SmogRank / History / City race
Cities in Czechia, 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 Czechia for PM2.5 over the 30 days to 17 Jan 2025: Ostrava 33.7 µg/m³, Bohumín 33.2 µg/m³ and Havířov 31.5 µg/m³.
- 1OstravaMoravian-Silesian Region33.7
- 2BohumínMoravian-Silesian Region33.2
- 3HavířovMoravian-Silesian Region31.5
- 4StudénkaMoravian-Silesian Region29.5
- 5Frýdek-MístekMoravian-Silesian Region28.4
- 6PřerovOlomouc Region27.2
- 7Valašské MeziříčíZlín25.5
- 8OlomoucOlomouc Region25.1
- 9ZlínZlín24.6
- 10Moravská TřebováPardubice Region24.0
- 11Český TěšínMoravian-Silesian Region23.4
- 12TřinecMoravian-Silesian Region22.6
- 13ZnojmoSouth Moravian21.5
- 14BerounCentral Bohemia20.4
- 15BrnoSouth Moravian20.2
- 16DěčínÚstí nad Labem Region19.8
- 17ŽideniceSouth Moravian19.3
- 18SlatinaSouth Moravian19.3
- 19KroměřížZlín19.1
- 20TepliceÚstí nad Labem Region18.8
+ 15 more cities, the next at 16.9 µg/m³
Not counted on this day, too few days measured: Opava since 14 Jan 2025 and Náchod since 10 Jan 2025.
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 reader for China's network. Turkey's network doesn't answer requests from outside the country, so we can't read it. Most cities there are missing from this board, not clean. Why.