SmogRank / World / Germany / North Rhine-Westphalia / December 2025

Most polluted cities in North Rhine-Westphalia, Germany, December 2025

33 cities in North Rhine-Westphalia, Germany ranked by their average PM2.5 over the 31 days. Worst: Krefeld at 14.1 µg/m³, #786 of 2,960 cities in the world. Cleanest: Roetgen at 5.0. A city needs measurements on 70% of the days to be ranked.

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.

← Krefeld 3% 3%0
Every city in North Rhine-Westphalia, Germany ranked for December 2025, one column each, ranked by unhealthy days: height is the share of its measured days that were unhealthy, colour its average. Point at it to read a city; tap to open it.
  1. 1Krefeld
    3%
  2. 2Hagen
    0%
  3. 3Unna
    0%
  4. 3Dortmund
    0%
  5. 3Datteln
    0%
  6. 3Bottrop
    0%
  7. 7Münster
    0%
  8. 7Gelsenkirchen
    0%
  9. 9Oberhausen
    0%
  10. 10Düsseldorf
    0%
  11. 10Duisburg
    0%
  12. 12Köln
    0%
  13. 12Bielefeld
    0%
  14. 14Olpelow-cost sensors
    0%
  15. 15Essen
    0%
  16. 16Borken
    0%
  17. 17Leverkusen
    0%
  18. 17Bonn
    0%
  19. 19Wuppertal
    0%
  20. 19Titz
    0%
  21. 19Sinnersdorf
    0%
  22. 19Schwerte
    0%
  23. 23Ratingen
    0%
  24. 24Kaldenkirchen
    0%
  25. 25Hattingen
    0%
  26. 26Niederzier
    0%
  27. 26Mönchengladbach
    0%
  28. 28Wesel
    0%
  29. 29Warstein
    0%
  30. 30Soest
    0%
  31. 31Lüdenscheid
    0%
  32. 31Aachen
    0%
  33. 33Roetgen
    0%

Low-cost sensors: consumer units, counted only in cities with no government-grade monitor; they read close to reference monitors on the whole, but 15 to 25% high in humid air. How we use them.

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

All cities in the world, December 2025 · All cities in Germany, December 2025 · North Rhine-Westphalia now

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SmogRank, most polluted cities in North Rhine-Westphalia, Germany, PM2.5, December 2025, smogrank.com/de/region/north-rhine-westphalia/history/2025-12 (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.