SmogRank / Episodes / United States

North-eastern United States and Canada, 12 to 16 July 2025

For 5 days, from 12 to 16 July 2025, 119 cities in the United States and Canada had PM2.5 at least twice their usual for the time of year. The worst reading was Superior, Wisconsin, United States: 117.0 µg/m³ on 12 July, about 12× its usual 10.0.

No cause namedWe have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached119in 2 countries
Days512 to 16 July 2025
Worst day14 July97 cities counted
Furthest above usual12×Duluth

Day by day

14 July 97 cities at twice their usual or more
St. ThomasErieHermitageMedinaYoungstownOregonCantonPerrysburgLimaAltoonaHollandState CollegeSyracuseUticaScrantonAllentownOak LawnBethlehemRandolphAlbanyNewburghPatersonNew CityLindenElizabethBayonneJersey CityFort LeeNew York CityPittsfieldWhite PlainsRutlandDanburyWaterburyBridgeportGreenfieldNew HavenNorth ChicopeeHolbrookSpringfieldHartfordPeoriaKeeneClintonMolineNew LondonDavenportWorcesterLaconiaCoventryMilfordDerryFraminghamLowellMuscatineProvidencePawtucketLexingtonHaverhillBostonFall RiverQuincyLynnBrocktonIowa CityPortsmouthCedar RapidsSaguenayPortlandLewistonWaterlooAugustaBangorDes MoinesBellevueOmahaLa VistaSaint JohnSioux FallsLincolnMonctonAberdeenGrand IslandDartmouthCharlottetownWyomingWarrenElginAnkenyKalamazooAuroraJenisonNapervilleBridgeviewClevelandAkronNorthbrookFort WayneShaker HeightsBuffaloSouth BendGrand RapidsCalumet CityCleveland HeightsRockfordGaryMichigan CityJolietFranklin ParkPortageChicagoDoltonAnn ArborRochesterElkhartElmwood ParkToledoNepeanBay CityCaryFort DodgeBrookfieldRedfordPainesvilleDes PlainesHammondWatertownLansingEast ChicagoHamiltonDearbornTaylorPort HuronDetroitBrossardLincoln ParkChathamRochesterOconomowocYpsilantiEdmundstonSarniaSouthfieldFrederictonSherbrookeSorel-TracyWindsorZionGranbyMilwaukeeMadisonDrummondvilleL'Ancienne-LoretteRivière-des-Prairies–Pointe-aux-TremblesOttawaShawiniganGuelphBrantfordKitchenerSaint-Jean-sur-RichelieuEastpointeCornwallMontréalLondonBrookingsSouth MilwaukeeTrois-RivièresQuébecMiramichiWaukeshaBarrieDorvalKingstonSt. CatharinesRouyn-NorandaMiltonMankatoAllistonEau ClaireNewmarketBramptonSault Ste. MarieGreater SudburyNorth BayWaterdownSaint PaulAppletonGreen BayOakvilleMinneapolisMarquetteShakopeeMississaugaSaint MichaelTorontoPeterboroughSaint CloudApple ValleyBellevilleBlaineBurnsvilleWest FargoSuperiorDuluth
9 Jul10111213141516171819
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

SuperiorSuperior, 9 July: 7.7 µg/m³Superior, 10 July: 7.9 µg/m³Superior, 11 July: 25.4 µg/m³Superior, 12 July: 117.0 µg/m³, 12× its usual 10.0Superior, 13 July: 63.5 µg/m³, 6.4× its usual 10.0Superior, 14 July: 50.1 µg/m³, 4.9× its usual 10.2Superior, 15 July: 22.5 µg/m³Superior, 16 July: 5.4 µg/m³Superior, 17 July: 9.0 µg/m³Superior, 18 July: 8.3 µg/m³Superior, 19 July: 5.9 µg/m³DuluthDuluth, 9 July: 6.8 µg/m³Duluth, 10 July: 6.9 µg/m³Duluth, 11 July: 23.8 µg/m³Duluth, 12 July: 112.0 µg/m³, 12× its usual 9.3Duluth, 13 July: 56.2 µg/m³, 5.9× its usual 9.5Duluth, 14 July: 47.9 µg/m³, 4.9× its usual 9.7Duluth, 15 July: 19.4 µg/m³Duluth, 16 July: 4.4 µg/m³Duluth, 17 July: 7.2 µg/m³Duluth, 18 July: 7.8 µg/m³Duluth, 19 July: 5.1 µg/m³West FargoWest Fargo, 9 July: 10.0 µg/m³West Fargo, 10 July: 4.3 µg/m³West Fargo, 11 July: 73.2 µg/m³West Fargo, 12 July: 93.2 µg/m³, 10× its usual 9.3West Fargo, 13 July: 27.6 µg/m³, 2.9× its usual 9.4West Fargo, 14 July: 20.0 µg/m³West Fargo, 15 July: 31.6 µg/m³West Fargo, 16 July: 5.3 µg/m³West Fargo, 17 July: 3.5 µg/m³West Fargo, 18 July: 2.8 µg/m³West Fargo, 19 July: 8.5 µg/m³BurnsvilleBurnsville, 9 July: 7.3 µg/m³Burnsville, 10 July: 5.0 µg/m³Burnsville, 11 July: 10.1 µg/m³Burnsville, 12 July: 88.3 µg/m³, 9.8× its usual 9.0Burnsville, 13 July: 56.6 µg/m³, 6.2× its usual 9.1Burnsville, 14 July: 32.1 µg/m³, 3.5× its usual 9.3Burnsville, 15 July: 14.3 µg/m³Burnsville, 16 July: 2.7 µg/m³Burnsville, 17 July: 3.7 µg/m³Burnsville, 18 July: 5.0 µg/m³Burnsville, 19 July: 6.7 