SmogRank / Episodes / United States
North-eastern United States and Canada, July 2023
For 6 days, from 14 to 19 July 2023, 241 cities in the United States and Canada had PM2.5 at least twice their usual for the time of year. The worst reading was Bloomington, Illinois, United States: 74.0 µg/m³ on 16 July, about 8.8× its usual 8.4.
Day by day
How it spread
Every city it reached
| City | Days | Highest | Above usual |
|---|---|---|---|
| Sioux FallsSouth Dakota, United States | 2 | 66.616 July | 12× |
| BrookingsSouth Dakota, United States | 3 | 71.615 July | 11× |
| BloomingtonIllinois, United States | 2 | 74.016 July | 8.8× |
| SaguenayQuebec, Canada | 1 | 74.313 July | 8.3× |
| MuscatineIowa, United States | 3 | 53.216 July | 8.1× |
| LaconiaNew Hampshire, United States | 2 | 39.018 July | 7.8× |
| McDonoughGeorgia, United States | 3 | 55.818 July | 7.7× |
| AnkenyIowa, United States | 2 | 68.516 July | 7.6× |
| Des MoinesIowa, United States | 2 | 65.316 July | 7.6× |
| EriePennsylvania, United States | 1 | 58.317 July | 7.6× |
| AberdeenSouth Dakota, United States | 3 | 37.515 July | 7.5× |
| AthensGeorgia, United States | 2 | 49.918 July | 7.2× |
| Shaker HeightsOhio, United States | 2 | 59.017 July | 7.1× |
| Iowa CityIowa, United States | 3 | 62.416 July | 7.1× |
| MolineIllinois, United States | 3 | 60.916 July | 7.1× |
| PainesvilleOhio, United States | 2 | 48.517 July | 7.0× |
| Warner RobinsGeorgia, United States | 3 | 56.418 July | 6.9× |
| MedinaOhio, United States | 2 | 60.417 July | 6.9× |
| DavenportIowa, United States | 3 | 59.016 July | 6.9× |
| GreenvilleSouth Carolina, United States | 2 | 46.418 July | 6.7× |
| AkronOhio, United States | 2 | 56.217 July | 6.7× |
| HermitagePennsylvania, United States | 1 | 50.217 July | 6.4× |
| WatertownSouth Dakota, United States | 3 | 49.515 July | 6.3× |
| HuntsvilleAlabama, United States | 2 | 48.617 July | 6.3× |
| KnoxvilleTennessee, United States | 2 | 51.717 July | 6.3× |
| LawrencevilleGeorgia, United States | 2 | 46.718 July | 6.1× |
| YoungstownOhio, United States | 2 | 58.017 July | 6.1× |
| WaterlooIowa, United States | 2 | 48.416 July | 6.1× |
| DecaturIllinois, United States | 2 | 56.016 July | 6.0× |
| SyracuseNew York, United States | 2 | 42.117 July | 6.0× |
| MaconGeorgia, United States | 3 | 56.818 July | 6.0× |
| RochesterNew York, United States | 2 | 49.217 July | 5.9× |
| Winston-SalemNorth Carolina, United States | 2 | 52.117 July | 5.9× |
| AlbanyGeorgia, United States | 2 | 46.718 July | 5.9× |
| BurlingtonVermont, United States | 2 | 41.918 July | 5.9× |
| Apple ValleyMinnesota, United States | 1 | 48.015 July | 5.9× |
| WarrenOhio, United States | 3 | 63.617 July | 5.8× |
| DublinOhio, United States | 2 | 51.717 July | 5.7× |
| East ChicagoIndiana, United States | 1 | 52.016 July | 5.7× |
| ClemmonsNorth Carolina, United States | 2 | 45.717 July | 5.7× |
| GahannaOhio, United States | 1 | 45.617 July | 5.7× |
| Candler-McAfeeGeorgia, United States | 2 | 49.018 July | 5.6× |
| GreenfieldMassachusetts, United States | 2 | 38.717 July | 5.6× |
| CantonOhio, United States | 2 | 61.017 July | 5.6× |
| JolietIllinois, United States | 2 | 57.516 July | 5.5× |
| GainesvilleGeorgia, United States | 2 | 50.318 July | 5.5× |
| AndersonIndiana, United States | 2 | 47.817 July | 5.5× |
