SmogRank / Episodes / Slovakia
South-eastern Europe, 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 named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 16 in 9 countries
Days 3 11 to 13 December 2023
Worst day 12 December 13 cities counted
Furthest above usual 3.2× Handlová
Day by day
Play 12 December 13 cities at twice their usual or more
Belgrade Novi Sad Liberpolis Pristina Tetovo Pécs Skopje Ilinden Dunaújváros Veles Gyál Bitola Esztergom Sofia Ceglie Messapica Győr Miskolc Botevgrad Kazincbarcika Nyíregyháza Nitra Zvolen Žiar nad Hronom Thessaloníki Cluj-Napoca Pylaía Bratislava Karlova Ves Košice Spišská Nová Ves Ružomberok Poprad Martin Trenčín Senica Prešov Dej Vranov nad Topľou Baden Žilina Mödling Perchtoldsdorf Vienna Humenné Rijeka Klosterneuburg Snina Zlín Wolfsberg Valašské Meziříčí Kroměříž Benevento Gabrovo Sankt Pölten Přerov Klagenfurt am Wörthersee Salerno Židenice Brno Znojmo Civitanova Marche Caserta Ancona Dimitrovgrad Amstetten Naples Bucharest Jesi Steyr Pesaro Ansfelden Traun Linz Wels České Budějovice Saalfelden am Steinernen Meer Salzburg Passau Burghausen Traunreut Prievidza Volos Graz Kavadarci Craiova Falconara Marittima Handlová Niš Haskovo Banja Luka Banská Bystrica Kochani Partizánske Trnava Ruse Sarajevo 8 Dec 9 10 11 12 13 14 15 16 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
Banja Luka Banja Luka, 8 December: 112.0 µg/m³, 2.1× usual Banja Luka, 9 December: no reading Banja Luka, 10 December: no reading Banja Luka, 11 December: no reading Banja Luka, 12 December: 127.0 µg/m³, 2.4× usual Banja Luka, 13 December: 29.7 µg/m³, 0.6× usual Banja Luka, 14 December: 43.2 µg/m³, 0.8× usual Banja Luka, 15 December: 40.7 µg/m³, 0.8× usual Banja Luka, 16 December: 86.0 µg/m³, 1.6× usual Sarajevo Sarajevo, 8 December: 46.6 µg/m³, 0.9× usual Sarajevo, 9 December: 108.0 µg/m³, 2.1× usual Sarajevo, 10 December: 162.0 µg/m³, 3.2× usual Sarajevo, 11 December: 161.0 µg/m³, 3.2× usual Sarajevo, 12 December: 144.0 µg/m³, 2.8× usual Sarajevo, 13 December: 36.3 µg/m³, 0.7× usual Sarajevo, 14 December: 25.5 µg/m³, 0.5× usual Sarajevo, 15 December: 25.2 µg/m³, 0.5× usual Sarajevo, 16 December: 25.9 µg/m³, 0.5× usual Niš Niš, 8 December: 47.9 µg/m³, 1.3× usual Niš, 9 December: 45.3 µg/m³, 1.2× usual Niš, 10 December: 37.5 µg/m³, 1.0× usual Niš, 11 December: 80.8 µg/m³, 2.2× usual Niš, 12 December: 81.4 µg/m³, 2.2× usual Niš, 13 December: 35.3 µg/m³, 1.0× usual Niš, 14 December: 35.9 µg/m³, 1.0× usual Niš, 15 December: 20.9 µg/m³, 0.6× usual Niš, 16 December: 20.2 µg/m³, 0.6× usual Ruse Ruse, 8 December: 19.6 µg/m³, 1.1× usual Ruse, 9 December: 19.4 µg/m³, 1.1× usual Ruse, 10 December: 16.4 µg/m³, 0.9× usual