µg/m³MinneapolisMinneapolis, 9 July: 8.2 µg/m³Minneapolis, 10 July: 6.1 µg/m³Minneapolis, 11 July: 14.7 µg/m³Minneapolis, 12 July: 81.5 µg/m³, 8.4× its usual 9.7Minneapolis, 13 July: 54.2 µg/m³, 5.5× its usual 9.8Minneapolis, 14 July: 26.1 µg/m³, 2.6× its usual 10.0Minneapolis, 15 July: 13.4 µg/m³Minneapolis, 16 July: 3.4 µg/m³Minneapolis, 17 July: 3.9 µg/m³Minneapolis, 18 July: 6.0 µg/m³Minneapolis, 19 July: 7.0 µg/m³BlaineBlaine, 9 July: 6.2 µg/m³Blaine, 10 July: 5.4 µg/m³Blaine, 11 July: 16.7 µg/m³Blaine, 12 July: 78.8 µg/m³, 9.6× its usual 8.2Blaine, 13 July: 53.3 µg/m³, 6.6× its usual 8.1Blaine, 14 July: 24.3 µg/m³Blaine, 15 July: 10.8 µg/m³Blaine, 16 July: 2.6 µg/m³Blaine, 17 July: 3.2 µg/m³Blaine, 18 July: 4.7 µg/m³Blaine, 19 July: 5.3 µg/m³ShakopeeShakopee, 9 July: 8.0 µg/m³Shakopee, 10 July: 5.5 µg/m³Shakopee, 11 July: 13.3 µg/m³Shakopee, 12 July: 77.7 µg/m³, 8.5× its usual 9.1Shakopee, 13 July: 48.2 µg/m³, 5.2× its usual 9.2Shakopee, 14 July: 26.7 µg/m³, 2.9× its usual 9.3Shakopee, 15 July: 12.0 µg/m³Shakopee, 16 July: 2.8 µg/m³Shakopee, 17 July: 3.2 µg/m³Shakopee, 18 July: 4.7 µg/m³Shakopee, 19 July: 6.8 µg/m³Saint PaulSaint Paul, 9 July: no readingSaint Paul, 10 July: no readingSaint Paul, 11 July: 10.1 µg/m³Saint Paul, 12 July: 75.2 µg/m³, 7.7× its usual 9.8Saint Paul, 13 July: 54.4 µg/m³, 5.5× its usual 9.9Saint Paul, 14 July: 25.1 µg/m³, 2.5× its usual 9.9Saint Paul, 15 July: 13.6 µg/m³Saint Paul, 16 July: 2.5 µg/m³Saint Paul, 17 July: 2.8 µg/m³Saint Paul, 18 July: 4.3 µg/m³Saint Paul, 19 July: 6.3 µg/m³Apple ValleyApple Valley, 9 July: 7.7 µg/m³Apple Valley, 10 July: 5.4 µg/m³Apple Valley, 11 July: 9.6 µg/m³Apple Valley, 12 July: 74.3 µg/m³, 9.2× its usual 8.1Apple Valley, 13 July: 46.9 µg/m³, 5.8× its usual 8.1Apple Valley, 14 July: 27.5 µg/m³, 3.4× its usual 8.1Apple Valley, 15 July: 12.3 µg/m³Apple Valley, 16 July: 3.6 µg/m³Apple Valley, 17 July: 3.8 µg/m³Apple Valley, 18 July: 5.3 µg/m³Apple Valley, 19 July: 6.6 µg/m³Saint CloudSaint Cloud, 9 July: 6.6 µg/m³Saint Cloud, 10 July: 5.3 µg/m³Saint Cloud, 11 July: 36.1 µg/m³Saint Cloud, 12 July: 73.4 µg/m³, 9.1× its usual 8.1Saint Cloud, 13 July: 43.5 µg/m³, 5.4× its usual 8.1Saint Cloud, 14 July: 20.6 µg/m³Saint Cloud, 15 July: 9.6 µg/m³Saint Cloud, 16 July: 4.4 µg/m³Saint Cloud, 17 July: 3.0 µg/m³Saint Cloud, 18 July: 4.1 µg/m³Saint Cloud, 19 July: 4.4 µg/m³Saint MichaelSaint Michael, 9 July: 7.0 µg/m³Saint Michael, 10 July: 4.8 µg/m³Saint Michael, 11 July: 18.6 µg/m³Saint Michael, 12 July: 72.9 µg/m³, 8.6× its usual 8.5Saint Michael, 13 July: 45.3 µg/m³, 5.3× its usual 8.5Saint Michael, 14 July: 21.4 µg/m³Saint Michael, 15 July: 9.8 µg/m³Saint Michael, 16 July: 2.3 µg/m³Saint Michael, 17 July: 2.9 µg/m³Saint Michael, 18 July: 4.3 µg/m³Saint Michael, 19 July: 5.3 µg/m³MankatoMankato, 9 July: 10.0 µg/m³Mankato, 10 July: 4.7 µg/m³Mankato, 11 July: 14.6 µg/m³Mankato, 12 July: 62.5 µg/m³, 6.6× its usual 9.5Mankato, 13 July: 45.4 µg/m³, 4.7× its usual 9.6Mankato, 14 July: 45.2 µg/m³, 4.7× its usual 9.7Mankato, 15 July: 18.4 µg/m³Mankato, 16 July: 5.1 µg/m³Mankato, 17 July: 4.3 µg/m³Mankato, 18 July: 8.0 µg/m³Mankato, 19 July: 7.9 µg/m³Eau ClaireEau Claire, 9 July: 7.2 µg/m³Eau Claire, 10 July: 7.3 µg/m³Eau Claire, 11 July: 5.8 µg/m³Eau Claire, 12 July: 46.0 µg/m³, 5.5× its usual 8.4Eau Claire, 13 July: 57.9 µg/m³, 6.9× its usual 8.4Eau Claire, 14 July: 28.4 µg/m³, 3.3× its usual 8.6Eau Claire, 15 July: 18.5 µg/m³Eau Claire, 16 July: 3.8 µg/m³Eau Claire, 17 July: 2.6 µg/m³Eau Claire, 18 July: 3.6 µg/m³Eau Claire, 19 July: 5.0 µg/m³RochesterRochester, 9 July: 8.6 µg/m³Rochester, 10 July: 6.7 µg/m³Rochester, 11 July: 6.6 µg/m³Rochester, 12 July: 41.1 µg/m³, 4.2× its usual 9.8Rochester, 13 July: 37.7 µg/m³, 3.8× its usual 9.9Rochester, 14 July: 28.7 µg/m³, 2.8× its usual 10.1Rochester, 15 July: 22.0 µg/m³Rochester, 16 July: 8.0 µg/m³Rochester, 17 July: 2.9 µg/m³Rochester, 18 July: 6.4 µg/m³Rochester, 19 July: 7.1 µg/m³MarquetteMarquette, 9 July: 6.5 µg/m³Marquette, 10 July: 6.1 µg/m³Marquette, 