| DurhamNorth Carolina, United States | 2 | 36.818 July | 5.5× |
| BurnsvilleMinnesota, United States | 1 | 52.715 July | 5.5× |
| East RidgeTennessee, United States | 2 | 52.717 July | 5.5× |
| SpringfieldIllinois, United States | 1 | 50.316 July | 5.5× |
| ChattanoogaTennessee, United States | 2 | 49.217 July | 5.5× |
| MaryvilleTennessee, United States | 2 | 41.817 July | 5.4× |
| ClevelandOhio, United States | 2 | 61.317 July | 5.4× |
| RoanokeVirginia, United States | 1 | 41.717 July | 5.4× |
| Eau ClaireWisconsin, United States | 1 | 47.115 July | 5.4× |
| CharlotteNorth Carolina, United States | 2 | 45.818 July | 5.4× |
| White OakOhio, United States | 1 | 39.016 July | 5.3× |
| SpartanburgSouth Carolina, United States | 2 | 50.718 July | 5.3× |
| WestervilleOhio, United States | 2 | 59.217 July | 5.3× |
| New CityNew York, United States | 2 | 31.417 July | 5.3× |
| Calumet CityIllinois, United States | 2 | 55.816 July | 5.3× |
| RaleighNorth Carolina, United States | 2 | 45.618 July | 5.3× |
| Weirton HeightsWest Virginia, United States | 1 | 41.317 July | 5.3× |
| KeeneNew Hampshire, United States | 2 | 37.517 July | 5.3× |
| SpringfieldOhio, United States | 2 | 53.317 July | 5.3× |
| ShakopeeMinnesota, United States | 1 | 50.615 July | 5.3× |
| FayettevilleNorth Carolina, United States | 2 | 47.918 July | 5.3× |
| SavannahGeorgia, United States | 2 | 38.119 July | 5.2× |
| HickoryNorth Carolina, United States | 2 | 43.018 July | 5.2× |
| GreenvilleNorth Carolina, United States | 1 | 42.918 July | 5.2× |
| Phenix CityAlabama, United States | 2 | 39.518 July | 5.1× |
| UticaNew York, United States | 2 | 36.317 July | 5.1× |
| HueytownAlabama, United States | 2 | 40.417 July | 5.0× |
| AshlandKentucky, United States | 1 | 39.417 July | 5.0× |
| KingsportTennessee, United States | 2 | 36.917 July | 5.0× |
| DaytonOhio, United States | 2 | 49.317 July | 5.0× |
| BuffaloNew York, United States | 2 | 47.817 July | 5.0× |
| St. CatharinesOntario, Canada | 2 | 40.317 July | 5.0× |
| LafayetteIndiana, United States | 1 | 46.216 July | 5.0× |
| HaverhillMassachusetts, United States | 1 | 33.717 July | 5.0× |
| BloomingtonIndiana, United States | 2 | 40.616 July | 5.0× |
| LexingtonNorth Carolina, United States | 2 | 43.018 July | 4.9× |
| AshevilleNorth Carolina, United States | 2 | 34.418 July | 4.9× |
| CharlottesvilleVirginia, United States | 2 | 39.817 July | 4.9× |
| MorrisvilleNorth Carolina, United States | 2 | 44.518 July | 4.9× |
| North ChicopeeMassachusetts, United States | 1 | 30.817 July | 4.9× |
| NewburghNew York, United States | 2 | 29.317 July | 4.9× |
| ElizabethtownKentucky, United States | 2 | 37.116 July | 4.9× |
| ClaytonNorth Carolina, United States | 2 | 41.018 July | 4.9× |
| PaducahKentucky, United States | 1 | 39.816 July | 4.9× |
| RutlandVermont, United States | 2 | 39.618 July | 4.8× |
| TrussvilleAlabama, United States | 2 | 36.117 July | 4.8× |
| PittsfieldMassachusetts, United States | 2 | 37.018 July | 4.8× |
| HammondIndiana, United States | 2 | 49.416 July | 4.8× |
| BethlehemPennsylvania, United States | 2 | 33.517 July | 4.8× |
| BellevueNebraska, United States | 2 | 30.615 July | 4.8× |
| AtlantaGeorgia, United States | 2 | 43.518 July | 4.8× |
| LebanonOhio, United States | 2 | 36.617 July | 4.8× |
