SmogRank / France / Pays de la Loire / Saint-Étienne-de-Montluc

Saint-Étienne-de-Montluc, month by month

Saint-Étienne-de-Montluc has a measured daily mean on 368 days since 4 April 2023. Its worst month was January 2024, at 59 US AQI (13.4 µg/m³), 574th of 2,385 cities on that month's world ranking. Its cleanest was July 2023, at 28 US AQI (5.0 µg/m³).

Every month since 2023

2026too few days for a mean (a year needs 200)22 days measured
Jan4 daysFebnoneMarnoneAprnoneMay3 daysJun2 daysJul4 daysAugnoneSep3 daysOct6 days
2025too few days for a mean (a year needs 256)1 day measured
Jan1 dayFebnoneMarnoneAprnoneMaynoneJunnoneJulnoneAugnoneSepnoneOctnoneNovnoneDecnone
2024too few days for a mean (a year needs 257)125 days measured
Jan59#574Feb41#1,342Mar15 daysApr29#1,887May29#2,222JunnoneJulnoneAugnoneSepnoneOctnoneNovnoneDecnone
2023too few days for a mean (a year needs 256)220 days measured
JanFebMarApr42#928May42#1,042Jun47#1,026Jul28#1,232Aug15 daysSep20 daysOct20 daysNov43#1,200Dec49#980
Each square is a month's mean PM2.5 in US AQI from Saint-Étienne-de-Montluc's measured days, with its place on that month's world ranking under it. A month has a mean once 70% of its days are measured, the rule the monthly rankings use; under that, the square gives the days measured. Each square opens that month's ranking with Saint-Étienne-de-Montluc marked; each year, the year's.
Good0–50
Moderate51–100
Unhealthy for 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

Months without a mean, and why

33 months
MonthWhy
Oct 20266 of 12 days measured; a month needs 9. The others: 2 with no readings from the monitor, 3 with readings for part of the day (a day needs 18 hours), 1 with under 18 hours of readings or readings that failed our checks.
Sep 20263 of 30 days measured; a month needs 21. The others: 27 with under 18 hours of readings or readings that failed our checks.
Aug 2026No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Jul 20264 of 31 days measured; a month needs 22. The others: 27 with under 18 hours of readings or readings that failed our checks.
Jun 20262 of 30 days measured; a month needs 21. The others: 28 with under 18 hours of readings or readings that failed our checks.
May 20263 of 31 days measured; a month needs 22. The others: 28 with under 18 hours of readings or readings that failed our checks.
Apr 2026No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
Mar 2026No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Feb 2026No day measured. The others: 28 with under 18 hours of readings or readings that failed our checks.
Jan 20264 of 31 days measured; a month needs 22. The others: 27 with under 18 hours of readings or readings that failed our checks.
Dec 2025No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Nov 2025No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
Oct 2025No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Sep 2025No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
Aug 2025No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Jul 2025No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Jun 2025No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
May 2025No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Apr 2025No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
Mar 2025No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Feb 2025No day measured. The others: 28 with under 18 hours of readings or readings that failed our checks.
Jan 20251 of 31 days measured; a month needs 22. The others: 30 with under 18 hours of readings or readings that failed our checks.
Dec 2024No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Nov 2024No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
Oct 2024No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Sep 2024No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
Aug 2024No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Jul 2024No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Jun 2024No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
Mar 202415 of 31 days measured; a month needs 22. The others: 16 with under 18 hours of readings or readings that failed our checks.
Oct 202320 of 31 days measured; a month needs 22. The others: 11 with under 18 hours of readings or readings that failed our checks.
Sep 202320 of 30 days measured; a month needs 21. The others: 10 with under 18 hours of readings or readings that failed our checks.
Aug 202315 of 31 days measured; a month needs 22. The others: 16 with under 18 hours of readings or readings that failed our checks.

A day counts once 18 hours of it are measured; a month needs 70% of its days.

Saint-Étienne-de-Montluc's worst months

MonthUS AQIDays measuredWorld rankEpisode
January 2024 5913.4 µg/m³28 of 31574thof 2,385Europe, 8 to 27 January 2024
Western Europe, January 2024
December 2023 498.9 µg/m³31 of 31980thof 2,247–
June 2023 478.5 µg/m³27 of 301,026thof 1,603–
November 2023 437.8 µg/m³30 of 301,200thof 2,243–
April 2023 427.5 µg/m³24 of 30928thof 1,622–
May 2023 427.5 µg/m³31 of 311,042ndof 1,600–

Monthly means over the days measured; finished months only. World rank: its place on that month's world ranking of every city with enough days. Each month opens that ranking.

Saint-Étienne-de-Montluc's worst days

DayUS AQIEpisode
14 Jan 2024 10537.3 µg/m³Europe, 8 to 27 January 2024
Western Europe, January 2024
10 Jan 2024 8929.7 µg/m³Europe, 8 to 27 January 2024
11 Jan 2024 8728.4 µg/m³Europe, 8 to 27 January 2024
13 Jan 2024 8125.4 µg/m³Europe, 8 to 27 January 2024
2 Dec 2023 7823.8 µg/m³–
18 Apr 2023 7321.1 µg/m³–
20 Jan 2024 7119.7 µg/m³Europe, 8 to 27 January 2024
6 Sept 2023 7119.6 µg/m³–
9 Jan 2024 7019.2 µg/m³Europe, 8 to 27 January 2024
8 Feb 2024 6818.0 µg/m³–

Daily means, the highest since 4 Apr 2023; the WHO's daily guideline is 15 µg/m³. Each date opens that day's world ranking, and each episode the bad-air spell it was part of.

Use this history

SmogRank, PM2.5 monthly and daily means, Saint-Étienne-de-Montluc, France, 4 Apr 2023 – 12 Oct 2026. Monitor data from EEA, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/fr/saint-etienne-de-montluc/history (accessed 13 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.

Saint-Étienne-de-Montluc now: the last 24 hours, its ranks today and the last 12 months day by day.

Updated 2026-10-13 04:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index. Some low-cost readings: Sensor.Community, ODbL (data and licence). Some readings: Uzhydromet (Uzbekistan's Hydrometeorological Service); Department of Environment, Nepal; Vietnam's government monitors; Aurassure; Umhverfisstofnun (Environment Agency of Iceland); RMCAB (Secretaría Distrital de Ambiente, Bogotá); Love My Air (City and County of Denver), no reuse terms published (why we use them).