11 July: 8.8 µg/m³Marquette, 12 July: 37.0 µg/m³Marquette, 13 July: 76.0 µg/m³, 8.5× its usual 8.9Marquette, 14 July: 33.1 µg/m³, 3.7× its usual 9.0Marquette, 15 July: 18.1 µg/m³Marquette, 16 July: 2.1 µg/m³Marquette, 17 July: 2.9 µg/m³Marquette, 18 July: 3.7 µg/m³Marquette, 19 July: 4.4 µg/m³Green BayGreen Bay, 9 July: 8.2 µg/m³Green Bay, 10 July: 8.6 µg/m³Green Bay, 11 July: 7.4 µg/m³Green Bay, 12 July: 22.1 µg/m³Green Bay, 13 July: 73.5 µg/m³, 8.0× its usual 9.2Green Bay, 14 July: 37.6 µg/m³, 4.0× its usual 9.4Green Bay, 15 July: 17.2 µg/m³Green Bay, 16 July: 9.6 µg/m³Green Bay, 17 July: 1.9 µg/m³Green Bay, 18 July: 3.6 µg/m³Green Bay, 19 July: 5.8 µg/m³AppletonAppleton, 9 July: 8.0 µg/m³Appleton, 10 July: 7.7 µg/m³Appleton, 11 July: 6.5 µg/m³Appleton, 12 July: 20.7 µg/m³Appleton, 13 July: 66.4 µg/m³, 7.9× its usual 8.4Appleton, 14 July: 31.6 µg/m³, 3.7× its usual 8.5Appleton, 15 July: 15.5 µg/m³Appleton, 16 July: 7.0 µg/m³Appleton, 17 July: 1.8 µg/m³Appleton, 18 July: 3.0 µg/m³Appleton, 19 July: 4.7 µg/m³NewmarketNewmarket, 9 July: 10.4 µg/m³Newmarket, 10 July: 10.4 µg/m³Newmarket, 11 July: 13.8 µg/m³Newmarket, 12 July: 11.3 µg/m³Newmarket, 13 July: 29.3 µg/m³, 3.4× its usual 8.7Newmarket, 14 July: 64.0 µg/m³, 7.0× its usual 9.2Newmarket, 15 July: 35.0 µg/m³, 3.8× its usual 9.3Newmarket, 16 July: 31.1 µg/m³, 3.3× its usual 9.3Newmarket, 17 July: 5.5 µg/m³Newmarket, 18 July: 4.5 µg/m³Newmarket, 19 July: 5.6 µg/m³Greater SudburyGreater Sudbury, 9 July: 8.6 µg/m³Greater Sudbury, 10 July: 8.0 µg/m³Greater Sudbury, 11 July: 8.5 µg/m³Greater Sudbury, 12 July: 10.2 µg/m³Greater Sudbury, 13 July: 41.5 µg/m³, 5.0× its usual 8.3Greater Sudbury, 14 July: 63.4 µg/m³, 7.6× its usual 8.3Greater Sudbury, 15 July: 33.0 µg/m³, 4.0× its usual 8.3Greater Sudbury, 16 July: 18.6 µg/m³Greater Sudbury, 17 July: 1.7 µg/m³Greater Sudbury, 18 July: 17.6 µg/m³Greater Sudbury, 19 July: 5.8 µg/m³North BayNorth Bay, 9 July: 7.8 µg/m³North Bay, 10 July: 8.1 µg/m³North Bay, 11 July: 8.6 µg/m³North Bay, 12 July: 7.7 µg/m³North Bay, 13 July: 25.9 µg/m³, 3.2× its usual 8.0North Bay, 14 July: 62.0 µg/m³, 7.7× its usual 8.1North Bay, 15 July: 40.0 µg/m³, 5.0× its usual 8.0North Bay, 16 July: 19.8 µg/m³North Bay, 17 July: 1.9 µg/m³North Bay, 18 July: 15.3 µg/m³North Bay, 19 July: 6.7 µg/m³Sault Ste. MarieSault Ste. Marie, 9 July: 8.1 µg/m³Sault Ste. Marie, 10 July: 8.0 µg/m³Sault Ste. Marie, 11 July: 9.0 µg/m³Sault Ste. Marie, 12 July: 6.2 µg/m³Sault Ste. Marie, 13 July: 61.3 µg/m³, 7.1× its usual 8.6Sault Ste. Marie, 14 July: 48.8 µg/m³, 5.7× its usual 8.6Sault Ste. Marie, 15 July: 25.3 µg/m³, 2.9× its usual 8.8Sault Ste. Marie, 16 July: 14.4 µg/m³Sault Ste. Marie, 17 July: 1.8 µg/m³Sault Ste. Marie, 18 July: 6.8 µg/m³Sault Ste. Marie, 19 July: 4.5 µg/m³OconomowocOconomowoc, 9 July: 15.9 µg/m³Oconomowoc, 10 July: 14.3 µg/m³Oconomowoc, 11 July: 8.0 µg/m³Oconomowoc, 12 July: 13.4 µg/m³Oconomowoc, 13 July: 59.2 µg/m³, 4.2× its usual 14.1Oconomowoc, 14 July: 37.2 µg/m³, 2.6× its usual 14.4Oconomowoc, 15 July: 24.9 µg/m³Oconomowoc, 16 July: 17.1 µg/m³Oconomowoc, 17 July: 2.2 µg/m³Oconomowoc, 18 July: 5.2 µg/m³Oconomowoc, 19 July: 9.3 µg/m³BarrieBarrie, 9 July: 10.5 µg/m³Barrie, 10 July: 10.4 µg/m³Barrie, 11 July: 11.3 µg/m³Barrie, 12 July: 9.7 µg/m³Barrie, 13 July: 34.5 µg/m³, 3.6× its usual 9.5Barrie, 14 July: 56.8 µg/m³, 5.9× its usual 9.6Barrie, 15 July: 31.7 µg/m³, 3.2× its usual 9.9Barrie, 16 July: 27.0 µg/m³, 2.7× its usual 10.0Barrie, 17 July: 5.8 µg/m³Barrie, 18 July: 8.2 µg/m³Barrie, 19 July: 6.2 µg/m³Rouyn-NorandaRouyn-Noranda, 9 July: 5.9 µg/m³Rouyn-Noranda, 10 July: 5.9 µg/m³Rouyn-Noranda, 11 July: 8.1 µg/m³Rouyn-Noranda, 12 July: 9.3 µg/m³Rouyn-Noranda, 13 July: 55.5 µg/m³, 6.5× its usual 8.6Rouyn-Noranda, 14 July: 48.7 µg/m³, 5.5× its usual 8.8Rouyn-Noranda, 15 July: 18.3 µg/m³Rouyn-Noranda, 16 July: 4.3 µg/m³Rouyn-Noranda, 17 July: 2.7 µg/m³Rouyn-Noranda, 18 July: 31.4 µg/m³Rouyn-Noranda, 19 July: 15.9 µg/m³AllistonAlliston, 9 July: 9.0 µg/m³Alliston, 10 July: 8.1 