Most & Least Polluted Cities
City-level rankings across the federal pollution corpus. TRI air ranks each city by the chemical releases reported inside its place polygon. PM2.5 and lifetime cancer risk are county-grain measurements — for those tables, each county is represented by its largest city so the ranking doesn't fill with sibling cities tied at the same value. Spans 50 ingested states (17256 cities total).
Tables marked county-grain measurementuse the value for the city's containing county — federal PM2.5 monitors and AirToxScreen surfaces are reported at the county level, not the place polygon.
PM2.5 Annual Mean (µg/m³)What is PM2.5?Fine inhalable particles 2.5 micrometers or smaller — about 1/30th the width of a human hair. They travel deep into the lungs and into the bloodstream, and are linked to asthma, heart disease, stroke, and premature death.
Cities with the highest annual PM2.5 concentrations — measured at the containing county's AQS monitors.
County-grain measurement · cities shown are the largest in each county.
| # | City | County | State | Population | PM2.5 Annual Mean |
|---|---|---|---|---|---|
| 1 | American Falls | Power County | Idaho | 4,573 | 22.854 |
| 2 | Atmore | Escambia County | Alabama | 8,465 | 16.850 |
| 3 | Concord | Cabarrus County | North Carolina | 105,335 | 16.672 |
| 4 | Covington | Kenton County | Kentucky | 40,923 | 16.242 |
| 5 | Brownsville | Cameron County | Texas | 186,999 | 15.608 |
| 6 | Columbus | Lowndes County | Mississippi | 23,896 | 15.536 |
| 7 | Weaverville | Trinity County | California | 3,582 | 15.517 |
| 8 | Greenwood | Greenwood County | South Carolina | 22,528 | 15.509 |
| 9 | Blytheville | Mississippi County | Arkansas | 13,276 | 15.465 |
| 10 | Burns | Harney County | Oregon | 2,735 | 15.460 |
PM2.5 Annual Mean (µg/m³)What is PM2.5?Fine inhalable particles 2.5 micrometers or smaller — about 1/30th the width of a human hair. They travel deep into the lungs and into the bloodstream, and are linked to asthma, heart disease, stroke, and premature death.
Cities with the lowest annual PM2.5 concentrations — measured at the containing county's AQS monitors.
County-grain measurement · cities shown are the largest in each county.
| # | City | County | State | Population | PM2.5 Annual Mean |
|---|---|---|---|---|---|
| 1 | Fairplay | Park County | Colorado | 782 | 1.673 |
| 2 | Healy | Denali Borough | Alaska | 865 | 1.765 |
| 3 | Pierre | Hughes County | South Dakota | 14,105 | 2.203 |
| 4 | Lihue | Kauai County | Hawaii | 8,649 | 2.292 |
| 5 | Hilo | Hawaii County | Hawaii | 47,627 | 2.407 |
| 6 | Laramie | Albany County | Wyoming | 31,735 | 2.453 |
| 7 | Amarillo | Potter County | Texas | 200,360 | 2.470 |
| 8 | Rawlins | Carbon County | Wyoming | 8,287 | 2.567 |
| 9 | Worland | Washakie County | Wyoming | 4,812 | 2.636 |
| 10 | Jerome | Jerome County | Idaho | 12,482 | 2.667 |
Lifetime Cancer Risk (All Pollutants) (per million)What this meansEPA-modeled added cancer cases per million residents from a lifetime of breathing local air toxics (AirToxScreen). EPA flags 100-in-a-million as elevated.
Cities with the highest AirToxScreen-modeled lifetime cancer risk — using the containing county's value.
County-grain measurement · cities shown are the largest in each county.
| # | City | County | State | Population | Lifetime Cancer Risk (All Pollutants) |
|---|---|---|---|---|---|
| 1 | Laplace | St. John the Baptist Parish | Louisiana | 28,956 | 78.9 |
| 2 | Lake Oswego | Clackamas County | Oregon | 40,457 | 77.3 |
| 3 | Santa Cruz | Santa Cruz County | California | 61,367 | 70.0 |
| 4 | Chico | Butte County | California | 102,790 | 54.8 |
| 5 | Prairieville | Ascension Parish | Louisiana | 34,215 | 53.9 |
| 6 | Portland | Multnomah County | Oregon | 646,101 | 51.9 |
| 7 | Cape Girardeau | Cape Girardeau County | Missouri | 39,795 | 50.8 |
| 8 | St. Gabriel | Iberville Parish | Louisiana | 6,526 | 49.5 |
| 9 | Sacramento | Sacramento County | California | 523,600 | 49.0 |
| 10 | Roseville | Placer County | California | 148,879 | 48.1 |
Lifetime Cancer Risk (All Pollutants) (per million)What this meansEPA-modeled added cancer cases per million residents from a lifetime of breathing local air toxics (AirToxScreen). EPA flags 100-in-a-million as elevated.
