SmogRank / History / May 4, 2023

Most polluted cities on May 4, 2023

1,506 cities ranked by their average PM2.5 over the day; the worst was Piedras Negras, Mexico, at 355.0 µg/m³. Each city's own local calendar day.

Bad-air episodes during May 4, 2023. All episodes.

← Piedras Negras 355.0 µg/m³ 300 µg/m³15 WHO 24-hour guideline
Every city ranked for May 4, 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+23.7×
  2. 2OsornoLos Lagos Region, Chile
    2129.1×
  3. 3BloemfonteinFree State, South Africa
    1947.8×
  4. 4Puerto VarasLos Lagos Region, Chile
    1846.8×
  5. 5Puerto MonttLos Lagos Region, Chile
    1806.4×
  6. 6ValdiviaLos Ríos Region, Chile
    1776.1×
  7. 7La UniónLos Ríos Region, Chile
    1665.1×
  8. 8BaghdadBaghdad, Iraq
    1645.0×
  9. 9Tha BoNong Khai, Thailand
    1644.9×
  10. 10Puerto AysénAysén, Chile
    1594.4×
  11. 11GuadalajaraJalisco, Mexico
    1574.3×
  12. 12ZapopanJalisco, Mexico
    1564.2×
  13. 13Hacienda Santa FeJalisco, Mexico
    1564.2×
  14. 14Ubon RatchathaniUbon Ratchathani, Thailand
    1564.1×
  15. 15NanNan, Thailand
    1554.1×
  16. 16Dhakalow-cost sensorsDhaka Division, Bangladesh
    1544.0×
  17. 17CelayaGuanajuato, Mexico
    1423.5×
  18. 18ChiguayanteBiobio, Chile
    1383.4×
  19. 18Ciudad Benito JuárezNuevo León, Mexico
    1383.4×
  20. 20DelhiDelhi, India
    1383.4×
  21. 21CholulaPuebla, Mexico
    1353.3×
  22. 21RancaguaO'Higgins Region, Chile
    1353.3×
  23. 23MukdahanMukdahan, Thailand
    1323.2×
  24. 24Peshawarlow-cost sensorsKhyber Pakhtunkhwa, Pakistan
    1313.2×
  25. 25NacimientoBiobio, Chile
    1303.2×
  26. 26SukhothaiSukhothai, Thailand
    1283.1×
  27. 27SantiagoSantiago Metropolitan, Chile
    1273.1×
  28. 28Ga-RankuwaNorth West, South Africa
    1263.0×
  29. 29HualquiBiobio, Chile
    1253.0×
  30. 30RengoO'Higgins Region, Chile
    1243.0×
  31. 31San CarlosÑuble, Chile
    1233.0×
  32. 32BamakoBamako, Mali
    1222.9×
  33. 33KigaliKigali, Rwanda
    1222.9×
  34. 34Silao de la VictoriaGuanajuato, Mexico
    1212.9×
  35. 35CoronelBiobio, Chile
    1192.9×
  36. 36RabinalBaja Verapaz, Guatemala
    1172.8×
  37. 36Guatemala CityGuatemala, Guatemala
    1172.8×
  38. 38GuanajuatoGuanajuato, Mexico
    1162.8×
  39. 39Puente AltoSantiago Metropolitan, Chile
    1162.8×
  40. 40León de los AldamaGuanajuato, Mexico
    1152.7×
  41. 41KalasinKalasin, Thailand
    1142.7×
  42. 41ToméBiobio, Chile
    1142.7×
  43. 43Addis AbabaAddis Ababa, Ethiopia
    1132.7×
  44. 44Roi EtRoi Et, Thailand
    1122.7×
  45. 45Zacatepec de HidalgoMorelos, Mexico
    1122.7×
  46. 46PhraePhrae, Thailand
    1082.6×
  47. 46SalamancaGuanajuato, Mexico
    1082.6×
  48. 48Tepeji del Río de OcampoHidalgo, Mexico
    1072.5×
  49. 49Lahorelow-cost sensorsPunjab, Pakistan
    1072.5×
  50. 49San Andrés TuxtlaVeracruz, Mexico
    1072.5×
  51. 51Si Sa KetSi Sa Ket, Thailand
    1062.5×
  52. 51CuricóMaule Region, Chile
    1062.5×
  53. 53Ciudad ApodacaNuevo León, Mexico
    1052.5×
  54. 54UttaraditUttaradit, Thailand
    1052.5×
  55. 55PueblaPuebla, Mexico
    1042.4×
  56. 56Santiago de QuerétaroQuerétaro, Mexico
    1042.4×
  57. 57TalaganteSantiago Metropolitan, Chile
    1032.4×
  58. 58TlaxcalaTlaxcala, Mexico
    1032.4×
  59. 59Naucalpan de JuárezMéxico, Mexico
    1032.4×
  60. 60PhetchabunPhetchabun, Thailand
    1032.4×
  61. 61LinaresMaule Region, Chile
    1022.4×
  62. 62San Juan del RíoQuerétaro, Mexico
    1012.4×
  63. 62SaltilloCoahuila, Mexico
    1012.4×
  64. 64Karachilow-cost sensorsSindh, Pakistan
