SmogRank / Episodes / United Kingdom

United Kingdom, Belgium and France, June 2023

For 2 days, from 11 to 12 June 2023, 10 cities in the United Kingdom, Belgium, France and 1 more countries had PM2.5 at least twice their usual for the time of year. The worst reading was Bexley, England, United Kingdom: 37.1 µg/m³ on 12 June, about 6.5× its usual 5.7.

No cause namedWe have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached10in 4 countries
Days211 to 12 June 2023
Worst day12 June6 cities counted
Furthest above usual6.5×Bexley

Day by day

12 June 6 cities at twice their usual or more
DieppeAmiensBeauvaisRouenCalaisCreilÉvreuxDomontBéthuneSarcellesDreuxParisRambouilletSainte-Geneviève-des-BoisDouaiCanterburyChartresKoksijdeLilleÉtampesSaint-QuentinLe HavreLisieuxRoubaixMenenMelunDenainCoulommiersSeafordFontainebleauTournaiGillinghamValenciennesClacton-on-SeaWaregemBrightonGraysOlivetCaenMaldegemAlençonGentMonsEvergemBloisLondonLe MansReimsÉpernayLochristiHayesNewmarketCharleroiBrusselsAuxerreGrimbergenBeverenWillebroekBiggleswadePortsmouthZwijndrechtAntwerpStabroekReadingKapellen's-GravenzandeSouthamptonMaassluisAngersAarschotThe HagueAndoverRotterdamAndenneOxfordRidderkerkSaint-DizierBredaMolMarche-en-FamenneHillegomVerdunTilburgFlémalle-HauteRennesBadhoevedorpLiègeIJsselsteinRoyal Leamington SpaMaarssenAmsterdamUtrechtEindhovenEsch-sur-AlzetteHeerlenEupenLuxembourgAachenBarneveldThionvilleBristolMetzVenrayNijmegenNancySaint-BrieucJülichMönchengladbachJüchenTrierNewportLunévilleVannesVesoulBergheimDüsseldorfForbachDuisburgNewton AbbotRatingenKölnSaarbrückenOberhausenLeverkusenBonnLorientBorkenSolingenEssenWuppertalGelsenkirchenMontbéliardEnschedeHattingenBriton FerryNeuwiedPlymouthBarnstapleKoblenzBendorfDattelnSaltashHagenDortmundMulhouseSchwerteLüdenscheidKaiserslauternBad KreuznachUnnaKehlMünsterMüllheimBaselBrestLörrachFreiburgIzegemDunkirkKrefeldRoeselareKortrijkTroyesCardiffCanvey IslandDagenhamBexley
8 Jun9101112131415
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