| Des PlainesIllinois, United States | 1 | 45.616 July | 4.8× |
| GreensboroNorth Carolina, United States | 2 | 40.818 July | 4.7× |
| LimaOhio, United States | 2 | 47.917 July | 4.7× |
| Rose HillVirginia, United States | 2 | 37.917 July | 4.7× |
| ValdostaGeorgia, United States | 2 | 37.419 July | 4.7× |
| BismarckNorth Dakota, United States | 3 | 52.115 July | 4.7× |
| LouisvilleKentucky, United States | 2 | 44.316 July | 4.7× |
| JeffersontownKentucky, United States | 2 | 41.516 July | 4.7× |
| KokomoIndiana, United States | 1 | 42.216 July | 4.6× |
| Lexington-FayetteKentucky, United States | 2 | 33.317 July | 4.6× |
| JeffersonvilleIndiana, United States | 2 | 41.116 July | 4.6× |
| ColumbiaTennessee, United States | 2 | 34.617 July | 4.6× |
| KenmoreNew York, United States | 2 | 43.117 July | 4.6× |
| Saint MichaelMinnesota, United States | 1 | 39.615 July | 4.6× |
| BrunswickGeorgia, United States | 2 | 30.019 July | 4.5× |
| RockfordIllinois, United States | 2 | 44.016 July | 4.5× |
| BirminghamAlabama, United States | 2 | 42.617 July | 4.5× |
| PittsburghPennsylvania, United States | 2 | 45.517 July | 4.5× |
| ClarksvilleTennessee, United States | 2 | 34.516 July | 4.5× |
| GaryIndiana, United States | 1 | 45.216 July | 4.5× |
| OwensboroKentucky, United States | 2 | 41.616 July | 4.5× |
| LowellMassachusetts, United States | 1 | 31.317 July | 4.5× |
| Saint CloudMinnesota, United States | 2 | 37.015 July | 4.5× |
| St. ThomasOntario, Canada | 1 | 37.517 July | 4.4× |
| RochesterMinnesota, United States | 2 | 45.815 July | 4.4× |
| Saint MatthewsKentucky, United States | 2 | 37.816 July | 4.4× |
| HagerstownMaryland, United States | 1 | 25.317 July | 4.4× |
| EdgewoodMaryland, United States | 2 | 32.718 July | 4.4× |
| CaryIllinois, United States | 1 | 40.616 July | 4.3× |
| NorthbrookIllinois, United States | 1 | 42.616 July | 4.3× |
| Saint AndrewsSouth Carolina, United States | 1 | 38.218 July | 4.3× |
| State CollegePennsylvania, United States | 2 | 31.317 July | 4.3× |
| Saint PaulMinnesota, United States | 1 | 43.215 July | 4.3× |
| SteubenvilleOhio, United States | 1 | 43.817 July | 4.3× |
| BaltimoreMaryland, United States | 2 | 32.717 July | 4.2× |
| NapervilleIllinois, United States | 1 | 47.916 July | 4.2× |
| WilkinsburgPennsylvania, United States | 1 | 41.117 July | 4.2× |
| LancasterPennsylvania, United States | 2 | 36.917 July | 4.2× |
| Hunt ValleyMaryland, United States | 2 | 28.517 July | 4.2× |
| NewarkDelaware, United States | 2 | 33.118 July | 4.2× |
| FlorenceSouth Carolina, United States | 2 | 37.718 July | 4.2× |
| Fort ThomasKentucky, United States | 2 | 33.016 July | 4.2× |
| Franklin ParkIllinois, United States | 1 | 48.316 July | 4.2× |
| Terre HauteIndiana, United States | 1 | 41.616 July | 4.2× |
| MadisonWisconsin, United States | 2 | 34.916 July | 4.2× |
| IndianapolisIndiana, United States | 2 | 44.316 July | 4.1× |
| AllentownPennsylvania, United States | 1 | 31.717 July | 4.1× |
| DerryNew Hampshire, United States | 1 | 29.217 July | 4.1× |
| WorcesterMassachusetts, United States | 1 | 28.717 July | 4.1× |
| WaterdownOntario, Canada | 1 | 34.317 July | 4.1× |
| SpringfieldVirginia, United States | 2 | 34.117 July | 4.1× |
| Valley StationKentucky, United States | 2 | 36.716 July | 4.0× |
