SmogRank / World / Czechia / Central Bohemia / 2023

Most polluted cities in Central Bohemia, Czechia, 2023

2 cities in Central Bohemia, Czechia ranked by their average PM2.5 over the 365 days; 2 above the WHO annual guideline (5.0 µg/m³). Worst: Beroun at 14.7 µg/m³, #122 of 1,302 cities in the world. Cleanest: Mladá Boleslav at 12.3. A city needs measurements on 70% of the days to be ranked.

OpenAQ's archive, where our readings come from, has almost none for 56 of these 365 days. Cities in the United States and Europe have them from the EPA's and the European Environment Agency's own records of the same monitors; elsewhere a city's average is over its other days. Why.

Ranked by unhealthy days: the share of each city's measured days with a daily mean over 35.4 µg/m³ (US AQI 101+), Unhealthy for Sensitive Groups or worse on the US EPA's scale. Ties go to the higher average.

  1. 1Beroun
    3%
  2. 2Mladá Boleslav
    3%
Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

The US EPA's Air Quality Index for PM2.5 (2024 breakpoints). Show values as: µg/m³ · US AQI · India AQI · China AQI · European AQI · UK DAQI · Canada AQHI+. About the scales

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SmogRank, most polluted cities in Central Bohemia, Czechia, PM2.5, 2023, smogrank.com/cz/region/central-bohemia/history/2023 (accessed 6 Oct 2026).

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You're welcome to reuse a single chart, image or figure with this citation and a link. Terms. Raw monitor readings in bulk are published by OpenAQ, under each provider's licence.