Rankings · Health

Lowest winter aqi by state

Winter air quality index.

Average daily EPA Air Quality Index for December through February. Lower is cleaner; the AQI reports the day’s worst measured pollutant, so it captures smoke and ozone as well as particle pollution.

  1. 1Montana32.9
  2. 2Vermont33.1
  3. 3Idaho34.1
  4. 4Hawaii34.2
  5. 5South Dakota34.3
  6. 6North Dakota34.8
  7. 7Virginia36.2
  8. 8Missouri36.6
  9. 9Wyoming36.6
  10. 10Nebraska36.9
  11. 11Minnesota37.4
  12. 12Maine37.5
  13. 13New Hampshire37.8
  14. 14New Jersey37.8
  15. 15Louisiana38.0
  16. 16West Virginia38.4
  17. 17Wisconsin38.6
  18. 18Rhode Island38.7
  19. 19Mississippi39.3
  20. 20Iowa39.4
  21. 21Massachusetts39.7
  22. 22Maryland40.1
  23. 23Alaska40.3
  24. 24Tennessee40.6
  25. 25North Carolina40.9
  26. 26Alabama41.4
  27. 27Oregon41.4
  28. 28Kansas41.7
  29. 29Oklahoma42.0
  30. 30Florida42.2
  31. 31Kentucky42.2
  32. 32New York42.2
  33. 33Washington42.6
  34. 34District of Columbia43.0
  35. 35Michigan43.3
  36. 36Arkansas43.4
  37. 37Colorado44.4
  38. 38Indiana44.6
  39. 39Utah44.7
  40. 40Pennsylvania44.9
  41. 41Illinois45.2
  42. 42Delaware45.5
  43. 43South Carolina45.5
  44. 44Georgia45.9
  45. 45Texas47.1
  46. 46Ohio47.6
  47. 47New Mexico51.5
  48. 48Nevada56.9
  49. 49California65.1
  50. 50Arizona68.1

Not ranked, because this measure is not published for them: Connecticut. EPA publishes this only for counties with nearby reporting monitors. A blank is no sufficiently complete monitoring record, not clean air.

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Source: EPA AirData (2025). · How this is built