SmogRank / Countries / United States / September 2026
Most polluted cities in United States, September 2026
694 cities in United States ranked by their average PM2.5 over the 30 days. Worst: Calexico at 23.0 µg/m³, #134 of 2,332 cities in the world. Cleanest: Oro Valley at 0.1. A city needs measurements on 70% of the days to be ranked.
- 1CalexicoCalifornia 23.0
- 2Jurupa ValleyCalifornia 12.9
- 3RiversideCalifornia 12.3
- 4Little RockArkansas 12.2
- 5HanfordCalifornia 12.1
- 6OceansideCalifornia 11.9
- 7LaredoTexas 11.4
- 8CorcoranCalifornia 11.1
- 8FontanaCalifornia 11.1
- 10ShreveportLouisiana 11.0
- 10Wake Forestlow-cost sensorsNorth Carolina 11.0
- 10ClovisCalifornia 11.0
- 13West MemphisArkansas 10.9
- 14WyomingMichigan 10.8
- 14FresnoCalifornia 10.8
- 16DallasTexas 10.6
- 16Los AngelesCalifornia 10.6
- 18MaconGeorgia 10.5
- 18WhittierCalifornia 10.5
- 20LimaOhio 10.4
- 21MiddletownOhio 10.3
- 22MonroeLouisiana 10.2
- 23SpringdaleArkansas 10.1
- 23BartlettTennessee 10.1
- 25ComptonCalifornia 9.9
- 25San DiegoCalifornia 9.9
- 27Granite CityIllinois 9.8
- 27MissionTexas 9.8
- 27Wheatonlow-cost sensorsIllinois 9.8
- 30Durantlow-cost sensorsOklahoma 9.7
- 30BrownsvilleTexas 9.7
- 30RichmondCalifornia 9.7
- 33Oklahoma CityOklahoma 9.6
- 33ChattanoogaTennessee 9.6
- 33Chula VistaCalifornia 9.6
- 33Tularelow-cost sensorsCalifornia 9.6
- 37BirminghamAlabama 9.5
- 37EdmondOklahoma 9.5
- 37TulsaOklahoma 9.5
- 37Hawthornelow-cost sensorsCalifornia 9.5
- 37Great FallsMontana 9.5
- 42GlendoraCalifornia 9.4
- 43MaderaCalifornia 9.3
- 44EdinburgTexas 9.2
- 44San AntonioTexas 9.2
- 44Mission ViejoCalifornia 9.2
- 44OdessaTexas 9.2
- 48AustinTexas 9.0
- 48Corpus ChristiTexas 9.0
- 48DentonTexas 9.0
- 48PasadenaTexas 9.0
- 48MercedCalifornia 9.0
- 53NorwoodOhio 8.9
- 53Live OakTexas 8.9
- 53Arroyo GrandeCalifornia 8.9
- 53BakersfieldCalifornia 8.9
- 53Carsonlow-cost sensorsCalifornia 8.9
- 53PortervilleCalifornia 8.9
- 53Santa ClaritaCalifornia 8.9
- 60AtlantaGeorgia 8.8
- 60Upper AltonIllinois 8.8
- 60JacksonTennessee 8.8
- 60Fort WorthTexas 8.8
- 64WichitaKansas 8.7
- 64LouisvilleKentucky 8.7
- 64NashvilleTennessee 8.7
- 64BridgeviewIllinois 8.7
- 64BurbankCalifornia 8.7
- 69MontgomeryAlabama 8.6
- 69Valley StationKentucky 8.6
- 69Agouralow-cost sensorsCalifornia 8.6
- 69Lake ElsinoreCalifornia 8.6
- 73East Saint LouisIllinois 8.5
- 73IndianapolisIndiana 8.5
- 73HernandoMississippi 8.5
- 73MooreOklahoma 8.5
- 73Ponca CityOklahoma 8.5
- 73BaytownTexas 8.5
- 73TexarkanaTexas 8.5
