Daily report · most polluted
US air quality on 18 October 2026
Billings Montana84
ModerateUS AQI
Billings had the most polluted air of 271 US cities
Updated · AirNow
At 4:00 pm ET on 18 October 2026, 271 US cities were reporting. Billings had the most polluted air at US AQI 84 (Moderate), followed by Santa Maria (72) and Hanford (70). The median across all cities was 32, up from 27 the day before. 0 cities were at Unhealthy or worse (0 the day before). Concord had the cleanest air at 1.
The biggest deterioration was in Shreveport, from 23 to 54. El Cajon improved most, from 87 to 42.
- Good 258
- Moderate 13
10 most polluted cities
| # | City | State | US AQI | Change |
|---|---|---|---|---|
| 1 | Billings | Montana | 84Moderate | ▲ 14 |
| 2 | Santa Maria | California | 72Moderate | ▲ 13 |
| 3 | Hanford | California | 70Moderate | ▲ 8 |
| 4 | San Francisco | California | 63Moderate | ▲ 11 |
| 5 | San Antonio | Texas | 58Moderate | ▲ 17 |
| 6 | San Jose | California | 58Moderate | ▲ 2 |
| 7 | Fresno | California | 58Moderate | 0 |
| 8 | Lewiston Orchards | Idaho | 58Moderate | ▼ 6 |
| 9 | Portland | Oregon | 55Moderate | ▼ 7 |
| 10 | San Mateo | California | 55Moderate | ▲ 3 |
10 cleanest cities
| # | City | State | US AQI | Change |
|---|---|---|---|---|
| 1 | Concord | New Hampshire | 1Good | 0 |
| 2 | Findlay | Ohio | 3Good | 0 |
| 3 | Kingman | Arizona | 5Good | ▼ 1 |
| 4 | Clarksville | Tennessee | 6Good | new |
| 5 | Ridgecrest | California | 8Good | ▼ 4 |
| 6 | Binghamton | New York | 9Good | new |
| 7 | Pocatello | Idaho | 9Good | 0 |
| 8 | Burlington | Vermont | 9Good | ▲ 3 |
| 9 | Albany | Georgia | 12Good | ▼ 7 |
| 10 | Midland | Texas | 13Good | ▲ 5 |
Biggest rises
All 271 cities on 18 October 2026
| # | City | State | US AQI | Change |
|---|---|---|---|---|
| 1 | Billings | Montana | 84Moderate | ▲ 14 |
| 2 | Santa Maria | California | 72Moderate | ▲ 13 |
| 3 | Hanford | California | 70Moderate | ▲ 8 |
| 4 | San Francisco | California | 63Moderate | ▲ 11 |
| 5 | San Antonio | Texas | 58Moderate | ▲ 17 |
| 6 | San Jose | California | 58Moderate | ▲ 2 |
| 7 | Fresno | California | 58Moderate | 0 |
| 8 | Lewiston Orchards | Idaho | 58Moderate | ▼ 6 |
| 9 | Portland | Oregon | 55Moderate | ▼ 7 |
| 10 | San Mateo | California | 55Moderate | ▲ 3 |
| 11 | Sacramento | California | 54Moderate | ▲ 7 |
| 12 | Shreveport | Louisiana | 54Moderate | ▲ 31 |
| 13 | Pittsburgh | Pennsylvania | 51Moderate | ▲ 20 |
| 14 | Reno | Nevada | 49Good | ▲ 8 |
| 15 | Redding | California | 48Good | ▲ 2 |
| 16 | Prescott Valley | Arizona | 48Good | ▲ 5 |
| 17 | Colorado Springs | Colorado | 46Good | ▲ 2 |
| 18 | Lafayette | Indiana | 46Good | ▲ 18 |
| 19 | Reedley | California | 46Good | ▲ 11 |
| 20 | Denver | Colorado | 45Good | ▼ 3 |
| 21 | Columbus | Ohio | 44Good | ▲ 15 |
| 22 | Los Angeles | California | 44Good | ▼ 11 |
