SmogRank / History / August 31, 2023

Most polluted cities on August 31, 2023

1,801 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 August 31, 2023. All episodes.

← Piedras Negras 986.0 µg/m³ 900 µg/m³15 WHO 24-hour guideline
Every city ranked for August 31, 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. 2Fort McMurrayAlberta, Canada
    2149.3×
  3. 3Dhakalow-cost sensorsDhaka Division, Bangladesh
    2028.5×
  4. 4RoseburgOregon, United States
    1675.2×
  5. 5JakartaJakarta, Indonesia
    1645.0×
  6. 6KolkataWest Bengal, India
    1624.8×
  7. 7Grants PassOregon, United States
    1564.2×
  8. 8Puerto VarasLos Lagos Region, Chile
    1564.2×
  9. 9DushanbeDushanbe, Tajikistan
    1564.2×
  10. 10NacimientoBiobio, Chile
    1544.0×
  11. 11Peshawarlow-cost sensorsKhyber Pakhtunkhwa, Pakistan
    1533.9×
  12. 12EdmontonAlberta, Canada
    1413.5×
  13. 13Lahorelow-cost sensorsPunjab, Pakistan
    1393.4×
  14. 14NairobiNairobi County, Kenya
    1373.3×
  15. 15AlexandriaAlexandria, Egypt
    1343.2×
  16. 16Islamabadlow-cost sensorsIslamabad, Pakistan
    1303.2×
  17. 17KigaliKigali, Rwanda
    1293.1×
  18. 18ValdiviaLos Ríos Region, Chile
    1283.1×
  19. 19Kampalalow-cost sensorsCentral Region, Uganda
    1253.0×
  20. 20HyderabadTelangana, India
    1233.0×
  21. 21Red DeerAlberta, Canada
    1222.9×
  22. 22BendOregon, United States
    1192.9×
  23. 23CalgaryAlberta, Canada
    1182.8×
  24. 24TemucoAraucania, Chile
    1182.8×
  25. 25CuranilahueBiobio, Chile
    1172.8×
  26. 26HanoiHanoi, Vietnam
    1162.8×
  27. 27DelhiDelhi, India
    1142.7×
  28. 28CuernavacaMorelos, Mexico
    1132.7×
  29. 29Samut SakhonSamut Sakhon, Thailand
    1112.6×
  30. 30ReddingCalifornia, United States
    1092.6×
  31. 31La UniónLos Ríos Region, Chile
    1082.6×
  32. 32TurlockCalifornia, United States
    1072.5×
  33. 33San CarlosÑuble, Chile
    1072.5×
  34. 34ToméBiobio, Chile
    1052.5×
  35. 35Puerto MonttLos Lagos Region, Chile
    1042.4×
  36. 36Los ÁngelesBiobio, Chile
    1022.4×
  37. 36MexicaliBaja California, Mexico
    1022.4×
  38. 38UkiahCalifornia, United States
    1012.4×
  39. 39OsornoLos Lagos Region, Chile
    992.3×
  40. 40Grande PrairieAlberta, Canada
    972.3×
  41. 41RedmondOregon, United States
    972.2×
  42. 42CoyhaiqueAysén, Chile
    952.2×
  43. 43XonacatlánMéxico, Mexico
    942.2×
  44. 43HualquiBiobio, Chile
    942.2×
  45. 45MercedCalifornia, United States
    942.1×
  46. 46San Salvador TizatlalliMéxico, Mexico
    932.1×
  47. 47CoronelBiobio, Chile
    932.1×
  48. 48Addis AbabaAddis Ababa, Ethiopia
    922.1×
  49. 49StocktonCalifornia, United States
    912.1×
  50. 50SantiagoSantiago Metropolitan, Chile
    912.0×
  51. 51TolucaMéxico, Mexico
    912.0×
  52. 51ModestoCalifornia, United States
    912.0×
  53. 53Ciudad NezahualcoyotlMéxico, Mexico
    912.0×
  54. 53AirdrieAlberta, Canada
    912.0×
  55. 55TalcahuanoBiobio, Chile
    902.0×
  56. 55WoodlandCalifornia, United States
    902.0×
  57. 57ConcepciónBiobio, Chile
    902.0×
  58. 58Puente AltoSantiago Metropolitan, Chile
    892.0×
  59. 59AshlandOregon, United States
    892.0×
  60. 60Puerto AysénAysén, Chile
    881.9×
  61. 60ChillánÑuble, Chile
    881.9×
  62. 62San JoseCalifornia, United States
    881.9×
  63. 63OrchardsWashington, United States
    881.9×
  64. 64St. AlbertAlberta, Canada
    871.9×
  65. 65ShenyangLiaoning, China
    861.9×
  66. 66MedfordOregon, United States
    861.9×
  67. 67TalaganteSantiago Metropolitan, Chile
    851.8×
  68. 68CauquenesMaule Region, Chile