µg/m³Alliston, 11 July: 10.0 µg/m³Alliston, 12 July: 7.6 µg/m³Alliston, 13 July: 31.3 µg/m³, 4.0× its usual 7.8Alliston, 14 July: 52.8 µg/m³, 6.8× its usual 7.8Alliston, 15 July: 28.4 µg/m³, 3.6× its usual 7.8Alliston, 16 July: 24.3 µg/m³Alliston, 17 July: 4.5 µg/m³Alliston, 18 July: 5.0 µg/m³Alliston, 19 July: 5.0 µg/m³WaukeshaWaukesha, 9 July: 10.1 µg/m³Waukesha, 10 July: 9.7 µg/m³Waukesha, 11 July: 5.4 µg/m³Waukesha, 12 July: 8.9 µg/m³Waukesha, 13 July: 47.2 µg/m³, 5.5× its usual 8.6Waukesha, 14 July: 28.1 µg/m³, 3.2× its usual 8.7Waukesha, 15 July: 16.5 µg/m³Waukesha, 16 July: 10.3 µg/m³Waukesha, 17 July: 3.1 µg/m³Waukesha, 18 July: 4.4 µg/m³Waukesha, 19 July: 5.4 µg/m³MilwaukeeMilwaukee, 9 July: 11.2 µg/m³Milwaukee, 10 July: 9.3 µg/m³Milwaukee, 11 July: 7.8 µg/m³Milwaukee, 12 July: 8.8 µg/m³Milwaukee, 13 July: 46.9 µg/m³, 4.7× its usual 9.9Milwaukee, 14 July: 27.5 µg/m³, 2.8× its usual 10.0Milwaukee, 15 July: 20.2 µg/m³Milwaukee, 16 July: 10.6 µg/m³Milwaukee, 17 July: 3.2 µg/m³Milwaukee, 18 July: 4.9 µg/m³Milwaukee, 19 July: 7.1 µg/m³South MilwaukeeSouth Milwaukee, 9 July: 9.3 µg/m³South Milwaukee, 10 July: 7.9 µg/m³South Milwaukee, 11 July: 5.8 µg/m³South Milwaukee, 12 July: 6.9 µg/m³South Milwaukee, 13 July: 42.7 µg/m³, 5.4× its usual 7.9South Milwaukee, 14 July: 25.9 µg/m³, 3.2× its usual 8.0South Milwaukee, 15 July: 17.8 µg/m³South Milwaukee, 16 July: 8.6 µg/m³South Milwaukee, 17 July: 2.7 µg/m³South Milwaukee, 18 July: 4.1 µg/m³South Milwaukee, 19 July: 5.6 µg/m³TorontoToronto, 9 July: 11.3 µg/m³Toronto, 10 July: 11.7 µg/m³Toronto, 11 July: 14.0 µg/m³Toronto, 12 July: 9.0 µg/m³Toronto, 13 July: 20.7 µg/m³Toronto, 14 July: 78.8 µg/m³, 8.7× its usual 9.1Toronto, 15 July: 37.5 µg/m³, 4.0× its usual 9.3Toronto, 16 July: 30.6 µg/m³, 3.2× its usual 9.6Toronto, 17 July: 5.4 µg/m³Toronto, 18 July: 3.9 µg/m³Toronto, 19 July: 6.7 µg/m³OakvilleOakville, 9 July: 10.0 µg/m³Oakville, 10 July: 8.8 µg/m³Oakville, 11 July: 13.0 µg/m³Oakville, 12 July: 8.9 µg/m³Oakville, 13 July: 13.8 µg/m³Oakville, 14 July: 74.2 µg/m³, 8.3× its usual 8.9Oakville, 15 July: 36.2 µg/m³, 4.0× its usual 9.0Oakville, 16 July: 28.3 µg/m³, 3.1× its usual 9.1Oakville, 17 July: 4.3 µg/m³Oakville, 18 July: 3.2 µg/m³Oakville, 19 July: 4.8 µg/m³BellevilleBelleville, 9 July: 8.0 µg/m³Belleville, 10 July: 10.5 µg/m³Belleville, 11 July: 10.3 µg/m³Belleville, 12 July: 9.2 µg/m³Belleville, 13 July: 6.0 µg/m³Belleville, 14 July: 68.5 µg/m³, 9.4× its usual 7.3Belleville, 15 July: 41.9 µg/m³, 5.6× its usual 7.5Belleville, 16 July: 27.1 µg/m³, 3.6× its usual 7.6Belleville, 17 July: 3.8 µg/m³Belleville, 18 July: 2.8 µg/m³Belleville, 19 July: 4.0 µg/m³PeterboroughPeterborough, 9 July: 9.5 µg/m³Peterborough, 10 July: 11.0 µg/m³Peterborough, 11 July: 9.7 µg/m³Peterborough, 12 July: 8.2 µg/m³Peterborough, 13 July: 17.7 µg/m³Peterborough, 14 July: 68.3 µg/m³, 8.9× its usual 7.7Peterborough, 15 July: 29.2 µg/m³, 3.7× its usual 7.8Peterborough, 16 July: 27.8 µg/m³, 3.5× its usual 7.9Peterborough, 17 July: 5.6 µg/m³Peterborough, 18 July: 3.0 µg/m³Peterborough, 19 July: 4.3 µg/m³MississaugaMississauga, 9 July: 8.9 µg/m³Mississauga, 10 July: 7.9 µg/m³Mississauga, 11 July: 11.7 µg/m³Mississauga, 12 July: 7.4 µg/m³Mississauga, 13 July: 13.4 µg/m³Mississauga, 14 July: 68.2 µg/m³, 8.6× its usual 7.9Mississauga, 15 July: 32.8 µg/m³, 4.1× its usual 8.0Mississauga, 16 July: 25.4 µg/m³, 3.2× its usual 8.0Mississauga, 17 July: 3.7 µg/m³Mississauga, 18 July: 3.0 µg/m³Mississauga, 19 July: 4.8 µg/m³WaterdownWaterdown, 9 July: 9.8 µg/m³Waterdown, 10 July: 6.8 µg/m³Waterdown, 11 July: 12.0 µg/m³Waterdown, 12 July: 7.5 µg/m³Waterdown, 13 July: 11.0 µg/m³Waterdown, 14 July: 67.0 µg/m³, 7.7× its usual 8.7Waterdown, 15 July: 36.0 µg/m³, 4.1× its usual 8.8Waterdown, 16 July: 27.1 µg/m³, 3.0× its usual 8.9Waterdown, 17 July: 3.7 µg/m³Waterdown, 18 July: 3.2 µg/m³Waterdown, 19 July: 4.4 µg/m³MiltonMilton, 9 July: 10.3 µg/m³Milton, 10 July: 10.4 µg/m³Milton, 11 July: 13.1 µg/m³Milton, 12 July: 10.1 µg/m³Milton, 13 July: 