SmogRank / History / September 20, 2023

Most polluted cities on September 20, 2023

1,844 cities ranked by their average PM2.5 over the day; the worst was Piedras Negras, Mexico, at 986.0 µg/m³. Each city's own local calendar day.

Bad-air episodes during September 20, 2023. All episodes.

← Piedras Negras 986.0 µg/m³ 900 µg/m³15 WHO 24-hour guideline
Every city ranked for September 20, 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. 1Piedras NegrasCoahuila, Mexico
    500+65.7×
  2. 2San Luis PotosíSan Luis Potosí, Mexico
    500+24.3×
  3. 3CoyhaiqueAysén, Chile
    2018.4×
  4. 4Fort McMurrayAlberta, Canada
    1776.2×
  5. 5Lahorelow-cost sensorsPunjab, Pakistan
    1665.1×
  6. 6Grande PrairieAlberta, Canada
    1655.0×
  7. 7Prince GeorgeBritish Columbia, Canada
    1584.4×
  8. 8RancaguaO'Higgins Region, Chile
    1554.0×
  9. 9Kampalalow-cost sensorsCentral Region, Uganda
    1523.8×
  10. 10JakartaJakarta, Indonesia
    1423.5×
  11. 11RengoO'Higgins Region, Chile
    1323.2×
  12. 12San JoseCalifornia, United States
    1313.2×
  13. 13OaklandCalifornia, United States
    1273.1×
  14. 14Peshawarlow-cost sensorsKhyber Pakhtunkhwa, Pakistan
    1273.1×
  15. 15PleasantonCalifornia, United States
    1243.0×
  16. 16San FranciscoCalifornia, United States
    1212.9×
  17. 17SalinasCalifornia, United States
    1212.9×
  18. 18LivermoreCalifornia, United States
    1192.9×
  19. 18San LeandroCalifornia, United States
    1192.9×
  20. 20GilroyCalifornia, United States
    1182.8×
  21. 21Redwood CityCalifornia, United States
    1182.8×
  22. 22SantiagoSantiago Metropolitan, Chile
    1172.8×
  23. 23Santa RosaCalifornia, United States
    1162.8×
  24. 24HollisterCalifornia, United States
    1152.8×
  25. 25RichmondCalifornia, United States
    1132.7×
  26. 26Santa CruzCalifornia, United States
    1122.7×
  27. 27Addis AbabaAddis Ababa, Ethiopia
    1122.7×
  28. 27NacimientoBiobio, Chile
    1122.7×
  29. 29ConcordCalifornia, United States
    1102.6×
  30. 30MantecaCalifornia, United States
    1072.5×
  31. 31CuricóMaule Region, Chile
    1052.5×
  32. 31StocktonCalifornia, United States
    1052.5×
  33. 33GaltCalifornia, United States
    1042.5×
  34. 34West FargoNorth Dakota, United States
    1022.4×
  35. 35Puerto VarasLos Lagos Region, Chile
    1012.4×
  36. 36Puente AltoSantiago Metropolitan, Chile
    992.3×
  37. 37BogotáBogota D.C., Colombia
    992.3×
  38. 38SacramentoCalifornia, United States
    992.3×
  39. 39San Luis ObispoCalifornia, United States
    982.3×
  40. 40DelhiDelhi, India
    982.3×
  41. 41NipomoCalifornia, United States
    982.3×
  42. 42Arroyo GrandeCalifornia, United States
    972.2×
  43. 43MexicaliBaja California, Mexico
    972.2×
  44. 44WoodlandCalifornia, United States
    962.2×
  45. 45San CarlosÑuble, Chile
    952.2×
  46. 45CuranilahueBiobio, Chile
    952.2×
  47. 45CoronelBiobio, Chile
    952.2×
  48. 48LincolnCalifornia, United States
    942.2×
  49. 49Arden-ArcadeCalifornia, United States
    942.1×
  50. 50DushanbeDushanbe, Tajikistan
    942.1×
  51. 51FolsomCalifornia, United States
    932.1×
  52. 51RosevilleCalifornia, United States
    932.1×
  53. 53San RafaelCalifornia, United States
    932.1×
  54. 54ModestoCalifornia, United States
    922.1×
  55. 55Yuba CityCalifornia, United States
    912.0×
  56. 56NiihamaEhime, Japan
    902.0×
  57. 57TalaganteSantiago Metropolitan, Chile
    902.0×
  58. 57Puerto MonttLos Lagos Region, Chile