    841.8×
  69. 69CoquimboCoquimbo Region, Chile
    841.8×
  70. 70Sherwood ParkAlberta, Canada
    831.8×
  71. 71QuinteroValparaiso, Chile
    821.7×
  72. 71ChiguayanteBiobio, Chile
    821.7×
  73. 71GaltCalifornia, United States
    821.7×
  74. 71MaderaCalifornia, United States
    821.7×
  75. 75SacramentoCalifornia, United States
    821.7×
  76. 75LethbridgeAlberta, Canada
    821.7×
  77. 77RancaguaO'Higgins Region, Chile
    811.7×
  78. 77Santa CatarinaNuevo León, Mexico
    811.7×
  79. 79LimaLima Province, Peru
    811.7×
  80. 80Mexico CityMexico City, Mexico
    801.7×
  81. 81Shakaskraallow-cost sensorsKwaZulu-Natal, South Africa
    801.6×
  82. 82San Francisco TlalcilalcalpanMéxico, Mexico
    801.6×
  83. 82AntofagastaAntofagasta, Chile
    801.6×
  84. 84LawtonOklahoma, United States
    801.6×
  85. 84Casa GrandeArizona, United States
    801.6×
  86. 84AltamontOregon, United States
    801.6×
  87. 87Port ArthurTexas, United States
    791.6×
  88. 88TocopillaAntofagasta, Chile
    791.6×
  89. 88MantecaCalifornia, United States
    791.6×
  90. 90Victoria de DurangoDurango, Mexico
    781.6×
  91. 90VacavilleCalifornia, United States
    781.6×
  92. 92ConcordCalifornia, United States
    781.6×
  93. 93LivermoreCalifornia, United States
    781.6×
  94. 94Naucalpan de JuárezMéxico, Mexico
    781.6×
  95. 95PristinaPristina, Kosovo
    771.5×
  96. 96CopiapóAtacama, Chile
    761.5×
  97. 97DallasTexas, United States
    761.5×
  98. 98La SerenaCoquimbo Region, Chile
    761.5×
  99. 99West FargoNorth Dakota, United States
    761.5×
  100. 100Kathmandulow-cost sensorsBagmati Province, Nepal
    751.5×
  101. 100Yuba CityCalifornia, United States
    751.5×
  102. 102Ciudad Benito JuárezNuevo León, Mexico
    751.5×
  103. 102WatertownSouth Dakota, United States
    751.5×
  104. 104SulphurLouisiana, United States
    751.5×
  105. 105Fort St. JohnBritish Columbia, Canada
    741.4×
  106. 106LincolnCalifornia, United States
    741.4×
  107. 107BeijingBeijing, China
    741.4×
  108. 107N'DjamenaN’Djaména, Chad
    741.4×
  109. 107Medicine HatAlberta, Canada
    741.4×
  110. 110CholulaPuebla, Mexico
    741.4×
  111. 110GilroyCalifornia, United States
    741.4×
  112. 112QuillotaValparaiso, Chile
    741.4×
  113. 112CuricóMaule Region, Chile
    741.4×
  114. 112Santa Anita - Los FicusLima region, Peru
    741.4×
  115. 115HollisterCalifornia, United States
    731.4×
  116. 116RengoO'Higgins Region, Chile
    731.4×
  117. 117Şabāḩ as SālimMubārak al Kabīr, Kuwait
    731.4×
  118. 117ZapopanJalisco, Mexico
    731.4×
  119. 119AberdeenSouth Dakota, United States
    721.4×
  120. 120ChennaiTamil Nadu, India
    721.4×
  121. 120TracyCalifornia, United States
    721.4×
  122. 122Fort WorthTexas, United States
    721.4×
  123. 123Karachilow-cost sensorsSindh, Pakistan
    721.4×
  124. 123RosevilleCalifornia, United States
    721.4×
  125. 125SliemaTas-Sliema, Malta
    721.3×
  126. 125Prince AlbertSaskatchewan, Canada
    721.3×
  127. 127FresnoCalifornia, United States
    711.3×
  128. 127Redwood CityCalifornia, United States
    711.3×
  129. 129Wan ChaiWan Chai, Hong Kong
    711.3×
  130. 129AricaArica y Parinacota Region, Chile
    711.3×
  131. 131Ulu BedokSingapore
    711.3×
  132. 131RiversideCalifornia, United States
    711.3×
  133. 131Santa CruzCalifornia, United States
    711.3×
  134. 134ConcónValparaiso, Chile
    701.3×
  135. 135Khlong LuangPathum Thani, Thailand
    701.3×
  136. 135HanfordCalifornia, United States
    701.3×
  137. 137Los AngelesCalifornia, United States
