SmogRank / Episodes / United States

North-eastern United States and Canada, July 2025

For 4 days, from 24 to 27 July 2025, 90 cities in the United States and Canada had PM2.5 at least twice their usual for the time of year. The worst reading was Sorel-Tracy, Quebec, Canada: 88.4 µg/m³ on 26 July, about 8.8× its usual 10.1.

No cause namedWe have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached90in 2 countries
Days424 to 27 July 2025
Worst day26 July60 cities counted
Furthest above usual10×Marquette

Day by day

26 July 60 cities at twice their usual or more
Bay CityPort HuronSarniaSouthfieldEastpointeRedfordDearbornDetroitWindsorLincoln ParkTaylorAnn ArborYpsilantiLansingChathamToledoLondonSt. ThomasGrand RapidsWyomingJenisonKalamazooKitchenerClevelandCleveland HeightsHollandPainesvilleShaker HeightsGuelphMedinaBrantfordLimaFort WayneAkronElkhartMiltonAllistonWaterdownHamiltonBramptonSouth BendWarrenCantonOakvilleMississaugaErieWestervilleDublinYoungstownGahannaHermitageColumbusTorontoSpringfieldSt. CatharinesMichigan CityDaytonMuncieKokomoWeirtonSteubenvilleAndersonWeirton HeightsPortageMiddletownLebanonBuffaloGarySouth MilwaukeeMasonMilwaukeeEast ChicagoZionHammondFishersCalumet CityChicagoPittsburghNorthbrookDoltonWhite OakNorwoodWilkinsburgElmwood ParkCincinnatiDes PlainesOak LawnFranklin ParkFort ThomasWest MifflinBridgeviewLafayetteBrookfieldMcKeesportWaukeshaIndianapolisPeterboroughPortsmouthCaryOconomowocNapervilleElginJolietColumbusAuroraJohnstownBloomingtonRochesterBellevilleRockfordTerre HauteMadisonChampaignState CollegeBloomingtonKingstonDecaturPeoriaHagerstownClintonCarlisleSyracuseHarrisburgSpringfieldMolineAshburnDavenportYorkOttawaRockvilleSpringfieldScaggsvilleHunt ValleyLancasterWashingtonRose HillScrantonSouth LaurelMuscatineUticaBaltimoreOxon Hill-GlassmanorReadingEssexEdgewoodUpper AltonIowa CityAllentownCedar RapidsGranite CityEast Saint LouisBethlehemElktonSt. LouisNewarkUniversity CityBearWilmingtonChesterAbingtonWaterlooCamdenRochesterDoverSuperiorSouth VinelandToms RiverColumbiaAnkenyDes MoinesMankatoFort DodgeCoventryLibertyProvidencePawtucketKansas CityRaymoreSaint JosephKansas CityLeawoodOlatheBellevueOmahaLa VistaTopekaSioux FallsLincolnWatertownBangorAberdeenGrand IslandEdmundstonNepeanPhiladelphiaNewmarketElizabethTrentonJersey CityBensalemEwingShakopeeLebanonLindenRouyn-NorandaBarrieAppletonSaguenayNew BrunswickPennsaukenRandolphPatersonBridgeportNorristownNew York CityFort LeeNew LondonLexingtonNorth BayPortsmouthAtlantic CityGreen BayApple ValleyBostonPleasantvilleGreater SudburyBurnsvilleWest FargoLowellFraminghamSewellDerryLynnBrocktonNew HavenBrookingsCornwallHolbrookWorcesterHartfordHaverhillPortlandMilfordSaint MichaelSaint CloudAugustaQuincyFall RiverSaint PaulBayonneWaterburySault Ste. MarieMinneapolisAlbanyDanburyMarquetteEau ClairePittsfieldGreenfieldKeeneSpringfieldLewistonBlaineRutlandNewburghLaconiaL'Ancienne-LoretteNorth ChicopeeWhite PlainsNew CityQuébecDuluthBrossardShawiniganSorel-TracyRivière-des-Prairies–Pointe-aux-TremblesSaint-Jean-sur-RichelieuGranbyTrois-RivièresMontréalDrummondvilleSherbrookeDorval
21 Jul222324252627282930
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

Eau ClaireEau Claire, 21 July: 33.4 µg/m³, 3.8× usualEau Claire, 22 July: 12.3 µg/m³, 1.4× usualEau Claire, 23 July: 6.9 µg/m³, 0.8× usualEau Claire, 24 July: 5.2 µg/m³, 0.6× usualEau Claire, 25 July: 44.4 µg/m³, 5.0× usualEau Claire, 26 July: 9.4 µg/m³, 1.1× usualEau Claire, 27 July: 4.8 µg/m³, 0.5× usualEau Claire, 28 July: 5.6 µg/m³, 0.6× usualEau Claire, 29 July: 11.1 µg/m³, 1.2× usualEau Claire, 30 July: 59.2 µg/m³, 6.7× usualMinneapolisMinneapolis, 21 July: 25.6 µg/m³, 2.5× usualMinneapolis, 22 July: 13.1 µg/m³, 1.3× usualMinneapolis, 23 July: 7.4 µg/m³, 0.7× usualMinneapolis, 24 July: 15.8 µg/m³, 1.5× usualMinneapolis, 25 July: 49.3 µg/m³, 4.8× usualMinneapolis, 26 July: 8.8 µg/m³, 0.9× usualMinneapolis, 27 July: 5.6 µg/m³, 0.5× usualMinneapolis, 28 July: 7.2 µg/m³, 0.7× usualMinneapolis, 29 July: 9.5 µg/m³, 0.9× usualMinneapolis, 30 July: 54.0 µg/m³, 5.3× usualSaint PaulSaint Paul, 21 July: 26.2 µg/m³, 2.6× usualSaint Paul, 22 July: 11.2 µg/m³, 1.1× usualSaint Paul, 23 July: 6.6 µg/m³, 0.7× usualSaint Paul, 24 July: 13.8 µg/m³, 1.4× usualSaint Paul, 25 July: 47.7 µg/m³, 4.7× usualSaint Paul, 26 July: 10.1 µg/m³, 1.0× usualSaint Paul, 27 