- 73AnaheimCalifornia 8.5
- 73El CajonCalifornia 8.5
- 73Santa Monicalow-cost sensorsCalifornia 8.5
- 83EvansvilleIndiana 8.4
- 83CincinnatiOhio 8.4
- 83PortsmouthOhio 8.4
- 83SpartanburgSouth Carolina 8.4
- 83Blue Islandlow-cost sensorsIllinois 8.4
- 83PowayCalifornia 8.4
- 89Calumet CityIllinois 8.3
- 89Franklin ParkIllinois 8.3
- 89Oak LawnIllinois 8.3
- 89Inglewoodlow-cost sensorsCalifornia 8.3
- 89El PasoTexas 8.3
- 94DecaturAlabama 8.2
- 94HuntsvilleAlabama 8.2
- 94Kansas CityKansas 8.2
- 94St. LouisMissouri 8.2
- 94HoustonTexas 8.2
- 94Long BeachCalifornia 8.2
- 100Terre HauteIndiana 8.1
- 100KnoxvilleTennessee 8.1
- 100Evergreen Parklow-cost sensorsIllinois 8.1
- 100Skokielow-cost sensorsIllinois 8.1
- 100San JoseCalifornia 8.1
- 100TurlockCalifornia 8.1
- 106GadsdenAlabama 8.0
- 106JasperIndiana 8.0
- 106JeffersonvilleIndiana 8.0
- 106DerbyKansas 8.0
- 106TopekaKansas 8.0
- 106LawtonOklahoma 8.0
- 106Nileslow-cost sensorsIllinois 8.0
- 106OrcuttCalifornia 8.0
- 114New AlbanyIndiana 7.9
- 114JenksOklahoma 7.9
- 114Saint AndrewsSouth Carolina 7.9
- 114NapervilleIllinois 7.9
- 114Park Ridgelow-cost sensorsIllinois 7.9
- 114Lomitalow-cost sensorsCalifornia 7.9
- 114MantecaCalifornia 7.9
- 114SalinasCalifornia 7.9
- 122AthensGeorgia 7.8
- 122OlatheKansas 7.8
- 122Saint MatthewsKentucky 7.8
- 122LemayMissouri 7.8
- 122HattiesburgMississippi 7.8
- 122CharlotteNorth Carolina 7.8
- 122Cedar ParkTexas 7.8
- 122Candler-McAfeeGeorgia 7.8
- 130TallahasseeFlorida 7.7
- 130ColumbusOhio 7.7
- 130ConroeTexas 7.7
- 130BrookfieldIllinois 7.7
- 130PeoriaIllinois 7.7
- 130MuncieIndiana 7.7
- 130LewistonIdaho 7.7
- 137AugustaGeorgia 7.6
- 137ValdostaGeorgia 7.6
- 137DecaturIllinois 7.6
- 137McAlesterOklahoma 7.6
- 137HendersonvilleTennessee 7.6
- 137SaginawTexas 7.6
- 137San LeandroCalifornia 7.6
- 144Kendale LakesFlorida 7.5
- 144Warner RobinsGeorgia 7.5
- 144OwensboroKentucky 7.5
- 144Baton RougeLouisiana 7.5
- 144Winston-SalemNorth Carolina 7.5
- 144College StationTexas 7.5
- 144Deer ParkTexas 7.5
- 144Evanstonlow-cost sensorsIllinois 7.5
- 144WestervilleOhio 7.5
- 144Torrancelow-cost sensorsCalifornia 7.5
- 154AshevilleNorth Carolina 7.4
- 154DyersburgTennessee 7.4
- 154DoltonIllinois 7.4
- 154BuffaloNew York 7.4
- 154ClevelandOhio 7.4
- 154HobbsNew Mexico 7.4
- 160BessemerAlabama 7.3
- 160FayettevilleNorth Carolina 7.3
- 160BeltonTexas 7.3
- 160CorsicanaTexas 7.3
- 160PerrysburgOhio 7.3
- 160Oconomowoclow-cost sensorsWisconsin 7.3
- 160Pasadenalow-cost sensorsCalifornia 7.3
- 160Santa CruzCalifornia 7.3
