SmogRank / World / United States / California / April 2023

Most polluted cities in California, United States, April 2023

88 cities in California, United States ranked by their average PM2.5 over the 30 days. Worst: Los Angeles at 15.6 µg/m³, #156 of 1,567 cities in the world. Cleanest: Tracy at 2.6. A city needs measurements on 70% of the days to be ranked.

OpenAQ's archive, where our readings come from, has almost none for 3 of these 30 days. Cities in the United States and Europe have them from the EPA's and the European Environment Agency's own records of the same monitors; elsewhere a city's average is over its other days. Why.

Ranked by unhealthy days: the share of each city's measured days with a daily mean over 35.4 µg/m³ (US AQI 101+), Unhealthy for Sensitive Groups or worse on the US EPA's scale. Ties go to the higher average.

← Brawley 3% 3%0
Every city in California, United States ranked for April 2023, one column each, ranked by unhealthy days: height is the share of its measured days that were unhealthy, colour its average. Point at it to read a city; tap to open it.
  1. 1Brawley
    3%
  2. 2Los Angeles
    0%
  3. 3Jurupa Valley
    0%
  4. 4Compton
    0%
  5. 5San Diego
    0%
  6. 6Burbank
    0%
  7. 7El Cajon
    0%
  8. 8Glendora
    0%
  9. 8Long Beach
    0%
  10. 10Anaheim
    0%
  11. 10Carsonlow-cost sensors
    0%
  12. 12Banning
    0%
  13. 13Hawthornelow-cost sensors
    0%
  14. 13Santa Clarita
    0%
  15. 15Oceanside
    0%
  16. 15Visalia
    0%
  17. 15La Crescenta-Montroselow-cost sensors
    0%
  18. 18Lomitalow-cost sensors
    0%
  19. 18Torrancelow-cost sensors
    0%
  20. 20Bakersfield
    0%
  21. 20Inglewoodlow-cost sensors
    0%
  22. 22Santa Monicalow-cost sensors
    0%
  23. 23Calexico
    0%
  24. 23Oceano
    0%
  25. 23Paradise
    0%
  26. 26Agouralow-cost sensors
    0%
  27. 27Porterville
    0%
  28. 27Richmond
    0%
  29. 29Rio Vista
    0%
  30. 30Hanford
    0%
  31. 31Fresno
    0%
  32. 32Alta Sierra
    0%
  33. 32Crestline
    0%
  34. 34Corcoran
    0%
  35. 35Salinas
    0%
  36. 35Victorville
    0%
  37. 37Big Bear City
    0%
  38. 37Madera
    0%
  39. 39Clovis
    0%
  40. 40Guadalupe
    0%
  41. 40Sacramento
    0%
  42. 42Lake Elsinore
    0%
  43. 43Fillmore
    0%
  44. 43Manteca
    0%
  45. 45Oakland
    0%
  46. 46Lompoc
    0%
  47. 47Stockton
    0%
  48. 48Modesto
    0%
  49. 48Orcutt
    0%
  50. 48Truckee
    0%
  51. 51Pleasanton
    0%
  52. 51Arden-Arcade
    0%
  53. 53Ukiah
    0%
  54. 54Folsom
    0%
  55. 54Yuba City
    0%
  56. 54Crescent City
    0%
  57. 57Merced
    0%
  58. 57San Francisco
    0%
  59. 59Roseville
    0%
  60. 59San Jose
    0%
  61. 59Turlock
    0%
  62. 62Concord
    0%
  63. 63Grass Valley
    0%
  64. 63San Leandro
    0%
  65. 65Chico
    0%
  66. 65Colusa
    0%
  67. 65Livermore
    0%
  68. 68Ben Lomond
    0%
  69. 68San Luis Obispo
    0%
  70. 70Rancho Murieta
    0%
  71. 70Redding
    0%
  72. 72Gilroy
    0%
  73. 72Hollister
    0%
  74. 72Huron
    0%
  75. 72Lancaster
    0%
  76. 72Santa Cruz
    0%
  77. 72Willows
    0%
  78. 72Yreka
    0%
  79. 79Galt
    0%
  80. 80Davis
    0%
  81. 80San Rafael
    0%
  82. 82Woodland
    0%
  83. 83Lincoln
    0%
  84. 83North Auburn
    0%
  85. 83Sebastopol
    0%
  86. 86Atascadero
    0%
  87. 87Vacaville
    0%
  88. 88Tracy
    0%

Low-cost sensors: consumer units, counted only in cities with no government-grade monitor; they read close to reference monitors on the whole, but 15 to 25% high in humid air. How we use them.

Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

The US EPA's Air Quality Index for PM2.5 (2024 breakpoints). Show values as: µg/m³ · US AQI · India AQI · China AQI · European AQI · UK DAQI · Canada AQHI+. About the scales

All cities in the world, April 2023 · All cities in United States, April 2023 · California now

Use this board

SmogRank, most polluted cities in California, United States, PM2.5, April 2023, smogrank.com/us/region/california/history/2023-04 (accessed 6 Oct 2026).

Download top 10 (PNG)

You're welcome to reuse a single chart, image or figure with this citation and a link. Terms. Raw monitor readings in bulk are published by OpenAQ, under each provider's licence.