SmogRank / World / United States / California / May 2024

Most polluted cities in California, United States, May 2024

103 cities in California, United States ranked by their average PM2.5 over the 31 days. Worst: Fontana at 15.0 µg/m³, #271 of 2,641 cities in the world. Cleanest: Florin 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.

← Fontana 0% 0.75%0
Every city in California, United States ranked for May 2024, 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. 1Fontana
    0%
  2. 2La Crescenta-Montroselow-cost sensors
    0%
  3. 3Santa Clarita
    0%
  4. 4Los Angeles
    0%
  5. 5Indio
    0%
  6. 6Jurupa Valley
    0%
  7. 7Brawley
    0%
  8. 8Simi Valley
    0%
  9. 9Berkeley
    0%
  10. 9Burbank
    0%
  11. 11Riverside
    0%
  12. 12Agouralow-cost sensors
    0%
  13. 13Imperial Beach
    0%
  14. 14Alpine
    0%
  15. 15Banning
    0%
  16. 16Chula Vista
    0%
  17. 17Anaheim
    0%
  18. 18El Cajon
    0%
  19. 19San Diego
    0%
  20. 19Victorville
    0%
  21. 21Compton
    0%
  22. 22Santa Monicalow-cost sensors
    0%
  23. 23Bakersfield
    0%
  24. 23El Centro
    0%
  25. 25Porterville
    0%
  26. 25Poway
    0%
  27. 25San Jose
    0%
  28. 28Carsonlow-cost sensors
    0%
  29. 28Hawthornelow-cost sensors
    0%
  30. 28Inglewoodlow-cost sensors
    0%
  31. 31Salinas
    0%
  32. 32Oakland
    0%
  33. 33Torrancelow-cost sensors
    0%
  34. 34Fillmore
    0%
  35. 34Oceano
    0%
  36. 34Rio Vista
    0%
  37. 37Crescent City
    0%
  38. 38Lomitalow-cost sensors
    0%
  39. 39Calexico
    0%
  40. 39Hollister
    0%
  41. 41Hanford
    0%
  42. 41Oceanside
    0%
  43. 43Thousand Oaks
    0%
  44. 44San Leandro
    0%
  45. 45Guadalupe
    0%
  46. 45King City
    0%
  47. 45Lake Elsinore
    0%
  48. 48Clovis
    0%
  49. 48Fresno
    0%
  50. 48Long Beach
    0%
  51. 51Santa Barbara
    0%
  52. 52Crestline
    0%
  53. 52Santa Cruz
    0%
  54. 54Visalia
    0%
  55. 55Carpinteria
    0%
  56. 56Ukiah
    0%
  57. 57Ojai
    0%
  58. 57San Francisco
    0%
  59. 59Huron
    0%
  60. 59Stockton
    0%
  61. 59Turlock
    0%
  62. 62Ben Lomond
    0%
  63. 62Lompoc
    0%
  64. 62San Luis Obispo
    0%
  65. 65Madera
    0%
  66. 65San Rafael
    0%
  67. 67Corcoran
    0%
  68. 67Lancaster
    0%
  69. 67Orcutt
    0%
  70. 70Modesto
    0%
  71. 71Manteca
    0%
  72. 71North Auburn
    0%
  73. 73Roseville
    0%
  74. 74Arden-Arcade
    0%
  75. 75Galt
    0%
  76. 75Seasidelow-cost sensors
    0%
  77. 77Lincoln
    0%
  78. 77Yuba City
    0%
  79. 79Redwood City
    0%
  80. 79Sacramento
    0%
  81. 81Grass Valley
    0%
  82. 81Gridley
    0%
  83. 81Sunnyvalelow-cost sensors
    0%
  84. 84Folsom
    0%
  85. 85Atascadero
    0%
  86. 85Merced
    0%
  87. 87Solvang
    0%
  88. 88Tracy
    0%
  89. 89Woodland
    0%
  90. 89Red Bluff
    0%
  91. 91Colusa
    0%
  92. 92Davis
    0%
  93. 92Truckee
    0%
  94. 94Redding
    0%
  95. 95Paradise
    0%
  96. 95Rancho Murieta
    0%
  97. 95Willows
    0%
  98. 98Chico
    0%
  99. 99Alta Sierra
    0%
  100. 100Vacaville
    0%
  101. 100Yreka
    0%
  102. 102Elk Grovelow-cost sensors
    0%
  103. 103Florinlow-cost sensors
    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, May 2024 · All cities in United States, May 2024 · California now

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SmogRank, most polluted cities in California, United States, PM2.5, May 2024, smogrank.com/us/region/california/history/2024-05 (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.