7.09.1×
Trois-RivièresQuebec, Canada2 56.36 June6.29.1×
SarniaOntario, Canada5 57.65 June6.49.0×
BrossardQuebec, Canada2 55.16 June6.19.0×
MadisonWisconsin, United States3 49.74 June5.59.0×
Rouyn-NorandaQuebec, Canada3 49.45 June5.59.0×
Elmwood ParkIllinois, United States5 70.65 June7.98.9×
RochesterMinnesota, United States3 61.93 June7.08.8×
Michigan CityIndiana, United States4 53.45 June6.18.8×
ElginIllinois, United States3 47.45 June5.48.8×
BarabooWisconsin, United States2 44.14 June4.78.8×
Cedar RapidsIowa, United States5 43.84 June4.98.8×
Presque IsleMaine, United States2 43.86 June4.58.8×
NewmarketOntario, Canada4 53.76 June6.28.7×
KitchenerOntario, Canada3 63.96 June7.48.6×
Port HuronMichigan, United States5 53.95 June6.38.6×
WaterdownOntario, Canada3 49.76 June5.88.6×
YpsilantiMichigan, United States4 56.06 June6.68.5×
AuroraIllinois, United States3 45.35 June5.38.5×
WarrenvilleIllinois, United States3 45.35 June5.38.5×
Saint-Jean-sur-RichelieuQuebec, Canada2 42.56 June4.88.5×
Sorel-TracyQuebec, Canada2 58.96 June7.08.4×
BrantfordOntario, Canada3 67.56 June8.18.3×
WindsorOntario, Canada4 61.36 June7.58.2×
WatertownSouth Dakota, United States2 61.21 June7.58.2×
Sioux FallsSouth Dakota, United States1 41.21 June3.88.2×
TomahWisconsin, United States3 42.24 June5.38.0×
DoltonIllinois, United States4 60.15 June7.67.9×
TaylorMichigan, United States3 53.66 June6.87.9×
Winthrop HarborIllinois, United States3 44.24 June5.67.9×
ZionIllinois, United States3 44.24 June5.67.9×
GranbyQuebec, Canada3 44.06 June5.67.9×
Des PlainesIllinois, United States5 55.55 June7.17.8×
ChicagoIllinois, United States4 58.45 June7.67.7×
HammondIndiana, United States5 58.35 June7.67.7×
Lincoln ParkMichigan, United States3 56.86 June7.57.6×
TecumsehMichigan, United States4 54.56 June7.27.6×
BraidwoodIllinois, United States3 46.55 June6.17.6×
RochesterNew York, United States2 45.87 June6.07.6×
ChathamOntario, Canada3 45.56 June6.07.6×
East ChicagoIndiana, United States3 54.45 June7.37.5×
Parry SoundOntario, Canada4 41.45 June5.57.5×
AllistonOntario, Canada4 37.36 June4.47.5×
MarquetteMichigan, United States1 36.94 June3.77.4×
Franklin ParkIllinois, United States4 59.55 June8.17.3×
Greater SudburyOntario, Canada3 43.57 June6.07.3×
HamiltonOntario, Canada3 59.16 June8.27.2×
New BaltimoreMichigan, United States3 46.35 June6.47.2×
SyracuseNew York, United States2 37.58 June5.27.2×
BridgeviewIllinois, United States4 53.35 June7.57.1×
Calumet CityIllinois, United States4 54.15 June7.77.0×
St. ThomasOntario, Canada3 47.66 June6.96.9×
NorthbrookIllinois, United States3 46.65 June6.96.8×
BloomingtonIllinois, United States3 42.45 June6.26.8×
North BayOntario, Canada2 36.27 June5.36.8×
SherbrookeQuebec, Canada1 34.07 June4.56.8×
Oak LawnIllinois, United States3 48.95 June7.36.7×
DrummondvilleQuebec, Canada2 38.96 June5.86.7×
DearbornMichigan, United States4 56.06 June8.56.6×
CaryIllinois, United States3 45.25 June6.96.6×
DetroitMichigan, United States3 55.06 June8.46.5×
LansingMichigan, United States3 43.95 June6.86.5×
NapervilleIllinois, United States3 50.35 June7.86.4×
JolietIllinois, United States3 47.95 June7.56.4×
GreendaleWisconsin, United States3 40.55 June6.36.4×
South MilwaukeeWisconsin, United States3 40.55 June6.36.4×
OregonOhio, United States5 49.26 June7.86.3×
Iowa CityIowa, United States5 40.54 June6.46.3×
LynnMassachusetts, United States1 33.98 June5.46.3×