| OmahaNebraska, United States | 2 | 32.816 July | 4.0× |
| WheelingWest Virginia, United States | 1 | 34.617 July | 4.0× |
| BellevilleOntario, Canada | 1 | 29.717 July | 4.0× |
| YorkPennsylvania, United States | 2 | 31.217 July | 3.9× |
| NorristownPennsylvania, United States | 2 | 29.619 July | 3.9× |
| KingstonOntario, Canada | 2 | 31.517 July | 3.9× |
| SherbrookeQuebec, Canada | 2 | 29.918 July | 3.9× |
| PortageIndiana, United States | 1 | 39.316 July | 3.9× |
| OakvilleOntario, Canada | 1 | 34.517 July | 3.9× |
| AppletonWisconsin, United States | 2 | 33.616 July | 3.9× |
| South BendIndiana, United States | 2 | 38.616 July | 3.9× |
| West FargoNorth Dakota, United States | 2 | 37.014 July | 3.9× |
| ChathamOntario, Canada | 1 | 28.817 July | 3.9× |
| South LaurelMaryland, United States | 1 | 30.317 July | 3.9× |
| AltoonaPennsylvania, United States | 2 | 33.017 July | 3.9× |
| CookevilleTennessee, United States | 1 | 28.317 July | 3.9× |
| PeterboroughOntario, Canada | 1 | 30.017 July | 3.8× |
| DrummondvilleQuebec, Canada | 1 | 31.918 July | 3.8× |
| McKeesportPennsylvania, United States | 1 | 35.917 July | 3.8× |
| Saint-Jean-sur-RichelieuQuebec, Canada | 1 | 27.018 July | 3.8× |
| SpringfieldMassachusetts, United States | 1 | 29.617 July | 3.8× |
| North CharlestonSouth Carolina, United States | 1 | 31.419 July | 3.8× |
| EdmundstonNew Brunswick, Canada | 1 | 27.618 July | 3.8× |
| GranbyQuebec, Canada | 1 | 33.218 July | 3.8× |
| HamiltonOntario, Canada | 1 | 34.917 July | 3.8× |
| BrantfordOntario, Canada | 1 | 33.417 July | 3.7× |
| LynnMassachusetts, United States | 1 | 25.617 July | 3.7× |
| BensalemPennsylvania, United States | 2 | 33.119 July | 3.7× |
| AugustaGeorgia, United States | 1 | 26.818 July | 3.7× |
| ReadingPennsylvania, United States | 1 | 28.517 July | 3.7× |
| CarlislePennsylvania, United States | 2 | 28.117 July | 3.6× |
| AlbanyNew York, United States | 2 | 35.018 July | 3.6× |
| CheektowagaNew York, United States | 2 | 47.317 July | 3.6× |
| FishersIndiana, United States | 2 | 37.416 July | 3.6× |
| QuébecQuebec, Canada | 1 | 32.813 July | 3.6× |
| L'Ancienne-LoretteQuebec, Canada | 2 | 37.113 July | 3.6× |
| LincolnNebraska, United States | 1 | 25.015 July | 3.5× |
| WilmingtonDelaware, United States | 1 | 27.118 July | 3.5× |
| ElktonMaryland, United States | 1 | 25.418 July | 3.5× |
| MississaugaOntario, Canada | 1 | 27.317 July | 3.5× |
| University CityMissouri, United States | 1 | 26.916 July | 3.4× |
| BlaineMinnesota, United States | 1 | 29.315 July | 3.4× |
| WashingtonDistrict of Columbia, United States | 1 | 32.217 July | 3.4× |
| South MilwaukeeWisconsin, United States | 2 | 29.116 July | 3.4× |
| BostonMassachusetts, United States | 1 | 26.317 July | 3.4× |
| PatersonNew Jersey, United States | 1 | 29.619 July | 3.4× |
| HarrisburgPennsylvania, United States | 2 | 31.819 July | 3.4× |
| La CrosseWisconsin, United States | 2 | 34.415 July | 3.4× |
| West MifflinPennsylvania, United States | 1 | 38.717 July | 3.4× |
| MontréalQuebec, Canada | 1 | 29.518 July | 3.4× |
| MiddletownOhio, United States | 2 | 39.817 July | 3.3× |
| WaukeshaWisconsin, United States | 2 | 31.115 July | 3.3× |
| BrossardQuebec, Canada | 1 | 31.718 July | 3.3× |
| NorwoodOhio, United States | 2 | 38.016 July | 3.3× |
