SmogRank / Rankings

All 3,198 cities by unhealthy days, this year

Every city with enough measurements in this window, worst first.

CPCB in India: no readings since 12 Oct (488 monitors). EEA in Spain: no readings since 13 Oct (310 monitors). Their cities show older figures or are missing from this board, not clean.

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. Cities with the same share are ordered by more unhealthy days, then by the higher average.

  1. 1101BraşovBrașov County, Romania 1%4 of 283
  2. 1102CayenneGuyane, French Guiana 1%4 of 283
  3. 1103Columbia CityIndiana, United States 1%4 of 283
  4. =1104ArrecifeCanary Islands, Spain 1%4 of 283
  5. =1104HarrisburgPennsylvania, United States 1%4 of 283
  6. 1106St. ThomasOntario, Canada 1%4 of 283
  7. 1107New BrightonPennsylvania, United States 1%4 of 283
  8. 1108CanbyOregon, United States 1%4 of 283
  9. 1109MaumeeOhio, United States 1%4 of 284
  10. 1110PrievidzaTrenčín Region, Slovakia 1%4 of 284
  11. 1111MeulebekeFlanders, Belgium 1%4 of 284
  12. 1112WestervilleOhio, United States 1%4 of 284
  13. 1113LincolnwoodIllinois, United States 1%4 of 284
  14. 1114WarrenOhio, United States 1%4 of 284
  15. =1115HammondIndiana, United States 1%4 of 284
  16. =1115DuluthMinnesota, United States 1%4 of 284
  17. 1117TomahWisconsin, United States 1%4 of 284
  18. 1118New York Citylast full day 11 OctNew York, United States 1%4 of 284
  19. =1119Hanau am MainHesse, Germany 1%4 of 284
  20. =1119BensheimHesse, Germany 1%4 of 284
  21. =1119RiedstadtHesse, Germany 1%4 of 284
  22. 1122OakvilleOntario, Canada 1%4 of 284
  23. 1123OlpeNorth Rhine-Westphalia, Germany 1%4 of 284
  24. 1124Fort Leelast full day 11 OctNew Jersey, United States 1%4 of 284
  25. 1125MonsWallonia, Belgium 1%4 of 284
  26. 1126YeosuJeollanam-do, South Korea 1%4 of 285
  27. =1127BrookfieldIllinois, United States 1%4 of 285
  28. =1127ToledoOhio, United States 1%4 of 285
  29. 1129EdenderryLeinster, Ireland 1%4 of 285
  30. 1130Des PlainesIllinois, United States 1%4 of 285
  31. 1131JolietIllinois, United States 1%4 of 285
  32. 1132BramptonOntario, Canada 1%4 of 285
  33. 1133BraidwoodIllinois, United States 1%4 of 285
  34. 1134ProsserWashington, United States 1%4 of 285
  35. 1135KadaňÚstí nad Labem Region, Czechia 1%4 of 286
  36. 1136Franklin ParkIllinois, United States 1%4 of 286
  37. 1137WeizStyria, Austria 1%4 of 286
  38. 1138TullnLower Austria, Austria 1%4 of 286
  39. 1139West MifflinPennsylvania, United States 1%4 of 286
  40. 1140Fort WayneIndiana, United States 1%4 of 286
  41. 1141Bay CityMichigan, United States 1%4 of 286
  42. =1142ChicagoIllinois, United States 1%4 of 286
  43. =1142KalamazooMichigan, United States 1%4 of 286
  44. =1144Groß-EnzersdorfLower Austria, Austria 1%4 of 286
  45. =1144NapervilleIllinois, United States 1%4 of 286
  46. =1144Port HuronMichigan, United States 1%4 of 286
  47. 1147RockfordIllinois, United States 1%4 of 286
  48. 1148SalzburgSalzburg, Austria 1%4 of 286
  49. =1149RouenNormandy, France 1%4 of 286
  50. =1149WarrenvilleIllinois, United States 1%4 of 286
  51. =1149AkronOhio, United States 1%4 of 286
  52. =1152KoperUrban Municipality of Koper, Slovenia 1%4 of 286
  53. =1152South BendIndiana, United States 1%4 of 286
  54. 1154HalleinSalzburg, Austria 1%4 of 286
  55. 1155CaryIllinois, United States 1%4 of 286
  56. 1156St. CatharinesOntario, Canada 1%4 of 286
  57. 1157Mixquiahuala de JuárezHidalgo, Mexico 1%3 of 227
  58. 1158Doverlast full day 4 OctDelaware, United States 1%3 of 229
  59. 1159HuelvaAndalusia, Spain 1%3 of 230
  60. 1160VenloLimburg, The Netherlands 1%3 of 231
  61. 1161BeecherMichigan, United States 1%3 of 233
  62. 1162MendhamNew Jersey, United States 1%3 of 235
  63. 1163León de los AldamaGuanajuato, Mexico 1%3 of 241
  64. 1164New BrunswickNew Jersey, United States 1%3 of 243
  65. 1165Fremontlast full day 11 OctCalifornia, United States 1%3 of 247
  66. 1166BensalemPennsylvania, United States 1%3 of 251
  67. 1167MechelenFlanders, Belgium 1%3 of 251
  68. 1168DelmenhorstLower Saxony, Germany 1%3 of 254
  69. 1169Cadereyta JiménezNuevo León, Mexico 1%3 of 255
  70. 1170Sainte-Geneviève-des-BoisÎle-de-France, France 1%3 of 256
  71. 1171Port Isabellast full day 11 OctTexas, United States 1%3 of 256
  72. 1172GħarbL-Għarb, Malta 1%3 of 256
  73. 1173HermistonOregon, United States 1%3 of 256
  74. 1174BethlehemPennsylvania, United States 1%3 of 259
  75. 1175ParklandWashington, United States 1%3 of 259
  76. 1176EdinburgTexas, United States 1%3 of 261
  77. 1177ForbachGrand Est, France 1%3 of 261
  78. 1178Santa CatarinaNuevo León, Mexico 1%3 of 262
  79. 1179RigaRiga, Latvia 1%3 of 262
  80. 1180Rio ClaroSão Paulo, Brazil 1%3 of 263
  81. 1181Vancouverlast full day 5 OctWashington, United States 1%3 of 264
  82. 1182BreukelenUtrecht, The Netherlands 1%3 of 266
  83. 1183MelseleFlanders, Belgium 1%3 of 266
  84. 1184Greater SudburyOntario, Canada 1%3 of 266
  85. 1185AugustaGeorgia, United States 1%3 of 267
  86. 1186MaidstoneEngland, United Kingdom 1%3 of 267
  87. 1187WhittierCalifornia, United States 1%3 of 268
  88. 1188LansingMichigan, United States 1%3 of 268
  89. 1189RichmondNew South Wales, Australia 1%3 of 268
  90. 1190ElizabethNew Jersey, United States 1%3 of 269
  91. 1191DallasOregon, United States 1%3 of 270
  92. 1192Burghausenlast full day 10 OctBavaria, Germany 1%3 of 271
  93. 1193BaltimoreMaryland, United States 1%3 of 271
  94. 1194Ferraz de VasconcelosSão Paulo, Brazil 1%3 of 272
  95. 1195PaulsboroNew Jersey, United States 1%3 of 272
  96. 1196BearDelaware, United States 1%3 of 273
  97. 1197DewsburyEngland, United Kingdom 1%3 of 273
  98. 1198TrentonNew Jersey, United States 1%3 of 273
  99. 1199FrostburgMaryland, United States 1%3 of 273
  100. 1200HanfordCalifornia, United States 1%3 of 274