17.2 µg/m³Milton, 14 July: 62.3 µg/m³, 6.6× its usual 9.4Milton, 15 July: 37.5 µg/m³, 3.9× its usual 9.6Milton, 16 July: 29.0 µg/m³, 2.9× its usual 9.9Milton, 17 July: 4.9 µg/m³Milton, 18 July: 4.0 µg/m³Milton, 19 July: 6.5 µg/m³BramptonBrampton, 9 July: 9.3 µg/m³Brampton, 10 July: 9.8 µg/m³Brampton, 11 July: 11.8 µg/m³Brampton, 12 July: 9.0 µg/m³Brampton, 13 July: 17.5 µg/m³Brampton, 14 July: 57.3 µg/m³, 7.1× its usual 8.1Brampton, 15 July: 33.4 µg/m³, 4.0× its usual 8.3Brampton, 16 July: 25.8 µg/m³, 3.1× its usual 8.3Brampton, 17 July: 4.7 µg/m³Brampton, 18 July: 3.6 µg/m³Brampton, 19 July: 5.3 µg/m³NepeanNepean, 9 July: 9.8 µg/m³Nepean, 10 July: 17.7 µg/m³Nepean, 11 July: 21.0 µg/m³Nepean, 12 July: 27.3 µg/m³Nepean, 13 July: 16.9 µg/m³Nepean, 14 July: 56.2 µg/m³, 3.6× its usual 15.4Nepean, 15 July: 55.6 µg/m³, 3.7× its usual 15.0Nepean, 16 July: 43.2 µg/m³, 2.8× its usual 15.4Nepean, 17 July: 13.7 µg/m³Nepean, 18 July: 3.9 µg/m³Nepean, 19 July: 13.9 µg/m³L'Ancienne-LoretteL'Ancienne-Lorette, 9 July: 8.0 µg/m³L'Ancienne-Lorette, 10 July: no readingL'Ancienne-Lorette, 11 July: 9.6 µg/m³L'Ancienne-Lorette, 12 July: 11.6 µg/m³L'Ancienne-Lorette, 13 July: 10.0 µg/m³L'Ancienne-Lorette, 14 July: 25.9 µg/m³, 2.5× its usual 10.5L'Ancienne-Lorette, 15 July: 50.9 µg/m³, 4.8× its usual 10.6L'Ancienne-Lorette, 16 July: 34.5 µg/m³, 3.3× its usual 10.6L'Ancienne-Lorette, 17 July: 12.0 µg/m³L'Ancienne-Lorette, 18 July: 3.9 µg/m³L'Ancienne-Lorette, 19 July: 15.9 µg/m³St. CatharinesSt. Catharines, 9 July: 10.2 µg/m³St. Catharines, 10 July: 11.2 µg/m³St. Catharines, 11 July: 11.1 µg/m³St. Catharines, 12 July: 7.8 µg/m³St. Catharines, 13 July: 6.3 µg/m³St. Catharines, 14 July: 49.1 µg/m³, 6.1× its usual 8.0St. Catharines, 15 July: 28.6 µg/m³, 3.5× its usual 8.1St. Catharines, 16 July: 23.5 µg/m³St. Catharines, 17 July: 3.8 µg/m³St. Catharines, 18 July: 2.7 µg/m³St. Catharines, 19 July: 5.0 µg/m³KingstonKingston, 9 July: 5.8 µg/m³Kingston, 10 July: 10.3 µg/m³Kingston, 11 July: 9.4 µg/m³Kingston, 12 July: 10.4 µg/m³Kingston, 13 July: 7.4 µg/m³Kingston, 14 July: 47.8 µg/m³, 6.1× its usual 7.9Kingston, 15 July: 42.0 µg/m³, 5.3× its usual 8.0Kingston, 16 July: 25.5 µg/m³, 3.1× its usual 8.1Kingston, 17 July: 4.0 µg/m³Kingston, 18 July: 2.5 µg/m³Kingston, 19 July: 3.1 µg/m³DorvalDorval, 9 July: 10.2 µg/m³Dorval, 10 July: 12.2 µg/m³Dorval, 11 July: 12.9 µg/m³Dorval, 12 July: 14.0 µg/m³Dorval, 13 July: 7.1 µg/m³Dorval, 14 July: 36.7 µg/m³, 4.6× its usual 7.9Dorval, 15 July: 47.7 µg/m³, 6.0× its usual 8.0Dorval, 16 July: 29.8 µg/m³, 3.8× its usual 7.8Dorval, 17 July: 6.5 µg/m³Dorval, 18 July: 3.8 µg/m³Dorval, 19 July: 8.4 µg/m³WindsorWindsor, 9 July: 14.4 µg/m³Windsor, 10 July: 12.6 µg/m³Windsor, 11 July: 10.3 µg/m³Windsor, 12 July: 10.2 µg/m³Windsor, 13 July: 14.2 µg/m³Windsor, 14 July: 33.2 µg/m³, 3.3× its usual 10.0Windsor, 15 July: 46.9 µg/m³, 4.6× its usual 10.1Windsor, 16 July: 20.0 µg/m³Windsor, 17 July: 5.7 µg/m³Windsor, 18 July: 3.1 µg/m³Windsor, 19 July: 6.3 µg/m³LondonLondon, 9 July: 11.1 µg/m³London, 10 July: 11.6 µg/m³London, 11 July: 10.8 µg/m³London, 12 July: 7.7 µg/m³London, 13 July: 13.8 µg/m³London, 14 July: 46.4 µg/m³, 5.2× its usual 9.0London, 15 July: 35.1 µg/m³, 3.9× its usual 9.1London, 16 July: 22.8 µg/m³London, 17 July: 3.3 µg/m³London, 18 July: 3.4 µg/m³London, 19 July: 4.9 µg/m³KitchenerKitchener, 9 July: 9.3 µg/m³Kitchener, 10 July: 8.5 µg/m³Kitchener, 11 July: 10.8 µg/m³Kitchener, 12 July: 8.5 µg/m³Kitchener, 13 July: 18.8 µg/m³Kitchener, 14 July: 45.7 µg/m³, 4.9× its usual 9.3Kitchener, 15 July: 34.8 µg/m³, 3.7× its usual 9.5Kitchener, 16 July: 23.4 µg/m³Kitchener, 17 July: 4.3 µg/m³Kitchener, 18 July: 4.3 µg/m³Kitchener, 19 July: 6.3 µg/m³MontréalMontréal, 9 July: 12.3 µg/m³Montréal, 10 July: 11.6 µg/m³Montréal, 11 July: 13.1 µg/m³Montréal, 12 July: 13.8 µg/m³Montréal, 13 July: 7.1 µg/m³Montréal, 14 July: 34.3 µg/m³, 4.0× its usual 8.6Montréal, 15 July: 45.7 µg/m³, 5.2× its usual 8.8Montréal, 16 July: 29.4 µg/m³, 3.3× its usual 8.8Montréal, 17 