| LebanonPennsylvania, United States | 2 | 29.817 July | 3.3× |
| ChicagoIllinois, United States | 1 | 32.416 July | 3.3× |
| PortlandMaine, United States | 1 | 28.718 July | 3.3× |
| East Saint LouisIllinois, United States | 1 | 33.116 July | 3.3× |
| ArnoldMissouri, United States | 1 | 26.116 July | 3.3× |
| CornwallOntario, Canada | 1 | 26.518 July | 3.2× |
| HendersonvilleTennessee, United States | 2 | 27.117 July | 3.2× |
| ScrantonPennsylvania, United States | 2 | 28.417 July | 3.2× |
| PhiladelphiaPennsylvania, United States | 1 | 31.819 July | 3.1× |
| BramptonOntario, Canada | 1 | 26.017 July | 3.1× |
| Green BayWisconsin, United States | 2 | 29.615 July | 3.1× |
| MilwaukeeWisconsin, United States | 2 | 31.715 July | 3.1× |
| HollandMichigan, United States | 1 | 29.516 July | 3.1× |
| ScaggsvilleMaryland, United States | 2 | 29.817 July | 3.1× |
| Trois-RivièresQuebec, Canada | 1 | 27.318 July | 3.1× |
| LondonOntario, Canada | 1 | 27.917 July | 3.1× |
| ElkhartIndiana, United States | 2 | 31.216 July | 3.1× |
| JohnstownPennsylvania, United States | 1 | 26.117 July | 3.1× |
| CincinnatiOhio, United States | 2 | 35.616 July | 3.1× |
| Oak LawnIllinois, United States | 1 | 31.416 July | 3.0× |
| ToledoOhio, United States | 2 | 33.217 July | 3.0× |
| MiltonOntario, Canada | 1 | 30.017 July | 3.0× |
| ShawiniganQuebec, Canada | 1 | 28.218 July | 3.0× |
| TorontoOntario, Canada | 1 | 28.717 July | 2.9× |
| Granite CityIllinois, United States | 1 | 29.616 July | 2.9× |
| St. LouisMissouri, United States | 1 | 28.916 July | 2.9× |
| Lincoln ParkMichigan, United States | 2 | 28.716 July | 2.8× |
| YpsilantiMichigan, United States | 1 | 25.216 July | 2.8× |
| JacksonTennessee, United States | 2 | 27.016 July | 2.8× |
| DuluthMinnesota, United States | 1 | 25.914 July | 2.6× |
| DetroitMichigan, United States | 2 | 26.716 July | 2.5× |
| DearbornMichigan, United States | 2 | 28.116 July | 2.5× |
| KalamazooMichigan, United States | 1 | 27.216 July | 2.4× |
| WindsorOntario, Canada | 1 | 26.117 July | 2.4× |
| SuperiorWisconsin, United States | 1 | 25.414 July | 2.4× |
| LexingtonMassachusetts, United States | 1 | 27.918 July | 2.3× |
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 3 of 45 episodes in the United States and Canada since our records began, by cities reached.
- North-eastern United States and Canada, June and July 2023279
- North-eastern United States and Canada, May and June 2023260
- North-eastern United States and Canada, July 2023241
- North-eastern United States and Canada, June 2023161
- North-western United States and Canada, August 2023110
- North-eastern United States and Canada, July 202375
- Western United States, September 202361
- South-eastern United States, October 202347
- North-eastern United States, July 202346
- North-western United States and Canada, May 202342
- Western United States, December 202332
- Northern United States, January 202332
Bars: cities reached; colour: the level of the episode's highest daily reading. All 45.
Use this page
SmogRank, North-eastern United States and Canada, July 2023: 241 cities with PM2.5 at twice their usual or more, 14 to 19 July 2023, smogrank.com/episodes/2023-07-north-eastern-united-states-and-canada (accessed 2 October 2026).
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.