SmogRank / Episodes / France

France, January 2023

For 2 days, from 24 to 25 January 2023, 8 cities in France and Monaco had PM2.5 at least twice their usual for the time of year. The worst reading was Sallanches, Auvergne-Rhône-Alpes, France: 56.6 µg/m³ on 24 January, about 2.7× its usual 20.7.

No cause namedWe have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached8in 2 countries
Days224 to 25 January 2023
Worst day25 January7 cities counted
Furthest above usual2.7×Sallanches

Day by day

25 January 7 cities at twice their usual or more
GapAnnecyAostaTurinNiceCannesRomans-sur-IsèreFréjusValenceMeyzieuAix-en-ProvenceBourg-en-BresseGardanneLyonGivorsLa GardeSalon-de-ProvenceLons-le-SaunierVitrollesSavonaAvignonAlessandriaMarseilleMarignaneSaint-ChamondMâconSaint-ÉtienneFos-sur-MerArlesBesançonGenoaNîmesChalon-sur-SaôneLunelMontceau-les-MinesDijonMontpellierLa SpeziaClermont-FerrandMoulinsBastiaRodezAurillacMontluçonPerpignanRoveretoBourgesTrentoBolzanoInnsbruckAnnemasseMonacoGrenobleManosqueMeylanAlbertvilleChambérySallanches
21 Jan22232425262728
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

SallanchesSallanches, 21 January: 23.8 µg/m³, 1.1× usualSallanches, 22 January: 25.7 µg/m³, 1.2× usualSallanches, 23 January: 30.5 µg/m³, 1.5× usualSallanches, 24 January: 56.6 µg/m³, 2.7× usualSallanches, 25 January: 42.3 µg/m³, 2.0× usualSallanches, 26 January: 22.1 µg/m³, 1.1× usualSallanches, 27 January: 23.0 µg/m³, 1.1× usualSallanches, 28 January: 33.6 µg/m³, 1.6× usualMeylanMeylan, 21 January: 11.6 µg/m³, 0.7× usualMeylan, 22 January: 18.7 µg/m³, 1.2× usualMeylan, 23 January: 16.4 µg/m³, 1.1× usualMeylan, 24 January: 34.1 µg/m³, 2.2× usualMeylan, 25 January: 35.9 µg/m³, 2.3× usualMeylan, 26 January: 27.0 µg/m³, 1.7× usualMeylan, 27 January: 28.4 µg/m³, 1.8× usualMeylan, 28 January: 37.5 µg/m³, 2.4× usualGrenobleGrenoble, 21 January: 11.5 µg/m³, 0.8× usualGrenoble, 22 January: 13.7 µg/m³, 1.0× usualGrenoble, 23 January: 17.0 µg/m³, 1.2× usualGrenoble, 24 January: 30.1 µg/m³, 2.1× usualGrenoble, 25 January: 32.8 µg/m³, 2.3× usualGrenoble, 26 January: 28.3 µg/m³, 2.0× usualGrenoble, 27 January: 20.7 µg/m³, 1.5× usualGrenoble, 28 January: 23.1 µg/m³, 1.6× usualChambéryChambéry, 21 January: 15.4 µg/m³, 1.5× usualChambéry, 22 January: 15.2 µg/m³, 1.4× usualChambéry, 23 January: 18.6 µg/m³, 1.8× usualChambéry, 24 January: 27.2 µg/m³, 2.6× usualChambéry, 25 January: 28.6 µg/m³, 2.7× usualChambéry, 26 January: 21.4 µg/m³, 2.0× usualChambéry, 27 January: 19.1 µg/m³, 1.8× usualChambéry, 28 January: 23.5 µg/m³, 2.2× usualManosqueManosque, 21 January: 5.5 µg/m³, 0.5× usualManosque, 22 January: 11.0 µg/m³, 0.9× usualManosque, 23 January: 17.9 µg/m³, 1.5× usualManosque, 24 January: 25.9 µg/m³, 2.2× usualManosque, 25 January: 27.3 µg/m³, 2.3× usualManosque, 26 January: 25.4 µg/m³, 2.2× usualManosque, 27 January: 20.2 µg/m³, 1.7× usualManosque, 28 January: 18.7 µg/m³, 1.6× usualMonacoMonaco, 21 January: 13.4 µg/m³, 0.9× usualMonaco, 22 January: 17.1 µg/m³, 1.2× usualMonaco, 23 January: 26.9 µg/m³, 1.9× usualMonaco, 24 January: 7.1 µg/m³, 0.5× usualMonaco, 25 January: 33.6 µg/m³, 2.3× usualMonaco, 26 January: 23.5 µg/m³, 1.6× usualMonaco, 27 January: 18.6 µg/m³, 1.3× usualMonaco, 28 January: 22.0 µg/m³, 1.5× usualAnnemasseAnnemasse, 21 January: 15.1 µg/m³, 1.3× usualAnnemasse, 22 January: 9.6 µg/m³, 0.8× usualAnnemasse, 23 January: 16.2 µg/m³, 1.4× usualAnnemasse, 24 January: 23.3 µg/m³, 2.0× usualAnnemasse, 25 January: 25.9 µg/m³, 2.3× usualAnnemasse, 26 January: 18.7 µg/m³, 1.6× usualAnnemasse, 27 January: 13.3 µg/m³, 1.2× usualAnnemasse, 28 January: 13.5 µg/m³, 1.2× usualAlbertvilleAlbertville, 21 January: 7.6 µg/m³, 0.7× usualAlbertville, 22 January: 11.2 µg/m³, 1.0× usualAlbertville, 23 January: 15.3 µg/m³, 1.4× usualAlbertville, 24 January: 23.9 µg/m³, 2.2× usualAlbertville, 25 January: 25.4 µg/m³, 2.4× usualAlbertville, 26 January: 23.6 µg/m³, 2.2× usualAlbertville, 27 January: 19.3 µg/m³, 1.8× usualAlbertville, 28 January: 16.9 µg/m³, 1.6× usual21 Jan22232425262728
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
SallanchesAuvergne-Rhône-Alpes, France1 56.624 January20.72.7×
ChambéryAuvergne-Rhône-Alpes, France2 28.625 January10.62.7×
MeylanAuvergne-Rhône-Alpes, France2 37.528 January15.62.4×
AlbertvilleAuvergne-Rhône-Alpes, France1 25.425 January10.82.4×
MonacoMunicipality of Monaco, Monaco1 33.625 January14.42.3×
ManosqueProvence-Alpes-Côte d'Azur, France2 27.325 January11.82.3×
GrenobleAuvergne-Rhône-Alpes, France2 32.825 January14.22.3×
AnnemasseAuvergne-Rhône-Alpes, France1 25.925 January11.52.3×

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 Monaco

Number 12 of 12 episodes in France and Monaco 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, January 2023: 8 cities with PM2.5 at twice their usual or more, 24 to 25 January 2023, smogrank.com/episodes/2023-01-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.