SmogRank / World / North America

Most polluted cities in North America

8 of 825 measured cities in 6 countries were above the WHO 24-hour guideline over the last 7 days. The worst was Calexico, United States, at 29.5 µg/m³.

VenezuelaU.S. Virgin IslandsPuerto Rico: 1 measured cityUnited States: 687 measured citiesAnguillaCayman IslandsBermudaBritish Virgin IslandsTurks and Caicos IslandsTrinidad and TobagoSurinameSaint Vincent and the GrenadinesSaint LuciaSaint Kitts and NevisRussiaPanamaNicaraguaArubaCuracaoMexico: 42 measured citiesJamaicaHonduras: 1 measured cityHaitiGuyanaGuatemalaGrenadaFrance: 94 measured citiesSaint Pierre and MiquelonSaint Martin: 1 measured cityEl SalvadorDominican RepublicDominicaGreenlandCubaCosta RicaColombiaCanada: 93 measured citiesBrazil: 6 measured citiesBelizeBarbadosBahamasAntigua and BarbudaSint Maarten
Each dot is a measured city, coloured by its PM2.5 over the last 7 days; tap a country to open it.
← Calexico 29.5 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
Honduras119.4 San Pedro Sula 19.4
Mexico429.5 Hacienda Santa Fe 22.8
Puerto Rico18.5 Cataño 8.5
Saint Martin16.6 Marigot 6.6
United States6875.7 Calexico 29.5
Canada935.0 Barrie 7.3

Worst cities

  1. 1CalexicoCalifornia, United States 3
  2. 2Hacienda Santa FeJalisco, Mexico 3
  3. 3San Pedro Sulalow-cost sensorsCortés Department, Honduras 2
  4. 4San Salvador TizatlalliMéxico, Mexico 2
  5. 5TijuanaBaja California, Mexico 2
  6. 6Santa AnitaJalisco, Mexico 2
  7. 7AguascalientesAguascalientes, Mexico 2
  8. 8GuadalajaraJalisco, Mexico 2
  9. 9TlaquepaqueJalisco, Mexico 2
  10. 10Naucalpan de JuárezMéxico, Mexico 2
  11. 11Los AngelesCalifornia, United States 2
  12. 12Jurupa ValleyCalifornia, United States 2
  13. 13RichmondCalifornia, United States 2
  14. 14ClovisCalifornia, United States 2
  15. 15TepicNayarit, Mexico 2
  16. 16RiversideCalifornia, United States 2
  17. 17Little RockArkansas, United States 2
  18. 18HanfordCalifornia, United States 2
  19. 19FontanaCalifornia, United States 2
  20. 20WyomingMichigan, United States 2
  21. 21MexicaliBaja California, Mexico 2
  22. 22WhittierCalifornia, United States 2
  23. 23PueblaPuebla, Mexico 2
  24. 24Chula VistaCalifornia, United States 2
  25. 25San DiegoCalifornia, United States 2
All cities in the world
Low risk1–3
Moderate risk4–6
High risk7–10
Very high risk10+

Canada's AQHI+ for PM2.5 (1 point per 10 µg/m³), which is defined on hourly values. 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 Canada AQHI+ PM2.5 sub-index.