July: 5.2 µg/m³, 0.5× usualSaint Paul, 28 July: 6.1 µg/m³, 0.6× usualSaint Paul, 29 July: 9.2 µg/m³, 0.9× usualSaint Paul, 30 July: 53.3 µg/m³, 5.3× usualBlaineBlaine, 21 July: 25.5 µg/m³, 3.0× usualBlaine, 22 July: 10.4 µg/m³, 1.2× usualBlaine, 23 July: 6.1 µg/m³, 0.7× usualBlaine, 24 July: 16.6 µg/m³, 2.0× usualBlaine, 25 July: 47.3 µg/m³, 5.6× usualBlaine, 26 July: 9.0 µg/m³, 1.1× usualBlaine, 27 July: 5.2 µg/m³, 0.6× usualBlaine, 28 July: 6.4 µg/m³, 0.8× usualBlaine, 29 July: 8.4 µg/m³, 1.0× usualBlaine, 30 July: 49.7 µg/m³, 5.8× usualWest FargoWest Fargo, 21 July: 12.4 µg/m³, 1.3× usualWest Fargo, 22 July: 4.7 µg/m³, 0.5× usualWest Fargo, 23 July: 28.4 µg/m³, 2.9× usualWest Fargo, 24 July: 37.8 µg/m³, 3.9× usualWest Fargo, 25 July: 11.6 µg/m³, 1.2× usualWest Fargo, 26 July: no readingWest Fargo, 27 July: no readingWest Fargo, 28 July: no readingWest Fargo, 29 July: no readingWest Fargo, 30 July: 58.3 µg/m³, 6.0× usualDuluthDuluth, 21 July: 19.3 µg/m³, 2.0× usualDuluth, 22 July: 14.5 µg/m³, 1.5× usualDuluth, 23 July: 5.9 µg/m³, 0.6× usualDuluth, 24 July: 54.4 µg/m³, 5.7× usualDuluth, 25 July: 59.7 µg/m³, 6.3× usualDuluth, 26 July: 27.3 µg/m³, 2.9× usualDuluth, 27 July: 6.0 µg/m³, 0.6× usualDuluth, 28 July: 8.0 µg/m³, 0.8× usualDuluth, 29 July: 32.6 µg/m³, 3.4× usualDuluth, 30 July: 91.1 µg/m³, 9.6× usualSaint CloudSaint Cloud, 21 July: 16.9 µg/m³, 1.9× usualSaint Cloud, 22 July: 9.6 µg/m³, 1.1× usualSaint Cloud, 23 July: 4.0 µg/m³, 0.5× usualSaint Cloud, 24 July: 31.2 µg/m³, 3.5× usualSaint Cloud, 25 July: 38.4 µg/m³, 4.4× usualSaint Cloud, 26 July: 6.2 µg/m³, 0.7× usualSaint Cloud, 27 July: 4.9 µg/m³, 0.6× usualSaint Cloud, 28 July: 6.1 µg/m³, 0.7× usualSaint Cloud, 29 July: 9.8 µg/m³, 1.1× usualSaint Cloud, 30 July: 53.4 µg/m³, 6.1× usualMarquetteMarquette, 21 July: 6.9 µg/m³, 0.8× usualMarquette, 22 July: 9.7 µg/m³, 1.2× usualMarquette, 23 July: 13.3 µg/m³, 1.6× usualMarquette, 24 July: 16.5 µg/m³, 2.0× usualMarquette, 25 July: 39.0 µg/m³, 4.7× usualMarquette, 26 July: 40.7 µg/m³, 4.9× usualMarquette, 27 July: 8.6 µg/m³, 1.0× usualMarquette, 28 July: 11.0 µg/m³, 1.3× usualMarquette, 29 July: 42.7 µg/m³, 5.1× usualMarquette, 30 July: 112.0 µg/m³, 13× usualSorel-TracySorel-Tracy, 21 July: 2.8 µg/m³, 0.3× usualSorel-Tracy, 22 July: 4.8 µg/m³, 0.5× usualSorel-Tracy, 23 July: 6.0 µg/m³, 0.6× usualSorel-Tracy, 24 July: 11.3 µg/m³, 1.1× usualSorel-Tracy, 25 July: 46.0 µg/m³, 4.6× usualSorel-Tracy, 26 July: 88.4 µg/m³, 8.8× usualSorel-Tracy, 27 July: 33.5 µg/m³, 3.3× usualSorel-Tracy, 28 July: 25.1 µg/m³, 2.5× usualSorel-Tracy, 29 July: 16.9 µg/m³, 1.7× usualSorel-Tracy, 30 July: 31.5 µg/m³, 3.1× usualGreen BayGreen Bay, 21 July: 8.4 µg/m³, 0.9× usualGreen Bay, 22 July: 13.6 µg/m³, 1.4× usualGreen Bay, 23 July: 13.0 µg/m³, 1.3× usualGreen Bay, 24 July: 4.7 µg/m³, 0.5× usualGreen Bay, 25 July: 37.7 µg/m³, 3.8× usualGreen Bay, 26 July: 26.9 µg/m³, 2.7× usualGreen Bay, 27 July: 8.2 µg/m³, 0.8× usualGreen Bay, 28 July: 7.7 µg/m³, 0.8× usualGreen Bay, 29 July: 9.5 µg/m³, 1.0× usualGreen Bay, 30 July: 85.9 µg/m³, 8.8× usualMontréalMontréal, 21 July: 3.6 µg/m³, 0.4× usualMontréal, 22 July: 3.7 µg/m³, 0.4× usualMontréal, 23 July: 5.2 µg/m³, 0.6× usualMontréal, 24 July: 10.4 µg/m³, 1.2× usualMontréal, 25 July: 30.1 µg/m³, 3.6× usualMontréal, 26 July: 82.4 µg/m³, 9.8× usualMontréal, 27 July: 31.7 µg/m³, 3.8× usualMontréal, 28 July: 19.8 µg/m³, 2.4× usualMontréal, 29 July: 11.8 µg/m³, 1.4× usualMontréal, 30 July: 30.7 µg/m³, 3.7× usualGranbyGranby, 21 July: 4.4 µg/m³, 0.5× usualGranby, 22 July: 3.9 µg/m³, 0.4× usualGranby, 23 July: 4.4 µg/m³, 0.5× usualGranby, 24 July: 10.8 µg/m³, 1.2× usualGranby, 25 July: 37.1 µg/m³, 4.3× usualGranby, 26 July: 81.2 µg/m³, 9.3× usualGranby, 27 July: 31.2 µg/m³, 3.6× usualGranby, 28 July: 19.6 µg/m³, 2.3× usualGranby, 29 July: 13.6 µg/m³, 1.6× usualGranby, 30 July: 24.6 µg/m³, 2.8× usualDorvalDorval, 21 July: 3.9 µg/m³, 0.5× usualDorval, 22 July: 3.4 µg/m³, 0.4× usualDorval, 23 July: 4.5 µg/m³, 0.6× usualDorval, 24 July: 10.8 µg/m³, 1.4× usualDorval, 25 July: 28.9 µg/m³, 3.6× usualDorval, 26 July: 79.8 µg/m³, 10.0× usualDorval, 27 July: 33.2 µg/m³, 4.2× usualDorval, 28 July: 19.6 µg/m³, 2.5× usualDorval, 29 July: 12.7 µg/m³, 1.6× usualDorval, 30 July: 32.6 µg/m³, 4.1× usualAppletonAppleton, 21 July: 11.5 µg/m³, 1.3× usualAppleton, 22 July: 13.3 µg/m³, 1.5× usualAppleton, 