July: 7.0 µg/m³Montréal, 18 July: 4.1 µg/m³Montréal, 19 July: 9.3 µg/m³BrantfordBrantford, 9 July: 9.8 µg/m³Brantford, 10 July: 9.3 µg/m³Brantford, 11 July: 12.1 µg/m³Brantford, 12 July: 8.8 µg/m³Brantford, 13 July: 8.8 µg/m³Brantford, 14 July: 45.5 µg/m³, 4.9× its usual 9.2Brantford, 15 July: 37.3 µg/m³, 4.0× its usual 9.3Brantford, 16 July: 24.8 µg/m³Brantford, 17 July: 4.2 µg/m³Brantford, 18 July: 4.1 µg/m³Brantford, 19 July: 5.5 µg/m³Ann ArborAnn Arbor, 9 July: no readingAnn Arbor, 10 July: 10.9 µg/m³Ann Arbor, 11 July: 14.8 µg/m³Ann Arbor, 12 July: 14.5 µg/m³Ann Arbor, 13 July: no readingAnn Arbor, 14 July: 38.3 µg/m³, 3.0× its usual 12.8Ann Arbor, 15 July: 45.5 µg/m³, 3.5× its usual 12.9Ann Arbor, 16 July: 20.4 µg/m³Ann Arbor, 17 July: 3.1 µg/m³Ann Arbor, 18 July: 2.1 µg/m³Ann Arbor, 19 July: 6.0 µg/m³Trois-RivièresTrois-Rivières, 9 July: 9.2 µg/m³Trois-Rivières, 10 July: 8.3 µg/m³Trois-Rivières, 11 July: 9.9 µg/m³Trois-Rivières, 12 July: 11.6 µg/m³Trois-Rivières, 13 July: 8.1 µg/m³Trois-Rivières, 14 July: 27.3 µg/m³, 3.2× its usual 8.5Trois-Rivières, 15 July: 45.3 µg/m³, 5.4× its usual 8.4Trois-Rivières, 16 July: 31.2 µg/m³, 3.7× its usual 8.5Trois-Rivières, 17 July: 10.0 µg/m³Trois-Rivières, 18 July: 3.9 µg/m³Trois-Rivières, 19 July: 11.9 µg/m³Sorel-TracySorel-Tracy, 9 July: 10.3 µg/m³Sorel-Tracy, 10 July: 9.5 µg/m³Sorel-Tracy, 11 July: 11.1 µg/m³Sorel-Tracy, 12 July: 12.7 µg/m³Sorel-Tracy, 13 July: 7.7 µg/m³Sorel-Tracy, 14 July: 32.3 µg/m³, 3.3× its usual 9.8Sorel-Tracy, 15 July: 44.6 µg/m³, 4.6× its usual 9.8Sorel-Tracy, 16 July: 31.0 µg/m³, 3.2× its usual 9.8Sorel-Tracy, 17 July: 10.0 µg/m³Sorel-Tracy, 18 July: 4.9 µg/m³Sorel-Tracy, 19 July: 12.3 µg/m³DearbornDearborn, 9 July: 13.8 µg/m³Dearborn, 10 July: 10.8 µg/m³Dearborn, 11 July: 11.0 µg/m³Dearborn, 12 July: 9.9 µg/m³Dearborn, 13 July: 12.1 µg/m³Dearborn, 14 July: 29.3 µg/m³, 2.6× its usual 11.1Dearborn, 15 July: 44.3 µg/m³, 3.9× its usual 11.3Dearborn, 16 July: 19.0 µg/m³Dearborn, 17 July: 4.8 µg/m³Dearborn, 18 July: 2.8 µg/m³Dearborn, 19 July: 6.3 µg/m³GuelphGuelph, 9 July: 9.0 µg/m³Guelph, 10 July: 8.5 µg/m³Guelph, 11 July: 10.5 µg/m³Guelph, 12 July: 8.5 µg/m³Guelph, 13 July: 17.8 µg/m³Guelph, 14 July: 44.0 µg/m³, 4.9× its usual 8.9Guelph, 15 July: 33.6 µg/m³, 3.8× its usual 8.9Guelph, 16 July: 23.9 µg/m³Guelph, 17 July: 4.4 µg/m³Guelph, 18 July: 3.8 µg/m³Guelph, 19 July: 5.0 µg/m³CornwallCornwall, 9 July: 7.0 µg/m³Cornwall, 10 July: 9.9 µg/m³Cornwall, 11 July: 11.3 µg/m³Cornwall, 12 July: 11.2 µg/m³Cornwall, 13 July: 6.8 µg/m³Cornwall, 14 July: 35.7 µg/m³, 4.3× its usual 8.4Cornwall, 15 July: 44.0 µg/m³, 5.1× its usual 8.7Cornwall, 16 July: 23.8 µg/m³Cornwall, 17 July: 5.1 µg/m³Cornwall, 18 July: 3.5 µg/m³Cornwall, 19 July: 5.9 µg/m³DetroitDetroit, 9 July: 12.0 µg/m³Detroit, 10 July: 10.8 µg/m³Detroit, 11 July: 11.1 µg/m³Detroit, 12 July: 9.9 µg/m³Detroit, 13 July: 12.0 µg/m³Detroit, 14 July: 29.9 µg/m³, 2.8× its usual 10.6Detroit, 15 July: 44.0 µg/m³, 4.0× its usual 10.9Detroit, 16 July: 19.0 µg/m³Detroit, 17 July: 4.8 µg/m³Detroit, 18 July: 3.2 µg/m³Detroit, 19 July: 6.3 µg/m³DoltonDolton, 9 July: 12.5 µg/m³Dolton, 10 July: 8.0 µg/m³Dolton, 11 July: 9.0 µg/m³Dolton, 12 July: 6.0 µg/m³Dolton, 13 July: 21.1 µg/m³Dolton, 14 July: 43.2 µg/m³, 3.5× its usual 12.4Dolton, 15 July: 24.7 µg/m³Dolton, 16 July: 9.5 µg/m³Dolton, 17 July: 2.9 µg/m³Dolton, 18 July: 7.9 µg/m³Dolton, 19 July: 7.0 µg/m³SouthfieldSouthfield, 9 July: 10.6 µg/m³Southfield, 10 July: 8.3 µg/m³Southfield, 11 July: 9.5 µg/m³Southfield, 12 July: 7.6 µg/m³Southfield, 13 July: 15.3 µg/m³Southfield, 14 July: 29.6 µg/m³, 3.2× its usual 9.3Southfield, 15 July: 41.8 µg/m³, 4.5× its usual 9.3Southfield, 16 July: 18.0 µg/m³Southfield, 17 July: 3.3 µg/m³Southfield, 18 July: 2.7 µg/m³Southfield, 19 July: 5.2 µg/m³GranbyGranby, 9 July: 7.6 µg/m³Granby, 10 July: 7.7 µg/m³Granby, 11 July: 8.8 µg/m³Granby, 12 July: 11.4 µg/m³Granby, 13 July: 7.3 µg/m³Granby, 14 July: 33.1 µg/m³, 3.8× its usual 8.8Granby, 15 July: 41.5 µg/m³, 