SmogRank / Episodes / France

France and The Netherlands, January 2023

For 1 day, on 29 January 2023, 9 cities in France and The Netherlands had PM2.5 at least twice their usual for the time of year. The worst reading was Valenciennes, Hauts-de-France, France: 35.4 µg/m³ on 29 January, about 3.1× its usual 11.4.

No cause namedWe have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached9in 2 countries
Days129 January 2023
Worst day29 January9 cities counted
Furthest above usual3.3×Saint-Quentin

Day by day

29 January 9 cities at twice their usual or more
MelunFontainebleauÉpernayParisReimsSainte-Geneviève-des-BoisBeauvaisÉtampesTroyesAmiensAuxerreRambouilletBéthuneRoubaixOlivetChartresDreuxSaint-DizierÉvreuxRouenBourgesDunkirkVerdunDieppeCalaisDijonMontceau-les-MinesChâteaurouxChalon-sur-SaôneEsch-sur-AlzetteLisieuxToursBredaMetzThionvilleLuxembourgCanterburyNancyMaassluisLe HavreAlençonLe MansRotterdamTilburgRidderkerkHeerlenBesançonClacton-on-SeaSouthend-on-SeaSeafordBourg-en-BresseCaenCanvey IslandGraysForbachBrightonBexleyNijmegenDagenhamLondonAnnemasseHayesMulhousePortsmouthReadingSouthamptonRennesNantesAndoverOxfordSaint-NazaireSaint-BrieucVannesNewportEindhovenVenrayDouaiLilleBloisPoitiersValenciennesJoué-lès-ToursSaint-Quentin
26 Jan27282930311 Feb
Every measured city in the area, coloured by its PM2.5 that day; a dark ring marks a city at twice its usual or more. Bars: cities counted each day, coloured by their median level. Choose a day or press play; without JavaScript, the days link to that day's world ranking.