23 July: 12.2 µg/m³, 1.4× usualAppleton, 24 July: 4.3 µg/m³, 0.5× usualAppleton, 25 July: 27.7 µg/m³, 3.1× usualAppleton, 26 July: 24.1 µg/m³, 2.7× usualAppleton, 27 July: 5.5 µg/m³, 0.6× usualAppleton, 28 July: 5.3 µg/m³, 0.6× usualAppleton, 29 July: 8.4 µg/m³, 0.9× usualAppleton, 30 July: 79.1 µg/m³, 8.8× usualTrois-RivièresTrois-Rivières, 21 July: 3.1 µg/m³, 0.4× usualTrois-Rivières, 22 July: 3.2 µg/m³, 0.4× usualTrois-Rivières, 23 July: 4.6 µg/m³, 0.6× usualTrois-Rivières, 24 July: 9.7 µg/m³, 1.2× usualTrois-Rivières, 25 July: 48.4 µg/m³, 5.8× usualTrois-Rivières, 26 July: 77.9 µg/m³, 9.4× usualTrois-Rivières, 27 July: 35.3 µg/m³, 4.3× usualTrois-Rivières, 28 July: 22.6 µg/m³, 2.7× usualTrois-Rivières, 29 July: 12.7 µg/m³, 1.5× usualTrois-Rivières, 30 July: 24.3 µg/m³, 2.9× usualDrummondvilleDrummondville, 21 July: 3.7 µg/m³, 0.5× usualDrummondville, 22 July: 3.9 µg/m³, 0.5× usualDrummondville, 23 July: 4.1 µg/m³, 0.5× usualDrummondville, 24 July: 8.5 µg/m³, 1.1× usualDrummondville, 25 July: 41.4 µg/m³, 5.2× usualDrummondville, 26 July: 77.5 µg/m³, 9.8× usualDrummondville, 27 July: 28.4 µg/m³, 3.6× usualDrummondville, 28 July: 18.2 µg/m³, 2.3× usualDrummondville, 29 July: 14.6 µg/m³, 1.8× usualDrummondville, 30 July: 19.4 µg/m³, 2.5× usualSherbrookeSherbrooke, 21 July: 4.4 µg/m³, 0.6× usualSherbrooke, 22 July: 2.8 µg/m³, 0.4× usualSherbrooke, 23 July: 3.6 µg/m³, 0.5× usualSherbrooke, 24 July: 8.4 µg/m³, 1.1× usualSherbrooke, 25 July: 35.9 µg/m³, 4.7× usualSherbrooke, 26 July: 76.8 µg/m³, 10.0× usualSherbrooke, 27 July: 32.0 µg/m³, 4.2× usualSherbrooke, 28 July: 16.1 µg/m³, 2.1× usualSherbrooke, 29 July: 12.2 µg/m³, 1.6× usualSherbrooke, 30 July: 17.2 µg/m³, 2.2× usualRivière-des-Prairie…Rivière-des-Prairies–Pointe-aux-Trembles, 21 July: 3.2 µg/m³, 0.4× usualRivière-des-Prairies–Pointe-aux-Trembles, 22 July: 3.2 µg/m³, 0.4× usualRivière-des-Prairies–Pointe-aux-Trembles, 23 July: 5.3 µg/m³, 0.7× usualRivière-des-Prairies–Pointe-aux-Trembles, 24 July: 10.0 µg/m³, 1.3× usualRivière-des-Prairies–Pointe-aux-Trembles, 25 July: 28.0 µg/m³, 3.5× usualRivière-des-Prairies–Pointe-aux-Trembles, 26 July: 72.9 µg/m³, 9.2× usualRivière-des-Prairies–Pointe-aux-Trembles, 27 July: 29.8 µg/m³, 3.8× usualRivière-des-Prairies–Pointe-aux-Trembles, 28 July: 19.0 µg/m³, 2.4× usualRivière-des-Prairies–Pointe-aux-Trembles, 29 July: 11.2 µg/m³, 1.4× usualRivière-des-Prairies–Pointe-aux-Trembles, 30 July: 29.2 µg/m³, 3.7× usualShawiniganShawinigan, 21 July: 2.5 µg/m³, 0.3× usualShawinigan, 22 July: 3.3 µg/m³, 0.4× usualShawinigan, 23 July: 5.5 µg/m³, 0.6× usualShawinigan, 24 July: 9.0 µg/m³, 1.0× usualShawinigan, 25 July: 48.2 µg/m³, 5.3× usualShawinigan, 26 July: 72.3 µg/m³, 7.9× usualShawinigan, 27 July: 37.8 µg/m³, 4.2× usualShawinigan, 28 July: 24.5 µg/m³, 2.7× usualShawinigan, 29 July: 17.6 µg/m³, 1.9× usualShawinigan, 30 July: 30.5 µg/m³, 3.4× usualSault Ste. MarieSault Ste. Marie, 21 July: 4.0 µg/m³, 0.5× usualSault Ste. Marie, 22 July: 3.1 µg/m³, 0.4× usualSault Ste. Marie, 23 July: 8.9 µg/m³, 1.1× usualSault Ste. Marie, 24 July: 4.8 µg/m³, 0.6× usualSault Ste. Marie, 25 July: 34.1 µg/m³, 4.3× usualSault Ste. Marie, 26 July: 38.2 µg/m³, 4.8× usualSault Ste. Marie, 27 July: 12.8 µg/m³, 1.6× usualSault Ste. Marie, 28 July: 12.6 µg/m³, 1.6× usualSault Ste. Marie, 29 July: 19.5 µg/m³, 2.4× usualSault Ste. Marie, 30 July: 71.6 µg/m³, 9.0× usualBrossardBrossard, 21 July: 3.8 µg/m³, 0.4× usualBrossard, 22 July: 5.0 µg/m³, 0.5× usualBrossard, 23 July: 7.4 µg/m³, 0.8× usualBrossard, 24 July: 11.5 µg/m³, 1.3× usualBrossard, 25 July: 26.9 µg/m³, 3.0× usualBrossard, 26 July: 70.6 µg/m³, 7.8× usualBrossard, 27 July: 30.1 µg/m³, 3.3× usualBrossard, 28 July: 19.8 µg/m³, 2.2× usualBrossard, 29 July: 11.9 µg/m³, 1.3× usualBrossard, 30 July: 27.3 µg/m³, 3.0× usualGreater SudburyGreater Sudbury, 21 July: 3.3 µg/m³, 0.4× usualGreater Sudbury, 22 July: 4.6 µg/m³, 0.5× usualGreater Sudbury, 23 July: 4.8 µg/m³, 0.6× usualGreater Sudbury, 24 July: 5.3 µg/m³, 0.6× usualGreater Sudbury, 25 July: 32.0 µg/m³, 3.7× usualGreater Sudbury, 26 July: 33.6 µg/m³, 3.9× usualGreater Sudbury, 27 July: 22.4 µg/m³, 2.6× usualGreater Sudbury, 28 July: 8.3 µg/m³, 1.0× usualGreater Sudbury, 29 July: 11.1 µg/m³, 1.3× usualGreater Sudbury, 30 July: 63.1 µg/m³, 7.3× usualL'Ancienne-LoretteL'Ancienne-Lorette, 21 July: 1.8 µg/m³, 0.2× usualL'Ancienne-Lorette, 