- 160Yuba CityCalifornia 7.3
- 160SocorroTexas 7.3
- 170Lawrencelow-cost sensorsKansas 7.2
- 170JeffersontownKentucky 7.2
- 170ClemmonsNorth Carolina 7.2
- 170MorrisvilleNorth Carolina 7.2
- 170North CharlestonSouth Carolina 7.2
- 175Ferry PassFlorida 7.1
- 175ColumbusGeorgia 7.1
- 175ElizabethtownKentucky 7.1
- 175DaytonOhio 7.1
- 175ClarksvilleTennessee 7.1
- 175ChicagoIllinois 7.1
- 175Michigan CityIndiana 7.1
- 175Ann Arborlow-cost sensorsMichigan 7.1
- 175Elk Grovelow-cost sensorsCalifornia 7.1
- 175MidwayFlorida 7.1
- 185Columbialow-cost sensorsMissouri 7.0
- 185LexingtonNorth Carolina 7.0
- 185MaryvilleTennessee 7.0
- 185Missouri CityTexas 7.0
- 185Fort WayneIndiana 7.0
- 185KalamazooMichigan 7.0
- 185ToledoOhio 7.0
- 185WarrenOhio 7.0
- 185LivermoreCalifornia 7.0
- 185Redwood CityCalifornia 7.0
- 185South Lake TahoeCalifornia 7.0
- 185VictorvilleCalifornia 7.0
- 185SunnysideWashington 7.0
- 185La Crescenta-Montroselow-cost sensorsCalifornia 7.0
- 199PaducahKentucky 6.9
- 199BloomingtonIndiana 6.9
- 199New OrleansLouisiana 6.9
- 199JacksonMississippi 6.9
- 199ChampaignIllinois 6.9
- 199ElginIllinois 6.9
- 199PortageIndiana 6.9
- 199OregonOhio 6.9
- 199NipomoCalifornia 6.9
- 199Prunedalelow-cost sensorsCalifornia 6.9
- 199San FranciscoCalifornia 6.9
- 199Simi ValleyCalifornia 6.9
- 199AmarilloTexas 6.9
- 212Kansas CityMissouri 6.8
- 212University CityMissouri 6.8
- 212Roanoke RapidsNorth Carolina 6.8
- 212SpringfieldOhio 6.8
- 212CharlestonWest Virginia 6.8
- 212CantonOhio 6.8
- 212BrawleyCalifornia 6.8
- 212Thousand OaksCalifornia 6.8
- 220PrichardAlabama 6.7
- 220OcalaFlorida 6.7
- 220Ponte Vedra BeachFlorida 6.7
- 220SpringfieldIllinois 6.7
- 220SpringfieldMissouri 6.7
- 220Mission BendTexas 6.7
- 220ChesapeakeVirginia 6.7
- 220WaterlooIowa 6.7
- 220ElkhartIndiana 6.7
- 220LincolnNebraska 6.7
- 220FillmoreCalifornia 6.7
- 220BanningCalifornia 6.7
- 220DavisCalifornia 6.7
- 220Delanolow-cost sensorsCalifornia 6.7
- 220StocktonCalifornia 6.7
- 235SavannahGeorgia 6.6
- 235Lexington-FayetteKentucky 6.6
- 235ChalmetteLouisiana 6.6
- 235GulfportMississippi 6.6
- 235GreensboroNorth Carolina 6.6
- 235ColumbiaTennessee 6.6
- 235BloomingtonIllinois 6.6
- 235NorthbrookIllinois 6.6
- 235DearbornMichigan 6.6
- 235FlintMichigan 6.6
- 235West MifflinPennsylvania 6.6
- 235BerkeleyCalifornia 6.6
- 235VallejoCalifornia 6.6
- 235Arden-ArcadeCalifornia 6.6
- 249GainesvilleGeorgia 6.5
- 249LawrencevilleGeorgia 6.5
- 249ArnoldMissouri 6.5
- 249HickoryNorth Carolina 6.5
