SmogRank / Episodes / France

France, April 2025

For 1 day, on 27 April 2025, 8 cities in France and the United Kingdom had PM2.5 at least twice their usual for the time of year. The worst reading was Le Havre, Normandy, France: 29.1 µg/m³ on 27 April, about 3.6× its usual 8.1.

No cause namedWe have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached8in 2 countries
Days127 April 2025
Worst day27 April8 cities counted
Furthest above usual4.4×Alençon

Day by day

27 April 8 cities at twice their usual or more
DieppeSeafordBrightonCaenLouviersÉvreuxGillinghamBexleyBoulogne-sur-MerCanvey IslandLondonPortsmouthDreuxHayesCalaisSouthamptonReadingClacton-on-SeaRambouilletAndoverDomontNewmarketCreilDunkirkParisOxfordBéthuneÉtampesSaint HelierNorthamptonKoksijdeBloisOrléansOlivetDouaiWestburyFontainebleauMenenRoyal Leamington SpaRoubaixRoeselareSaint-QuentinCoulommiersIzegemKortrijkDenainTournaiMontargisValenciennesBristolMaldegemGentEvergemMonsNewportLochristiReimsVannesAuxerreNewton AbbotBrusselsBeverenCharleroiGrimbergenWillebroekZwijndrechtZaventemAntwerpStabroekRixensartMechelenLorientKapellen's-GravenzandeMaassluisSpijkenisseBriton FerryPlymouthThe HagueBarnstapleSchiedamSaltashNamurRotterdamAarschotRidderkerkBredaAndenneSaint-DizierQuimperHillegomMolVelserbroekTilburgMarche-en-FamenneBadhoevedorpBrestHasseltIJsselsteinAmsterdamHouthalenFlémalle-HauteMaarssenUtrechtLiègeEindhovenEsch-sur-AlzetteBarneveldHeerlenEupenAachenLuxembourgNijmegenVenrayThionvilleMetzVenloNancyAmiensLutonCherbourgRouenLe HavreChartresRennesAlençon
24 Apr252627282930
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

Le HavreLe Havre, 24 April: 17.0 µg/m³, 2.1× usualLe Havre, 25 April: 17.3 µg/m³, 2.1× usualLe Havre, 26 April: 27.8 µg/m³, 3.4× usualLe Havre, 27 April: 29.1 µg/m³, 3.6× usualLe Havre, 28 April: 22.5 µg/m³, 2.8× usualLe Havre, 29 April: 17.8 µg/m³, 2.2× usualLe Havre, 30 April: 14.4 µg/m³, 1.8× usualCherbourgCherbourg, 24 April: 12.1 µg/m³, 1.5× usualCherbourg, 25 April: 14.6 µg/m³, 1.8× usualCherbourg, 26 April: 25.1 µg/m³, 3.1× usualCherbourg, 27 April: 25.8 µg/m³, 3.2× usualCherbourg, 28 April: no readingCherbourg, 29 April: 23.1 µg/m³, 2.9× usualCherbourg, 30 April: 24.9 µg/m³, 3.1× usualRennesRennes, 24 April: 7.1 µg/m³, 1.1× usualRennes, 25 April: 15.2 µg/m³, 2.3× usualRennes, 26 April: 22.1 µg/m³, 3.3× usualRennes, 27 April: 28.8 µg/m³, 4.3× usualRennes, 28 April: 15.6 µg/m³, 2.3× usualRennes, 29 April: 8.4 µg/m³, 1.3× usualRennes, 30 April: 7.6 µg/m³, 1.1× usualRouenRouen, 24 April: 13.7 µg/m³, 1.8× usualRouen, 25 April: 16.2 µg/m³, 2.2× usualRouen, 26 April: no readingRouen, 27 April: 26.2 µg/m³, 3.5× usualRouen, 28 April: no readingRouen, 29 April: 13.2 µg/m³, 1.8× usualRouen, 30 April: 10.2 µg/m³, 1.4× usualLutonLuton, 24 April: no readingLuton, 25 April: no readingLuton, 26 April: 14.0 µg/m³, 1.6× usualLuton, 27 April: 25.9 µg/m³, 3.0× usualLuton, 28 April: 13.0 µg/m³, 1.5× usualLuton, 29 April: 13.0 µg/m³, 1.5× usualLuton, 30 April: 12.2 µg/m³, 1.4× usualAlençonAlençon, 24 April: no readingAlençon, 25 April: 13.1 µg/m³, 2.2× usualAlençon, 26 April: 19.8 µg/m³, 3.4× usualAlençon, 27 April: 25.8 µg/m³, 4.4× usualAlençon, 28 April: no readingAlençon, 29 April: 8.6 µg/m³, 1.5× usualAlençon, 30 April: 7.1 µg/m³, 1.2× usualAmiensAmiens, 24 April: 14.8 µg/m³, 1.7× usualAmiens, 25 April: 21.9 µg/m³, 2.5× usualAmiens, 26 April: 24.7 µg/m³, 2.8× usualAmiens, 27 April: 25.3 µg/m³, 2.8× usualAmiens, 28 April: 22.1 µg/m³, 2.5× usualAmiens, 29 April: 21.2 µg/m³, 2.4× usualAmiens, 30 April: 14.8 µg/m³, 1.7× usualChartresChartres, 24 April: 11.3 µg/m³, 1.8× usualChartres, 25 April: 16.5 µg/m³, 2.6× usualChartres, 26 April: no readingChartres, 27 April: 25.2 µg/m³, 4.0× usualChartres, 28 April: no readingChartres, 29 April: no readingChartres, 30 April: no reading24 Apr252627282930
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
AlençonNormandy, France1 25.827 April5.94.4×
RennesBrittany, France1 28.827 April6.74.3×
ChartresCentre-Val de Loire, France1 25.227 April6.34.0×
Le HavreNormandy, France1 29.127 April8.13.6×
RouenNormandy, France1 26.227 April7.53.5×
CherbourgNormandy, France1 25.827 April8.03.2×
LutonEngland, United Kingdom1 25.927 April8.53.0×
AmiensHauts-de-France, France1 25.327 April8.92.8×

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 United Kingdom

Number 22 of 26 episodes in France and the United Kingdom since our records began, by cities reached.

Bars: cities reached; colour: the level of the episode's highest daily reading. All 26.

Use this page

SmogRank, France, April 2025: 8 cities with PM2.5 at twice their usual or more, 27 April 2025, smogrank.com/episodes/2025-04-france (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.