4.7× its usual 8.8Granby, 16 July: 26.2 µg/m³, 3.0× its usual 8.8Granby, 17 July: 8.3 µg/m³Granby, 18 July: 3.9 µg/m³Granby, 19 July: 7.0 µg/m³OttawaOttawa, 9 July: 5.5 µg/m³Ottawa, 10 July: 7.7 µg/m³Ottawa, 11 July: 9.2 µg/m³Ottawa, 12 July: 11.4 µg/m³Ottawa, 13 July: 7.6 µg/m³Ottawa, 14 July: 40.9 µg/m³, 4.9× its usual 8.3Ottawa, 15 July: 37.4 µg/m³, 4.5× its usual 8.3Ottawa, 16 July: 26.2 µg/m³, 3.2× its usual 8.3Ottawa, 17 July: 7.4 µg/m³Ottawa, 18 July: 3.8 µg/m³Ottawa, 19 July: 8.7 µg/m³DrummondvilleDrummondville, 9 July: 7.5 µg/m³Drummondville, 10 July: 7.3 µg/m³Drummondville, 11 July: 7.7 µg/m³Drummondville, 12 July: 9.7 µg/m³Drummondville, 13 July: 6.2 µg/m³Drummondville, 14 July: 25.9 µg/m³, 3.1× its usual 8.4Drummondville, 15 July: 40.7 µg/m³, 4.8× its usual 8.4Drummondville, 16 July: 23.6 µg/m³Drummondville, 17 July: 7.0 µg/m³Drummondville, 18 July: 3.2 µg/m³Drummondville, 19 July: 7.4 µg/m³QuébecQuébec, 9 July: 6.8 µg/m³Québec, 10 July: 8.3 µg/m³Québec, 11 July: 8.6 µg/m³Québec, 12 July: 10.8 µg/m³Québec, 13 July: 9.3 µg/m³Québec, 14 July: 23.2 µg/m³Québec, 15 July: 48.7 µg/m³, 5.4× its usual 9.1Québec, 16 July: 33.0 µg/m³, 3.6× its usual 9.1Québec, 17 July: 10.6 µg/m³Québec, 18 July: 3.8 µg/m³Québec, 19 July: 14.7 µg/m³ShawiniganShawinigan, 9 July: 8.4 µg/m³Shawinigan, 10 July: 8.2 µg/m³Shawinigan, 11 July: 10.2 µg/m³Shawinigan, 12 July: 13.8 µg/m³Shawinigan, 13 July: 9.5 µg/m³Shawinigan, 14 July: 24.9 µg/m³Shawinigan, 15 July: 44.0 µg/m³, 4.9× its usual 9.0Shawinigan, 16 July: 33.1 µg/m³, 3.7× its usual 9.0Shawinigan, 17 July: 12.2 µg/m³Shawinigan, 18 July: 4.6 µg/m³Shawinigan, 19 July: 16.2 µg/m³9 Jul1113151719
The 60 cities with the highest readings of 119, 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 States3 112.012 July9.312×
SuperiorWisconsin, United States3 117.012 July10.012×
West FargoNorth Dakota, United States2 93.212 July9.310×
BurnsvilleMinnesota, United States3 88.312 July9.09.8×
BlaineMinnesota, United States2 78.812 July8.29.6×
BellevilleOntario, Canada3 68.514 July7.39.4×
Apple ValleyMinnesota, United States3 74.312 July8.19.2×
Saint CloudMinnesota, United States2 73.412 July8.19.1×
PeterboroughOntario, Canada3 68.314 July7.78.9×
TorontoOntario, Canada3 78.814 July9.18.7×
Saint MichaelMinnesota, United States2 72.912 July8.58.6×
MississaugaOntario, Canada3 68.214 July7.98.6×
ShakopeeMinnesota, United States3 77.712 July9.18.5×
MarquetteMichigan, United States2 76.013 July8.98.5×
MinneapolisMinnesota, United States3 81.512 July9.78.4×
OakvilleOntario, Canada3 74.214 July8.98.3×
Green BayWisconsin, United States2 73.513 July9.28.0×
AppletonWisconsin, United States2 66.413 July8.47.9×
Saint PaulMinnesota, United States3 75.212 July9.87.7×
WaterdownOntario, Canada3 67.014 July8.77.7×
North BayOntario, Canada3 62.014 July8.17.7×
Greater SudburyOntario, Canada3 63.414 July8.37.6×
Sault Ste. MarieOntario, Canada3 61.313 July8.67.1×
BramptonOntario, Canada3 57.314 July8.17.1×
NewmarketOntario, Canada4 64.014 July9.27.0×
Eau ClaireWisconsin, United States3 57.913 July8.46.9×
AllistonOntario, Canada3 52.814 July7.86.8×
MankatoMinnesota, United States3 62.512 July9.56.6×
MiltonOntario, Canada3 62.314 July9.46.6×
Rouyn-NorandaQuebec, Canada2 55.513 July8.66.5×
St. CatharinesOntario, Canada2 49.114 July8.06.1×
KingstonOntario, Canada3 47.814 July7.96.1×
DorvalQuebec, Canada3 47.715 July8.06.0×
BarrieOntario, Canada4 56.814 July9.65.9×
WaukeshaWisconsin, United States2 47.213 July8.65.5×
MiramichiNew Brunswick, Canada1 33.116 July6.05.5×
QuébecQuebec, Canada2 48.715 July9.15.4×
Trois-RivièresQuebec, Canada3 45.315 July8.45.4×
South MilwaukeeWisconsin, United States2 42.713 July7.95.4×
BrookingsSouth Dakota, United States1 32.612 July6.25.3×
LondonOntario, Canada2 46.414 July9.05.2×
MontréalQuebec, Canada3 45.715 July8.85.2×
CornwallOntario, Canada2 44.015 July8.75.1×
EastpointeMichigan, United States2 37.015 July7.45.0×
Saint-Jean-sur-RichelieuQuebec, Canada2 34.715 July7.05.0×
KitchenerOntario, Canada2 45.714 July9.34.9×