- 249PennsaukenNew Jersey 6.5
- 249AndersonIndiana 6.5
- 249HammondIndiana 6.5
- 249LancasterPennsylvania 6.5
- 249PittsburghPennsylvania 6.5
- 249LincolnCalifornia 6.5
- 249OxnardCalifornia 6.5
- 249NampaIdaho 6.5
- 249MillcreekUtah 6.5
- 249RentonWashington 6.5
- 263LeawoodKansas 6.4
- 263NicholasvilleKentucky 6.4
- 263ClaytonNorth Carolina 6.4
- 263Camdenlow-cost sensorsNew Jersey 6.4
- 263GreenvilleSouth Carolina 6.4
- 263CookevilleTennessee 6.4
- 263BristolVirginia 6.4
- 263AuroraIllinois 6.4
- 263Elmwood ParkIllinois 6.4
- 263RockfordIllinois 6.4
- 263GaryIndiana 6.4
- 263KokomoIndiana 6.4
- 263TemeculaCalifornia 6.4
- 263GreshamOregon 6.4
- 277Bonita SpringsFlorida 6.3
- 277AshlandKentucky 6.3
- 277Fort ThomasKentucky 6.3
- 277KennerLouisiana 6.3
- 277Saint JosephMissouri 6.3
- 277ClintonIowa 6.3
- 277JolietIllinois 6.3
- 277South BendIndiana 6.3
- 277LansingMichigan 6.3
- 277Maplewoodlow-cost sensorsMinnesota 6.3
- 287VeniceFlorida 6.2
- 287HarrisonburgVirginia 6.2
- 287HopewellVirginia 6.2
- 287Grand RapidsMichigan 6.2
- 287JenisonMichigan 6.2
- 287ElizabethNew Jersey 6.2
- 287HarrisburgPennsylvania 6.2
- 287GaltCalifornia 6.2
- 287LubbockTexas 6.2
- 287Columbia CityWashington 6.2
- 287TacomaWashington 6.2
- 298YorkPennsylvania 6.1
- 298GalvestonTexas 6.1
- 298DetroitMichigan 6.1
- 298SteubenvilleOhio 6.1
- 298McKeesportPennsylvania 6.1
- 298WaukeshaWisconsin 6.1
- 298ConcordCalifornia 6.1
- 298TigardOregon 6.1
- 306MiamiFlorida 6.0
- 306DurhamNorth Carolina 6.0
- 306RaleighNorth Carolina 6.0
- 306East HamptonVirginia 6.0
- 306SalemVirginia 6.0
- 306Cedar RapidsIowa 6.0
- 306Iowa CityIowa 6.0
- 306East ChicagoIndiana 6.0
- 306MedinaOhio 6.0
- 306WilkinsburgPennsylvania 6.0
- 306Florinlow-cost sensorsCalifornia 6.0
- 306Huntington Beachlow-cost sensorsCalifornia 6.0
- 306OaklandCalifornia 6.0
- 306RosevilleCalifornia 6.0
- 306WenatcheeWashington 6.0
- 321AnkenyIowa 5.9
- 321Bay CityMichigan 5.9
- 321Lincoln ParkMichigan 5.9
- 321YoungstownOhio 5.9
- 321BensalemPennsylvania 5.9
- 321El CentroCalifornia 5.9
- 321RenoNevada 5.9
- 321ReddingCalifornia 5.9
- 321West Valley CityUtah 5.9
- 321SeattleWashington 5.9
- 321VancouverWashington 5.9
- 332WashingtonDistrict of Columbia 5.8
- 332Fort LauderdaleFlorida 5.8
- 332ValricoFlorida 5.8
- 332West PensacolaFlorida 5.8
- 332AlbanyGeorgia 5.8
- 332SulphurLouisiana 5.8
- 332LebanonOhio 5.8
- 332MasonOhio 5.8
- 332DavenportIowa 5.8
- 341LafayetteLouisiana 5.7
- 341RaymoreMissouri 5.7
- 341PascagoulaMississippi 5.7
- 341ChambersburgPennsylvania 5.7
