SmogRank / World / United States / California / January 2026

Most polluted cities in California, United States, January 2026

126 cities in California, United States ranked by their average PM2.5 over the 31 days. Worst: Delano at 32.6 µg/m³, #151 of 2,593 cities in the world. Cleanest: Lompoc 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.

← Delano 55% 50%0
Every city in California, United States ranked for January 2026, 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. 1Delanolow-cost sensors
    55%
  2. 2Tularelow-cost sensors
    52%
  3. 3Elk Grovelow-cost sensors
    23%
  4. 4Bakersfield
    16%
  5. 5Fresno
    16%
  6. 6Visalia
    13%
  7. 7Hanford
    8%
  8. 8Whittier
    8%
  9. 9Mammoth Lakes
    7%
  10. 10Modesto
    6%
  11. 11Riverside
    6%
  12. 12Fremontlow-cost sensors
    4%
  13. 13Jurupa Valley
    3%
  14. 14Palo Altolow-cost sensors
    3%
  15. 15South Lake Tahoe
    3%
  16. 16Fontana
    3%
  17. 17Florinlow-cost sensors
    0%
  18. 18Rio Vista
    0%
  19. 19Corcoran
    0%
  20. 20Stockton
    0%
  21. 21Imperial Beach
    0%
  22. 21Arden-Arcade
    0%
  23. 23Madera
    0%
  24. 24Porterville
    0%
  25. 25Sacramento
    0%
  26. 25Woodland
    0%
  27. 27Manteca
    0%
  28. 28Merced
    0%
  29. 29Compton
    0%
  30. 29Hawthornelow-cost sensors
    0%
  31. 31Yuba City
    0%
  32. 32Clovis
    0%
  33. 33Oakland
    0%
  34. 34Chico
    0%
  35. 34Turlock
    0%
  36. 36Calexico
    0%
  37. 37Yreka
    0%
  38. 38Roseville
    0%
  39. 38South San Franciscolow-cost sensors
    0%
  40. 38Vallejo
    0%
  41. 41Lincoln
    0%
  42. 42Carsonlow-cost sensors
    0%
  43. 42San Jose
    0%
  44. 44Gridley
    0%
  45. 45Rancho Murieta
    0%
  46. 45San Francisco
    0%
  47. 47Galt
    0%
  48. 48Davis
    0%
  49. 49Long Beach
    0%
  50. 50Ukiah
    0%
  51. 51Inglewoodlow-cost sensors
    0%
  52. 52Anaheim
    0%
  53. 53Sunnyvalelow-cost sensors
    0%
  54. 53Torrancelow-cost sensors
    0%
  55. 55Richmond
    0%
  56. 55Vacaville
    0%
  57. 57Redding
    0%
  58. 58Sebastopol
    0%
  59. 59Berkeley
    0%
  60. 60Big Bear City
    0%
  61. 61San Leandro
    0%
  62. 62San Diego
    0%
  63. 63Los Angeles
    0%
  64. 64North Auburn
    0%
  65. 65Redwood City
    0%
  66. 66Folsom
    0%
  67. 67Burbank
    0%
  68. 67Livermore
    0%
  69. 67Pleasanton
    0%
  70. 70Atascadero
    0%
  71. 70Concord
    0%
  72. 70Huron
    0%
  73. 70Martinez
    0%
  74. 74Watsonvillelow-cost sensors
    0%
  75. 75El Cajon
    0%
  76. 76Alta Sierra
    0%
  77. 76Ben Lomond
    0%
  78. 78San Rafael
    0%
  79. 79Gilroy
    0%
  80. 79Lomitalow-cost sensors
    0%
  81. 81Tracy
    0%
  82. 82Willows
    0%
  83. 83Red Bluff
    0%
  84. 84Chula Vista
    0%
  85. 85Santa Monicalow-cost sensors
    0%
  86. 86San Luis Obispo
    0%
  87. 87Santa Cruz
    0%
  88. 88Prunedalelow-cost sensors
    0%
  89. 89Live Oaklow-cost sensors
    0%
  90. 90Mission Viejo
    0%
  91. 91Agouralow-cost sensors
    0%
  92. 92Santa Barbara
    0%
  93. 92Windsorlow-cost sensors
    0%
  94. 94Lake Elsinore
    0%
  95. 94Oceanside
    0%
  96. 96Glendora
    0%
  97. 97Orcutt
    0%
  98. 98Truckee
    0%
  99. 99Brawley
    0%
  100. 99Indio
    0%
  101. 99Paradise
    0%
  102. 99Salinas
    0%
  103. 103Santa Clarita
    0%
  104. 104La Crescenta-Montroselow-cost sensors
    0%
  105. 105Oceano
    0%
  106. 105Poway
    0%
  107. 107Ojai
    0%
  108. 107Seasidelow-cost sensors
    0%
  109. 109El Centro
    0%
  110. 109El Rio
    0%
  111. 109Simi Valley
    0%
  112. 112Guadalupe
    0%
  113. 113Crestline
    0%
  114. 114Temecula
    0%
  115. 115Thousand Oaks
    0%
  116. 116Carpinteria
    0%
  117. 116Hollister
    0%
  118. 118Banning
    0%
  119. 118Goletalow-cost sensors
    0%
  120. 118King City
    0%
  121. 121Alpine
    0%
  122. 121Lancaster
    0%
  123. 123Solvang
    0%
  124. 124Ridgecrest
    0%
  125. 125Fillmore
    0%
  126. 126Lompoc
    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 2026 · All cities in United States, January 2026 · California now

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SmogRank, most polluted cities in California, United States, PM2.5, January 2026, smogrank.com/us/region/california/history/2026-01 (accessed 7 Oct 2026).

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