    1002.3×
  65. 64San Luis PotosíSan Luis Potosí, Mexico
    1002.3×
  66. 66San Miguel de AllendeGuanajuato, Mexico
    992.3×
  67. 67ChillánÑuble, Chile
    992.3×
  68. 68IrapuatoGuanajuato, Mexico
    992.3×
  69. 69PhichitPhichit, Thailand
    982.3×
  70. 70LampangLampang, Thailand
    982.3×
  71. 71CauquenesMaule Region, Chile
    982.3×
  72. 72PakxanBolikhamsai, Laos
    972.3×
  73. 73YangonYangon, Myanmar
    962.2×
  74. 74CuernavacaMorelos, Mexico
    952.2×
  75. 75BeijingBeijing, China
    952.2×
  76. 76QuillotaValparaiso, Chile
    952.2×
  77. 77Santa CatarinaNuevo León, Mexico
    952.2×
  78. 78ConcepciónBiobio, Chile
    942.1×
  79. 79GarcíaNuevo León, Mexico
    942.1×
  80. 80Fort McMurrayAlberta, Canada
    932.1×
  81. 81HualpénBiobio, Chile
    932.1×
  82. 82ValjevoCentral Serbia, Serbia
    932.1×
  83. 83Ciudad NezahualcoyotlMéxico, Mexico
    922.1×
  84. 84PhayaoPhayao, Thailand
    922.1×
  85. 84San Luis de la PazGuanajuato, Mexico
    922.1×
  86. 86HanoiHanoi, Vietnam
    922.1×
  87. 87Pachuca de SotoHidalgo, Mexico
    922.1×
  88. 88VeracruzVeracruz, Mexico
    912.1×
  89. 89Suphan BuriSuphan Buri, Thailand
    912.0×
  90. 89Khon KaenKhon Kaen, Thailand
    912.0×
  91. 91Mexico CityMexico City, Mexico
    902.0×
  92. 92Sakon NakhonSakon Nakhon, Thailand
    902.0×
  93. 92TemucoAraucania, Chile
    902.0×
  94. 92AbasoloGuanajuato, Mexico
    902.0×
  95. 95TalcaMaule Region, Chile
    892.0×
  96. 96Kamphaeng PhetKamphaeng Phet, Thailand
    892.0×
  97. 97Nakhon RatchasimaNakhon Ratchasima, Thailand
    881.9×
  98. 98Udon ThaniUdon Thani, Thailand
    871.9×
  99. 99ChaiyaphumChaiyaphum, Thailand
    861.9×
  100. 99Viña del MarValparaiso, Chile
    861.9×
  101. 101Buri RamBuriram, Thailand
    861.9×
  102. 102Si Maha PhotPrachin Buri, Thailand
    851.8×
  103. 102Nakhon SawanNakhon Sawan, Thailand
    851.8×
  104. 102BelmopanCayo District, Belize
    851.8×
  105. 102QuinteroValparaiso, Chile
    851.8×
  106. 106Chai NatChai Nat, Thailand
    851.8×
  107. 107KhartoumKhartoum, Sudan
    841.8×
  108. 107LazarevacCentral Serbia, Serbia
    841.8×
  109. 107LoeiLoei, Thailand
    841.8×
  110. 110AguascalientesAguascalientes, Mexico
    841.8×
  111. 111Chiang MaiChiang Mai, Thailand
    841.8×
  112. 112ShenyangLiaoning, China
    831.8×
  113. 113LotaBiobio, Chile
    831.7×
  114. 114Cadereyta JiménezNuevo León, Mexico
    821.7×
  115. 115Sing BuriSing Buri, Thailand
    821.7×
  116. 116ConcónValparaiso, Chile
    821.7×
  117. 117Mae SaiChiang Rai, Thailand
    821.7×
  118. 118TalcahuanoBiobio, Chile
    821.7×
  119. 119Kinshasalow-cost sensorsKinshasa, Democratic Republic of the Congo
    811.7×
  120. 120Nong Bua LamphuNong Bua Lamphu, Thailand
    811.7×
  121. 121Mae SotTak, Thailand
    801.7×
  122. 122Lop BuriLopburi, Thailand
    801.6×
  123. 123Jastrzębie ZdrójSilesia, Poland
    791.6×
  124. 124PristinaPristina, Kosovo
    791.6×
  125. 124CoyhaiqueAysén, Chile
    791.6×
  126. 126Şabāḩ as SālimMubārak al Kabīr, Kuwait
    781.6×
  127. 127TakTak, Thailand
    781.6×
  128. 127LamphunLamphun, Thailand
    781.6×
  129. 129CoquimboCoquimbo Region, Chile
    781.6×
  130. 130La SerenaCoquimbo Region, Chile
    771.6×
  131. 131MonterreyNuevo León, Mexico
    771.5×
  132. 132ThembisaGauteng, South Africa
    771.5×
  133. 132AntofagastaAntofagasta, Chile
    771.5×
  134. 134DushanbeDushanbe, Tajikistan
    761.5×
  135. 134Bang NaBangkok, Thailand
    761.5×
  136. 136Khlong Sam WaBangkok, Thailand
    751.5×
  137. 137PirotCentral Serbia, Serbia
