SmogRank / France / New Aquitaine / Mont-de-Marsan

Mont-de-Marsan, month by month

Mont-de-Marsan has a measured daily mean on 652 days since 11 January 2023. Its worst month was November 2024, at 62 US AQI (15.2 µg/m³), 399th of 2,624 cities on that month's world ranking. Its cleanest was April 2023, at 23 US AQI (4.2 µg/m³).

Every month since 2023

202644 so far230 days measured1,876th of 2,793 in the world
Jan21 daysFeb43#2,022Mar47#2,003Apr33#2,210May33#1,982Jun16 daysJul53#1,259Aug38#2,142Sep34#1,641Oct26#2,247
2025too few days for a mean (a year needs 256)205 days measured
Jan15 daysFeb14 daysMar16 daysApr14 daysMay11 daysJun9 daysJul21 daysAug14 daysSep29#2,453Oct14 daysNov53#955Dec58#871
2024too few days for a mean (a year needs 257)89 days measured
Jan3 daysFeb49#866Mar8 daysApr2 daysMaynoneJunnoneJulnoneAugnoneSepnoneOct14 daysNov62#399Dec14 days
2023too few days for a mean (a year needs 256)128 days measured
Jan10 daysFeb61#398Mar49#362Apr23#1,458May32#1,323JunnoneJulnoneAugnoneSepnoneOctnoneNovnoneDecnone
Each square is a month's mean PM2.5 in US AQI from Mont-de-Marsan'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 Mont-de-Marsan marked; each year, the year's. A dashed square is the running month, so far.
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

Months without a mean, and why

29 months
MonthWhy
Jun 202616 of 30 days measured; a month needs 21. The others: 14 with under 18 hours of readings or readings that failed our checks.
Jan 202621 of 31 days measured; a month needs 22. The others: 10 with under 18 hours of readings or readings that failed our checks.
Oct 202514 of 31 days measured; a month needs 22. The others: 17 with under 18 hours of readings or readings that failed our checks.
Aug 202514 of 31 days measured; a month needs 22. The others: 17 with under 18 hours of readings or readings that failed our checks.
Jul 202521 of 31 days measured; a month needs 22. The others: 10 with under 18 hours of readings or readings that failed our checks.
Jun 20259 of 30 days measured; a month needs 21. The others: 21 with under 18 hours of readings or readings that failed our checks.
May 202511 of 31 days measured; a month needs 22. The others: 20 with under 18 hours of readings or readings that failed our checks.
Apr 202514 of 30 days measured; a month needs 21. The others: 16 with under 18 hours of readings or readings that failed our checks.
Mar 202516 of 31 days measured; a month needs 22. The others: 15 with under 18 hours of readings or readings that failed our checks.
Feb 202514 of 28 days measured; a month needs 20. The others: 14 with under 18 hours of readings or readings that failed our checks.
Jan 202515 of 31 days measured; a month needs 22. The others: 16 with under 18 hours of readings or readings that failed our checks.
Dec 202414 of 31 days measured; a month needs 22. The others: 17 with under 18 hours of readings or readings that failed our checks.
Oct 202414 of 31 days measured; a month needs 22. The others: 17 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.
May 2024No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Apr 20242 of 30 days measured; a month needs 21. The others: 28 with under 18 hours of readings or readings that failed our checks.
Mar 20248 of 31 days measured; a month needs 22. The others: 23 with under 18 hours of readings or readings that failed our checks.
Jan 20243 of 31 days measured; a month needs 22. The others: 28 with under 18 hours of readings or readings that failed our checks.
Dec 2023No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Nov 2023No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
Oct 2023No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Sep 2023No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
Aug 2023No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Jul 2023No day measured. The others: 1 missing from OpenAQ's archive, 30 with under 18 hours of readings or readings that failed our checks.
Jun 2023No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
Jan 202310 of 31 days measured; a month needs 22. The others: 11 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.

Mont-de-Marsan's worst months

MonthUS AQIDays measuredWorld rankEpisode
November 2024 6215.2 µg/m³25 of 30399thof 2,624–
February 2023 6114.2 µg/m³28 of 28398thof 1,129Europe, 28 February to 4 March 2023
December 2025 5812.9 µg/m³29 of 31871stof 3,006–
November 2025 5310.4 µg/m³27 of 30955thof 2,715–
July 2026 5310.4 µg/m³29 of 311,259thof 2,784–
March 2023 498.9 µg/m³30 of 31362ndof 911Europe, 4 to 7 March 2023
Europe, 28 February to 4 March 2023

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.

Mont-de-Marsan's worst days

DayUS AQIEpisode
20 Jan 2025 10838.2 µg/m³Germany, France and 19 more countries, January 2025
5 Jan 2026 9935.1 µg/m³–
17 Dec 2025 9532.7 µg/m³–
3 Mar 2023 9331.8 µg/m³Europe, 28 February to 4 March 2023
5 Feb 2025 9331.6 µg/m³Europe, 1 to 14 February 2025
13 Dec 2024 9231.3 µg/m³–
14 Nov 2024 9231.0 µg/m³–
29 Dec 2025 9030.0 µg/m³–
17 Nov 2024 8829.1 µg/m³–
4 Jan 2026 8828.8 µg/m³France, January 2026

Daily means, the highest since 11 Jan 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, Mont-de-Marsan, France, 11 Jan 2023 – 12 Oct 2026. Monitor data from EEA, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/fr/mont-de-marsan/history (accessed 12 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.

Mont-de-Marsan now: the last 24 hours, its ranks today and the last 12 months day by day.

Updated 2026-10-12 22:07 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).