| 23 | Bakersfield | California | 44Good | ▼ 21 |
| 24 | Rancho Palos Verdes | California | 44Good | ▼ 8 |
| 25 | San Diego | California | 43Good | ▼ 44 |
| 26 | Cheyenne | Wyoming | 42Good | ▼ 2 |
| 27 | El Cajon | California | 42Good | ▼ 45 |
| 28 | Houston | Texas | 41Good | ▲ 13 |
| 29 | Albuquerque | New Mexico | 41Good | ▲ 4 |
| 30 | Austin | Texas | 41Good | ▲ 7 |
| 31 | Miami | Florida | 41Good | ▲ 22 |
| 32 | Cleveland | Ohio | 41Good | ▲ 8 |
| 33 | Oxnard | California | 41Good | ▲ 1 |
| 34 | Rio Rancho | New Mexico | 41Good | ▲ 4 |
| 35 | Rapid City | South Dakota | 41Good | ▲ 6 |
| 36 | Carlsbad | New Mexico | 41Good | ▲ 10 |
| 37 | Casper | Wyoming | 40Good | ▼ 1 |
| 38 | Las Vegas | Nevada | 39Good | ▲ 2 |
| 39 | Corpus Christi | Texas | 39Good | ▲ 8 |
| 40 | Palm Bay | Florida | 39Good | ▼ 2 |
| 41 | Twin Falls | Idaho | 39Good | ▲ 1 |
| 42 | Kingsville | Texas | 39Good | ▲ 8 |
| 43 | Brownsville | Texas | 38Good | ▲ 17 |
| 44 | Chico | California | 38Good | ▼ 3 |
| 45 | Santa Fe | New Mexico | 38Good | ▲ 5 |
| 46 | Medford | Oregon | 37Good | ▼ 3 |
| 47 | Elmira | New York | 37Good | ▲ 8 |
| 48 | Jacksonville | Florida | 36Good | ▲ 7 |
| 49 | Columbia | South Carolina | 36Good | ▲ 12 |
| 50 | Oklahoma City | Oklahoma | 36Good | ▲ 8 |
| 51 | Rochester | New York | 36Good | ▲ 8 |
| 52 | Asheville | North Carolina | 36Good | ▲ 12 |
| 53 | Greenville | South Carolina | 36Good | ▲ 14 |
| 54 | San Luis | Arizona | 36Good | ▲ 14 |
| 55 | Providence | Rhode Island | 35Good | ▲ 13 |
| 56 | Lexington-Fayette | Kentucky | 35Good | ▲ 12 |
| 57 | Salt Lake City | Utah | 35Good | ▲ 2 |
| 58 | El Paso | Texas | 35Good | 0 |
| 59 | Raleigh | North Carolina | 35Good | ▲ 12 |
| 60 | Orlando | Florida | 35Good | ▼ 19 |
| 61 | Buffalo | New York | 35Good | ▲ 4 |
| 62 | Fort Lauderdale | Florida | 35Good | ▲ 9 |
| 63 | Syracuse | New York | 35Good | ▲ 7 |
| 64 | Port Arthur | Texas | 35Good | ▲ 8 |
| 65 | Niagara Falls | New York | 35Good | ▲ 4 |
| 66 | Mentor | Ohio | 35Good | ▲ 2 |
| 67 | State College | Pennsylvania | 35Good | ▲ 8 |
| 68 | Weatherford | Texas | 35Good | ▲ 7 |
| 69 | Wilmington | Delaware | 34Good | ▲ 11 |
| 70 | Atlanta | Georgia | 34Good | ▲ 7 |
| 71 | Jackson | Mississippi | 34Good | ▼ 4 |
| 72 | Tucson | Arizona | 34Good | ▼ 10 |
| 73 | Nashville | Tennessee | 34Good | ▲ 7 |
| 74 | Louisville | Kentucky | 34Good | ▲ 8 |
| 75 | Spokane | Washington | 34Good | ▼ 15 |
| 76 | Columbus | Georgia | 34Good | ▲ 8 |
| 77 | Huntsville | Alabama | 34Good | ▲ 7 |
| 78 | Cape Coral | Florida | 34Good | ▲ 10 |
| 79 | Springfield | Missouri | 34Good | ▲ 7 |
| 80 | Salem | Oregon | 34Good | ▲ 2 |
| 81 | Rochester | Minnesota | 34Good | ▲ 5 |
| 82 | The Woodlands | Texas | 34Good | ▲ 10 |
| 83 | Deltona | Florida | 34Good | ▼ 18 |
| 84 | Lehigh Acres | Florida | 34Good | ▲ 10 |
| 85 | Missoula | Montana | 34Good | ▼ 6 |
| 86 | Flagstaff | Arizona | 34Good | ▼ 9 |
