SmogRank / World / North America

Most polluted cities in North America

34 of 562 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 34.6 µg/m³.

VenezuelaU.S. Virgin IslandsPuerto Rico: 1 measured cityUnited States: 471 measured citiesAnguillaCayman IslandsBermudaBritish Virgin IslandsTurks and Caicos IslandsTrinidad and TobagoSurinameSaint Vincent and the GrenadinesSaint LuciaSaint Kitts and NevisRussiaPanamaNicaraguaArubaCuracaoMexico: 28 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 34.6 µg/m³ 30 µg/m³15 WHO 24-hour guideline0
Every measured city in North America, one column each, worst on the left and cleanest on the right; height is PM2.5 in µg/m³. Point at it to read a city; tap to open it.

Countries

CountryCitiesMedianCities by bandWorst city
Honduras127.7 San Pedro Sula 27.7
Mexico2811.6 San Luis Potosí 34.6
United States4717.0 Calexico 22.3
Puerto Rico16.5 Cataño 6.5
Canada606.1 Nepean 16.8
Saint Martin14.6 Marigot 4.6

Worst cities

  1. 1San Luis PotosíSan Luis Potosí, Mexico 582.3×
  2. 2Naucalpan de JuárezMéxico, Mexico 482.0×
  3. 3Mexico CityMexico City, Mexico 471.9×
  4. 4San Pedro Sulalow-cost sensorsCortés Department, Honduras 471.8×
  5. 5Ciudad NezahualcoyotlMéxico, Mexico 421.7×
  6. 6CalexicoCalifornia, United States 371.5×
  7. 7San Salvador TizatlalliMéxico, Mexico 371.5×
  8. 8San Francisco TlalcilalcalpanMéxico, Mexico 351.4×
  9. 9Jurupa ValleyCalifornia, United States 351.4×
  10. 10TijuanaBaja California, Mexico 351.4×
  11. 11Los AngelesCalifornia, United States 331.3×
  12. 12HanfordCalifornia, United States 331.3×
  13. 13MexicaliBaja California, Mexico 321.3×
  14. 14OregonOhio, United States 301.2×
  15. 15FresnoCalifornia, United States 301.2×
  16. 16WhittierCalifornia, United States 301.2×
  17. 17Wake Forestlow-cost sensorsNorth Carolina, United States 301.2×
  18. 18Mission ViejoCalifornia, United States 281.1×
  19. 19Ann Arborlow-cost sensorsMichigan, United States 281.1×
  20. 20San DiegoCalifornia, United States 281.1×
  21. 21CorcoranCalifornia, United States 281.1×
  22. 22Nepeanlow-cost sensorsOntario, Canada 281.1×
  23. 23PortsmouthOhio, United States 281.1×
  24. 24Wheatonlow-cost sensorsIllinois, United States 281.1×
  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 07:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the India AQI PM2.5 sub-index.