22 July: 4.4 µg/m³, 0.4× usualL'Ancienne-Lorette, 23 July: 6.0 µg/m³, 0.6× usualL'Ancienne-Lorette, 24 July: 10.4 µg/m³, 1.0× usualL'Ancienne-Lorette, 25 July: 37.0 µg/m³, 3.7× usualL'Ancienne-Lorette, 26 July: 58.1 µg/m³, 5.8× usualL'Ancienne-Lorette, 27 July: 45.0 µg/m³, 4.5× usualL'Ancienne-Lorette, 28 July: 27.4 µg/m³, 2.7× usualL'Ancienne-Lorette, 29 July: no readingL'Ancienne-Lorette, 30 July: 38.8 µg/m³, 3.8× usualQuébecQuébec, 21 July: 2.0 µg/m³, 0.2× usualQuébec, 22 July: 4.7 µg/m³, 0.5× usualQuébec, 23 July: 5.8 µg/m³, 0.7× usualQuébec, 24 July: 10.1 µg/m³, 1.1× usualQuébec, 25 July: 33.3 µg/m³, 3.7× usualQuébec, 26 July: 54.7 µg/m³, 6.1× usualQuébec, 27 July: 41.6 µg/m³, 4.7× usualQuébec, 28 July: 25.4 µg/m³, 2.9× usualQuébec, 29 July: 18.4 µg/m³, 2.1× usualQuébec, 30 July: 35.4 µg/m³, 4.0× usualBurnsvilleBurnsville, 21 July: 22.4 µg/m³, 2.2× usualBurnsville, 22 July: 10.7 µg/m³, 1.1× usualBurnsville, 23 July: 6.9 µg/m³, 0.7× usualBurnsville, 24 July: 9.1 µg/m³, 0.9× usualBurnsville, 25 July: 39.3 µg/m³, 3.9× usualBurnsville, 26 July: 8.0 µg/m³, 0.8× usualBurnsville, 27 July: 5.1 µg/m³, 0.5× usualBurnsville, 28 July: 6.0 µg/m³, 0.6× usualBurnsville, 29 July: no readingBurnsville, 30 July: 53.8 µg/m³, 5.3× usualShakopeeShakopee, 21 July: 15.3 µg/m³, 1.5× usualShakopee, 22 July: 9.2 µg/m³, 0.9× usualShakopee, 23 July: 6.4 µg/m³, 0.6× usualShakopee, 24 July: 10.3 µg/m³, 1.0× usualShakopee, 25 July: 28.3 µg/m³, 2.9× usualShakopee, 26 July: 6.6 µg/m³, 0.7× usualShakopee, 27 July: 5.0 µg/m³, 0.5× usualShakopee, 28 July: 5.9 µg/m³, 0.6× usualShakopee, 29 July: 8.5 µg/m³, 0.9× usualShakopee, 30 July: 49.4 µg/m³, 5.0× usualSaint MichaelSaint Michael, 21 July: 17.2 µg/m³, 1.9× usualSaint Michael, 22 July: 10.1 µg/m³, 1.1× usualSaint Michael, 23 July: 4.9 µg/m³, 0.6× usualSaint Michael, 24 July: 18.8 µg/m³, 2.1× usualSaint Michael, 25 July: 39.1 µg/m³, 4.4× usualSaint Michael, 26 July: 6.7 µg/m³, 0.8× usualSaint Michael, 27 July: 4.8 µg/m³, 0.5× usualSaint Michael, 28 July: 6.3 µg/m³, 0.7× usualSaint Michael, 29 July: 8.2 µg/m³, 0.9× usualSaint Michael, 30 July: 46.3 µg/m³, 5.2× usualApple ValleyApple Valley, 21 July: 18.7 µg/m³, 2.2× usualApple Valley, 22 July: 9.5 µg/m³, 1.1× usualApple Valley, 23 July: 6.7 µg/m³, 0.8× usualApple Valley, 24 July: 7.3 µg/m³, 0.9× usualApple Valley, 25 July: 32.1 µg/m³, 3.8× usualApple Valley, 26 July: 5.9 µg/m³, 0.7× usualApple Valley, 27 July: 4.1 µg/m³, 0.5× usualApple Valley, 28 July: 5.4 µg/m³, 0.6× usualApple Valley, 29 July: 7.9 µg/m³, 0.9× usualApple Valley, 30 July: 46.0 µg/m³, 5.5× usualSaint-Jean-sur-Rich…Saint-Jean-sur-Richelieu, 21 July: 3.5 µg/m³, 0.5× usualSaint-Jean-sur-Richelieu, 22 July: 2.9 µg/m³, 0.4× usualSaint-Jean-sur-Richelieu, 23 July: 3.3 µg/m³, 0.5× usualSaint-Jean-sur-Richelieu, 24 July: 7.5 µg/m³, 1.1× usualSaint-Jean-sur-Richelieu, 25 July: 21.7 µg/m³, 3.2× usualSaint-Jean-sur-Richelieu, 26 July: 63.3 µg/m³, 9.3× usualSaint-Jean-sur-Richelieu, 27 July: 25.5 µg/m³, 3.8× usualSaint-Jean-sur-Richelieu, 28 July: 15.6 µg/m³, 2.3× usualSaint-Jean-sur-Richelieu, 29 July: 9.7 µg/m³, 1.4× usualSaint-Jean-sur-Richelieu, 30 July: 21.5 µg/m³, 3.2× usualNepeanNepean, 21 July: 4.7 µg/m³, 0.3× usualNepean, 22 July: 2.4 µg/m³, 0.1× usualNepean, 23 July: 3.9 µg/m³, 0.2× usualNepean, 24 July: 15.1 µg/m³, 0.9× usualNepean, 25 July: 22.6 µg/m³, 1.4× usualNepean, 26 July: 35.8 µg/m³, 2.2× usualNepean, 27 July: 30.5 µg/m³, 1.8× usualNepean, 28 July: 31.7 µg/m³, 1.9× usualNepean, 29 July: 23.8 µg/m³, 1.4× usualNepean, 30 July: 57.6 µg/m³, 3.5× usualNorth BayNorth Bay, 21 July: 2.1 µg/m³, 0.3× usualNorth Bay, 22 July: 3.3 µg/m³, 0.4× usualNorth Bay, 23 July: 5.1 µg/m³, 0.6× usualNorth Bay, 24 July: 6.9 µg/m³, 0.9× usualNorth Bay, 25 July: 20.6 µg/m³, 2.6× usualNorth Bay, 26 July: 30.3 µg/m³, 3.8× usualNorth Bay, 27 July: 20.3 µg/m³, 2.5× usualNorth Bay, 28 July: 8.1 µg/m³, 1.0× usualNorth Bay, 29 July: 13.6 µg/m³, 1.7× usualNorth Bay, 30 July: 53.0 µg/m³, 6.6× usualAlbanyAlbany, 21 July: 8.8 µg/m³, 0.9× usualAlbany, 22 July: 3.9 µg/m³, 0.4× usualAlbany, 23 July: 7.6 µg/m³, 0.8× usualAlbany, 24 July: 12.4 µg/m³, 1.3× usualAlbany, 25 July: 13.4 µg/m³, 1.4× usualAlbany, 26 July: 47.8 µg/m³, 4.9× usualAlbany, 27 July: 44.4 µg/m³, 4.6× usualAlbany, 28 July: 18.4 µg/m³, 1.9× usualAlbany, 29 July: 16.0 µg/m³, 1.6× usualAlbany, 30 July: 12.7 