SmogRank / World / United States / California / January 2025

Most polluted cities in California, United States, January 2025

110 cities in California, United States ranked by their average PM2.5 over the 31 days. Worst: Fresno at 23.8 µg/m³, #196 of 2,426 cities in the world. Cleanest: Ridgecrest at 2.7. 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.

← Compton 13% 10%0
Every city in California, United States ranked for January 2025, 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. 1Compton
    13%
  2. 2Imperial Beach
    10%
  3. 3Hawthornelow-cost sensors
    9%
  4. 4Long Beach
    7%
  5. 5Chula Vista
    7%
  6. 6Los Angeles
    6%
  7. 7Jurupa Valley
    6%
  8. 8Burbank
    6%
  9. 9Riverside
    6%
  10. 10Carsonlow-cost sensors
    4%
  11. 11Torrancelow-cost sensors
    4%
  12. 12Inglewoodlow-cost sensors
    4%
  13. 13La Crescenta-Montroselow-cost sensors
    4%
  14. 14Santa Monicalow-cost sensors
    4%
  15. 15El Rio
    4%
  16. 16Hanford
    3%
  17. 17Fresno
    3%
  18. 18Corcoran
    3%
  19. 19Calexico
    3%
  20. 20Anaheim
    3%
  21. 21Fontana
    3%
  22. 22Visalia
    0%
  23. 23Bakersfield
    0%
  24. 24Clovis
    0%
  25. 25Stockton
    0%
  26. 26Modesto
    0%
  27. 27Porterville
    0%
  28. 28Manteca
    0%
  29. 29Madera
    0%
  30. 29Turlock
    0%
  31. 31Merced
    0%
  32. 32Arden-Arcade
    0%
  33. 33Ukiah
    0%
  34. 34Woodland
    0%
  35. 35Ben Lomond
    0%
  36. 36Lomitalow-cost sensors
    0%
  37. 37Sacramento
    0%
  38. 38Yuba City
    0%
  39. 39Roseville
    0%
  40. 40Berkeley
    0%
  41. 41San Jose
    0%
  42. 42San Diego
    0%
  43. 43El Cajon
    0%
  44. 44Vallejo
    0%
  45. 45Rancho Murieta
    0%
  46. 45Santa Barbara
    0%
  47. 47Lincoln
    0%
  48. 48Atascadero
    0%
  49. 48Gridley
    0%
  50. 50Martinez
    0%
  51. 51Folsom
    0%
  52. 51Galt
    0%
  53. 53Oakland
    0%
  54. 54Yreka
    0%
  55. 55Agouralow-cost sensors
    0%
  56. 55Livermore
    0%
  57. 55Victorville
    0%
  58. 58Tracy
    0%
  59. 59Santa Clarita
    0%
  60. 60Glendora
    0%
  61. 60North Auburn
    0%
  62. 60Oceanside
    0%
  63. 63Vacaville
    0%
  64. 64Big Bear City
    0%
  65. 64Huron
    0%
  66. 66Colusa
    0%
  67. 67Lake Elsinore
    0%
  68. 68Sebastopol
    0%
  69. 69San Francisco
    0%
  70. 70Gilroy
    0%
  71. 71Guadalupe
    0%
  72. 72Davis
    0%
  73. 73Indio
    0%
  74. 74Lompoc
    0%
  75. 74Willows
    0%
  76. 76Crescent City
    0%
  77. 77San Leandro
    0%
  78. 78San Luis Obispo
    0%
  79. 79Pleasanton
    0%
  80. 79Redding
    0%
  81. 81Banning
    0%
  82. 81Crestline
    0%
  83. 81Poway
    0%
  84. 81Redwood City
    0%
  85. 85Salinas
    0%
  86. 86Alta Sierra
    0%
  87. 86Brawley
    0%
  88. 86Concord
    0%
  89. 86San Rafael
    0%
  90. 86Red Bluff
    0%
  91. 91King City
    0%
  92. 91Santa Cruz
    0%
  93. 93Goletalow-cost sensors
    0%
  94. 93South Lake Tahoe
    0%
  95. 95El Centro
    0%
  96. 95Simi Valley
    0%
  97. 97Alpine
    0%
  98. 97Oceano
    0%
  99. 97Orcutt
    0%
  100. 100Temecula
    0%
  101. 101Thousand Oaks
    0%
  102. 102Grass Valley
    0%
  103. 102Ojai
    0%
  104. 104Lancaster
    0%
  105. 105Hollister
    0%
  106. 106Paradise
    0%
  107. 107Solvang
    0%
  108. 108Carpinteria
    0%
  109. 109Truckee
    0%
  110. 110Ridgecrest
    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, January 2025 · All cities in United States, January 2025 · California now

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SmogRank, most polluted cities in California, United States, PM2.5, January 2025, smogrank.com/us/region/california/history/2025-01 (accessed 7 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.