    902.0×
  59. 59LompocCalifornia, United States
    902.0×
  60. 60Puerto AysénAysén, Chile
    902.0×
  61. 61OsornoLos Lagos Region, Chile
    892.0×
  62. 62SarajevoFederation of B&H, Bosnia and Herzegovina
    881.9×
  63. 63Şabāḩ as SālimMubārak al Kabīr, Kuwait
    881.9×
  64. 63TurlockCalifornia, United States
    881.9×
  65. 65DavisCalifornia, United States
    881.9×
  66. 66PristinaPristina, Kosovo
    871.9×
  67. 66LimaLima Province, Peru
    871.9×
  68. 66BirminghamAlabama, United States
    871.9×
  69. 69IyoEhime, Japan
    871.9×
  70. 69MatsuyamaEhime, Japan
    871.9×
  71. 71TalcahuanoBiobio, Chile
    871.9×
  72. 71CauquenesMaule Region, Chile
    871.9×
  73. 73BamakoBamako, Mali
    861.9×
  74. 74La UniónLos Ríos Region, Chile
    851.8×
  75. 75OrcuttCalifornia, United States
    841.8×
  76. 76ChennaiTamil Nadu, India
    831.8×
  77. 77TalcaMaule Region, Chile
    831.8×
  78. 77VacavilleCalifornia, United States
    831.8×
  79. 79Ciudad JuárezChihuahua, Mexico
    831.7×
  80. 80Kan’onjichōKagawa, Japan
    821.7×
  81. 80HualquiBiobio, Chile
    821.7×
  82. 80AberdeenSouth Dakota, United States
    821.7×
  83. 83DavenportIowa, United States
    821.7×
  84. 84NaplesCampania, Italy
    811.7×
  85. 85TolucaMéxico, Mexico
    811.7×
  86. 86Bang Bo DistrictSamut Prakan, Thailand
    811.7×
  87. 86UkiahCalifornia, United States
    811.7×
  88. 88ZentsujichóKagawa, Japan
    811.7×
  89. 88QuillotaValparaiso, Chile
    811.7×
  90. 90Samut SakhonSamut Sakhon, Thailand
    801.7×
  91. 91BakuBaki, Azerbaijan
    801.6×
  92. 91XonacatlánMéxico, Mexico
    801.6×
  93. 93SaijōEhime, Japan
    801.6×
  94. 93ImabariEhime, Japan
    801.6×
  95. 93ReginaSaskatchewan, Canada
    801.6×
  96. 96SliemaTas-Sliema, Malta
    801.6×
  97. 97NairobiNairobi County, Kenya
    791.6×
  98. 97ShidoKagawa, Japan
    791.6×
  99. 97San Pedro de la PazBiobio, Chile
    791.6×
  100. 100TemucoAraucania, Chile
    791.6×
  101. 100Los ÁngelesBiobio, Chile
    791.6×
  102. 102Islamabadlow-cost sensorsIslamabad, Pakistan
    791.6×
  103. 103BangkokBangkok, Thailand
    781.6×
  104. 103MarugameKagawa, Japan
    781.6×
  105. 105TsurusakiOita, Japan
    781.6×
  106. 106MinamataKumamoto, Japan
    781.6×
  107. 107HanoiHanoi, Vietnam
    771.6×
  108. 107IkedachōTokushima, Japan
    771.6×
  109. 107AtascaderoCalifornia, United States
    771.6×
  110. 107MimaTokushima, Japan
    771.6×
  111. 111MolineIllinois, United States
    771.5×
  112. 112ŌtakeHiroshima, Japan
    771.5×
  113. 113TakinomiyaKagawa, Japan
    761.5×
  114. 114Shakaskraallow-cost sensorsKwaZulu-Natal, South Africa
    761.5×
  115. 115San Francisco TlalcilalcalpanMéxico, Mexico
    761.5×
  116. 115QuinteroValparaiso, Chile
    761.5×
  117. 117KasaokaOkayama, Japan
    761.5×
  118. 117AntofagastaAntofagasta, Chile
    761.5×
  119. 119TamanoOkayama, Japan
    751.5×
  120. 119MostaIl-Mosta, Malta
    751.5×
  121. 121GuangzhouGuangdong, China
    751.5×
  122. 121AricaArica y Parinacota Region, Chile
    751.5×
  123. 123Quezon Citylow-cost sensorsNational Capital Region, Philippines
    741.4×
  124. 123ShinagawaEhime, Japan
    741.4×
  125. 125Santa Anita - Los FicusLima region, Peru
    741.4×
  126. 126ŻabbarĦaż-Żabbar, Malta
    741.4×
  127. 126LotaBiobio, Chile
    741.4×
  128. 126ConcepciónBiobio, Chile
    741.4×
  129. 126Prince AlbertSaskatchewan, Canada
    741.4×
  130. 130TakamatsuKagawa, Japan
    731.4×