µg/m³, 1.3× usualRouyn-NorandaRouyn-Noranda, 21 July: 1.5 µg/m³, 0.2× usualRouyn-Noranda, 22 July: 3.4 µg/m³, 0.4× usualRouyn-Noranda, 23 July: no readingRouyn-Noranda, 24 July: no readingRouyn-Noranda, 25 July: 21.9 µg/m³, 2.7× usualRouyn-Noranda, 26 July: 25.1 µg/m³, 3.1× usualRouyn-Noranda, 27 July: 28.9 µg/m³, 3.6× usualRouyn-Noranda, 28 July: 21.7 µg/m³, 2.7× usualRouyn-Noranda, 29 July: 47.3 µg/m³, 5.8× usualRouyn-Noranda, 30 July: 42.2 µg/m³, 5.2× usualRutlandRutland, 21 July: 4.6 µg/m³, 0.6× usualRutland, 22 July: 3.1 µg/m³, 0.4× usualRutland, 23 July: 4.3 µg/m³, 0.5× usualRutland, 24 July: 10.6 µg/m³, 1.3× usualRutland, 25 July: 11.6 µg/m³, 1.5× usualRutland, 26 July: 46.0 µg/m³, 5.8× usualRutland, 27 July: 27.6 µg/m³, 3.5× usualRutland, 28 July: 13.8 µg/m³, 1.7× usualRutland, 29 July: 11.5 µg/m³, 1.4× usualRutland, 30 July: 8.5 µg/m³, 1.1× usualSpringfieldSpringfield, 21 July: 8.9 µg/m³, 1.2× usualSpringfield, 22 July: 3.9 µg/m³, 0.5× usualSpringfield, 23 July: 5.8 µg/m³, 0.8× usualSpringfield, 24 July: 7.6 µg/m³, 1.0× usualSpringfield, 25 July: 8.6 µg/m³, 1.1× usualSpringfield, 26 July: 42.6 µg/m³, 5.5× usualSpringfield, 27 July: 35.4 µg/m³, 4.6× usualSpringfield, 28 July: 20.5 µg/m³, 2.7× usualSpringfield, 29 July: 13.2 µg/m³, 1.7× usualSpringfield, 30 July: 9.6 µg/m³, 1.2× usualPittsfieldPittsfield, 21 July: 8.5 µg/m³, 1.1× usualPittsfield, 22 July: no readingPittsfield, 23 July: 5.8 µg/m³, 0.8× usualPittsfield, 24 July: 9.5 µg/m³, 1.2× usualPittsfield, 25 July: 9.5 µg/m³, 1.2× usualPittsfield, 26 July: 41.9 µg/m³, 5.4× usualPittsfield, 27 July: 35.1 µg/m³, 4.6× usualPittsfield, 28 July: no readingPittsfield, 29 July: 12.0 µg/m³, 1.6× usualPittsfield, 30 July: 7.8 µg/m³, 1.0× usualDanburyDanbury, 21 July: 11.2 µg/m³, 1.3× usualDanbury, 22 July: 5.1 µg/m³, 0.6× usualDanbury, 23 July: 5.5 µg/m³, 0.7× usualDanbury, 24 July: 7.2 µg/m³, 0.9× usualDanbury, 25 July: 10.4 µg/m³, 1.3× usualDanbury, 26 July: 41.0 µg/m³, 4.9× usualDanbury, 27 July: 32.0 µg/m³, 3.9× usualDanbury, 28 July: 13.6 µg/m³, 1.6× usualDanbury, 29 July: 12.8 µg/m³, 1.5× usualDanbury, 30 July: 10.0 µg/m³, 1.2× usualKeeneKeene, 21 July: 5.0 µg/m³, 0.7× usualKeene, 22 July: 3.0 µg/m³, 0.4× usualKeene, 23 July: 5.1 µg/m³, 0.7× usualKeene, 24 July: 9.3 µg/m³, 1.3× usualKeene, 25 July: 8.3 µg/m³, 1.2× usualKeene, 26 July: 39.8 µg/m³, 5.5× usualKeene, 27 July: 33.9 µg/m³, 4.7× usualKeene, 28 July: 16.0 µg/m³, 2.2× usualKeene, 29 July: 12.0 µg/m³, 1.7× usualKeene, 30 July: 7.8 µg/m³, 1.1× usualPortlandPortland, 21 July: 5.6 µg/m³, 0.6× usualPortland, 22 July: 2.5 µg/m³, 0.3× usualPortland, 23 July: 5.5 µg/m³, 0.6× usualPortland, 24 July: 9.0 µg/m³, 1.0× usualPortland, 25 July: 13.7 µg/m³, 1.5× usualPortland, 26 July: 39.1 µg/m³, 4.4× usualPortland, 27 July: 23.2 µg/m³, 2.6× usualPortland, 28 July: 13.3 µg/m³, 1.5× usualPortland, 29 July: 14.2 µg/m³, 1.6× usualPortland, 30 July: 11.9 µg/m³, 1.3× usualGreenfieldGreenfield, 21 July: 6.5 µg/m³, 0.9× usualGreenfield, 22 July: 2.8 µg/m³, 0.4× usualGreenfield, 23 July: 4.4 µg/m³, 0.6× usualGreenfield, 24 July: 7.3 µg/m³, 1.0× usualGreenfield, 25 July: 6.2 µg/m³, 0.9× usualGreenfield, 26 July: 39.0 µg/m³, 5.4× usualGreenfield, 27 July: 34.5 µg/m³, 4.8× usualGreenfield, 28 July: 15.5 µg/m³, 2.2× usualGreenfield, 29 July: 10.6 µg/m³, 1.5× usualGreenfield, 30 July: 6.9 µg/m³, 1.0× usualWaterburyWaterbury, 21 July: 10.5 µg/m³, 1.3× usualWaterbury, 22 July: 3.9 µg/m³, 0.5× usualWaterbury, 23 July: 5.0 µg/m³, 0.6× usualWaterbury, 24 July: 6.7 µg/m³, 0.8× usualWaterbury, 25 July: 9.3 µg/m³, 1.1× usualWaterbury, 26 July: 38.7 µg/m³, 4.8× usualWaterbury, 27 July: 32.7 µg/m³, 4.0× usualWaterbury, 28 July: 14.1 µg/m³, 1.7× usualWaterbury, 29 July: 12.7 µg/m³, 1.6× usualWaterbury, 30 July: 8.6 µg/m³, 1.1× usualLewistonLewiston, 21 July: 5.5 µg/m³, 0.8× usualLewiston, 22 July: 3.2 µg/m³, 0.5× usualLewiston, 23 July: 5.5 µg/m³, 0.8× usualLewiston, 24 July: 8.0 µg/m³, 1.2× usualLewiston, 25 July: 15.8 µg/m³, 2.3× usualLewiston, 26 July: 38.0 µg/m³, 5.6× usualLewiston, 27 July: 19.3 µg/m³, 2.8× usualLewiston, 28 July: 12.9 µg/m³, 1.9× usualLewiston, 29 July: 10.3 µg/m³, 1.5× usualLewiston, 30 July: 12.1 µg/m³, 1.8× usualNorth ChicopeeNorth Chicopee, 21 July: 6.4 µg/m³, 1.0× usualNorth Chicopee, 22 July: 3.0 µg/m³, 0.5× usualNorth Chicopee, 23 July: 4.6 µg/m³, 0.7× usualNorth Chicopee, 24 July: 