- 341PhiladelphiaPennsylvania 5.7
- 341RoanokeVirginia 5.7
- 341MolineIllinois 5.7
- 341YpsilantiMichigan 5.7
- 341AkronOhio 5.7
- 341JohnstownPennsylvania 5.7
- 341GilroyCalifornia 5.7
- 341SacramentoCalifornia 5.7
- 341Seasidelow-cost sensorsCalifornia 5.7
- 341South San Franciscolow-cost sensorsCalifornia 5.7
- 341West JordanUtah 5.7
- 356Fort SmithArkansas 5.6
- 356BaltimoreMaryland 5.6
- 356KingsportTennessee 5.6
- 356RichmondVirginia 5.6
- 356Short PumpVirginia 5.6
- 356CaryIllinois 5.6
- 356Abingtonlow-cost sensorsPennsylvania 5.6
- 356Green BayWisconsin 5.6
- 356South MilwaukeeWisconsin 5.6
- 356WeirtonWest Virginia 5.6
- 356AuburnWashington 5.6
- 356BellinghamWashington 5.6
- 368FairhopeAlabama 5.5
- 368DoverDelaware 5.5
- 368Toms RiverNew Jersey 5.5
- 368Cleveland HeightsOhio 5.5
- 368Fort DodgeIowa 5.5
- 368Des PlainesIllinois 5.5
- 368TaylorMichigan 5.5
- 368Jersey CityNew Jersey 5.5
- 368LindenNew Jersey 5.5
- 368DublinOhio 5.5
- 368Shaker HeightsOhio 5.5
- 368Upper Saint ClairPennsylvania 5.5
- 368NogalesArizona 5.5
- 368YumaArizona 5.5
- 368MeridianIdaho 5.5
- 368KentWashington 5.5
- 384PleasantvilleNew Jersey 5.4
- 384CharlottesvilleVirginia 5.4
- 384MuscatineIowa 5.4
- 384RochesterMinnesota 5.4
- 384GahannaOhio 5.4
- 384LebanonPennsylvania 5.4
- 384TucsonArizona 5.4
- 384ModestoCalifornia 5.4
- 384UkiahCalifornia 5.4
- 384Sunland ParkNew Mexico 5.4
- 384Coeur d'AleneIdaho 5.4
- 395BrunswickGeorgia 5.3
- 395McDonoughGeorgia 5.3
- 395FishersIndiana 5.3
- 395White OakOhio 5.3
- 395MinneapolisMinnesota 5.3
- 395OmahaNebraska 5.3
- 395ScrantonPennsylvania 5.3
- 395Eau ClaireWisconsin 5.3
- 395ParadiseCalifornia 5.3
- 395Salt Lake CityUtah 5.3
- 395Spanish ForkUtah 5.3
- 395BremertonWashington 5.3
- 407JacksonvilleFlorida 5.2
- 407LibertyMissouri 5.2
- 407La PorteTexas 5.2
- 407SpringfieldVirginia 5.2
- 407LafayetteIndiana 5.2
- 407Port HuronMichigan 5.2
- 407MankatoMinnesota 5.2
- 407EwingNew Jersey 5.2
- 407TrentonNew Jersey 5.2
- 407PainesvilleOhio 5.2
- 407PawtucketRhode Island 5.2
- 407Weirton HeightsWest Virginia 5.2
- 407TracyCalifornia 5.2
- 407TruckeeCalifornia 5.2
- 407Watsonvillelow-cost sensorsCalifornia 5.2
- 407The DallesOregon 5.2
- 407TooeleUtah 5.2
- 407SheridanWyoming 5.2
- 425Pompano BeachFlorida 5.1
- 425ScaggsvilleMaryland 5.1
- 425GreenvilleNorth Carolina 5.1
- 425AshburnVirginia 5.1
- 425Des MoinesIowa 5.1
- 425SouthfieldMichigan 5.1
- 425NewarkNew Jersey 5.1
- 425HermitagePennsylvania 5.1
- 425Windsorlow-cost sensorsCalifornia 5.1
- 425BountifulUtah 5.1
