SmogRank / History / September 21, 2023

Most polluted cities on September 21, 2023

1,924 cities ranked by their average PM2.5 over the day; the worst was Coyhaique, Chile, at 110.0 µg/m³. Each city's own local calendar day.

Bad-air episodes during September 21, 2023. All episodes.

← Coyhaique 110.0 µg/m³ 100 µg/m³15 WHO 24-hour guideline
Every city ranked for September 21, 2023, one column each, worst on the left and cleanest on the right; height is PM2.5 in µg/m³. Point at it to read a city; tap to open it.
  1. 1CoyhaiqueAysén, Chile
    1897.3×
  2. 2Lahorelow-cost sensorsPunjab, Pakistan
    1634.9×
  3. 3Fort McMurrayAlberta, Canada
    1544.0×
  4. 4Kampalalow-cost sensorsCentral Region, Uganda
    1523.8×
  5. 5OsornoLos Lagos Region, Chile
    1523.8×
  6. 6Puerto VarasLos Lagos Region, Chile
    1473.6×
  7. 7Puerto MonttLos Lagos Region, Chile
    1403.4×
  8. 8JakartaJakarta, Indonesia
    1253.0×
  9. 9Peshawarlow-cost sensorsKhyber Pakhtunkhwa, Pakistan
    1243.0×
  10. 10NacimientoBiobio, Chile
    1233.0×
  11. 11Puerto AysénAysén, Chile
    1233.0×
  12. 12MexicaliBaja California, Mexico
    1122.7×
  13. 13Quezon Citylow-cost sensorsNational Capital Region, Philippines
    1102.6×
  14. 14Santa RosaCalifornia, United States
    1082.6×
  15. 15PristinaPristina, Kosovo
    1052.5×
  16. 16Addis AbabaAddis Ababa, Ethiopia
    1032.4×
  17. 17RichmondCalifornia, United States
    1032.4×
  18. 18RengoO'Higgins Region, Chile
    1022.4×
  19. 19RancaguaO'Higgins Region, Chile
    1012.4×
  20. 20La UniónLos Ríos Region, Chile
    1012.4×
  21. 21Dhakalow-cost sensorsDhaka Division, Bangladesh
    992.3×
  22. 21MaderaCalifornia, United States
    992.3×
  23. 23SalinasCalifornia, United States
    992.3×
  24. 24FresnoCalifornia, United States
    972.3×
  25. 24PleasantonCalifornia, United States
    972.3×
  26. 26DushanbeDushanbe, Tajikistan
    972.2×
  27. 26ClovisCalifornia, United States
    972.2×
  28. 28Redwood CityCalifornia, United States
    962.2×
  29. 29OaklandCalifornia, United States
    962.2×
  30. 29San JoseCalifornia, United States
    962.2×
  31. 31MercedCalifornia, United States
    952.2×
  32. 32DelhiDelhi, India
    942.2×
  33. 32LompocCalifornia, United States
    942.2×
  34. 34Arroyo GrandeCalifornia, United States
    942.1×
  35. 35NipomoCalifornia, United States
    932.1×
  36. 36Santa CruzCalifornia, United States
    932.1×
  37. 37HollisterCalifornia, United States
    932.1×
  38. 38Şabāḩ as SālimMubārak al Kabīr, Kuwait
    922.1×
  39. 38AntananarivoAnalamanga, Madagascar
    922.1×
  40. 40San LeandroCalifornia, United States
    922.1×
  41. 41HanfordCalifornia, United States
    912.0×
  42. 42XonacatlánMéxico, Mexico
    892.0×
  43. 43ConcordCalifornia, United States
    892.0×
  44. 44TolucaMéxico, Mexico
    892.0×
  45. 45San Luis ObispoCalifornia, United States
    892.0×
  46. 45San RafaelCalifornia, United States
    892.0×
  47. 47San FranciscoCalifornia, United States
    881.9×
  48. 48GilroyCalifornia, United States
    881.9×
  49. 49TlaquepaqueJalisco, Mexico
    881.9×
  50. 50CuranilahueBiobio, Chile
    881.9×
  51. 50AtascaderoCalifornia, United States
    881.9×
  52. 50LivermoreCalifornia, United States
    881.9×
  53. 53TurlockCalifornia, United States
    871.9×
  54. 54TemucoAraucania, Chile
    871.9×
  55. 55ReginaSaskatchewan, Canada
    861.8×
  56. 56GuangzhouGuangdong, China
    851.8×
  57. 56San Francisco TlalcilalcalpanMéxico, Mexico
    851.8×
  58. 56DavisCalifornia, United States
    851.8×
  59. 56UkiahCalifornia, United States
    851.8×
  60. 60CuricóMaule Region, Chile
    851.8×
  61. 60Grande PrairieAlberta, Canada
    851.8×
  62. 62BamakoBamako, Mali