| 87 | Victoria | Texas | 34Good | ▲ 3 |
| 88 | Auburn | Alabama | 34Good | ▲ 8 |
| 89 | Butte | Montana | 34Good | ▲ 22 |
| 90 | Pleasure Ridge Park | Kentucky | 34Good | ▲ 8 |
| 91 | Bridgeport | Connecticut | 33Good | ▲ 10 |
| 92 | Manchester | New Hampshire | 33Good | ▲ 3 |
| 93 | Chicago | Illinois | 33Good | ▼ 1 |
| 94 | Wichita | Kansas | 33Good | ▲ 4 |
| 95 | Omaha | Nebraska | 33Good | ▲ 2 |
| 96 | Birmingham | Alabama | 33Good | ▲ 6 |
| 97 | Phoenix | Arizona | 33Good | ▼ 45 |
| 98 | Laredo | Texas | 33Good | ▲ 3 |
| 99 | Gilbert | Arizona | 33Good | ▼ 11 |
| 100 | Montgomery | Alabama | 33Good | ▲ 7 |
| 101 | Grand Rapids | Michigan | 33Good | ▼ 6 |
| 102 | McAllen | Texas | 33Good | ▲ 9 |
| 103 | Evansville | Indiana | 33Good | ▲ 2 |
| 104 | Beaumont | Texas | 33Good | ▲ 9 |
| 105 | Yuma | Arizona | 33Good | ▼ 29 |
| 106 | Greenville | North Carolina | 33Good | ▲ 14 |
| 107 | Fort Smith | Arkansas | 33Good | ▲ 7 |
| 108 | Bismarck | North Dakota | 33Good | ▲ 8 |
| 109 | Bozeman | Montana | 33Good | ▲ 3 |
| 110 | Houma | Louisiana | 33Good | ▲ 3 |
| 111 | Aberdeen | South Dakota | 33Good | ▲ 2 |
| 112 | Newark | New Jersey | 32Good | ▲ 9 |
| 113 | Philadelphia | Pennsylvania | 32Good | ▲ 9 |
| 114 | Baltimore | Maryland | 32Good | ▲ 8 |
| 115 | Virginia Beach | Virginia | 32Good | ▲ 10 |
| 116 | Washington, D.C. | District of Columbia | 32Good | ▲ 5 |
| 117 | Memphis | Tennessee | 32Good | ▲ 5 |
| 118 | Cincinnati | Ohio | 32Good | ▲ 10 |
| 119 | Toledo | Ohio | 32Good | ▲ 3 |
| 120 | Baton Rouge | Louisiana | 32Good | ▲ 7 |
| 121 | Overland Park | Kansas | 32Good | ▲ 8 |
| 122 | Eugene | Oregon | 32Good | ▼ 10 |
| 123 | Norman | Oklahoma | 32Good | ▲ 7 |
| 124 | Wilmington | North Carolina | 32Good | ▲ 13 |
| 125 | Provo | Utah | 32Good | ▼ 5 |
| 126 | Lansing | Michigan | 32Good | ▲ 4 |
| 127 | South Bend | Indiana | 32Good | ▲ 2 |
| 128 | Erie | Pennsylvania | 32Good | ▲ 5 |
| 129 | Flint | Michigan | 32Good | ▲ 3 |
| 130 | Yakima | Washington | 32Good | ▼ 39 |
| 131 | Southaven | Mississippi | 32Good | ▲ 5 |
| 132 | Collierville | Tennessee | 32Good | ▲ 5 |
| 133 | Palm Springs | California | 32Good | ▼ 23 |
| 134 | Altoona | Pennsylvania | 32Good | ▲ 4 |
| 135 | Mankato | Minnesota | 32Good | ▲ 2 |
| 136 | Hobbs | New Mexico | 32Good | ▲ 4 |
| 137 | Pleasant Grove | Utah | 32Good | ▼ 5 |
| 138 | Morgantown | West Virginia | 32Good | ▲ 3 |
| 139 | New York City | New York | 31Good | ▲ 7 |
| 140 | Indianapolis | Indiana | 31Good | ▲ 5 |
| 141 | Detroit | Michigan | 31Good | 0 |
| 142 | Des Moines | Iowa | 31Good | ▲ 4 |
| 143 | Minneapolis | Minnesota | 31Good | ▲ 1 |
| 144 | Charlotte | North Carolina | 31Good | ▲ 6 |
| 145 | New Orleans | Louisiana | 31Good | ▲ 4 |
| 146 | Tulsa | Oklahoma | 31Good | ▲ 4 |
| 147 | Tampa | Florida | 31Good | ▼ 23 |
| 148 | St. Louis | Missouri | 31Good | ▲ 4 |
