SmogRank / World / United States / California / January 2024

Most polluted cities in California, United States, January 2024

104 cities in California, United States ranked by their average PM2.5 over the 31 days. Worst: Imperial Beach at 16.2 µg/m³, #400 of 2,341 cities in the world. Cleanest: Solvang at 2.1. 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.

← Calexico 7% 6%0
Every city in California, United States ranked for January 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. 1Calexico
    7%
  2. 2Lake Elsinore
    4%
  3. 3Imperial Beach
    0%
  4. 4Bakersfield
    0%
  5. 4Compton
    0%
  6. 6Hanford
    0%
  7. 7Fresno
    0%
  8. 8Visalia
    0%
  9. 9Jurupa Valley
    0%
  10. 10Hawthornelow-cost sensors
    0%
  11. 11Stockton
    0%
  12. 12Carsonlow-cost sensors
    0%
  13. 13Los Angeles
    0%
  14. 13Merced
    0%
  15. 15Corcoran
    0%
  16. 16Riverside
    0%
  17. 17Burbank
    0%
  18. 17Torrancelow-cost sensors
    0%
  19. 19Indio
    0%
  20. 19Turlock
    0%
  21. 21Fontana
    0%
  22. 22Modesto
    0%
  23. 23Richmond
    0%
  24. 24Long Beach
    0%
  25. 25Inglewoodlow-cost sensors
    0%
  26. 26Anaheim
    0%
  27. 26Clovis
    0%
  28. 28Madera
    0%
  29. 29Porterville
    0%
  30. 30Chula Vista
    0%
  31. 31El Centro
    0%
  32. 31Rio Vista
    0%
  33. 33San Diego
    0%
  34. 34El Cajon
    0%
  35. 35Manteca
    0%
  36. 35Redwood City
    0%
  37. 37Lomitalow-cost sensors
    0%
  38. 37Santa Monicalow-cost sensors
    0%
  39. 39Huron
    0%
  40. 40Big Bear City
    0%
  41. 41La Crescenta-Montroselow-cost sensors
    0%
  42. 42Agouralow-cost sensors
    0%
  43. 42Brawley
    0%
  44. 42Arden-Arcade
    0%
  45. 45Chico
    0%
  46. 45Yreka
    0%
  47. 47Sacramento
    0%
  48. 48Oceanside
    0%
  49. 49Glendora
    0%
  50. 49Santa Clarita
    0%
  51. 49Woodland
    0%
  52. 52Banning
    0%
  53. 52Yuba City
    0%
  54. 54Victorville
    0%
  55. 55San Jose
    0%
  56. 56Roseville
    0%
  57. 57North Auburn
    0%
  58. 58Rancho Murieta
    0%
  59. 58Ukiah
    0%
  60. 60Galt
    0%
  61. 60Lincoln
    0%
  62. 60Truckee
    0%
  63. 60Redding
    0%
  64. 64Poway
    0%
  65. 65Oakland
    0%
  66. 65San Francisco
    0%
  67. 65Simi Valley
    0%
  68. 65Thousand Oaks
    0%
  69. 69Crestline
    0%
  70. 69Hollister
    0%
  71. 69Santa Barbara
    0%
  72. 72Pleasanton
    0%
  73. 73Colusa
    0%
  74. 74Santa Cruz
    0%
  75. 74Tracy
    0%
  76. 76Alta Sierra
    0%
  77. 76Davis
    0%
  78. 76Vacaville
    0%
  79. 79Red Bluff
    0%
  80. 80Livermore
    0%
  81. 81Willows
    0%
  82. 82Ben Lomond
    0%
  83. 82Folsom
    0%
  84. 84Oceano
    0%
  85. 84Paradise
    0%
  86. 86Atascadero
    0%
  87. 86Concord
    0%
  88. 86Ojai
    0%
  89. 86Sebastopol
    0%
  90. 90Salinas
    0%
  91. 90San Leandro
    0%
  92. 92Alpine
    0%
  93. 93Gilroy
    0%
  94. 93Orcutt
    0%
  95. 93San Rafael
    0%
  96. 96Carpinteria
    0%
  97. 97Grass Valley
    0%
  98. 98Fillmore
    0%
  99. 99Guadalupe
    0%
  100. 100South Lake Tahoe
    0%
  101. 101King City
    0%
  102. 102Lompoc
    0%
  103. 103Lancaster
    0%
  104. 104Solvang
    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 2024 · All cities in United States, January 2024 · California now

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SmogRank, most polluted cities in California, United States, PM2.5, January 2024, smogrank.com/us/region/california/history/2024-01 (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.