CardiffCardiff, 8 June: 15.2 µg/m³, 2.3× usualCardiff, 9 June: 15.8 µg/m³, 2.4× usualCardiff, 10 June: 20.7 µg/m³, 3.1× usualCardiff, 11 June: 29.0 µg/m³, 4.4× usualCardiff, 12 June: no readingCardiff, 13 June: 18.7 µg/m³, 2.8× usualCardiff, 14 June: 18.7 µg/m³, 2.8× usualCardiff, 15 June: no readingCanvey IslandCanvey Island, 8 June: 9.0 µg/m³, 1.5× usualCanvey Island, 9 June: 12.0 µg/m³, 2.0× usualCanvey Island, 10 June: 22.3 µg/m³, 3.7× usualCanvey Island, 11 June: 28.2 µg/m³, 4.7× usualCanvey Island, 12 June: no readingCanvey Island, 13 June: 25.3 µg/m³, 4.2× usualCanvey Island, 14 June: 13.0 µg/m³, 2.2× usualCanvey Island, 15 June: no readingTroyesTroyes, 8 June: 11.1 µg/m³, 1.6× usualTroyes, 9 June: 9.2 µg/m³, 1.4× usualTroyes, 10 June: 5.5 µg/m³, 0.8× usualTroyes, 11 June: 26.5 µg/m³, 3.9× usualTroyes, 12 June: 9.5 µg/m³, 1.4× usualTroyes, 13 June: 9.4 µg/m³, 1.4× usualTroyes, 14 June: 10.2 µg/m³, 1.5× usualTroyes, 15 June: 8.9 µg/m³, 1.3× usualDunkirkDunkirk, 8 June: 14.1 µg/m³, 1.6× usualDunkirk, 9 June: 19.2 µg/m³, 2.2× usualDunkirk, 10 June: 20.7 µg/m³, 2.4× usualDunkirk, 11 June: 26.0 µg/m³, 3.0× usualDunkirk, 12 June: 16.9 µg/m³, 1.9× usualDunkirk, 13 June: 17.8 µg/m³, 2.0× usualDunkirk, 14 June: 14.8 µg/m³, 1.7× usualDunkirk, 15 June: 15.1 µg/m³, 1.7× usualBexleyBexley, 8 June: 9.0 µg/m³, 1.6× usualBexley, 9 June: 11.2 µg/m³, 2.0× usualBexley, 10 June: 17.8 µg/m³, 3.1× usualBexley, 11 June: 20.0 µg/m³, 3.5× usualBexley, 12 June: 37.1 µg/m³, 6.5× usualBexley, 13 June: 18.5 µg/m³, 3.2× usualBexley, 14 June: 11.3 µg/m³, 2.0× usualBexley, 15 June: 11.5 µg/m³, 2.0× usualKrefeldKrefeld, 8 June: 17.1 µg/m³, 1.8× usualKrefeld, 9 June: 24.4 µg/m³, 2.6× usualKrefeld, 10 June: 18.9 µg/m³, 2.0× usualKrefeld, 11 June: 16.6 µg/m³, 1.8× usualKrefeld, 12 June: 29.2 µg/m³, 3.1× usualKrefeld, 13 June: 21.7 µg/m³, 2.3× usualKrefeld, 14 June: 21.1 µg/m³, 2.2× usualKrefeld, 15 June: 18.9 µg/m³, 2.0× usualDagenhamDagenham, 8 June: 5.5 µg/m³, 1.0× usualDagenham, 9 June: 10.1 µg/m³, 1.9× usualDagenham, 10 June: 15.8 µg/m³, 2.9× usualDagenham, 11 June: 17.9 µg/m³, 3.3× usualDagenham, 12 June: 28.0 µg/m³, 5.2× usualDagenham, 13 June: 11.3 µg/m³, 2.1× usualDagenham, 14 June: 10.7 µg/m³, 2.0× usualDagenham, 15 June: 10.8 µg/m³, 2.0× usualRoeselareRoeselare, 8 June: 17.4 µg/m³, 2.1× usualRoeselare, 9 June: 14.8 µg/m³, 1.8× usualRoeselare, 10 June: 20.9 µg/m³, 2.5× usualRoeselare, 11 June: 20.8 µg/m³, 2.5× usualRoeselare, 12 June: 26.7 µg/m³, 3.2× usualRoeselare, 13 June: 17.2 µg/m³, 2.0× usualRoeselare, 14 June: 15.6 µg/m³, 1.9× usualRoeselare, 15 June: 13.7 µg/m³, 1.6× usualIzegemIzegem, 8 June: 18.7 µg/m³, 2.0× usualIzegem, 9 June: 13.7 µg/m³, 1.5× usualIzegem, 10 June: 19.0 µg/m³, 2.0× usualIzegem, 11 June: 18.0 µg/m³, 1.9× usualIzegem, 12 June: 25.6 µg/m³, 2.8× usualIzegem, 13 June: 15.9 µg/m³, 1.7× usualIzegem, 14 June: 13.8 µg/m³, 1.5× usualIzegem, 15 June: 12.4 µg/m³, 1.3× usualKortrijkKortrijk, 8 June: 18.8 µg/m³, 2.7× usualKortrijk, 9 June: 13.7 µg/m³, 2.0× usualKortrijk, 10 June: 16.9 µg/m³, 2.4× usualKortrijk, 11 June: 16.2 µg/m³, 2.3× usualKortrijk, 12 June: 25.1 µg/m³, 3.6× usualKortrijk, 13 June: 15.9 µg/m³, 2.3× usualKortrijk, 14 June: 14.2 µg/m³, 2.0× usualKortrijk, 15 June: 10.8 µg/m³, 1.5× usual8 Jun9101112131415
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
BexleyEngland, United Kingdom1 37.112 June5.76.5×
DagenhamEngland, United Kingdom1 28.012 June5.45.2×
Canvey IslandEngland, United Kingdom1 28.211 June6.04.7×
CardiffWales, United Kingdom1 29.011 June6.64.4×
TroyesGrand Est, France1 26.511 June6.83.9×
KortrijkFlanders, Belgium1 25.112 June7.03.6×
RoeselareFlanders, Belgium1 26.712 June8.43.2×
KrefeldNorth Rhine-Westphalia, Germany1 29.212 June9.43.1×
DunkirkHauts-de-France, France1 26.011 June8.73.0×
IzegemFlanders, Belgium1 25.612 June9.32.8×

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 the United Kingdom and Belgium

Number 7 of 9 episodes in the United Kingdom and Belgium since our records began, by cities reached.

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

Use this page

SmogRank, United Kingdom, Belgium and France, June 2023: 10 cities with PM2.5 at twice their usual or more, 11 to 12 June 2023, smogrank.com/episodes/2023-06-united-kingdom-belgium-and-france (accessed 2 October 2026).

Download top 10 (PNG)

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.