SmogRank / World / United States / California / August 2023

Most polluted cities in California, United States, August 2023

103 cities in California, United States ranked by their average PM2.5 over the 31 days. Worst: Yreka at 40.8 µg/m³, #32 of 1,926 cities in the world. Cleanest: Atascadero at 3.7. 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.

← Yreka 39% 30%0
Every city in California, United States ranked for August 2023, 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. 1Yreka
    39%
  2. 2Crescent City
    13%
  3. 3Ukiah
    8%
  4. 4Anderson
    8%
  5. 5Redding
    6%
  6. 6Red Bluff
    6%
  7. 7Rio Vista
    3%
  8. 8Turlock
    3%
  9. 9Anaheim
    0%
  10. 9Compton
    0%
  11. 9Fontana
    0%
  12. 9Los Angeles
    0%
  13. 13Madera
    0%
  14. 14Yuba City
    0%
  15. 15Bakersfield
    0%
  16. 16Richmond
    0%
  17. 16Riverside
    0%
  18. 18Chula Vista
    0%
  19. 19Burbank
    0%
  20. 19Indio
    0%
  21. 19Modesto
    0%
  22. 19Visalia
    0%
  23. 23Fresno
    0%
  24. 23Jurupa Valley
    0%
  25. 25Porterville
    0%
  26. 26Colusa
    0%
  27. 26Hanford
    0%
  28. 28Brawley
    0%
  29. 28Inglewoodlow-cost sensors
    0%
  30. 28Stockton
    0%
  31. 31Willows
    0%
  32. 32Hawthornelow-cost sensors
    0%
  33. 32Long Beach
    0%
  34. 32Salinas
    0%
  35. 32Santa Barbara
    0%
  36. 36Carsonlow-cost sensors
    0%
  37. 36San Diego
    0%
  38. 36Santa Monicalow-cost sensors
    0%
  39. 39Glendora
    0%
  40. 39Gridley
    0%
  41. 39Oceanside
    0%
  42. 39Torrancelow-cost sensors
    0%
  43. 43Chico
    0%
  44. 43Merced
    0%
  45. 45Clovis
    0%
  46. 46Lomitalow-cost sensors
    0%
  47. 47San Jose
    0%
  48. 48Oakland
    0%
  49. 49Manteca
    0%
  50. 50Corcoran
    0%
  51. 50Santa Clarita
    0%
  52. 52El Cajon
    0%
  53. 52Poway
    0%
  54. 52Redwood City
    0%
  55. 55Woodland
    0%
  56. 56Roseville
    0%
  57. 57Lincoln
    0%
  58. 57Paradise
    0%
  59. 57La Crescenta-Montroselow-cost sensors
    0%
  60. 60Sacramento
    0%
  61. 61Galt
    0%
  62. 61Huron
    0%
  63. 63El Centro
    0%
  64. 63Oceano
    0%
  65. 65Agouralow-cost sensors
    0%
  66. 65Concord
    0%
  67. 65Livermore
    0%
  68. 68Thousand Oaks
    0%
  69. 68Victorville
    0%
  70. 70Davis
    0%
  71. 71King City
    0%
  72. 72Fillmore
    0%
  73. 72Tracy
    0%
  74. 74Lake Elsinore
    0%
  75. 74North Auburn
    0%
  76. 76Alta Sierra
    0%
  77. 76Crestline
    0%
  78. 78Guadalupe
    0%
  79. 79Banning
    0%
  80. 79Calexico
    0%
  81. 79Simi Valley
    0%
  82. 82San Leandro
    0%
  83. 83Alpine
    0%
  84. 84Rancho Murieta
    0%
  85. 85San Rafael
    0%
  86. 86Santa Cruz
    0%
  87. 87Folsom
    0%
  88. 88Lompoc
    0%
  89. 88Arden-Arcade
    0%
  90. 90Vacaville
    0%
  91. 91Ben Lomond
    0%
  92. 91Truckee
    0%
  93. 93Grass Valley
    0%
  94. 93Hollister
    0%
  95. 93Sebastopol
    0%
  96. 96San Luis Obispo
    0%
  97. 97Ojai
    0%
  98. 98Solvang
    0%
  99. 99Gilroy
    0%
  100. 100Big Bear City
    0%
  101. 101Orcutt
    0%
  102. 102Lancaster
    0%
  103. 103Atascadero
    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 2023 · All cities in United States, August 2023 · California now

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SmogRank, most polluted cities in California, United States, PM2.5, August 2023, smogrank.com/us/region/california/history/2023-08 (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.