SmogRank / World / United States / California / May 2023

Most polluted cities in California, United States, May 2023

96 cities in California, United States ranked by their average PM2.5 over the 31 days. Worst: Paradise at 13.8 µg/m³, #159 of 1,543 cities in the world. Cleanest: Atascadero at 1.8. A city needs measurements on 70% of the days to be ranked.

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 May 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. 2Paradise
    0%
  3. 3Indio
    0%
  4. 4Richmond
    0%
  5. 4La Crescenta-Montroselow-cost sensors
    0%
  6. 6Riverside
    0%
  7. 7Rio Vista
    0%
  8. 8Banning
    0%
  9. 8Santa Clarita
    0%
  10. 10Alpine
    0%
  11. 11Jurupa Valley
    0%
  12. 12Agouralow-cost sensors
    0%
  13. 13Victorville
    0%
  14. 14Mammoth Lakes
    0%
  15. 15Alta Sierra
    0%
  16. 15Glendora
    0%
  17. 17Hawthornelow-cost sensors
    0%
  18. 18Visalia
    0%
  19. 19Burbank
    0%
  20. 19Compton
    0%
  21. 19Santa Monicalow-cost sensors
    0%
  22. 22Inglewoodlow-cost sensors
    0%
  23. 23El Cajon
    0%
  24. 24Carsonlow-cost sensors
    0%
  25. 24Crestline
    0%
  26. 24Redwood City
    0%
  27. 27Bakersfield
    0%
  28. 27Torrancelow-cost sensors
    0%
  29. 29Calexico
    0%
  30. 29Hanford
    0%
  31. 29Sacramento
    0%
  32. 29San Diego
    0%
  33. 33Fresno
    0%
  34. 34Porterville
    0%
  35. 35Modesto
    0%
  36. 35Thousand Oaks
    0%
  37. 37Chico
    0%
  38. 37Grass Valley
    0%
  39. 37Salinas
    0%
  40. 40Lomitalow-cost sensors
    0%
  41. 40Santa Barbara
    0%
  42. 42Madera
    0%
  43. 42Oceanside
    0%
  44. 44Anaheim
    0%
  45. 44Long Beach
    0%
  46. 44Turlock
    0%
  47. 44Arden-Arcade
    0%
  48. 48Corcoran
    0%
  49. 49Folsom
    0%
  50. 49Galt
    0%
  51. 49Yuba City
    0%
  52. 52Clovis
    0%
  53. 52Oakland
    0%
  54. 52Crescent City
    0%
  55. 55Redding
    0%
  56. 56Colusa
    0%
  57. 57Willows
    0%
  58. 58Manteca
    0%
  59. 58Roseville
    0%
  60. 58Simi Valley
    0%
  61. 61Big Bear City
    0%
  62. 62Fillmore
    0%
  63. 62Lake Elsinore
    0%
  64. 64Huron
    0%
  65. 64King City
    0%
  66. 64Truckee
    0%
  67. 67Concord
    0%
  68. 67Ukiah
    0%
  69. 69Rancho Murieta
    0%
  70. 70Davis
    0%
  71. 71Merced
    0%
  72. 71San Francisco
    0%
  73. 73San Leandro
    0%
  74. 74Solvang
    0%
  75. 75Lancaster
    0%
  76. 75San Jose
    0%
  77. 77Ben Lomond
    0%
  78. 77Livermore
    0%
  79. 77Santa Cruz
    0%
  80. 77Yreka
    0%
  81. 81Lincoln
    0%
  82. 81Oceano
    0%
  83. 81Orcutt
    0%
  84. 81Anderson
    0%
  85. 85San Rafael
    0%
  86. 86Hollister
    0%
  87. 87Gilroy
    0%
  88. 88Sebastopol
    0%
  89. 89Guadalupe
    0%
  90. 90Tracy
    0%
  91. 91Ojai
    0%
  92. 91Vacaville
    0%
  93. 93San Luis Obispo
    0%
  94. 94Lompoc
    0%
  95. 95North Auburn
    0%
  96. 96Atascadero
    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

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SmogRank, most polluted cities in California, United States, PM2.5, May 2023, smogrank.com/us/region/california/history/2023-05 (accessed 6 Oct 2026).

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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.