HartfordVermont, United States1 31.58 June5.06.3×
HaverhillMassachusetts, United States1 31.48 June5.06.3×
AltoonaPennsylvania, United States2 34.68 June5.66.2×
QuincyMassachusetts, United States1 31.78 June5.16.2×
MilwaukeeWisconsin, United States4 45.65 June7.56.1×
MaumeeOhio, United States4 45.56 June7.46.1×
PerrysburgOhio, United States4 45.56 June7.46.1×
PortageIndiana, United States3 44.05 June7.26.1×
PeoriaIllinois, United States3 43.05 June7.06.1×
YoungstownOhio, United States1 42.97 June7.06.1×
HudsonvilleMichigan, United States3 40.45 June6.66.1×
JenisonMichigan, United States3 40.45 June6.66.1×
WaukeshaWisconsin, United States4 38.64 June6.36.1×
HermitagePennsylvania, United States1 37.67 June6.26.1×
KalamazooMichigan, United States4 47.46 June7.96.0×
Grand RapidsMichigan, United States3 45.45 June7.66.0×
St. CatharinesOntario, Canada3 39.06 June6.56.0×
LowellMassachusetts, United States1 33.58 June5.66.0×
UticaNew York, United States1 29.68 June4.55.9×
Beaver FallsPennsylvania, United States4 45.67 June7.95.8×
BostonMassachusetts, United States2 34.18 June5.95.8×
MolineIllinois, United States3 32.16 June5.55.8×
RutlandVermont, United States2 31.28 June5.45.8×
ToledoOhio, United States4 44.16 June7.75.7×
PortsmouthNew Hampshire, United States1 32.58 June5.75.7×
ChampaignIllinois, United States2 31.36 June5.55.7×
PierreSouth Dakota, United States1 28.331 May3.85.7×
FraminghamMassachusetts, United States2 28.38 June4.45.7×
WarrenOhio, United States1 46.77 June8.45.6×
GaryIndiana, United States3 46.05 June8.25.6×
PortsmouthOhio, United States2 40.64 June7.35.6×
WheelersburgOhio, United States2 40.64 June7.35.6×
DerryNew Hampshire, United States1 28.18 June4.85.6×
LondonderryNew Hampshire, United States1 28.18 June4.85.6×
PainesvilleOhio, United States2 33.07 June6.15.4×
RedfordMichigan, United States3 51.06 June9.75.3×
South BendIndiana, United States3 37.47 June7.15.3×
Warrensville HeightsOhio, United States1 33.57 June6.35.3×
AlbanyNew York, United States2 33.18 June6.35.3×
DavenportIowa, United States3 32.36 June6.15.3×
WeirtonWest Virginia, United States2 32.27 June6.15.3×
WorcesterMassachusetts, United States2 28.88 June5.45.3×
North ChicopeeMassachusetts, United States1 26.48 June4.85.3×
BrookfieldIllinois, United States1 34.05 June6.65.2×
PortlandMaine, United States2 29.88 June5.75.2×
GreenfieldMassachusetts, United States2 27.08 June5.25.2×
KeeneNew Hampshire, United States1 26.68 June5.15.2×
BarrieOntario, Canada4 38.06 June7.55.1×
AkronOhio, United States1 37.47 June7.45.1×
HollandMichigan, United States3 37.05 June7.35.1×
SpringfieldIllinois, United States2 36.46 June7.25.1×
Fort WayneIndiana, United States2 33.77 June6.65.1×
New BrightonPennsylvania, United States2 33.37 June6.55.1×
EriePennsylvania, United States2 32.87 June6.45.1×
BlairNebraska, United States2 27.51 June5.45.1×
North AdamsMassachusetts, United States1 27.28 June5.35.1×
GahannaOhio, United States3 26.57 June5.25.1×
New AlbanyOhio, United States3 26.57 June5.25.1×
MilfordMassachusetts, United States1 25.49 June4.35.1×
UxbridgeMassachusetts, United States1 25.49 June4.35.1×
CantonOhio, United States1 43.47 June8.75.0×
Wood RiverIllinois, United States1 30.67 June6.15.0×
State CollegePennsylvania, United States2 30.18 June6.05.0×
BenningtonVermont, United States1 25.28 June4.65.0×
WareMassachusetts, United States1 25.08 June4.65.0×
AberdeenSouth Dakota, United States1 25.08 June3.65.0×
