SmogRank / Episodes / Slovakia

South-eastern Europe, 11 to 13 December 2023

For 3 days, from 11 to 13 December 2023, 16 cities in Slovakia, Bulgaria, Bosnia and Herzegovina and 6 more countries had PM2.5 at least twice their usual for the time of year. The worst reading was Sarajevo, Federation of B&H, Bosnia and Herzegovina: 161.0 µg/m³ on 11 December, about 3.2× its usual 51.1.

No cause namedWe have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached16in 9 countries
Days311 to 13 December 2023
Worst day12 December13 cities counted
Furthest above usual3.2×Sarajevo

Day by day

12 December 13 cities at twice their usual or more
BelgradeNovi SadLiberpolisPristinaTetovoPécsSkopjeIlindenDunaújvárosVelesGyálBitolaEsztergomSofiaCeglie MessapicaGyőrMiskolcBotevgradKazincbarcikaNyíregyházaNitraZvolenŽiar nad HronomThessaloníkiCluj-NapocaPylaíaBratislavaKarlova VesKošiceSpišská Nová VesRužomberokPopradMartinTrenčínSenicaPrešovDejVranov nad TopľouBadenŽilinaMödlingPerchtoldsdorfViennaHumennéRijekaKlosterneuburgSninaZlínWolfsbergValašské MeziříčíKroměřížBeneventoGabrovoSankt PöltenPřerovKlagenfurt am WörtherseeSalernoŽideniceBrnoZnojmoCivitanova MarcheCasertaAnconaAmstettenNaplesBucharestJesiSteyrPesaroAnsfeldenTraunLinzWelsČeské BudějoviceSaalfelden am Steinernen MeerSalzburgPassauBurghausenTraunreutPrievidzaCraiovaGrazVolosKavadarciHandlováFalconara MarittimaNišHaskovoBanská BystricaBanja LukaPartizánskeKochaniTrnavaRuseSarajevo
8 Dec910111213141516
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

