SmogRank / World / United States / California / July 2026

Most polluted cities in California, United States, July 2026

111 cities in California, United States ranked by their average PM2.5 over the 31 days. Worst: Jurupa Valley at 17.4 µg/m³, #407 of 2,751 cities in the world. Cleanest: San Mateo at 0.9. 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.

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

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SmogRank, most polluted cities in California, United States, PM2.5, July 2026, smogrank.com/us/region/california/history/2026-07 (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.