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 1 Apr 2023: Kosovo 16.8 µg/m³, Romania 16.7 µg/m³ and Poland 16.2 µg/m³.
- 1Kosovo3 cities16.8
- 2Romania4 cities16.7
- 3Poland61 cities16.2
- 4Slovakia19 cities14.3
- 5Greece7 cities13.6
- 6Italy13 cities, was 612.7
- 7Czechia25 cities12.1
- 8Austria13 cities10.6
- 9France94 cities9.3
- 10Brazil22 cities9.1
- 11Spain71 cities8.2
- 12Belgium25 cities7.5
- 13Germany148 cities7.4
- 14The Netherlands23 cities6.8
- 15United States380 cities6.8
- 16Portugal6 cities6.6
- 17Norway17 cities6.5
- 18Australia22 cities6.3
- 19Sweden6 cities5.0
- 20Finland8 cities4.3
Not counted on this day, too few cities measured: Bosnia and Herzegovina since 30 Mar 2023, Latvia since 30 Mar 2023, North Macedonia since 30 Mar 2023 and 17 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, Turkey and Iran, which publish only on their own websites. We are building the reader for China's network. The networks of Turkey and Iran don't answer requests from outside their countries, so we can't read them. Most cities there are missing from this board, not clean. Why.