Bay CityMichigan, United States3 34.25 June7.04.9×
TopekaKansas, United States1 33.04 June6.84.9×
RockfordIllinois, United States4 32.65 June6.74.9×
MedinaOhio, United States1 31.87 June6.54.9×
Upper AltonIllinois, United States1 31.57 June6.44.9×
MuncieIndiana, United States2 29.17 June6.04.9×
Cleveland HeightsOhio, United States1 28.27 June5.84.9×
FlatwoodsKentucky, United States1 34.44 June7.24.8×
OlatheKansas, United States1 32.14 June6.74.8×
HuntingtonWest Virginia, United States1 31.34 June6.54.8×
AugustaMaine, United States1 25.88 June5.44.8×
UniontownPennsylvania, United States1 25.65 June5.34.8×
LafayetteIndiana, United States1 32.27 June6.94.7×
JerseyvilleIllinois, United States1 29.87 June6.44.7×
ClintonIowa, United States3 29.66 June6.34.7×
WestervilleOhio, United States3 34.67 June7.54.6×
BuffaloNew York, United States2 34.48 June7.54.6×
LincolnNebraska, United States1 25.41 June5.54.6×
SavoyIllinois, United States1 27.86 June6.24.5×
ColumbusOhio, United States4 33.54 June7.64.4×
DecaturIllinois, United States2 31.66 June7.24.4×
Weirton HeightsWest Virginia, United States2 28.18 June6.44.4×
Natrona HeightsPennsylvania, United States2 26.28 June5.94.4×
WaterlooIowa, United States2 32.84 June7.64.3×
DerbyKansas, United States1 30.04 June7.04.3×
HaysvilleKansas, United States1 30.04 June7.04.3×
DublinOhio, United States3 29.77 June6.94.3×
OmahaNebraska, United States1 26.81 June6.34.3×
Columbia CityIndiana, United States3 29.66 June7.14.2×
Kansas CityKansas, United States1 30.14 June7.34.1×
WilkinsburgPennsylvania, United States1 28.95 June7.04.1×
MuscatineIowa, United States1 26.06 June6.44.1×
ColumbiaMissouri, United States1 25.98 June6.34.1×
SpringfieldMassachusetts, United States1 25.58 June6.24.1×
SteubenvilleOhio, United States4 33.57 June8.34.0×
PittsburghPennsylvania, United States3 30.08 June7.54.0×
AshlandKentucky, United States1 29.94 June7.44.0×
KokomoIndiana, United States1 27.97 June7.04.0×
AndersonIndiana, United States1 25.37 June6.34.0×
Des MoinesIowa, United States3 28.27 June7.23.9×
WyomingMichigan, United States3 38.25 June10.13.8×
WichitaKansas, United States1 29.24 June7.63.8×
LimaOhio, United States2 32.27 June8.83.7×
Kennedy TownshipPennsylvania, United States2 30.28 June8.23.7×
East Saint LouisIllinois, United States1 28.87 June8.13.6×
ScrantonPennsylvania, United States1 25.68 June7.23.6×
ClevelandOhio, United States4 31.97 June9.23.5×
WheelingWest Virginia, United States2 28.84 June8.33.5×
FlintMichigan, United States3 30.78 June9.13.4×
MoundsvilleWest Virginia, United States2 26.25 June7.83.4×
AnkenyIowa, United States2 26.37 June8.03.3×
DaytonOhio, United States1 26.24 June7.93.3×
SpringfieldOhio, United States2 26.07 June8.03.3×
ElkhartIndiana, United States1 25.26 June7.63.3×
Granite CityIllinois, United States1 28.37 June8.83.2×
CincinnatiOhio, United States1 25.34 June8.03.2×
LouisvilleKentucky, United States1 25.04 June7.73.2×
West MifflinPennsylvania, United States3 29.45 June9.63.1×
NorwoodOhio, United States1 26.44 June8.53.1×
MiddletownOhio, United States1 28.14 June9.43.0×
St. LouisMissouri, United States1 26.27 June9.92.6×

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 6 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, May and June 2025: 247 cities with PM2.5 at twice their usual or more, 31 May to 9 June 2025, smogrank.com/episodes/2025-05-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.