SmogRank / Episodes / The Netherlands

Germany, The Netherlands and United Kingdom, April 2023

For 1 day, on 10 April 2023, 8 cities in The Netherlands, Germany and the United Kingdom had PM2.5 at least twice their usual for the time of year. The worst reading was Schwerte, North Rhine-Westphalia, Germany: 38.3 µg/m³ on 10 April, about 5.5× its usual 7.0. Ended 10 April.

Few fires were detected near these cities on those days. Spreads like this usually come from still weather trapping smoke from heating, traffic and industry, or from dust.
Cities reached8in 3 countries
Days110 April 2023
Worst day10 April8 cities counted
Furthest above usual5.5×Schwerte

Day by day

10 April 8 cities at twice their usual or more
NoordwijkerhoutHillegomVelsen-ZuidThe HagueBadhoevedorpZaanstadWormer's-GravenzandeRotterdamMaassluisAmsterdamRidderkerkPurmerendBreukelenLopikMaarssenIJsselsteinUtrechtMedemblikBredaStabroekKapellenTilburgAntwerpZwijndrechtMelseleBeverenBarneveldLunterenWillebroekZelzateMolLochristiEindhovenWaalreEvergemAarschotGentMaldegemBrusselsNijmegenDammeGingelomVenrayMeulebekeIzegemRoeselareKortrijkChampionCharleroiMonsAndenneMenenTournaiFlémalle-HauteLiègeRoubaixHeerlenKoksijdeVeurneValenciennesLilleAachenCouvinMönchengladbachKrefeldEupenJülichTitzRevinRoetgenBorkenDuisburgNiederzierBéthuneOberhausenDüsseldorfBergheimRatingenEssenGelsenkirchenLeverkusenKölnSolingenCalaisHattingenWuppertalDattelnBonnClacton-on-SeaLüdenscheidBrightlingseaFriesoytheCanterburyBöselOsnabrückBendorfKoblenzSoestHöhr-GrenzhausenWilhelmshavenOldenburgCanvey IslandNetphenHooNewmarketWarsteinBurwellBielefeldDieppeLimburg an der LahnGraysDelmenhorstLemwerderBremerhavenDagenhamBexleyBremenWiesbadenMarsbergMainzSeafordGießenMarburg an der LahnLondonRüsselsheim am MainOytenRintelnSulzbachEschbornBrightonFrankfurt am MainHayesKingston upon HullKasselGroßostheimAschaffenburgHannoverItzehoeReadingPickeringFuldaFlensburgGöttingenNottinghamHamburgOxfordPortsmouthYorkChesterfieldRoyal Leamington SpaSheffieldSouthamptonSalzgitterAndoverGoslarTrappenkampKielEisenachMiddlesbroughBraunschweigLeedsMühlhausenMeiningenBirminghamNordhausenLübeckStoke-on-TrentHalberstadtManchesterErfurtCoburgDortmundSheringhamGroningenEnschedeNorwichMünsterKollumSchwerte
7 Apr8910111213
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

SchwerteSchwerte, 7 April: 4.9 µg/m³Schwerte, 8 April: 13.2 µg/m³Schwerte, 9 April: 16.1 µg/m³Schwerte, 10 April: 38.3 µg/m³, 5.5× its usual 7.0Schwerte, 11 April: 4.9 µg/m³Schwerte, 12 April: 2.8 µg/m³Schwerte, 13 April: 3.6 µg/m³MünsterMünster, 7 April: 6.3 µg/m³Münster, 8 April: 14.3 µg/m³Münster, 9 April: 32.0 µg/m³Münster, 10 April: 38.3 µg/m³, 4.9× its usual 7.8Münster, 11 April: 4.8 µg/m³Münster, 12 April: 3.9 µg/m³Münster, 13 April: 5.3 µg/m³NorwichNorwich, 7 April: 4.2 µg/m³Norwich, 8 April: 6.9 µg/m³Norwich, 9 April: 22.7 µg/m³Norwich, 10 April: 27.4 µg/m³, 4.7× its usual 5.8Norwich, 11 April: 3.8 µg/m³Norwich, 12 April: 3.8 µg/m³Norwich, 13 April: no readingDortmundDortmund, 7 April: 6.9 µg/m³Dortmund, 8 April: 16.5 µg/m³Dortmund, 9 April: 19.4 µg/m³Dortmund, 10 April: 27.3 µg/m³, 3.2× its usual 8.6Dortmund, 11 April: 5.8 µg/m³Dortmund, 12 April: 3.6 µg/m³Dortmund, 13 April: 4.4 µg/m³EnschedeEnschede, 7 April: 5.0 µg/m³Enschede, 8 April: 10.9 µg/m³Enschede, 9 April: 27.3 µg/m³Enschede, 10 April: 27.0 µg/m³, 4.7× its usual 5.7Enschede, 11 April: 2.2 µg/m³Enschede, 12 April: 2.8 µg/m³Enschede, 13 April: no readingSheringhamSheringham, 7 April: 6.3 µg/m³Sheringham, 8 April: 8.3 µg/m³Sheringham, 9 April: 21.5 µg/m³Sheringham, 10 April: 26.7 µg/m³, 3.8× its usual 7.1Sheringham, 11 April: 3.7 µg/m³Sheringham, 12 April: 3.5 µg/m³Sheringham, 13 April: no readingGroningenGroningen, 7 April: 8.7 µg/m³Groningen, 8 April: 20.5 µg/m³Groningen, 9 April: 22.3 µg/m³Groningen, 10 April: 26.4 µg/m³, 4.1× its usual 6.5Groningen, 11 April: 3.7 µg/m³Groningen, 12 April: 3.1 µg/m³Groningen, 13 April: no readingKollumKollum, 7 April: 10.4 µg/m³Kollum, 8 April: 16.7 µg/m³Kollum, 9 April: 26.0 µg/m³Kollum, 10 April: 25.9 µg/m³, 5.2× its usual 4.9Kollum, 11 April: 3.0 µg/m³Kollum, 12 April: 2.7 µg/m³Kollum, 13 April: no reading7 Apr8910111213
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
SchwerteNorth Rhine-Westphalia, Germany1 38.310 April7.05.5×
KollumFriesland, The Netherlands1 25.910 April4.95.2×
MünsterNorth Rhine-Westphalia, Germany1 38.310 April7.84.9×
NorwichEngland, United Kingdom1 27.410 April5.84.7×
EnschedeOverijssel, The Netherlands1 27.010 April5.74.7×
GroningenGroningen, The Netherlands1 26.410 April6.54.1×
SheringhamEngland, United Kingdom1 26.710 April7.13.8×
DortmundNorth Rhine-Westphalia, Germany1 27.310 April8.63.2×

Daily means in µg/m³, over the days each city counted in this episode. Highest: its highest of those days. Usual: the city's median for the time of year of that day (its days within 21 days of the date, every year, leaving out the week around it). Above usual: its highest day against that, with a usual under 5 µg/m³ taken as 5.

Against other episodes in The Netherlands and Germany

Number 32 of 32 episodes in The Netherlands and Germany since our records began, by cities reached.

Bars: cities reached; colour: the level of the episode's highest daily reading. All 32.

Use this page

SmogRank, Germany, The Netherlands and United Kingdom, April 2023: 8 cities with PM2.5 at twice their usual or more, 10 April 2023, smogrank.com/episodes/2023-04-germany-the-netherlands-and-united-kingdom (accessed 5 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. Fire detections from NASA FIRMS; smoke maps from NOAA HMS.