SmogRank / World / United States / California / April 2024

Most polluted cities in California, United States, April 2024

100 cities in California, United States ranked by their average PM2.5 over the 30 days. Worst: Fontana at 11.8 µg/m³, #730 of 2,482 cities in the world. Cleanest: Davis at 3.1. 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.

← Fontana 0% 0.75%0
Every city in California, United States ranked for April 2024, 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. 1Fontana
    0%
  2. 2Los Angeles
    0%
  3. 3Imperial Beach
    0%
  4. 4Porterville
    0%
  5. 5Compton
    0%
  6. 6Hanford
    0%
  7. 7Anaheim
    0%
  8. 8Burbank
    0%
  9. 8Santa Clarita
    0%
  10. 10Riverside
    0%
  11. 11Indio
    0%
  12. 12Carsonlow-cost sensors
    0%
  13. 12Hawthornelow-cost sensors
    0%
  14. 14Chula Vista
    0%
  15. 14Inglewoodlow-cost sensors
    0%
  16. 16La Crescenta-Montroselow-cost sensors
    0%
  17. 17Jurupa Valley
    0%
  18. 18San Diego
    0%
  19. 18Visalia
    0%
  20. 20Fresno
    0%
  21. 21Bakersfield
    0%
  22. 21Oceano
    0%
  23. 21Simi Valley
    0%
  24. 24Santa Monicalow-cost sensors
    0%
  25. 24Torrancelow-cost sensors
    0%
  26. 26Corcoran
    0%
  27. 27San Jose
    0%
  28. 28Stockton
    0%
  29. 29Agouralow-cost sensors
    0%
  30. 29Ukiah
    0%
  31. 29Rio Vista
    0%
  32. 32El Cajon
    0%
  33. 33Clovis
    0%
  34. 33Crescent City
    0%
  35. 35Lomitalow-cost sensors
    0%
  36. 35Turlock
    0%
  37. 37Glendora
    0%
  38. 37Oakland
    0%
  39. 39Banning
    0%
  40. 39Calexico
    0%
  41. 39Guadalupe
    0%
  42. 39Long Beach
    0%
  43. 43Hollister
    0%
  44. 43Modesto
    0%
  45. 43San Leandro
    0%
  46. 46El Centro
    0%
  47. 47Oceanside
    0%
  48. 48Poway
    0%
  49. 48Santa Barbara
    0%
  50. 50Brawley
    0%
  51. 51Madera
    0%
  52. 51Santa Cruz
    0%
  53. 51Victorville
    0%
  54. 54Huron
    0%
  55. 55Lincoln
    0%
  56. 56Alpine
    0%
  57. 56Salinas
    0%
  58. 56San Francisco
    0%
  59. 59Carpinteria
    0%
  60. 59Manteca
    0%
  61. 61Crestline
    0%
  62. 62Big Bear City
    0%
  63. 62San Luis Obispo
    0%
  64. 62Yuba City
    0%
  65. 65Fillmore
    0%
  66. 65King City
    0%
  67. 65Lompoc
    0%
  68. 65Thousand Oaks
    0%
  69. 65Arden-Arcade
    0%
  70. 70Roseville
    0%
  71. 70Sacramento
    0%
  72. 72Ben Lomond
    0%
  73. 72Folsom
    0%
  74. 72Lake Elsinore
    0%
  75. 72San Rafael
    0%
  76. 76Lancaster
    0%
  77. 77Merced
    0%
  78. 77Orcutt
    0%
  79. 77Redwood City
    0%
  80. 80Grass Valley
    0%
  81. 81Ojai
    0%
  82. 82Rancho Murieta
    0%
  83. 82Tracy
    0%
  84. 84Galt
    0%
  85. 85Gridley
    0%
  86. 85North Auburn
    0%
  87. 85Woodland
    0%
  88. 88Paradise
    0%
  89. 88Red Bluff
    0%
  90. 90Alta Sierra
    0%
  91. 91Truckee
    0%
  92. 91Redding
    0%
  93. 93Colusa
    0%
  94. 93Solvang
    0%
  95. 95Chico
    0%
  96. 95Willows
    0%
  97. 97Yreka
    0%
  98. 98Atascadero
    0%
  99. 98Vacaville
    0%
  100. 100Davis
    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, April 2024 · All cities in United States, April 2024 · California now

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SmogRank, most polluted cities in California, United States, PM2.5, April 2024, smogrank.com/us/region/california/history/2024-04 (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.