Cities with the lowest AirToxScreen-modeled lifetime cancer risk — using the containing county's value.
County-grain measurement · cities shown are the largest in each county.
| # | City | County | State | Population | Lifetime Cancer Risk (All Pollutants) |
|---|---|---|---|---|---|
| 1 | Akutan | Aleutians East Borough | Alaska | 911 | 7.2 |
| 2 | Unalaska | Aleutians West Census Area | Alaska | 4,342 | 7.4 |
| 3 | Nome | Nome Census Area | Alaska | 3,710 | 7.4 |
| 4 | Prudhoe Bay | North Slope Borough | Alaska | 1,986 | 8.1 |
| 5 | Kotzebue | Northwest Arctic Borough | Alaska | 3,088 | 8.5 |
| 6 | Bethel | Bethel Census Area | Alaska | 6,312 | 8.9 |
| 7 | Kokhanok | Lake and Peninsula Borough | Alaska | 115 | 9.0 |
| 8 | Haines | Haines Borough | Alaska | 1,762 | 9.1 |
| 9 | Lake City | Hinsdale County | Colorado | 465 | 9.1 |
| 10 | Dillingham | Dillingham Census Area | Alaska | 2,175 | 9.2 |
TRI Air Releases (lb)What this meansToxic chemicals reported by industrial facilities as released to the air — fugitive leaks plus smokestack emissions. Higher pounds means more inhaled exposure for nearby residents. Self-reported under EPA's Toxics Release Inventory.
Cities whose industrial facilities reported the largest air releases under TRI.
| # | City | County | State | Population | TRI Air Releases |
|---|---|---|---|---|---|
| 1 | Whiting | Lake County | Indiana | 4,574 | 6.9M lb |
| 2 | Norco | St. Charles Parish | Louisiana | 2,848 | 6.4M lb |
| 3 | Enid | Garfield County | Oklahoma | 50,961 | 6.0M lb |
| 4 | Augusta-Richmond County consolidated government (balance) | Richmond County | Georgia | 201,615 | 5.4M lb |
| 5 | Baytown | Harris County | Texas | 84,449 | 4.3M lb |
| 6 | Clinton | Clinton County | Iowa | 24,524 | 3.1M lb |
| 7 | Baton Rouge | East Baton Rouge Parish | Louisiana | 225,500 | 3.1M lb |
| 8 | Fort Madison | Lee County | Iowa | 10,293 | 2.7M lb |
| 9 | Prattville | Autauga County | Alabama | 38,124 | 2.6M lb |
| 10 | Danville | Vermilion County | Illinois | 29,100 | 2.5M lb |
TRI Air Releases (lb)What this meansToxic chemicals reported by industrial facilities as released to the air — fugitive leaks plus smokestack emissions. Higher pounds means more inhaled exposure for nearby residents. Self-reported under EPA's Toxics Release Inventory.
Cities with the smallest reported TRI air releases among those with reporting facilities.
Among cities with reported activity · cities with zero tri air releasesare excluded so the ranking isn't filled with places that simply host no facilities.
| # | City | County | State | Population | TRI Air Releases |
|---|---|---|---|---|---|
| 1 | Prudhoe Bay | North Slope Borough | Alaska | 1,986 | 1 lb |
| 2 | Gurley | Madison County | Alabama | 580 | 1 lb |
| 3 | Trussville | Jefferson County | Alabama | 25,621 | 1 lb |
| 4 | Peoria | Maricopa County | Arizona | 191,292 | 1 lb |
| 5 | Scottsdale | Maricopa County | Arizona | 240,537 | 1 lb |
| 6 | Stotonic Village | Pinal County | Arizona | 470 | 1 lb |
| 7 | Walnut Creek | Mohave County | Arizona | 642 | 1 lb |
| 8 | Cabazon | Riverside County | California | 1,946 | 1 lb |
| 9 | Gardena | Los Angeles County | California | 60,377 | 1 lb |
| 10 | Hemet | Riverside County | California | 89,651 | 1 lb |