    751.5×
  138. 137Chiang RaiChiang Rai, Thailand
    751.5×
  139. 139TexarkanaTexas, United States
    751.5×
  140. 140HyderabadTelangana, India
    741.4×
  141. 141ObrenovacCentral Serbia, Serbia
    741.4×
  142. 142VereenigingGauteng, South Africa
    741.4×
  143. 142Ban HouakhouaBokeo, Laos
    741.4×
  144. 142ConakryConakry, Guinea
    741.4×
  145. 142AricaArica y Parinacota Region, Chile
    741.4×
  146. 146Kathmandulow-cost sensorsBagmati Province, Nepal
    731.4×
  147. 147LaredoTexas, United States
    721.4×
  148. 148GuangzhouGuangdong, China
    721.4×
  149. 149Frýdek-MístekMoravian-Silesian Region, Czechia
    721.4×
  150. 150BéthuneHauts-de-France, France
    711.3×
  151. 150EdinburgTexas, United States
    711.3×
  152. 152ŠabacCentral Serbia, Serbia
    711.3×
  153. 153RatchaburiRatchaburi, Thailand
    711.3×
  154. 154MumbaiMaharashtra, India
    711.3×
  155. 155Khlong LuangPathum Thani, Thailand
    701.3×
  156. 155Český TěšínMoravian-Silesian Region, Czechia
    701.3×
  157. 155CopiapóAtacama, Chile
    701.3×
  158. 158ThabazimbiLimpopo, South Africa
    701.3×
  159. 159Nong KhaemBangkok, Thailand
    701.3×
  160. 160Islamabadlow-cost sensorsIslamabad, Pakistan
    701.3×
  161. 160TocopillaAntofagasta, Chile
    701.3×
  162. 162GraysEngland, United Kingdom
    691.3×
  163. 162BrightonEngland, United Kingdom
    691.3×
  164. 162CalamaAntofagasta, Chile
    691.3×
  165. 165KanchanaburiKanchanaburi, Thailand
    691.2×
  166. 165Khan Na YaoBangkok, Thailand
    691.2×
  167. 165Canvey IslandEngland, United Kingdom
    691.2×
  168. 168Haskovolow-cost sensorsHaskovo, Bulgaria
    691.2×
  169. 168Los ÁngelesBiobio, Chile
    691.2×
  170. 168Coconut CreekFlorida, United States
    691.2×
  171. 171Dún LaoghaireLeinster, Ireland
    691.2×
  172. 172ThessaloníkiCentral Macedonia, Greece
    681.2×
  173. 172CuranilahueBiobio, Chile
    681.2×
  174. 174Dimitrovgradlow-cost sensorsHaskovo, Bulgaria
    681.2×
  175. 175Valašské MeziříčíZlín, Czechia
    681.2×
  176. 175Bielsko-BialaSilesia, Poland
    681.2×
  177. 177Samut PrakanSamut Prakan, Thailand
    681.2×
  178. 178Ciudad JuárezChihuahua, Mexico
    671.2×
  179. 179HavířovMoravian-Silesian Region, Czechia
    671.2×
  180. 179Czechowice-DziedziceSilesia, Poland
    671.2×
  181. 181ConroeTexas, United States
    671.2×
  182. 182DublinLeinster, Ireland
    671.2×
  183. 183Lak SiBangkok, Thailand
    671.2×
  184. 184AthensAttica, Greece
    661.2×
  185. 184Botevgradlow-cost sensorsSofia, Bulgaria
    661.2×
  186. 184Novi SadVojvodina, Serbia
    661.2×
  187. 184Saphan SungBangkok, Thailand
    661.2×
  188. 188ŻyrardówMazovia, Poland
    661.2×
  189. 188OtwockMazovia, Poland
    661.2×
  190. 188ČačakCentral Serbia, Serbia
    661.2×
  191. 191SenicaTrnava Region, Slovakia
    661.1×
  192. 192SalorTashkent Region, Uzbekistan
    661.1×
  193. 192Phra Nakhon Si AyutthayaPhra Nakhon Si Ayutthaya, Thailand
    661.1×
  194. 192ChanthaburiChanthaburi, Thailand
    661.1×
  195. 192Ban Samae DamBangkok, Thailand
    661.1×
  196. 192BerounCentral Bohemia, Czechia
    661.1×
  197. 192St. LouisMissouri, United States
    661.1×
  198. 198BrakpanGauteng, South Africa
    661.1×
  199. 199BanbridgeNorthern Ireland, United Kingdom
    651.1×
  200. 199TrnavaTrnava Region, Slovakia
    651.1×

Top 200 of 1,506 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, May 4, 2023, smogrank.com/history/2023-05-04 (accessed 2 Oct 2026).

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