    841.8×
  63. 62WoodlandCalifornia, United States
    841.8×
  64. 64MantecaCalifornia, United States
    841.8×
  65. 65Los ÁngelesBiobio, Chile
    831.8×
  66. 66GaltCalifornia, United States
    821.7×
  67. 66StocktonCalifornia, United States
    821.7×
  68. 68FolsomCalifornia, United States
    821.7×
  69. 69ModestoCalifornia, United States
    821.7×
  70. 70Bang NaBangkok, Thailand
    821.7×
  71. 71NairobiNairobi County, Kenya
    821.7×
  72. 72Puente AltoSantiago Metropolitan, Chile
    811.7×
  73. 72SacramentoCalifornia, United States
    811.7×
  74. 72VisaliaCalifornia, United States
    811.7×
  75. 75CorcoranCalifornia, United States
    811.7×
  76. 75LincolnCalifornia, United States
    811.7×
  77. 77OrcuttCalifornia, United States
    811.7×
  78. 78RosevilleCalifornia, United States
    801.7×
  79. 79SantiagoSantiago Metropolitan, Chile
    801.6×
  80. 80PortervilleCalifornia, United States
    801.6×
  81. 81São PauloSão Paulo, Brazil
    801.6×
  82. 81ValdiviaLos Ríos Region, Chile
    801.6×
  83. 83CelayaGuanajuato, Mexico
    791.6×
  84. 84Prince AlbertSaskatchewan, Canada
    781.6×
  85. 84SaskatoonSaskatchewan, Canada
    781.6×
  86. 86Islamabadlow-cost sensorsIslamabad, Pakistan
    781.6×
  87. 87LimaLima Province, Peru
    781.6×
  88. 88ChennaiTamil Nadu, India
    771.6×
  89. 88Arden-ArcadeCalifornia, United States
    771.6×
  90. 90CoronelBiobio, Chile
    771.5×
  91. 91BirminghamAlabama, United States
    771.5×
  92. 91Khlong Sam WaBangkok, Thailand
    771.5×
  93. 93TijuanaBaja California, Mexico
    761.5×
  94. 93Santa BarbaraCalifornia, United States
    761.5×
  95. 95Little RockArkansas, United States
    761.5×
  96. 96SarajevoFederation of B&H, Bosnia and Herzegovina
    751.5×
  97. 97AricaArica y Parinacota Region, Chile
    751.5×
  98. 98VacavilleCalifornia, United States
    741.4×
  99. 99NiihamaEhime, Japan
    741.4×
  100. 100ShenyangLiaoning, China
    741.4×
  101. 101AsprópyrgosAttica, Greece
    741.4×
  102. 102Naucalpan de JuárezMéxico, Mexico
    741.4×
  103. 103BeijingBeijing, China
    741.4×
  104. 103ComptonCalifornia, United States
    741.4×
  105. 105NagaiYamagata, Japan
    731.4×
  106. 105HualquiBiobio, Chile
    731.4×
  107. 105BakersfieldCalifornia, United States
    731.4×
  108. 108CuernavacaMorelos, Mexico
    731.4×
  109. 108TalaganteSantiago Metropolitan, Chile
    731.4×
  110. 110PueblaPuebla, Mexico
    721.4×
  111. 111Samut SakhonSamut Sakhon, Thailand
    721.3×
  112. 111Santa Anita - Los FicusLima region, Peru
    721.3×
  113. 113Bang Bo DistrictSamut Prakan, Thailand
    711.3×
  114. 114NaplesCampania, Italy
    711.3×
  115. 114West FargoNorth Dakota, United States
    711.3×
  116. 114Khan Na YaoBangkok, Thailand
    711.3×
  117. 117CauquenesMaule Region, Chile
    711.3×
  118. 117Carsonlow-cost sensorsCalifornia, United States
    711.3×
  119. 119AntofagastaAntofagasta, Chile
    711.3×
  120. 120CoquimboCoquimbo Region, Chile
    701.3×
  121. 121Torrancelow-cost sensorsCalifornia, United States
    701.3×
  122. 122Wan ChaiWan Chai, Hong Kong
    701.3×
  123. 123Los AngelesCalifornia, United States
    701.3×
  124. 124HanoiHanoi, Vietnam
    701.3×
  125. 124TocopillaAntofagasta, Chile
    701.3×
  126. 124Yuba CityCalifornia, United States
    701.3×
  127. 127QuillotaValparaiso, Chile
    691.3×
  128. 128Hawthornelow-cost sensorsCalifornia, United States
    691.3×
  129. 129San CarlosÑuble, Chile
    691.3×
  130. 129AnaheimCalifornia, United States
    691.3×
  131. 131KasaokaOkayama, Japan
    691.2×
  132. 131TalcaMaule Region, Chile
    691.2×
  133. 131ConcónValparaiso, Chile
    691.2×
  134. 131TracyCalifornia, United States