  131. 131CoquimboCoquimbo Region, Chile
    731.4×
  132. 131ShikokuchūōEhime, Japan
    731.4×
  133. 133Dhakalow-cost sensorsDhaka Division, Bangladesh
    731.4×
  134. 133Viña del MarValparaiso, Chile
    731.4×
  135. 135MuscatineIowa, United States
    731.4×
  136. 136HyderabadTelangana, India
    721.4×
  137. 136IwakuniYamaguchi, Japan
    721.4×
  138. 136Little RockArkansas, United States
    721.4×
  139. 139UmeåVästerbotten, Sweden
    721.4×
  140. 139ToméBiobio, Chile
    721.4×
  141. 139ChillánÑuble, Chile
    721.4×
  142. 142ConcónValparaiso, Chile
    721.4×
  143. 142Ciudad ApodacaNuevo León, Mexico
    721.4×
  144. 142ClintonIowa, United States
    721.4×
  145. 145Phra PradaengSamut Prakan, Thailand
    711.3×
  146. 145ŌitaOita, Japan
    711.3×
  147. 145QuilpuéValparaiso, Chile
    711.3×
  148. 148OnomichiHiroshima, Japan
    711.3×
  149. 148HigashinozoeHyōgo, Japan
    711.3×
  150. 150AkashiHyōgo, Japan
    711.3×
  151. 150HiroshimaHiroshima, Japan
    711.3×
  152. 152Nong KhaemBangkok, Thailand
    711.3×
  153. 153NobeokaMiyazaki, Japan
    701.3×
  154. 153CopiapóAtacama, Chile
    701.3×
  155. 155Wan ChaiWan Chai, Hong Kong
    701.3×
  156. 155AnanTokushima, Japan
    701.3×
  157. 157FukuyamaHiroshima, Japan
    701.3×
  158. 157FujinomiyaShizuoka, Japan
    701.3×
  159. 157ChiguayanteBiobio, Chile
    701.3×
  160. 157YawatahamaEhime, Japan
    701.3×
  161. 157HiragiKagawa, Japan
    701.3×
  162. 157KunisakiOita, Japan
    701.3×
  163. 163YamaguchiYamaguchi, Japan
    701.3×
  164. 163KureHiroshima, Japan
    701.3×
  165. 163TocopillaAntofagasta, Chile
    701.3×
  166. 166KurashikiOkayama, Japan
    701.3×
  167. 166AmagasakiHyōgo, Japan
    701.3×
  168. 168TamanaKumamoto, Japan
    691.3×
  169. 168Iowa CityIowa, United States
    691.3×
  170. 170MiyakonojōMiyazaki, Japan
    691.3×
  171. 170MaderaCalifornia, United States
    691.3×
  172. 172BizenOkayama, Japan
    691.3×
  173. 173Ciudad NezahualcoyotlMéxico, Mexico
    691.2×
  174. 173BrandonManitoba, Canada
    691.2×
  175. 173ShūnanYamaguchi, Japan
    691.2×
  176. 176SalorTashkent Region, Uzbekistan
    691.2×
  177. 176ZapopanJalisco, Mexico
    691.2×
  178. 176MercedCalifornia, United States
    691.2×
  179. 179GionHiroshima, Japan
    691.2×
  180. 179La OrotavaCanary Islands, Spain
    691.2×
  181. 181Nara-shiNara, Japan
    681.2×
  182. 181MiharaHiroshima, Japan
    681.2×
  183. 181Kakogawachō-honmachiHyōgo, Japan
    681.2×
  184. 184HonmachiKumamoto, Japan
    681.2×
  185. 184MiuraKanagawa, Japan
    681.2×
  186. 184ValdiviaLos Ríos Region, Chile
    681.2×
  187. 187Narutochō-mitsuishiTokushima, Japan
    681.2×
  188. 187HanfordCalifornia, United States
    681.2×
  189. 189East Saint LouisIllinois, United States
    681.2×
  190. 190Kamojimachō-jōgejimaTokushima, Japan
    681.2×
  191. 190UwajimaEhime, Japan
    681.2×
  192. 190NagaiYamagata, Japan
    681.2×
  193. 190SōsaChiba, Japan
    681.2×
  194. 194OkayamaOkayama, Japan
    671.2×
  195. 194Kashihara-shiNara, Japan
    671.2×
  196. 194Alto HospicioTarapacá, Chile
    671.2×
  197. 194KirishimaKagoshima, Japan
    671.2×
  198. 198YamagaKumamoto, Japan
    671.2×
  199. 198SaikiOita, Japan
    671.2×
  200. 198KobayashiMiyazaki, Japan
    671.2×

Top 200 of 1,844 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 20, 2023, smogrank.com/history/2023-09-20 (accessed 2 Oct 2026).

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