6.4 µg/m³, 1.0× usualNorth Chicopee, 25 July: 7.1 µg/m³, 1.1× usualNorth Chicopee, 26 July: 37.8 µg/m³, 5.9× usualNorth Chicopee, 27 July: 30.8 µg/m³, 4.8× usualNorth Chicopee, 28 July: 15.0 µg/m³, 2.3× usualNorth Chicopee, 29 July: 10.9 µg/m³, 1.7× usualNorth Chicopee, 30 July: 7.4 µg/m³, 1.2× usualHartfordHartford, 21 July: 10.8 µg/m³, 1.2× usualHartford, 22 July: 4.2 µg/m³, 0.5× usualHartford, 23 July: 6.4 µg/m³, 0.7× usualHartford, 24 July: 7.7 µg/m³, 0.9× usualHartford, 25 July: 10.0 µg/m³, 1.1× usualHartford, 26 July: 37.6 µg/m³, 4.3× usualHartford, 27 July: 34.8 µg/m³, 4.0× usualHartford, 28 July: 18.0 µg/m³, 2.1× usualHartford, 29 July: 13.8 µg/m³, 1.6× usualHartford, 30 July: 11.3 µg/m³, 1.3× usualNew CityNew City, 21 July: 7.3 µg/m³, 1.2× usualNew City, 22 July: 2.1 µg/m³, 0.3× usualNew City, 23 July: 3.9 µg/m³, 0.6× usualNew City, 24 July: 6.6 µg/m³, 1.0× usualNew City, 25 July: 8.1 µg/m³, 1.3× usualNew City, 26 July: 37.5 µg/m³, 6.0× usualNew City, 27 July: 25.6 µg/m³, 4.1× usualNew City, 28 July: 8.1 µg/m³, 1.3× usualNew City, 29 July: 7.6 µg/m³, 1.2× usualNew City, 30 July: 9.4 µg/m³, 1.5× usualAugustaAugusta, 21 July: 4.5 µg/m³, 0.6× usualAugusta, 22 July: 2.6 µg/m³, 0.3× usualAugusta, 23 July: 4.5 µg/m³, 0.6× usualAugusta, 24 July: 7.3 µg/m³, 0.9× usualAugusta, 25 July: 14.8 µg/m³, 1.9× usualAugusta, 26 July: 36.7 µg/m³, 4.6× usualAugusta, 27 July: 21.6 µg/m³, 2.7× usualAugusta, 28 July: 15.5 µg/m³, 2.0× usualAugusta, 29 July: 9.9 µg/m³, 1.3× usualAugusta, 30 July: 11.8 µg/m³, 1.5× usualWhite PlainsWhite Plains, 21 July: 8.2 µg/m³, 1.3× usualWhite Plains, 22 July: 2.5 µg/m³, 0.4× usualWhite Plains, 23 July: 3.0 µg/m³, 0.5× usualWhite Plains, 24 July: 5.1 µg/m³, 0.8× usualWhite Plains, 25 July: 10.4 µg/m³, 1.7× usualWhite Plains, 26 July: 36.6 µg/m³, 6.0× usualWhite Plains, 27 July: 29.2 µg/m³, 4.8× usualWhite Plains, 28 July: 7.3 µg/m³, 1.2× usualWhite Plains, 29 July: 11.1 µg/m³, 1.8× usualWhite Plains, 30 July: 10.7 µg/m³, 1.8× usualNewburghNewburgh, 21 July: 5.9 µg/m³, 1.0× usualNewburgh, 22 July: 2.4 µg/m³, 0.4× usualNewburgh, 23 July: 4.6 µg/m³, 0.8× usualNewburgh, 24 July: 7.1 µg/m³, 1.2× usualNewburgh, 25 July: 7.2 µg/m³, 1.2× usualNewburgh, 26 July: 35.3 µg/m³, 5.8× usualNewburgh, 27 July: 24.9 µg/m³, 4.1× usualNewburgh, 28 July: 8.5 µg/m³, 1.4× usualNewburgh, 29 July: 12.8 µg/m³, 2.1× usualNewburgh, 30 July: 9.4 µg/m³, 1.5× usualSewellSewell, 21 July: 11.7 µg/m³, 1.3× usualSewell, 22 July: 17.7 µg/m³, 2.0× usualSewell, 23 July: 10.3 µg/m³, 1.2× usualSewell, 24 July: 10.3 µg/m³, 1.2× usualSewell, 25 July: 18.8 µg/m³, 2.1× usualSewell, 26 July: 27.1 µg/m³, 3.1× usualSewell, 27 July: 34.9 µg/m³, 4.0× usualSewell, 28 July: 15.3 µg/m³, 1.7× usualSewell, 29 July: 18.9 µg/m³, 2.1× usualSewell, 30 July: 18.0 µg/m³, 2.0× usualCornwallCornwall, 21 July: 5.0 µg/m³, 0.6× usualCornwall, 22 July: 3.8 µg/m³, 0.5× usualCornwall, 23 July: 4.1 µg/m³, 0.5× usualCornwall, 24 July: 11.4 µg/m³, 1.4× usualCornwall, 25 July: 12.9 µg/m³, 1.6× usualCornwall, 26 July: 34.3 µg/m³, 4.3× usualCornwall, 27 July: 14.3 µg/m³, 1.8× usualCornwall, 28 July: 16.8 µg/m³, 2.1× usualCornwall, 29 July: 12.9 µg/m³, 1.6× usualCornwall, 30 July: 33.4 µg/m³, 4.2× usualPleasantvillePleasantville, 21 July: 6.5 µg/m³, 0.8× usualPleasantville, 22 July: 9.9 µg/m³, 1.2× usualPleasantville, 23 July: 4.5 µg/m³, 0.5× usualPleasantville, 24 July: 4.1 µg/m³, 0.5× usualPleasantville, 25 July: 9.0 µg/m³, 1.1× usualPleasantville, 26 July: 33.4 µg/m³, 3.9× usualPleasantville, 27 July: 23.9 µg/m³, 2.8× usualPleasantville, 28 July: 8.8 µg/m³, 1.0× usualPleasantville, 29 July: 12.7 µg/m³, 1.5× usualPleasantville, 30 July: 14.2 µg/m³, 1.7× usualNew HavenNew Haven, 21 July: 11.6 µg/m³, 1.4× usualNew Haven, 22 July: 4.4 µg/m³, 0.5× usualNew Haven, 23 July: 6.4 µg/m³, 0.8× usualNew Haven, 24 July: 6.5 µg/m³, 0.8× usualNew Haven, 25 July: 12.2 µg/m³, 1.5× usualNew Haven, 26 July: 33.2 µg/m³, 4.1× usualNew Haven, 27 July: 31.0 µg/m³, 3.8× usualNew Haven, 28 July: 14.2 µg/m³, 1.8× usualNew Haven, 29 July: 17.5 µg/m³, 2.2× usualNew Haven, 30 July: 12.9 µg/m³, 1.6× usualAtlantic CityAtlantic City, 21 July: 5.7 µg/m³, 0.7× usualAtlantic City, 22 July: 9.3 µg/m³, 1.1× usualAtlantic City, 23 July: 4.1 µg/m³, 0.5× usualAtlantic City, 24 July: 4.1 µg/m³, 0.5× usualAtlantic City, 25 July: 13.1 µg/m³, 1.5× usualAtlantic City, 26 July: 33.0 