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 18 Feb 2023: Romania 22.2 µg/m³, Slovakia 21.8 µg/m³ and Poland 21.4 µg/m³.
- 1Romania4 cities22.2
- 2Slovakia19 cities21.8
- 3Poland61 cities21.4
- 4Greece8 cities19.1
- 5France80 cities17.9
- 6Czechia25 cities17.8
- 7Italy9 cities16.2
- 8The Netherlands22 cities14.8
- 9Spain56 cities10.7
- 10Norway17 cities10.2
- 11United States374 cities7.5
- 12Sweden6 cities5.9
- 13Finland8 cities3.7
Not counted on this day, too few cities measured: Portugal since 18 Feb 2023, Bulgaria since 6 Feb 2023, United Kingdom since 6 Feb 2023 and 13 more countries. 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.