- 425Moses LakeWashington 5.1
- 425PullmanWashington 5.1
- 437ColumbusIndiana 5.0
- 437BayonneNew Jersey 5.0
- 437Sioux FallsSouth Dakota 5.0
- 437TempeArizona 5.0
- 437Northglennlow-cost sensorsColorado 5.0
- 437ThorntonColorado 5.0
- 437Brigham CityUtah 5.0
- 437MagnaUtah 5.0
- 445WilmingtonDelaware 4.9
- 445GainesvilleFlorida 4.9
- 445ZionIllinois 4.9
- 445BlaineMinnesota 4.9
- 445Saint PaulMinnesota 4.9
- 445PatersonNew Jersey 4.9
- 445New York CityNew York 4.9
- 445SuperiorWisconsin 4.9
- 445ChicoCalifornia 4.9
- 445Los Banoslow-cost sensorsCalifornia 4.9
- 445BillingsMontana 4.9
- 445EllensburgWashington 4.9
- 445ShorelineWashington 4.9
- 445YakimaWashington 4.9
- 459BearDelaware 4.8
- 459BartowFlorida 4.8
- 459Oak RidgeFlorida 4.8
- 459South LaurelMaryland 4.8
- 459BurnsvilleMinnesota 4.8
- 459RochesterNew York 4.8
- 459State CollegePennsylvania 4.8
- 459MadisonWisconsin 4.8
- 459FlagstaffArizona 4.8
- 459PhoenixArizona 4.8
- 459AtascaderoCalifornia 4.8
- 459RidgecrestCalifornia 4.8
- 459San RafaelCalifornia 4.8
- 459Cedar CityUtah 4.8
- 459GreeleyColorado 4.8
- 459HermistonOregon 4.8
- 459MarysvilleWashington 4.8
- 459Port AngelesWashington 4.8
- 459BadgerAlaska 4.8
- 459Four CornersFlorida 4.8
- 479Delray BeachFlorida 4.7
- 479Hunt ValleyMaryland 4.7
- 479Rose HillVirginia 4.7
- 479BrocktonMassachusetts 4.7
- 479RedfordMichigan 4.7
- 479Saint MichaelMinnesota 4.7
- 479RutlandVermont 4.7
- 479IndioCalifornia 4.7
- 479Westminsterlow-cost sensorsColorado 4.7
- 479PocatelloIdaho 4.7
- 479CanbyOregon 4.7
- 479HerrimanUtah 4.7
- 479Spokane ValleyWashington 4.7
- 479RandolphNew Jersey 4.7
- 493Coconut CreekFlorida 4.6
- 493Deerfield BeachFlorida 4.6
- 493SpringfieldMassachusetts 4.6
- 493EastpointeMichigan 4.6
- 493Apple ValleyMinnesota 4.6
- 493ShakopeeMinnesota 4.6
- 493EriePennsylvania 4.6
- 493HollisterCalifornia 4.6
- 493Rapid CitySouth Dakota 4.6
- 493OremUtah 4.6
- 493BurienWashington 4.6
- 493SpokaneWashington 4.6
- 493Walla WallaWashington 4.6
- 506Palm CityFlorida 4.5
- 506EdgewoodMaryland 4.5
- 506ElktonMaryland 4.5
- 506HagerstownMaryland 4.5
- 506Atlantic CityNew Jersey 4.5
- 506PortlandMaine 4.5
- 506Saint CloudMinnesota 4.5
- 506AllentownPennsylvania 4.5
- 506ReadingPennsylvania 4.5
- 506LancasterCalifornia 4.5
- 506Spanish SpringsNevada 4.5
- 506Fort CollinsColorado 4.5
- 506BozemanMontana 4.5
- 506PortlandOregon 4.5
- 506LongviewWashington 4.5
- 521NewarkDelaware 4.4
- 521Daytona BeachFlorida 4.4
- 521Lake MaryFlorida 4.4
- 521St. PetersburgFlorida 4.4