    701.3×
  138. 138GuangzhouGuangdong, China
    691.3×
  139. 138TalcaMaule Region, Chile
    691.3×
  140. 138EdmondOklahoma, United States
    691.3×
  141. 138BrookingsSouth Dakota, United States
    691.3×
  142. 142BamakoBamako, Mali
    691.3×
  143. 142JenksOklahoma, United States
    691.3×
  144. 144CorcoranCalifornia, United States
    691.2×
  145. 145RichmondCalifornia, United States
    691.2×
  146. 146Nong KhaemBangkok, Thailand
    691.2×
  147. 146SaskatoonSaskatchewan, Canada
    691.2×
  148. 146Arden-ArcadeCalifornia, United States
    691.2×
  149. 149GalvestonTexas, United States
    681.2×
  150. 149BurbankCalifornia, United States
    681.2×
  151. 151MooreOklahoma, United States
    681.2×
  152. 151SaginawTexas, United States
    681.2×
  153. 153DerbyKansas, United States
    681.2×
  154. 153TulsaOklahoma, United States
    681.2×
  155. 155Ang Mo Kio New TownSingapore
    681.2×
  156. 155ChicoCalifornia, United States
    681.2×
  157. 157San Andrés TuxtlaVeracruz, Mexico
    681.2×
  158. 158SarajevoFederation of B&H, Bosnia and Herzegovina
    671.2×
  159. 158TijuanaBaja California, Mexico
    671.2×
  160. 158FontanaCalifornia, United States
    671.2×
  161. 161PasadenaTexas, United States
    671.2×
  162. 162Alto HospicioTarapacá, Chile
    671.2×
  163. 162Oklahoma CityOklahoma, United States
    671.2×
  164. 162San DiegoCalifornia, United States
    671.2×
  165. 165Tuen MunTuen Mun, Hong Kong
    671.2×
  166. 165Tepeji del Río de OcampoHidalgo, Mexico
    671.2×
  167. 165FolsomCalifornia, United States
    671.2×
  168. 168HoustonTexas, United States
    661.2×
  169. 168AnaheimCalifornia, United States
    661.2×
  170. 170Queenstown Estatelow-cost sensorsSingapore
    661.2×
  171. 170NagaiYamagata, Japan
    661.2×
  172. 170Jurupa ValleyCalifornia, United States
    661.2×
  173. 170SalinasCalifornia, United States
    661.2×
  174. 174YangonYangon, Myanmar
    661.1×
  175. 174TehuacánPuebla, Mexico
    661.1×
  176. 174OceansideCalifornia, United States
    661.1×
  177. 177BaytownTexas, United States
    661.1×
  178. 177CorsicanaTexas, United States
    661.1×
  179. 177ComptonCalifornia, United States
    661.1×
  180. 177GlendoraCalifornia, United States
    661.1×
  181. 181McAlesterOklahoma, United States
    661.1×
  182. 182Ponca CityOklahoma, United States
    651.1×
  183. 182Chula VistaCalifornia, United States
    651.1×
  184. 184Gómez PalacioDurango, Mexico
    651.1×
  185. 185Viña del MarValparaiso, Chile
    651.1×
  186. 186BirminghamAlabama, United States
    651.1×
  187. 186EugeneOregon, United States
    651.1×
  188. 188Missouri CityTexas, United States
    651.1×
  189. 189LotaBiobio, Chile
    641.1×
  190. 189La PorteTexas, United States
    641.1×
  191. 189BakersfieldCalifornia, United States
    641.1×
  192. 189Inglewoodlow-cost sensorsCalifornia, United States
    641.1×
  193. 189Santa RosaCalifornia, United States
    641.1×
  194. 194MumbaiMaharashtra, India
    641.1×
  195. 194Villa Poeta José Gálvez BarrenecheaLima region, Peru
    641.1×
  196. 196Bang Bo DistrictSamut Prakan, Thailand
    641.1×
  197. 196WichitaKansas, United States
    641.1×
  198. 196ParadiseCalifornia, United States
    641.1×
  199. 199Prince GeorgeBritish Columbia, Canada
    641.1×
  200. 199San Francisco De BorjaLima region, Peru
    641.1×

Top 200 of 1,801 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, August 31, 2023, smogrank.com/history/2023-08-31 (accessed 2 Oct 2026).

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