SmogRank / World / United States / California / 2026

Most polluted cities in California, United States, 2026

114 cities in California, United States ranked by their average PM2.5 so far (278 of 365 days); 102 above the WHO annual guideline (5.0 µg/m³). Worst: Jurupa Valley at 14.1 µg/m³, #609 of 2,745 cities in the world. Cleanest: San Mateo at 3.3. 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.

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

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SmogRank, most polluted cities in California, United States, PM2.5, 2026 (so far), smogrank.com/us/region/california/history/2026 (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.