SmogRank / History / City race
Cities, worst air first, day by day
Each measured city's average over the 30 days to every day since January 2023, worst first. Find your own city to follow it through the race, or keep to one country.
The worst cities for PM2.5 over the 7 days to 9 Jun 2023: Tha Bo 102.6 µg/m³, New Holland 88.6 µg/m³ and Bloemfontein 84.8 µg/m³.
- 1Tha BoThailand102.6
- 2New HollandUnited States88.6
- 3BloemfonteinSouth Africa84.8
- 4Rouyn-NorandaCanada79.9
- 5DhakaBangladesh77.5
- 6LahorePakistan76.2
- 7BethlehemUnited States73.2
- 8NacimientoChile72.7
- 9AllentownUnited States69.9
- 10ReadingUnited States69.4
- 11WyomissingUnited States69.4
- 12LancasterUnited States68.9
- 13NorristownUnited States67.5
- 14LebanonUnited States66.6
- 15ScrantonUnited States66.3
- 16PennsaukenUnited States65.9
- 17HarrisburgUnited States65.4
- 18ClaymontUnited States64.6
- 19ChesterUnited States64.6
- 20WilmingtonUnited States63.7
+ 1,819 more cities, 63.2 µg/m³ and below
Not counted on this day, too few days measured: Manama since 8 Jun 2023, Ash Shīḩānīyah since 5 Jun 2023, Ubon Ratchathani since 24 May 2023 and 13 more cities.
Cities counted each day
A city's number is its average over the 30 days, shown only when 21 of them were measured (5 of 7 on the 7-day race), the same minimum as the 30- and 7-day boards. A city whose monitors go quiet fades out where it stood rather than sliding down, so a gap never reads as cleaner air. Some large countries are thin or missing because their monitors' licences don't allow reuse. How we rank.
Not covered: the government monitoring networks of China and Turkey, which publish only on their own websites; we are building the readers for them. Most cities there are missing from this board, not clean. Why.