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 25 Jan 2023: Greece 24.7 µg/m³, Romania 23.5 µg/m³ and Poland 16.9 µg/m³.
- 1Greece7 cities24.7
- 2Romania3 cities23.5
- 3Poland59 cities16.9
- 4Slovakia16 cities14.1
- 5Czechia21 cities13.9
- 6France52 cities10.1
- 7The Netherlands21 cities9.4
- 8Spain17 cities8.9
- 9Norway17 cities8.4
- 10United States355 cities7.8
- 11Sweden6 cities4.6
- 12Finland8 cities4.0
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.