µg/m³, 3.8× usualAtlantic City, 27 July: 23.4 µg/m³, 2.7× usualAtlantic City, 28 July: 8.7 µg/m³, 1.0× usualAtlantic City, 29 July: 13.4 µg/m³, 1.6× usualAtlantic City, 30 July: 13.4 µg/m³, 1.6× usualNew York CityNew York City, 21 July: 10.8 µg/m³, 1.2× usualNew York City, 22 July: 5.4 µg/m³, 0.6× usualNew York City, 23 July: 5.2 µg/m³, 0.6× usualNew York City, 24 July: 6.3 µg/m³, 0.7× usualNew York City, 25 July: 12.3 µg/m³, 1.4× usualNew York City, 26 July: 30.4 µg/m³, 3.5× usualNew York City, 27 July: 32.6 µg/m³, 3.7× usualNew York City, 28 July: 12.4 µg/m³, 1.4× usualNew York City, 29 July: 17.5 µg/m³, 2.0× usualNew York City, 30 July: 14.1 µg/m³, 1.6× usualFall RiverFall River, 21 July: 10.2 µg/m³, 1.5× usualFall River, 22 July: 3.0 µg/m³, 0.4× usualFall River, 23 July: 3.2 µg/m³, 0.5× usualFall River, 24 July: 3.8 µg/m³, 0.5× usualFall River, 25 July: 7.5 µg/m³, 1.1× usualFall River, 26 July: 32.3 µg/m³, 4.6× usualFall River, 27 July: 19.4 µg/m³, 2.8× usualFall River, 28 July: 18.5 µg/m³, 2.6× usualFall River, 29 July: 12.2 µg/m³, 1.7× usualFall River, 30 July: 10.0 µg/m³, 1.4× usualBrocktonBrockton, 21 July: 8.3 µg/m³, 1.1× usualBrockton, 22 July: 3.1 µg/m³, 0.4× usualBrockton, 23 July: 4.0 µg/m³, 0.5× usualBrockton, 24 July: 5.2 µg/m³, 0.7× usualBrockton, 25 July: 8.0 µg/m³, 1.0× usualBrockton, 26 July: 32.0 µg/m³, 4.1× usualBrockton, 27 July: 27.5 µg/m³, 3.5× usualBrockton, 28 July: 19.3 µg/m³, 2.5× usualBrockton, 29 July: 14.8 µg/m³, 1.9× usualBrockton, 30 July: 11.1 µg/m³, 1.4× usualBridgeportBridgeport, 21 July: 11.0 µg/m³, 1.2× usualBridgeport, 22 July: 4.0 µg/m³, 0.4× usualBridgeport, 23 July: 4.2 µg/m³, 0.5× usualBridgeport, 24 July: 5.5 µg/m³, 0.6× usualBridgeport, 25 July: 10.7 µg/m³, 1.2× usualBridgeport, 26 July: 31.7 µg/m³, 3.6× usualBridgeport, 27 July: 30.3 µg/m³, 3.4× usualBridgeport, 28 July: 11.2 µg/m³, 1.3× usualBridgeport, 29 July: 13.5 µg/m³, 1.5× usualBridgeport, 30 July: 10.0 µg/m³, 1.1× usualLaconiaLaconia, 21 July: 3.3 µg/m³, 0.6× usualLaconia, 22 July: 1.2 µg/m³, 0.2× usualLaconia, 23 July: 1.9 µg/m³, 0.4× usualLaconia, 24 July: 6.0 µg/m³, 1.1× usualLaconia, 25 July: 7.3 µg/m³, 1.4× usualLaconia, 26 July: 30.9 µg/m³, 5.8× usualLaconia, 27 July: 21.0 µg/m³, 4.0× usualLaconia, 28 July: 11.1 µg/m³, 2.1× usualLaconia, 29 July: 8.9 µg/m³, 1.7× usualLaconia, 30 July: 5.7 µg/m³, 1.1× usualQuincyQuincy, 21 July: 7.0 µg/m³, 1.0× usualQuincy, 22 July: 2.8 µg/m³, 0.4× usualQuincy, 23 July: 3.7 µg/m³, 0.6× usualQuincy, 24 July: 5.3 µg/m³, 0.8× usualQuincy, 25 July: 7.5 µg/m³, 1.1× usualQuincy, 26 July: 30.7 µg/m³, 4.6× usualQuincy, 27 July: 23.8 µg/m³, 3.6× usualQuincy, 28 July: 16.8 µg/m³, 2.5× usualQuincy, 29 July: 12.6 µg/m³, 1.9× usualQuincy, 30 July: 10.2 µg/m³, 1.5× usualLexingtonLexington, 21 July: no readingLexington, 22 July: no readingLexington, 23 July: no readingLexington, 24 July: no readingLexington, 25 July: no readingLexington, 26 July: no readingLexington, 27 July: 41.0 µg/m³, 3.8× usualLexington, 28 July: 30.0 µg/m³, 2.8× usualLexington, 29 July: 23.2 µg/m³, 2.2× usualLexington, 30 July: 14.4 µg/m³, 1.3× usual21 Jul222324252627282930
The 60 cities with the highest readings of 90, 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 States2 112.030 July8.313×
DorvalQuebec, Canada3 79.826 July8.010.0×
SherbrookeQuebec, Canada3 76.826 July7.710.0×
DrummondvilleQuebec, Canada3 77.526 July7.99.8×
MontréalQuebec, Canada3 82.426 July8.49.8×
DuluthMinnesota, United States2 91.130 July9.59.6×
Trois-RivièresQuebec, Canada3 77.926 July8.39.4×
GranbyQuebec, Canada3 81.226 July8.79.3×
Saint-Jean-sur-RichelieuQuebec, Canada2 63.326 July6.89.3×
Rivière-des-Prairies–Pointe-aux-TremblesQuebec, Canada3 72.926 July7.99.2×
Sault Ste. MarieOntario, Canada2 71.630 July8.09.0×
AppletonWisconsin, United States1 79.130 July9.08.8×
Green BayWisconsin, United States2 85.930 July9.88.8×
Sorel-TracyQuebec, Canada3 88.426 July10.18.8×
ShawiniganQuebec, Canada3 72.326 July9.17.9×
BrossardQuebec, Canada3 70.626 July9.17.8×
Greater SudburyOntario, Canada2 63.130 July8.67.3×
Eau ClaireWisconsin, United States1 59.230 July8.96.7×
North BayOntario, Canada1 53.030 July8.06.6×
QuébecQuebec, Canada3 54.726 July8.96.1×
Saint CloudMinnesota, United States2 53.430 July8.86.1×
West FargoNorth Dakota, United States1 58.330 July9.76.0×
White PlainsNew York, United States2 36.626 July6.16.0×