| 149 | Ironville | Kentucky | 31Good | ▲ 5 |
| 150 | Lincoln | Nebraska | 31Good | ▲ 6 |
| 151 | Fort Wayne | Indiana | 31Good | ▲ 3 |
| 152 | Fayetteville | North Carolina | 31Good | ▲ 6 |
| 153 | Knoxville | Tennessee | 31Good | ▲ 12 |
| 154 | Chattanooga | Tennessee | 31Good | ▲ 13 |
| 155 | Dayton | Ohio | 31Good | ▲ 6 |
| 156 | Cedar Rapids | Iowa | 31Good | ▲ 7 |
| 157 | Topeka | Kansas | 31Good | ▲ 6 |
| 158 | Allentown | Pennsylvania | 31Good | ▲ 6 |
| 159 | Athens | Georgia | 31Good | ▲ 7 |
| 160 | Springfield | Illinois | 31Good | ▲ 9 |
| 161 | Peoria | Illinois | 31Good | ▲ 5 |
| 162 | Tyler | Texas | 31Good | ▲ 7 |
| 163 | Las Cruces | New Mexico | 31Good | 0 |
| 164 | Roanoke | Virginia | 31Good | ▲ 12 |
| 165 | Columbia | Maryland | 31Good | ▲ 6 |
| 166 | Albany | New York | 31Good | ▲ 1 |
| 167 | Tuscaloosa | Alabama | 31Good | ▲ 6 |
| 168 | Champaign | Illinois | 31Good | ▲ 2 |
| 169 | Sioux City | Iowa | 31Good | ▲ 6 |
| 170 | Lake Charles | Louisiana | 31Good | ▲ 4 |
| 171 | Gulfport | Mississippi | 31Good | ▲ 6 |
| 172 | Kingsport | Tennessee | 31Good | ▲ 8 |
| 173 | Minot | North Dakota | 31Good | ▲ 3 |
| 174 | Cleveland | Tennessee | 31Good | ▲ 13 |
| 175 | Augusta | Georgia | 31Good | ▲ 4 |
| 176 | Farmington | New Mexico | 31Good | 0 |
| 177 | Muskegon | Michigan | 31Good | ▲ 4 |
| 178 | Navarre | Florida | 31Good | ▲ 4 |
| 179 | Myrtle Beach | South Carolina | 31Good | ▲ 2 |
| 180 | Cedar City | Utah | 31Good | ▼ 4 |
| 181 | Port Huron | Michigan | 31Good | ▼ 3 |
| 182 | North Kingstown | Rhode Island | 31Good | ▲ 10 |
| 183 | Saratoga Springs | New York | 31Good | 0 |
| 184 | Sioux Falls | South Dakota | 30Good | ▲ 4 |
| 185 | Richmond | Virginia | 30Good | ▲ 10 |
| 186 | Amarillo | Texas | 30Good | ▲ 21 |
| 187 | Mobile | Alabama | 30Good | ▲ 2 |
| 188 | Worcester | Massachusetts | 30Good | ▲ 9 |
| 189 | Joliet | Illinois | 30Good | ▲ 5 |
| 190 | Waco | Texas | 30Good | ▲ 4 |
| 191 | Davenport | Iowa | 30Good | ▲ 4 |
| 192 | Saint George | Utah | 30Good | ▼ 9 |
| 193 | Bowling Green | Kentucky | 30Good | ▲ 11 |
| 194 | Quincy | Illinois | 30Good | ▲ 5 |
| 195 | Annapolis | Maryland | 30Good | ▲ 5 |
| 196 | Parkersburg | West Virginia | 30Good | ▲ 1 |
| 197 | Aiken | South Carolina | 30Good | 0 |
| 198 | Boston | Massachusetts | 29Good | ▲ 5 |
| 199 | Boise | Idaho | 29Good | ▲ 1 |
| 200 | Dallas | Texas | 29Good | ▲ 5 |
| 201 | Greensboro | North Carolina | 29Good | ▲ 9 |
| 202 | Tallahassee | Florida | 29Good | ▲ 4 |
| 203 | Rockford | Illinois | 29Good | ▲ 4 |
| 204 | Columbia | Missouri | 29Good | ▲ 6 |
| 205 | Harrisonburg | Virginia | 29Good | ▲ 2 |
| 206 | Joplin | Missouri | 29Good | ▲ 4 |
| 207 | Monroe | Louisiana | 29Good | ▲ 9 |
| 208 | Coeur d'Alene | Idaho | 29Good | ▼ 9 |
| 209 | Pullman | Washington | 29Good | ▼ 16 |
| 210 | Winchester | Virginia | 29Good | ▲ 6 |
| 211 | Greenville | Texas | 29Good | ▲ 7 |