SarajevoSarajevo, 8 December: 46.6 µg/m³Sarajevo, 9 December: 108.0 µg/m³Sarajevo, 10 December: 162.0 µg/m³Sarajevo, 11 December: 161.0 µg/m³, 3.2× its usual 51.1Sarajevo, 12 December: 144.0 µg/m³, 2.9× its usual 49.7Sarajevo, 13 December: 36.3 µg/m³Sarajevo, 14 December: 25.5 µg/m³Sarajevo, 15 December: 25.2 µg/m³Sarajevo, 16 December: 25.9 µg/m³NišNiš, 8 December: 47.9 µg/m³Niš, 9 December: 45.3 µg/m³Niš, 10 December: 37.5 µg/m³Niš, 11 December: 80.8 µg/m³, 2.2× its usual 36.5Niš, 12 December: 81.4 µg/m³, 2.2× its usual 36.5Niš, 13 December: 35.3 µg/m³Niš, 14 December: 35.9 µg/m³Niš, 15 December: 20.9 µg/m³Niš, 16 December: 20.2 µg/m³RuseRuse, 8 December: 19.6 µg/m³Ruse, 9 December: 19.4 µg/m³Ruse, 10 December: 16.4 µg/m³Ruse, 11 December: 50.0 µg/m³, 2.9× its usual 17.4Ruse, 12 December: 32.1 µg/m³Ruse, 13 December: no readingRuse, 14 December: 30.4 µg/m³Ruse, 15 December: 8.9 µg/m³Ruse, 16 December: 9.6 µg/m³HaskovoHaskovo, 8 December: 17.5 µg/m³Haskovo, 9 December: no readingHaskovo, 10 December: 27.8 µg/m³Haskovo, 11 December: 39.9 µg/m³, 2.1× its usual 19.4Haskovo, 12 December: 45.2 µg/m³, 2.3× its usual 19.6Haskovo, 13 December: 45.0 µg/m³, 2.2× its usual 20.3Haskovo, 14 December: 61.6 µg/m³Haskovo, 15 December: 11.9 µg/m³Haskovo, 16 December: no readingBanja LukaBanja Luka, 8 December: 112.0 µg/m³Banja Luka, 9 December: no readingBanja Luka, 10 December: no readingBanja Luka, 11 December: no readingBanja Luka, 12 December: 127.0 µg/m³, 2.4× its usual 53.5Banja Luka, 13 December: 29.7 µg/m³Banja Luka, 14 December: 43.2 µg/m³Banja Luka, 15 December: 40.7 µg/m³Banja Luka, 16 December: 86.0 µg/m³KavadarciKavadarci, 8 December: 14.1 µg/m³Kavadarci, 9 December: 40.3 µg/m³Kavadarci, 10 December: 61.6 µg/m³Kavadarci, 11 December: 80.0 µg/m³Kavadarci, 12 December: 92.2 µg/m³, 2.0× its usual 46.1Kavadarci, 13 December: 96.1 µg/m³, 2.1× its usual 46.1Kavadarci, 14 December: 30.7 µg/m³Kavadarci, 15 December: 15.1 µg/m³Kavadarci, 16 December: 7.0 µg/m³GrazGraz, 8 December: 33.0 µg/m³Graz, 9 December: 35.4 µg/m³Graz, 10 December: 38.1 µg/m³Graz, 11 December: 42.9 µg/m³Graz, 12 December: 45.9 µg/m³, 2.1× its usual 21.5Graz, 13 December: 44.5 µg/m³Graz, 14 December: 31.0 µg/m³Graz, 15 December: 20.4 µg/m³Graz, 16 December: 24.2 µg/m³PartizánskePartizánske, 8 December: 25.8 µg/m³Partizánske, 9 December: 22.3 µg/m³Partizánske, 10 December: 24.8 µg/m³Partizánske, 11 December: 32.4 µg/m³Partizánske, 12 December: 36.3 µg/m³, 2.6× its usual 14.1Partizánske, 13 December: 12.9 µg/m³Partizánske, 14 December: 25.5 µg/m³Partizánske, 15 December: 13.4 µg/m³Partizánske, 16 December: 27.7 µg/m³Falconara MarittimaFalconara Marittima, 8 December: 22.5 µg/m³Falconara Marittima, 9 December: 30.6 µg/m³Falconara Marittima, 10 December: 28.3 µg/m³Falconara Marittima, 11 December: 21.4 µg/m³Falconara Marittima, 12 December: 36.0 µg/m³, 2.2× its usual 16.5Falconara Marittima, 13 December: 13.2 µg/m³Falconara Marittima, 14 December: 27.9 µg/m³Falconara Marittima, 15 December: 23.6 µg/m³Falconara Marittima, 16 December: 13.8 µg/m³TrnavaTrnava, 8 December: 24.9 µg/m³Trnava, 9 December: 22.8 µg/m³Trnava, 10 December: 19.5 µg/m³Trnava, 11 December: 20.0 µg/m³Trnava, 12 December: 30.8 µg/m³, 2.7× its usual 11.4Trnava, 13 December: 12.5 µg/m³Trnava, 14 December: 17.7 µg/m³Trnava, 15 December: 11.5 µg/m³Trnava, 16 December: 22.4 µg/m³CraiovaCraiova, 8 December: 11.9 µg/m³Craiova, 