New CityNew York, United States2 37.526 July6.36.0×
North ChicopeeMassachusetts, United States2 37.826 July6.45.9×
BlaineMinnesota, United States1 49.730 July8.55.8×
Rouyn-NorandaQuebec, Canada1 47.329 July8.15.8×
LaconiaNew Hampshire, United States1 30.926 July5.35.8×
NewburghNew York, United States1 35.326 July6.15.8×
L'Ancienne-LoretteQuebec, Canada3 58.126 July10.15.8×
RutlandVermont, United States2 46.026 July8.05.8×
LewistonMaine, United States1 38.026 July6.85.6×
SpringfieldMassachusetts, United States2 42.626 July7.75.5×
KeeneNew Hampshire, United States2 39.826 July7.25.5×
Apple ValleyMinnesota, United States1 46.030 July8.45.5×
PittsfieldMassachusetts, United States2 41.926 July7.75.4×
GreenfieldMassachusetts, United States2 39.026 July7.25.4×
BurnsvilleMinnesota, United States1 53.830 July10.15.3×
MinneapolisMinnesota, United States1 54.030 July10.25.3×
Saint PaulMinnesota, United States1 53.330 July10.15.3×
Saint MichaelMinnesota, United States1 46.330 July8.95.2×
ShakopeeMinnesota, United States1 49.430 July9.95.0×
DanburyConnecticut, United States2 41.026 July8.34.9×
AlbanyNew York, United States2 47.826 July9.74.9×
WaterburyConnecticut, United States2 38.726 July8.14.8×
BayonneNew Jersey, United States1 27.127 July5.74.8×
AugustaMaine, United States1 36.726 July7.94.6×
Fall RiverMassachusetts, United States1 32.326 July7.04.6×
QuincyMassachusetts, United States1 30.726 July6.74.6×
HaverhillMassachusetts, United States1 28.727 July6.54.4×
PortlandMaine, United States1 39.126 July8.94.4×
MilfordMassachusetts, United States2 27.027 July6.24.4×
HartfordConnecticut, United States2 37.626 July8.74.3×
CornwallOntario, Canada1 34.326 July8.04.3×
WorcesterMassachusetts, United States2 29.926 July7.04.3×
HolbrookNew York, United States2 30.726 July7.24.3×
BrookingsSouth Dakota, United States1 28.824 July6.84.2×
DerryNew Hampshire, United States1 28.927 July7.04.1×
BrocktonMassachusetts, United States2 32.026 July7.84.1×
New HavenConnecticut, United States2 33.226 July8.14.1×
LynnMassachusetts, United States2 28.026 July6.94.1×
FraminghamMassachusetts, United States1 25.127 July6.24.0×
LowellMassachusetts, United States1 27.527 July6.84.0×
SewellNew Jersey, United States2 34.927 July8.84.0×
PleasantvilleNew Jersey, United States1 33.426 July8.53.9×
BostonMassachusetts, United States2 29.626 July7.63.9×
Atlantic CityNew Jersey, United States1 33.026 July8.63.8×
LexingtonMassachusetts, United States1 41.027 July10.73.8×
PortsmouthNew Hampshire, United States1 28.326 July7.43.8×
New LondonConnecticut, United States2 30.326 July8.13.7×
New York CityNew York, United States2 32.627 July8.83.7×
Fort LeeNew Jersey, United States2 28.727 July7.83.7×
NorristownPennsylvania, United States1 27.127 July7.43.7×
BridgeportConnecticut, United States2 31.726 July8.93.6×
NepeanOntario, Canada1 57.630 July16.63.5×
SaguenayQuebec, Canada1 30.530 July8.83.5×
RandolphNew Jersey, United States1 27.927 July8.13.4×
PatersonNew Jersey, United States1 30.427 July9.03.4×
PennsaukenNew Jersey, United States2 30.427 July9.13.3×
New BrunswickNew Jersey, United States2 27.627 July8.43.3×
BarrieOntario, Canada1 30.626 July10.03.1×
LebanonPennsylvania, United States1 26.327 July8.73.0×
LindenNew Jersey, United States2 27.827 July9.33.0×
EwingNew Jersey, United States1 27.727 July9.42.9×
BensalemPennsylvania, United States1 27.527 July9.52.9×
Jersey CityNew Jersey, United States1 26.727 July9.42.8×
TrentonNew Jersey, United States1 26.127 July9.32.8×
ElizabethNew Jersey, United States1 27.427 July10.12.7×
NewmarketOntario, Canada1 25.526 July10.02.6×
PhiladelphiaPennsylvania, United States1 25.927 July10.32.5×

Daily means in µg/m³. Usual: the city's median for this time of year (its days within 21 days of the date, every year, leaving out the week around it). Above usual: its highest day against that.

Against other episodes in the United States and Canada

Number 13 of 106 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 106.

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SmogRank, North-eastern United States and Canada, July 2025: 90 cities with PM2.5 at twice their usual or more, 24 to 27 July 2025, smogrank.com/episodes/2025-07-north-eastern-united-states-and-canada-2 (accessed 2 October 2026).

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

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