| 212 | Kansas City | Missouri | 28Good | ▲ 4 |
| 213 | Little Rock | Arkansas | 28Good | ▲ 9 |
| 214 | Seattle | Washington | 28Good | 0 |
| 215 | Savannah | Georgia | 28Good | ▲ 4 |
| 216 | Conway | Arkansas | 28Good | ▲ 9 |
| 217 | Grand Junction | Colorado | 28Good | ▼ 3 |
| 218 | Jefferson City | Missouri | 28Good | ▲ 4 |
| 219 | Sumter | South Carolina | 28Good | ▲ 9 |
| 220 | Cape Girardeau | Missouri | 28Good | ▲ 4 |
| 221 | Panama City | Florida | 28Good | ▲ 1 |
| 222 | Bartlesville | Oklahoma | 28Good | ▲ 2 |
| 223 | Carbondale | Illinois | 28Good | ▲ 4 |
| 224 | Portland | Maine | 27Good | 0 |
| 225 | Charleston | West Virginia | 27Good | 0 |
| 226 | Honolulu | Hawaii | 27Good | ▲ 5 |
| 227 | Duluth | Minnesota | 27Good | 0 |
| 228 | Kennewick | Washington | 27Good | ▼ 19 |
| 229 | Saint Cloud | Minnesota | 27Good | ▼ 2 |
| 230 | College Station | Texas | 26Good | ▼ 23 |
| 231 | Waterloo | Iowa | 26Good | ▼ 1 |
| 232 | Lorain | Ohio | 26Good | ▼ 3 |
| 233 | Bangor | Maine | 26Good | 0 |
| 234 | Eureka | California | 26Good | ▲ 11 |
| 235 | Fargo | North Dakota | 25Good | ▲ 3 |
| 236 | Gainesville | Florida | 25Good | ▼ 2 |
| 237 | Lawrence | Kansas | 25Good | ▲ 3 |
| 238 | Marysville | Washington | 25Good | ▼ 11 |
| 239 | Idaho Falls | Idaho | 24Good | ▼ 9 |
| 240 | Rexburg | Idaho | 24Good | ▼ 9 |
| 241 | Bend | Oregon | 23Good | ▼ 21 |
| 242 | Lynchburg | Virginia | 23Good | ▲ 2 |
| 243 | Gillette | Wyoming | 23Good | ▲ 12 |
| 244 | Charleston | South Carolina | 21Good | ▲ 9 |
| 245 | Bellingham | Washington | 21Good | ▼ 9 |
| 246 | Wenatchee | Washington | 21Good | ▼ 33 |
| 247 | Juneau | Alaska | 21Good | ▲ 15 |
| 248 | Fairbanks | Alaska | 20Good | ▲ 2 |
| 249 | Florence | Alabama | 19Good | ▲ 13 |
| 250 | Kahului | Hawaii | 19Good | ▼ 7 |
| 251 | Anchorage | Alaska | 18Good | ▼ 30 |
| 252 | Hattiesburg | Mississippi | 18Good | 0 |
| 253 | Redmond | Oregon | 18Good | ▼ 9 |
| 254 | Hilo | Hawaii | 17Good | ▼ 5 |
| 255 | Eau Claire | Wisconsin | 16Good | ▼ 1 |
| 256 | Middletown | Connecticut | 16Good | ▼ 4 |
| 257 | Milwaukee | Wisconsin | 14Good | ▲ 5 |
| 258 | Green Bay | Wisconsin | 14Good | ▲ 5 |
| 259 | Appleton | Wisconsin | 14Good | ▲ 3 |
| 260 | Dubuque | Iowa | 14Good | ▲ 7 |
| 261 | Madison | Wisconsin | 13Good | ▲ 7 |
| 262 | Midland | Texas | 13Good | ▲ 5 |
| 263 | Albany | Georgia | 12Good | ▼ 7 |
| 264 | Burlington | Vermont | 9Good | ▲ 3 |
| 265 | Pocatello | Idaho | 9Good | 0 |
| 266 | Binghamton | New York | 9Good | new |
| 267 | Ridgecrest | California | 8Good | ▼ 4 |
| 268 | Clarksville | Tennessee | 6Good | new |
| 269 | Kingman | Arizona | 5Good | ▼ 1 |
| 270 | Findlay | Ohio | 3Good | 0 |
| 271 | Concord | New Hampshire | 1Good | 0 |
Snapshot taken at 4:00 pm ET from US EPA AirNow. Values are the latest hourly readings at that time, not daily averages. Cities with no reading are left out.