Ruse, 11 December: 50.0 µg/m³, 2.9× usual Ruse, 12 December: 32.1 µg/m³, 1.8× usual Ruse, 13 December: no reading Ruse, 14 December: 30.4 µg/m³, 1.7× usual Ruse, 15 December: 8.9 µg/m³, 0.5× usual Ruse, 16 December: 9.6 µg/m³, 0.6× usual Graz Graz, 8 December: 33.0 µg/m³, 1.5× usual Graz, 9 December: 35.4 µg/m³, 1.6× usual Graz, 10 December: 38.1 µg/m³, 1.8× usual Graz, 11 December: 42.9 µg/m³, 2.0× usual Graz, 12 December: 45.9 µg/m³, 2.1× usual Graz, 13 December: 44.5 µg/m³, 2.1× usual Graz, 14 December: 31.0 µg/m³, 1.4× usual Graz, 15 December: 20.4 µg/m³, 0.9× usual Graz, 16 December: 24.2 µg/m³, 1.1× usual Haskovo Haskovo, 8 December: 17.5 µg/m³, 0.9× usual Haskovo, 9 December: no reading Haskovo, 10 December: 27.8 µg/m³, 1.4× usual Haskovo, 11 December: 39.9 µg/m³, 2.0× usual Haskovo, 12 December: 45.2 µg/m³, 2.3× usual Haskovo, 13 December: 45.0 µg/m³, 2.3× usual Haskovo, 14 December: 61.6 µg/m³, 3.1× usual Haskovo, 15 December: 11.9 µg/m³, 0.6× usual Haskovo, 16 December: no reading Partizánske Partizánske, 8 December: 25.8 µg/m³, 1.8× usual Partizánske, 9 December: 22.3 µg/m³, 1.6× usual Partizánske, 10 December: 24.8 µg/m³, 1.8× usual Partizánske, 11 December: 32.4 µg/m³, 2.3× usual Partizánske, 12 December: 36.3 µg/m³, 2.6× usual Partizánske, 13 December: 12.9 µg/m³, 0.9× usual Partizánske, 14 December: 25.5 µg/m³, 1.8× usual Partizánske, 15 December: 13.4 µg/m³, 1.0× usual Partizánske, 16 December: 27.7 µg/m³, 2.0× usual Prievidza Prievidza, 8 December: 22.7 µg/m³, 1.7× usual Prievidza, 9 December: 21.0 µg/m³, 1.5× usual Prievidza, 10 December: 18.5 µg/m³, 1.4× usual Prievidza, 11 December: 29.0 µg/m³, 2.1× usual Prievidza, 12 December: 27.4 µg/m³, 2.0× usual Prievidza, 13 December: 17.3 µg/m³, 1.3× usual Prievidza, 14 December: 21.5 µg/m³, 1.6× usual Prievidza, 15 December: 14.4 µg/m³, 1.1× usual Prievidza, 16 December: 30.6 µg/m³, 2.2× usual Kavadarci Kavadarci, 8 December: 14.1 µg/m³, 0.3× usual Kavadarci, 9 December: 40.3 µg/m³, 0.9× usual Kavadarci, 10 December: 61.6 µg/m³, 1.3× usual Kavadarci, 11 December: 80.0 µg/m³, 1.7× usual Kavadarci, 12 December: 92.2 µg/m³, 2.0× usual Kavadarci, 13 December: 96.1 µg/m³, 2.1× usual Kavadarci, 14 December: 30.7 µg/m³, 0.7× usual Kavadarci, 15 December: 15.1 µg/m³, 0.3× usual Kavadarci, 16 December: 7.0 µg/m³, 0.2× usual Falconara Marittima Falconara Marittima, 8 December: 22.5 µg/m³, 1.4× usual Falconara Marittima, 9 December: 30.6 µg/m³, 1.9× usual Falconara Marittima, 10 December: 28.3 µg/m³, 1.7× usual Falconara Marittima, 11 December: 21.4 µg/m³, 1.3× usual Falconara Marittima, 12 December: 36.0 µg/m³, 2.2× usual Falconara Marittima, 13 December: 13.2 µg/m³, 0.8× usual Falconara