BrantfordOntario, Canada2 45.514 July9.24.9×
GuelphOntario, Canada2 44.014 July8.94.9×
ShawiniganQuebec, Canada2 44.015 July9.04.9×
OttawaOntario, Canada3 40.914 July8.34.9×
Rivière-des-Prairies–Pointe-aux-TremblesQuebec, Canada3 39.515 July8.14.9×
L'Ancienne-LoretteQuebec, Canada3 50.915 July10.64.8×
DrummondvilleQuebec, Canada2 40.715 July8.44.8×
MadisonWisconsin, United States1 37.413 July7.84.8×
MilwaukeeWisconsin, United States2 46.913 July9.94.7×
GranbyQuebec, Canada3 41.515 July8.84.7×
ZionIllinois, United States3 34.214 July7.34.7×
WindsorOntario, Canada2 46.915 July10.14.6×
Sorel-TracyQuebec, Canada3 44.615 July9.84.6×
SherbrookeQuebec, Canada1 36.515 July8.04.6×
FrederictonNew Brunswick, Canada1 26.116 July5.74.6×
SouthfieldMichigan, United States2 41.815 July9.34.5×
SarniaOntario, Canada2 40.614 July9.04.5×
EdmundstonNew Brunswick, Canada2 33.615 July7.54.5×
YpsilantiMichigan, United States2 38.915 July8.94.4×
OconomowocWisconsin, United States2 59.213 July14.14.2×
RochesterMinnesota, United States3 41.112 July9.84.2×
ChathamOntario, Canada2 30.314 July7.34.2×
Lincoln ParkMichigan, United States2 40.315 July9.84.1×
BrossardQuebec, Canada2 39.115 July9.54.1×
DetroitMichigan, United States2 44.015 July10.94.0×
Port HuronMichigan, United States2 40.314 July10.14.0×
TaylorMichigan, United States2 38.815 July9.84.0×
DearbornMichigan, United States2 44.315 July11.33.9×
HamiltonOntario, Canada3 36.414 July9.33.9×
East ChicagoIndiana, United States1 35.414 July9.03.9×
LansingMichigan, United States2 35.214 July9.13.9×
WatertownSouth Dakota, United States1 30.512 July7.83.9×
HammondIndiana, United States1 38.214 July10.03.8×
Des PlainesIllinois, United States3 35.814 July9.33.8×
PainesvilleOhio, United States1 25.615 July6.73.8×
RedfordMichigan, United States2 37.015 July10.13.7×
BrookfieldIllinois, United States1 34.814 July9.53.7×
Fort DodgeIowa, United States2 34.713 July9.33.7×
CaryIllinois, United States2 33.813 July9.23.7×
Bay CityMichigan, United States3 33.814 July9.13.7×
NepeanOntario, Canada3 56.214 July15.43.6×
ToledoOhio, United States2 40.515 July11.13.6×
Elmwood ParkIllinois, United States2 39.214 July10.93.6×
ElkhartIndiana, United States2 35.914 July10.03.6×
RochesterNew York, United States2 29.415 July8.13.6×
Ann ArborMichigan, United States2 45.515 July12.93.5×
DoltonIllinois, United States1 43.214 July12.43.5×
ChicagoIllinois, United States1 34.414 July9.73.5×
PortageIndiana, United States1 33.614 July9.73.5×
Franklin ParkIllinois, United States2 38.614 July11.43.4×
JolietIllinois, United States1 34.614 July10.23.4×
Michigan CityIndiana, United States2 34.014 July10.03.4×
GaryIndiana, United States1 33.914 July9.93.4×
RockfordIllinois, United States1 31.613 July9.33.4×
Cleveland HeightsOhio, United States1 28.415 July8.43.4×
Calumet CityIllinois, United States1 33.614 July10.23.3×
Grand RapidsMichigan, United States2 33.114 July10.03.3×
South BendIndiana, United States2 31.614 July9.63.3×
BuffaloNew York, United States1 30.815 July9.43.3×
Shaker HeightsOhio, United States1 26.715 July8.13.3×
Fort WayneIndiana, United States2 30.315 July9.83.1×
NorthbrookIllinois, United States1 29.414 July9.83.0×
AkronOhio, United States1 25.015 July8.43.0×
ClevelandOhio, United States1 32.915 July11.32.9×
BridgeviewIllinois, United States2 34.414 July12.12.8×
NapervilleIllinois, United States2 30.814 July11.02.8×
JenisonMichigan, United States1 27.014 July9.52.8×
AuroraIllinois, United States2 26.714 July9.72.8×
KalamazooMichigan, United States2 30.914 July11.32.7×
AnkenyIowa, United States1 25.013 July9.52.6×
ElginIllinois, United States2 30.013 July12.02.5×
WarrenOhio, United States1 25.915 July10.92.4×
WyomingMichigan, United States1 28.814 July12.42.3×

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 8 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, 12 to 16 July 2025: 119 cities with PM2.5 at twice their usual or more, 12 to 16 July 2025, smogrank.com/episodes/2025-07-12-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.