- 521TampaFlorida 4.4
- 521New HavenConnecticut 4.4
- 521WaterburyConnecticut 4.4
- 521SyracuseNew York 4.4
- 521CarlislePennsylvania 4.4
- 521AppletonWisconsin 4.4
- 521Goletalow-cost sensorsCalifornia 4.4
- 521Twin FallsIdaho 4.4
- 521AltamontOregon 4.4
- 521EugeneOregon 4.4
- 521SalemOregon 4.4
- 521CentraliaWashington 4.4
- 521ParklandWashington 4.4
- 521Salmon CreekWashington 4.4
- 539DavieFlorida 4.3
- 539WellingtonFlorida 4.3
- 539ChesterPennsylvania 4.3
- 539HartfordConnecticut 4.3
- 539BostonMassachusetts 4.3
- 539Fort LeeNew Jersey 4.3
- 539BethlehemPennsylvania 4.3
- 539Casa GrandeArizona 4.3
- 539GlendaleArizona 4.3
- 539PaysonArizona 4.3
- 539FolsomCalifornia 4.3
- 539Santa RosaCalifornia 4.3
- 539LongmontColorado 4.3
- 539AlbanyOregon 4.3
- 539BeavertonOregon 4.3
- 539AberdeenWashington 4.3
- 539LaceyWashington 4.3
- 539KahuluiHawaii 4.3
- 557Belle GladeFlorida 4.2
- 557OrlandoFlorida 4.2
- 557South VinelandNew Jersey 4.2
- 557Fall RiverMassachusetts 4.2
- 557QuincyMassachusetts 4.2
- 557AugustaMaine 4.2
- 557New BrunswickNew Jersey 4.2
- 557BridgeportConnecticut 4.2
- 557MesaArizona 4.2
- 557DenverColorado 4.2
- 557Las CrucesNew Mexico 4.2
- 557Forest GroveOregon 4.2
- 557North OgdenUtah 4.2
- 557BellevueWashington 4.2
- 557KennewickWashington 4.2
- 557PascoWashington 4.2
- 573Fort MyersFlorida 4.1
- 573DanburyConnecticut 4.1
- 573LowellMassachusetts 4.1
- 573DuluthMinnesota 4.1
- 573BellevueNebraska 4.1
- 573PortsmouthNew Hampshire 4.1
- 573AlbanyNew York 4.1
- 573BurlingtonVermont 4.1
- 573Brookfieldlow-cost sensorsWisconsin 4.1
- 573Colorado SpringsColorado 4.1
- 573MoscowIdaho 4.1
- 573HillsboroOregon 4.1
- 585Safety HarborFlorida 4.0
- 585Winter ParkFlorida 4.0
- 585MarquetteMichigan 4.0
- 585KeeneNew Hampshire 4.0
- 585HolbrookNew York 4.0
- 585NorristownPennsylvania 4.0
- 585Casas AdobesArizona 4.0
- 585Palo Altolow-cost sensorsCalifornia 4.0
- 585WindsorColorado 4.0
- 585AshlandOregon 4.0
- 585BendOregon 4.0
- 585PendletonOregon 4.0
- 585Tri-CitiesWashington 4.0
- 598GreenfieldMassachusetts 3.9
- 598LynnMassachusetts 3.9
- 598MilfordMassachusetts 3.9
- 598DerryNew Hampshire 3.9
- 598WatertownSouth Dakota 3.9
- 598PuebloColorado 3.9
- 598Rio RanchoNew Mexico 3.9
- 598Las VegasNevada 3.9
- 598Apache JunctionArizona 3.9
- 598KīheiHawaii 3.9
- 598HonoluluHawaii 3.9
- 609East LakeFlorida 3.8
- 609SarasotaFlorida 3.8
- 609SewellNew Jersey 3.8
- 609PittsfieldMassachusetts 3.8
- 609AltoonaPennsylvania 3.8
- 609AlbuquerqueNew Mexico 3.8
- 609BismarckNorth Dakota 3.8
