What is the air quality trend in Les Ulis?

Over the past 8 days, Les Ulis had an average AQI of 35 based on station measurements. The worst day was 2026-10-19 with AQI 89.

How is Les Ulis air quality measured?

Air quality in Les Ulis is measured by ground-level monitoring stations that report PM2.5 and PM10 concentrations hourly. CERNS.IO aggregates readings from nearby stations and converts PM2.5 to the US EPA Air Quality Index (AQI) scale.

Air Quality History for Les Ulis, France

Name: Les Ulis Air Quality History
Creator: CERNS.IO
License: https://creativecommons.org/licenses/by/4.0/

Historical PM2.5 and AQI trend from monitoring stations near Les Ulis, France.

Current AQI
Good Station

48 Hours 7 Days 14 Days 20 Days

CSV JSON

Air Quality Index Station

167h

PM2.5 Station

167h · 3 stations

Temperature GFS model

28pt

Precipitation GFS model

mm/day

Daily Summary Station

Date	AQI	Range	PM2.5 avg	PM10 avg	Hours	Stations
2026-10-21	22	4–47	5.2 µg/m³	5.8	12h	3
2026-10-20	56	17–98	17.0 µg/m³	18.2	24h	4
2026-10-19	89	52–126	29.7 µg/m³	33.6	24h	3
2026-10-18	52	8–150	17.2 µg/m³	20.2	24h	3
2026-10-17	9	2–19	2.3 µg/m³	2.6	24h	4
2026-10-16	21	4–74	5.4 µg/m³	5.8	24h	4
2026-10-15	21	4–60	5.2 µg/m³	5.6	24h	4
2026-10-14	15	4–33	3.5 µg/m³	4.0	11h	4

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