SmogRank / History / City race
Cities in United States, 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 in United States for PM2.5 over the 30 days to 24 Feb 2023: Millcreek 18.7 µg/m³, Hanford 16.9 µg/m³ and West Jordan 15.0 µg/m³.
- 1MillcreekUtah18.7
- 2HanfordCalifornia16.9
- 3West JordanUtah15.0
- 4BakersfieldCalifornia14.9
- 5FresnoCalifornia14.7
- 6ModestoCalifornia14.7
- 7VisaliaCalifornia14.5
- 8StocktonCalifornia14.4
- 9West Valley CityUtah14.2
- 10Arden-ArcadeCalifornia13.2
- 11CorcoranCalifornia13.1
- 12Salt Lake CityUtah13.0
- 13MagnaUtah12.8
- 14Grants PassOregon12.6
- 15PennsaukenNew Jersey12.4
- 16MercedCalifornia12.3
- 17North OgdenUtah12.1
- 18BensalemPennsylvania11.9
- 19LancasterPennsylvania11.8
- 20TurlockCalifornia11.8
+ 396 more cities, 11.7 µg/m³ and below
Not counted on this day, too few days measured: Redford since 6 Feb 2023, Fort Lauderdale since 5 Feb 2023, Sandersville since 5 Feb 2023 and 17 more cities. Days missing from the source archive fall in this window, so fewer countries are counted.
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.