SmogRank / History / Country race
Countries, worst air first, day by day
Each country's typical measured city over the 30 days to every day since January 2023, worst first. Press Play to watch the order change, or drag the slider to any day.
The worst countries for PM2.5 over the 30 days to 26 Jan 2023: Bulgaria 28.0 µg/m³, Greece 21.3 µg/m³ and Romania 20.8 µg/m³.
- 1Bulgaria5 cities28.0
- 2Greece8 cities21.3
- 3Romania4 cities20.8
- 4Poland60 cities17.7
- 5Slovakia19 cities14.8
- 6Czechia23 cities14.0
- 7Italy3 cities12.0
- 8France56 cities10.2
- 9United Kingdom5 cities9.8
- 10The Netherlands21 cities9.6
- 11Spain31 cities8.4
- 12Norway17 cities8.4
- 13United States357 cities7.7
- 14Sweden6 cities4.5
- 15Finland8 cities3.9
Days missing from the source archive fall in this window, so fewer countries are counted.
Countries counted each day
A country's number is its typical measured city: the median of its cities' means over the 30 days (a city needs 21 of them measured; 5 of 7 on the 7-day race), shown only with 3 such cities. A country whose monitors go quiet fades out where it stood rather than sliding down, so a gap never reads as cleaner air; "was" beside a city count marks a month after many cities joined or left. 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.