SmogRank / World / France / Île-de-France / December 2025

Most unhealthy days in Île-de-France, France, December 2025

6 cities in Île-de-France, France ranked by their share of unhealthy days over the 31 days. The most unhealthy days: Coulommiers, France, 0 of 29 measured days. 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.

← Coulommiers 0% 0.75%0
Every city in Île-de-France, France 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. 1Coulommiers
    0 of 29
  2. 2Paris
    0 of 29
  3. 3Rambouillet
    0 of 29
  4. 4Beaumont-sur-Oise
    0 of 29
  5. 5Étampes
    0 of 29
  6. 6Fontainebleau
    0 of 29
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 France, December 2025 · Île-de-France now

Use this board

SmogRank, most polluted cities in Île-de-France, France, by unhealthy days, PM2.5, December 2025, smogrank.com/fr/region/ile-de-france/history/2025-12?by=days (accessed 7 Oct 2026).

Download top 10 by average (PNG)

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.