    691.2×
  135. 135QuinteroValparaiso, Chile
    691.2×
  136. 136Fort St. JohnBritish Columbia, Canada
    691.2×
  137. 137AthensAttica, Greece
    681.2×
  138. 137HyderabadTelangana, India
    681.2×
  139. 139ChillánÑuble, Chile
    681.2×
  140. 139San Pedro de la PazBiobio, Chile
    681.2×
  141. 141Franklin ParkIllinois, United States
    681.2×
  142. 141Thousand OaksCalifornia, United States
    681.2×
  143. 143Alto HospicioTarapacá, Chile
    681.2×
  144. 143Inglewoodlow-cost sensorsCalifornia, United States
    681.2×
  145. 143Simi ValleyCalifornia, United States
    681.2×
  146. 146Lop BuriLopburi, Thailand
    681.2×
  147. 147HernandoMississippi, United States
    671.2×
  148. 147Long BeachCalifornia, United States
    671.2×
  149. 147EdmontonAlberta, Canada
    671.2×
  150. 147Prince GeorgeBritish Columbia, Canada
    671.2×
  151. 151Ciudad NezahualcoyotlMéxico, Mexico
    671.2×
  152. 151Bueng KumBangkok, Thailand
    671.2×
  153. 153Ban Samae DamBangkok, Thailand
    671.2×
  154. 154SaijōEhime, Japan
    671.2×
  155. 154LotaBiobio, Chile
    671.2×
  156. 154CopiapóAtacama, Chile
    671.2×
  157. 157SliemaTas-Sliema, Malta
    671.2×
  158. 157Lomitalow-cost sensorsCalifornia, United States
    671.2×
  159. 159KanchanaburiKanchanaburi, Thailand
    661.2×
  160. 159La Crescenta-Montroselow-cost sensorsCalifornia, United States
    661.2×
  161. 161Ciudad JuárezChihuahua, Mexico
    661.2×
  162. 161Agouralow-cost sensorsCalifornia, United States
    661.2×
  163. 163Lat KrabangBangkok, Thailand
    661.1×
  164. 164NišCentral Serbia, Serbia
    661.1×
  165. 164ImabariEhime, Japan
    661.1×
  166. 164CalexicoCalifornia, United States
    661.1×
  167. 167AstanaAstana, Kazakhstan
    661.1×
  168. 167Chula VistaCalifornia, United States
    661.1×
  169. 167Sai MaiBangkok, Thailand
    661.1×
  170. 170JeddahMecca Region, Saudi Arabia
    661.1×
  171. 170Ban Talat BuengChon Buri, Thailand
    661.1×
  172. 170Laem ChabangChon Buri, Thailand
    661.1×
  173. 170La SerenaCoquimbo Region, Chile
    661.1×
  174. 174TalcahuanoBiobio, Chile
    651.1×
  175. 174BrandonManitoba, Canada
    651.1×
  176. 174Lak SiBangkok, Thailand
    651.1×
  177. 177OceansideCalifornia, United States
    651.1×
  178. 177Santa Monicalow-cost sensorsCalifornia, United States
    651.1×
  179. 179Bang KapiBangkok, Thailand
    651.1×
  180. 179Villa Poeta José Gálvez BarrenecheaLima region, Peru
    651.1×
  181. 179EvansvilleIndiana, United States
    651.1×
  182. 179NapervilleIllinois, United States
    651.1×
  183. 179FontanaCalifornia, United States
    651.1×
  184. 184Tula de AllendeHidalgo, Mexico
    651.1×
  185. 184Viña del MarValparaiso, Chile
    651.1×
  186. 184Green BayWisconsin, United States
    651.1×
  187. 187SalorTashkent Region, Uzbekistan
    651.1×
  188. 187MukdahanMukdahan, Thailand
    651.1×
  189. 187WaukeshaWisconsin, United States
    651.1×
  190. 190KolkataWest Bengal, India
    641.1×
  191. 190East Saint LouisIllinois, United States
    641.1×
  192. 190SpringfieldIllinois, United States
    641.1×
  193. 190Oak LawnIllinois, United States
    641.1×
  194. 194ZapopanJalisco, Mexico
    641.1×
  195. 194BartlettTennessee, United States
    641.1×
  196. 196SanoTochigi, Japan
    641.1×
  197. 196ChiguayanteBiobio, Chile
    641.1×
  198. 196CalamaAntofagasta, Chile
    641.1×
  199. 199Calumet CityIllinois, United States
    641.1×
  200. 200ŻabbarĦaż-Żabbar, Malta
    641.1×

Top 200 of 1,924 shown.

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, PM2.5, September 21, 2023, smogrank.com/history/2023-09-21 (accessed 2 Oct 2026).

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