How it spread

ValenciennesValenciennes, 26 January: 20.4 µg/m³, 1.8× usualValenciennes, 27 January: 7.7 µg/m³, 0.7× usualValenciennes, 28 January: 20.9 µg/m³, 1.8× usualValenciennes, 29 January: 35.4 µg/m³, 3.1× usualValenciennes, 30 January: 11.6 µg/m³, 1.0× usualValenciennes, 31 January: 10.3 µg/m³, 0.9× usualValenciennes, 1 February: 9.7 µg/m³, 0.9× usualSaint-QuentinSaint-Quentin, 26 January: 19.5 µg/m³, 2.0× usualSaint-Quentin, 27 January: 8.5 µg/m³, 0.9× usualSaint-Quentin, 28 January: 19.0 µg/m³, 1.9× usualSaint-Quentin, 29 January: 32.7 µg/m³, 3.3× usualSaint-Quentin, 30 January: 14.3 µg/m³, 1.4× usualSaint-Quentin, 31 January: 11.3 µg/m³, 1.1× usualSaint-Quentin, 1 February: 7.8 µg/m³, 0.8× usualDouaiDouai, 26 January: 17.7 µg/m³, 1.4× usualDouai, 27 January: 9.4 µg/m³, 0.7× usualDouai, 28 January: 20.9 µg/m³, 1.7× usualDouai, 29 January: 31.4 µg/m³, 2.5× usualDouai, 30 January: 9.5 µg/m³, 0.8× usualDouai, 31 January: 9.6 µg/m³, 0.8× usualDouai, 1 February: 10.9 µg/m³, 0.9× usualJoué-lès-ToursJoué-lès-Tours, 26 January: 22.2 µg/m³, 2.3× usualJoué-lès-Tours, 27 January: 7.1 µg/m³, 0.7× usualJoué-lès-Tours, 28 January: 12.9 µg/m³, 1.4× usualJoué-lès-Tours, 29 January: 30.3 µg/m³, 3.2× usualJoué-lès-Tours, 30 January: 19.1 µg/m³, 2.0× usualJoué-lès-Tours, 31 January: 16.9 µg/m³, 1.8× usualJoué-lès-Tours, 1 February: 11.9 µg/m³, 1.3× usualEindhovenEindhoven, 26 January: 21.0 µg/m³, 1.5× usualEindhoven, 27 January: 10.6 µg/m³, 0.8× usualEindhoven, 28 January: 17.4 µg/m³, 1.3× usualEindhoven, 29 January: 30.2 µg/m³, 2.2× usualEindhoven, 30 January: 13.6 µg/m³, 1.0× usualEindhoven, 31 January: 14.1 µg/m³, 1.0× usualEindhoven, 1 February: 11.1 µg/m³, 0.8× usualLilleLille, 26 January: 19.4 µg/m³, 1.7× usualLille, 27 January: 9.9 µg/m³, 0.9× usualLille, 28 January: 19.4 µg/m³, 1.7× usualLille, 29 January: 28.4 µg/m³, 2.6× usualLille, 30 January: 9.3 µg/m³, 0.8× usualLille, 31 January: 11.9 µg/m³, 1.1× usualLille, 1 February: 9.8 µg/m³, 0.9× usualVenrayVenray, 26 January: 16.6 µg/m³, 1.4× usualVenray, 27 January: 6.7 µg/m³, 0.6× usualVenray, 28 January: 12.0 µg/m³, 1.0× usualVenray, 29 January: 26.4 µg/m³, 2.2× usualVenray, 30 January: 9.7 µg/m³, 0.8× usualVenray, 31 January: 9.9 µg/m³, 0.8× usualVenray, 1 February: 8.2 µg/m³, 0.7× usualPoitiersPoitiers, 26 January: 20.2 µg/m³, 2.3× usualPoitiers, 27 January: 7.1 µg/m³, 0.8× usualPoitiers, 28 January: 12.3 µg/m³, 1.4× usualPoitiers, 29 January: 25.8 µg/m³, 3.0× usualPoitiers, 30 January: 24.6 µg/m³, 2.9× usualPoitiers, 31 January: no readingPoitiers, 1 February: 13.2 µg/m³, 1.5× usualBloisBlois, 26 January: 19.1 µg/m³, 2.2× usualBlois, 27 January: 7.1 µg/m³, 0.8× usualBlois, 28 January: 12.7 µg/m³, 1.5× usualBlois, 29 January: 25.8 µg/m³, 3.0× usualBlois, 30 January: 21.3 µg/m³, 2.4× usualBlois, 31 January: 13.5 µg/m³, 1.6× usualBlois, 1 February: 10.6 µg/m³, 1.2× usual26 Jan27282930311 Feb
Every counted city, in the order the episode reached them, 3 days before to 3 after. Each square is a day, coloured by that day's PM2.5; outlined: at twice the city's usual or more.
Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

Every city it reached

CityDaysHighestUsualAbove usual
Saint-QuentinHauts-de-France, France1 32.729 January10.03.3×
Joué-lès-ToursCentre-Val de Loire, France1 30.329 January9.53.2×
ValenciennesHauts-de-France, France1 35.429 January11.43.1×
PoitiersNew Aquitaine, France1 25.829 January8.63.0×
BloisCentre-Val de Loire, France1 25.829 January8.73.0×
LilleHauts-de-France, France1 28.429 January11.12.6×
DouaiHauts-de-France, France1 31.429 January12.62.5×
VenrayLimburg, The Netherlands1 26.429 January11.82.2×
EindhovenNorth Brabant, The Netherlands1 30.229 January13.82.2×

Daily means in µg/m³. Usual: the city's median for this time of year (its days within 21 days of the date, every year, leaving out the week around it). Above usual: its highest day against that.

Against other episodes in France and The Netherlands

Number 9 of 12 episodes in France and The Netherlands since our records began, by cities reached.

Bars: cities reached; colour: the level of the episode's highest daily reading.

Use this page

SmogRank, France and The Netherlands, January 2023: 9 cities with PM2.5 at twice their usual or more, 29 January 2023, smogrank.com/episodes/2023-01-france-and-the-netherlands (accessed 2 October 2026).

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You're welcome to reuse a single chart, image or figure with this citation and a link. Terms.

An episode is a run of days when many cities close to each other (four or more within 350 km on a day, 8 or more in all) each had a daily PM2.5 mean of at least 25 µg/m³ and at least 2 times their usual for that time of year. Found in our own measurements, not picked by hand. How we find episodes. Values are each city's daily mean of its own monitors; causes are the usual kinds for a pattern like this, not a confirmed source.