What stands behind each figure: Checked at 2+ sites One reference monitor Low-cost sensors About these marks

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
Unhealthy for 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

Not covered: the government monitoring networks of China, Turkey and Iran, which publish only on their own websites. We are building the reader for China's network. The networks of Turkey and Iran don't answer requests from outside their countries, so we can't read them. Most cities there are missing from this board, not clean. Why.

Use this board

SmogRank, all cities ranked by unhealthy days (PM2.5), this year to 14 Oct 2026, 07:00 UTC: each city's share of its measured days with a daily mean over 35.4 µg/m³, cities measured on 70% or more of the days since 1 January (at least 14). Monitor data from national networks via OpenAQ and the publishers listed at smogrank.com/sources. smogrank.com/rankings?w=year&by=days. Ranked on low-cost sensors, with no reference monitor in the city: #4 Kampala and #8 Faisalabad. Some values from Sensor.Community, ODbL. Some readings from Department of Environment, Nepal; Vietnam's government monitors; Aurassure; RMCAB (Secretaría Distrital de Ambiente, Bogotá); Umhverfisstofnun (Environment Agency of Iceland), no reuse terms published.

Download top 10 by average (PNG)

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.

Updated 2026-10-14 07:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index. Some low-cost readings: Sensor.Community, ODbL (data and licence). Some readings: Department of Environment, Nepal; Vietnam's government monitors; Aurassure; RMCAB (Secretaría Distrital de Ambiente, Bogotá); Umhverfisstofnun (Environment Agency of Iceland), no reuse terms published (why we use them).