SmogRank / World / North America

Most polluted cities in North America

29 of 565 measured cities in 6 countries were above the WHO 24-hour guideline over the last 24 hours. The worst was San Luis Potosí, Mexico, at 34.5 µg/m³.

VenezuelaU.S. Virgin IslandsPuerto Rico: 1 measured cityUnited States: 475 measured citiesAnguillaCayman IslandsBermudaBritish Virgin IslandsTurks and Caicos IslandsTrinidad and TobagoSurinameSaint Vincent and the GrenadinesSaint LuciaSaint Kitts and NevisRussiaPanamaNicaraguaArubaCuracaoMexico: 27 measured citiesJamaicaHonduras: 1 measured cityHaitiGuyanaGuatemalaGrenadaFrance: 81 measured citiesSaint Pierre and MiquelonSaint Martin: 1 measured cityEl SalvadorDominican RepublicDominicaGreenlandCubaCosta RicaColombiaCanada: 60 measured citiesBrazil: 6 measured citiesBelizeBarbadosBahamasAntigua and BarbudaSint Maarten
Each dot is a measured city, coloured by its PM2.5 over the last 24 hours; tap a country to open it.
← San Luis Potosí 34.5 WHO 24-hour guideline
Every measured city in North America, one column each, worst on the left and cleanest on the right. Point at it to read a city; tap to open it.

Countries

CountryCitiesMedianCities by bandWorst city
Honduras126.2 San Pedro Sula 26.2
Mexico2710.6 San Luis Potosí 34.5
United States4757.0 Calexico 22.1
Puerto Rico16.3 Cataño 6.3
Canada606.2 Nepean 16.1
Saint Martin14.7 Marigot 4.7

Worst cities

  1. 1San Luis PotosíSan Luis Potosí, Mexico 582.3×
  2. 2Naucalpan de JuárezMéxico, Mexico 502.0×
  3. 3Mexico CityMexico City, Mexico 471.9×
  4. 4San Pedro Sulalow-cost sensorsCortés Department, Honduras 431.7×
  5. 5Ciudad NezahualcoyotlMéxico, Mexico 421.7×
  6. 6CalexicoCalifornia, United States 371.5×
  7. 7TijuanaBaja California, Mexico 351.4×
  8. 8San Salvador TizatlalliMéxico, Mexico 351.4×
  9. 9Jurupa ValleyCalifornia, United States 351.4×
  10. 10Los AngelesCalifornia, United States 331.3×
  11. 11Wheatonlow-cost sensorsIllinois, United States 331.3×
  12. 12San Francisco TlalcilalcalpanMéxico, Mexico 331.3×
  13. 13HanfordCalifornia, United States 321.3×
  14. 14WhittierCalifornia, United States 301.2×
  15. 15Ann Arborlow-cost sensorsMichigan, United States 301.2×
  16. 16Wake Forestlow-cost sensorsNorth Carolina, United States 281.2×
  17. 17FresnoCalifornia, United States 281.2×
  18. 18OregonOhio, United States 281.1×
  19. 19San DiegoCalifornia, United States 281.1×
  20. 20ChattanoogaTennessee, United States 271.1×
  21. 21Mission ViejoCalifornia, United States 271.1×
  22. 22CorcoranCalifornia, United States 271.1×
  23. 23Nepeanlow-cost sensorsOntario, Canada 271.1×
  24. 24Granite CityIllinois, United States 271.1×
  25. 25LimaOhio, United States 271.1×
All cities in the world
Good0–50
Satisfactory51–100
Moderate101–200
Poor201–300
Very poor301–400
Severe401+

India's National Air Quality Index (CPCB), PM2.5 sub-index. Show values as: µg/m³ · US AQI · India AQI · China AQI · European AQI · UK DAQI · Canada AQHI+. About the scales

Updated 2026-10-02 04:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the India AQI PM2.5 sub-index.