- 609MedfordOregon 3.8
- 609WoodburnOregon 3.8
- 609Picnic Point-North LynnwoodWashington 3.8
- 619Palm BayFlorida 3.7
- 619West FargoNorth Dakota 3.7
- 619La VistaNebraska 3.7
- 619BoiseIdaho 3.7
- 619Coos BayOregon 3.7
- 619McMinnvilleOregon 3.7
- 619Mount VernonWashington 3.7
- 619AnchorageAlaska 3.7
- 627FraminghamMassachusetts 3.6
- 627HaverhillMassachusetts 3.6
- 627WorcesterMassachusetts 3.6
- 627LompocCalifornia 3.6
- 627South ValleyNew Mexico 3.6
- 632New LondonConnecticut 3.5
- 632HurricaneUtah 3.5
- 632Idaho FallsIdaho 3.5
- 632ButteMontana 3.5
- 632HelenaMontana 3.5
- 632Grants PassOregon 3.5
- 632MilwaukieOregon 3.5
- 632Oxon Hill-GlassmanorMaryland 3.5
- 640LewistonMaine 3.4
- 640MaranaArizona 3.4
- 640Arvadalow-cost sensorsColorado 3.4
- 640Carson CityNevada 3.4
- 640EnterpriseNevada 3.4
- 640Oregon CityOregon 3.4
- 640Monroelow-cost sensorsWashington 3.4
- 640HiloHawaii 3.4
- 648North ChicopeeMassachusetts 3.3
- 648BangorMaine 3.3
- 648UticaNew York 3.3
- 648HendersonNevada 3.3
- 648DallasOregon 3.3
- 648Inglewood-Finn Hilllow-cost sensorsWashington 3.3
- 654ProvidenceRhode Island 3.2
- 654Encinitaslow-cost sensorsCalifornia 3.2
- 654VacavilleCalifornia 3.2
- 654Spring ValleyNevada 3.2
- 654BoulderColorado 3.2
- 654RedmondOregon 3.2
- 654RoseburgOregon 3.2
- 654Bothelllow-cost sensorsWashington 3.2
- 662BrookingsSouth Dakota 3.1
- 662Ken CarylColorado 3.1
- 662CorvallisOregon 3.1
- 665Green ValleyArizona 3.0
- 665Cañon CityColorado 3.0
- 665AnacortesWashington 3.0
- 665CasperWyoming 3.0
- 665Summerlin SouthNevada 3.0
- 670Goldenlow-cost sensorsColorado 2.9
- 670Boulder CityNevada 2.9
- 670MesquiteNevada 2.9
- 673LittletonColorado 2.8
- 673MissoulaMontana 2.8
- 673Kirklandlow-cost sensorsWashington 2.8
- 676North Creeklow-cost sensorsWashington 2.7
- 676GilletteWyoming 2.7
- 676Union Hill-Novelty Hilllow-cost sensorsWashington 2.7
- 679LaconiaNew Hampshire 2.6
- 679Middletonlow-cost sensorsWisconsin 2.6
- 681FairbanksAlaska 2.5
- 682CheyenneWyoming 2.4
- 683New CityNew York 2.3
- 683NewburghNew York 2.3
- 685RockvilleMaryland 2.2
- 685AberdeenSouth Dakota 2.2
- 687White PlainsNew York 2.1
- 688Lakewoodlow-cost sensorsColorado 2.0
- 689LaramieWyoming 1.9
- 690Lexingtonlow-cost sensorsMassachusetts 1.6
- 691CoventryRhode Island 1.4
- 692Parkerlow-cost sensorsColorado 0.6
- 692Loganlow-cost sensorsUtah 0.6
- 694Oro Valleylow-cost sensorsArizona 0.1
Good0–9.0
Moderate9.1–35.4
Sensitive groups35.5–55.4
Unhealthy55.5–125.4
Very unhealthy125.5–225.4
Hazardous225.5+