9 December: 14.6 µg/m³Craiova, 10 December: 12.9 µg/m³Craiova, 11 December: 15.3 µg/m³Craiova, 12 December: 29.7 µg/m³, 2.1× its usual 14.0Craiova, 13 December: 20.9 µg/m³Craiova, 14 December: 17.7 µg/m³Craiova, 15 December: 9.6 µg/m³Craiova, 16 December: 13.1 µg/m³Banská BystricaBanská Bystrica, 8 December: 19.7 µg/m³Banská Bystrica, 9 December: 15.2 µg/m³Banská Bystrica, 10 December: 19.7 µg/m³Banská Bystrica, 11 December: 24.0 µg/m³Banská Bystrica, 12 December: 29.5 µg/m³, 2.4× its usual 12.1Banská Bystrica, 13 December: 27.0 µg/m³Banská Bystrica, 14 December: 28.9 µg/m³Banská Bystrica, 15 December: 14.8 µg/m³Banská Bystrica, 16 December: 24.2 µg/m³PrievidzaPrievidza, 8 December: 22.7 µg/m³Prievidza, 9 December: 21.0 µg/m³Prievidza, 10 December: 18.5 µg/m³Prievidza, 11 December: 29.0 µg/m³Prievidza, 12 December: 27.4 µg/m³, 2.0× its usual 13.7Prievidza, 13 December: 17.3 µg/m³Prievidza, 14 December: 21.5 µg/m³Prievidza, 15 December: 14.4 µg/m³Prievidza, 16 December: 30.6 µg/m³HandlováHandlová, 8 December: 22.2 µg/m³Handlová, 9 December: 15.8 µg/m³Handlová, 10 December: 18.5 µg/m³Handlová, 11 December: 15.4 µg/m³Handlová, 12 December: 25.4 µg/m³, 2.2× its usual 11.5Handlová, 13 December: 11.3 µg/m³Handlová, 14 December: 29.7 µg/m³Handlová, 15 December: 10.9 µg/m³Handlová, 16 December: 37.9 µg/m³KochaniKochani, 8 December: 13.5 µg/m³Kochani, 9 December: 22.0 µg/m³Kochani, 10 December: 33.3 µg/m³Kochani, 11 December: 37.2 µg/m³Kochani, 12 December: 40.8 µg/m³Kochani, 13 December: 80.8 µg/m³, 2.6× its usual 30.9Kochani, 14 December: 59.1 µg/m³Kochani, 15 December: 16.5 µg/m³Kochani, 16 December: 10.4 µg/m³VolosVolos, 8 December: 8.1 µg/m³Volos, 9 December: 25.9 µg/m³Volos, 10 December: 32.4 µg/m³Volos, 11 December: 29.1 µg/m³Volos, 12 December: 40.7 µg/m³Volos, 13 December: 62.8 µg/m³, 2.1× its usual 29.8Volos, 14 December: 57.7 µg/m³Volos, 15 December: no readingVolos, 16 December: no reading8 Dec910111213141516
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
SarajevoFederation of B&H, Bosnia and Herzegovina2 161.011 December51.13.2×
RuseRuse, Bulgaria1 50.011 December17.42.9×
TrnavaTrnava Region, Slovakia1 30.812 December11.42.7×
KochaniKochani, North Macedonia1 80.813 December30.92.6×
PartizánskeTrenčín Region, Slovakia1 36.312 December14.12.6×
Banja LukaSrpska, Bosnia and Herzegovina1 127.012 December53.52.4×
Banská BystricaBanská Bystrica Region, Slovakia1 29.512 December12.12.4×
HaskovoHaskovo, Bulgaria3 45.212 December19.62.3×
NišCentral Serbia, Serbia2 81.412 December36.52.2×
Falconara MarittimaThe Marches, Italy1 36.012 December16.52.2×
HandlováTrenčín Region, Slovakia1 25.412 December11.52.2×
KavadarciKavadarci, North Macedonia2 96.113 December46.12.1×
VolosThessaly, Greece1 62.813 December29.82.1×
GrazStyria, Austria1 45.912 December21.52.1×
CraiovaDolj, Romania1 29.712 December14.02.1×
PrievidzaTrenčín Region, Slovakia1 27.412 December13.72.0×

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 Slovakia and Bulgaria

Number 6 of 9 episodes in Slovakia and Bulgaria since our records began, by cities reached.

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

Use this page

SmogRank, South-eastern Europe, 11 to 13 December 2023: 16 cities with PM2.5 at twice their usual or more, 11 to 13 December 2023, smogrank.com/episodes/2023-12-11-south-eastern-europe (accessed 4 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.