SmogRank / World / United States / California / August 2026

Most polluted cities in California, United States, August 2026

110 cities in California, United States ranked by their average PM2.5 over the 31 days. Worst: Jurupa Valley at 14.5 µg/m³, #394 of 2,866 cities in the world. Cleanest: San Mateo at 1.6. 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.

← Jurupa Valley 0% 0.75%0
Every city in California, United States ranked for August 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. 1Jurupa Valley
    0%
  2. 2Corcoran
    0%
  3. 3Hanford
    0%
  4. 4Whittier
    0%
  5. 5Fontana
    0%
  6. 6Riverside
    0%
  7. 7Los Angeles
    0%
  8. 7Visalia
    0%
  9. 9Imperial Beach
    0%
  10. 10Fresno
    0%
  11. 11Glendora
    0%
  12. 12Clovis
    0%
  13. 13Burbank
    0%
  14. 14Santa Monicalow-cost sensors
    0%
  15. 15Compton
    0%
  16. 15Madera
    0%
  17. 17King City
    0%
  18. 18Bakersfield
    0%
  19. 19San Luis Obispo
    0%
  20. 20Lake Elsinore
    0%
  21. 20San Diego
    0%
  22. 22Anaheim
    0%
  23. 22Mission Viejo
    0%
  24. 24Chula Vista
    0%
  25. 24El Cajon
    0%
  26. 26Merced
    0%
  27. 27Santa Clarita
    0%
  28. 28Indio
    0%
  29. 29Torrancelow-cost sensors
    0%
  30. 30Long Beach
    0%
  31. 30Oceanside
    0%
  32. 32Orcutt
    0%
  33. 33Poway
    0%
  34. 33Richmond
    0%
  35. 35Alta Sierra
    0%
  36. 36Porterville
    0%
  37. 37Calexico
    0%
  38. 37San Jose
    0%
  39. 37Simi Valley
    0%
  40. 40Carpinteria
    0%
  41. 41Turlock
    0%
  42. 42Banning
    0%
  43. 42Huron
    0%
  44. 44Victorville
    0%
  45. 45Fillmore
    0%
  46. 45Alpine
    0%
  47. 45Goletalow-cost sensors
    0%
  48. 48Truckee
    0%
  49. 49Brawley
    0%
  50. 50Livermore
    0%
  51. 50Yuba City
    0%
  52. 52Salinas
    0%
  53. 53Ben Lomond
    0%
  54. 54Tularelow-cost sensors
    0%
  55. 55El Rio
    0%
  56. 55Gridley
    0%
  57. 57Delanolow-cost sensors
    0%
  58. 57Manteca
    0%
  59. 57Temecula
    0%
  60. 60Atascadero
    0%
  61. 61Davis
    0%
  62. 61Oceano
    0%
  63. 63El Centro
    0%
  64. 63Yreka
    0%
  65. 65Fremontlow-cost sensors
    0%
  66. 65Galt
    0%
  67. 65San Leandro
    0%
  68. 65Thousand Oaks
    0%
  69. 69Lincoln
    0%
  70. 70Berkeley
    0%
  71. 70Colusa
    0%
  72. 70Ojai
    0%
  73. 73Los Banoslow-cost sensors
    0%
  74. 73Stockton
    0%
  75. 75Vallejo
    0%
  76. 76Crestline
    0%
  77. 76Guadalupe
    0%
  78. 76Ridgecrest
    0%
  79. 76Roseville
    0%
  80. 76Red Bluff
    0%
  81. 81Concord
    0%
  82. 81Arden-Arcade
    0%
  83. 83Gilroy
    0%
  84. 83Paradise
    0%
  85. 85North Auburn
    0%
  86. 85Solvang
    0%
  87. 87Santa Cruz
    0%
  88. 87Ukiah
    0%
  89. 89Modesto
    0%
  90. 90Oakland
    0%
  91. 90Sacramento
    0%
  92. 90Willows
    0%
  93. 93Lancaster
    0%
  94. 93Crescent City
    0%
  95. 95Rancho Murieta
    0%
  96. 95Tracy
    0%
  97. 95Redding
    0%
  98. 98Hollister
    0%
  99. 99Chico
    0%
  100. 99San Francisco
    0%
  101. 101Folsom
    0%
  102. 102Palo Altolow-cost sensors
    0%
  103. 103Cereslow-cost sensors
    0%
  104. 103Vacaville
    0%
  105. 105Lompoc
    0%
  106. 106Big Bear City
    0%
  107. 107San Rafael
    0%
  108. 107Sebastopol
    0%
  109. 107Sunnyvalelow-cost sensors
    0%
  110. 110San 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, August 2026 · All cities in United States, August 2026 · California now

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SmogRank, most polluted cities in California, United States, PM2.5, August 2026, smogrank.com/us/region/california/history/2026-08 (accessed 6 Oct 2026).

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