Marittima, 14 December: 27.9 µg/m³, 1.7× usual Falconara Marittima, 15 December: 23.6 µg/m³, 1.4× usual Falconara Marittima, 16 December: 13.8 µg/m³, 0.8× usual Trnava Trnava, 8 December: 24.9 µg/m³, 2.2× usual Trnava, 9 December: 22.8 µg/m³, 2.0× usual Trnava, 10 December: 19.5 µg/m³, 1.7× usual Trnava, 11 December: 20.0 µg/m³, 1.8× usual Trnava, 12 December: 30.8 µg/m³, 2.7× usual Trnava, 13 December: 12.5 µg/m³, 1.1× usual Trnava, 14 December: 17.7 µg/m³, 1.6× usual Trnava, 15 December: 11.5 µg/m³, 1.0× usual Trnava, 16 December: 22.4 µg/m³, 2.0× usual Craiova Craiova, 8 December: 11.9 µg/m³, 0.9× usual Craiova, 9 December: 14.6 µg/m³, 1.0× usual Craiova, 10 December: 12.9 µg/m³, 0.9× usual Craiova, 11 December: 15.3 µg/m³, 1.1× usual Craiova, 12 December: 29.7 µg/m³, 2.1× usual Craiova, 13 December: 20.9 µg/m³, 1.5× usual Craiova, 14 December: 17.7 µg/m³, 1.3× usual Craiova, 15 December: 9.6 µg/m³, 0.7× usual Craiova, 16 December: 13.1 µg/m³, 0.9× usual Banská Bystrica Banská Bystrica, 8 December: 19.7 µg/m³, 1.6× usual Banská Bystrica, 9 December: 15.2 µg/m³, 1.3× usual Banská Bystrica, 10 December: 19.7 µg/m³, 1.6× usual Banská Bystrica, 11 December: 24.0 µg/m³, 2.0× usual Banská Bystrica, 12 December: 29.5 µg/m³, 2.4× usual Banská Bystrica, 13 December: 27.0 µg/m³, 2.2× usual Banská Bystrica, 14 December: 28.9 µg/m³, 2.4× usual Banská Bystrica, 15 December: 14.8 µg/m³, 1.2× usual Banská Bystrica, 16 December: 24.2 µg/m³, 2.0× usual Handlová Handlová, 8 December: 22.2 µg/m³, 1.9× usual Handlová, 9 December: 15.8 µg/m³, 1.4× usual Handlová, 10 December: 18.5 µg/m³, 1.6× usual Handlová, 11 December: 15.4 µg/m³, 1.3× usual Handlová, 12 December: 25.4 µg/m³, 2.2× usual Handlová, 13 December: 11.3 µg/m³, 1.0× usual Handlová, 14 December: 29.7 µg/m³, 2.6× usual Handlová, 15 December: 10.9 µg/m³, 0.9× usual Handlová, 16 December: 37.9 µg/m³, 3.3× usual Kochani Kochani, 8 December: 13.5 µg/m³, 0.4× usual Kochani, 9 December: 22.0 µg/m³, 0.7× usual Kochani, 10 December: 33.3 µg/m³, 1.1× usual Kochani, 11 December: 37.2 µg/m³, 1.2× usual Kochani, 12 December: 40.8 µg/m³, 1.3× usual Kochani, 13 December: 80.8 µg/m³, 2.6× usual Kochani, 14 December: 59.1 µg/m³, 1.9× usual Kochani, 15 December: 16.5 µg/m³, 0.5× usual Kochani, 16 December: 10.4 µg/m³, 0.3× usual Volos Volos, 8 December: 8.1 µg/m³, 0.3× usual Volos, 9 December: 25.9 µg/m³, 0.9× usual Volos, 10 December: 32.4 µg/m³, 1.1× usual Volos, 11 December: 29.1 µg/m³, 1.0× usual Volos, 12 December: 40.7 µg/m³, 1.4× usual Volos, 13 December: 62.8 µg/m³, 2.1× usual Volos, 14 December: 57.7 µg/m³, 1.9× usual Volos, 15 December: no reading Volos, 16 December: no reading 8 Dec 9 10 11 12 13 14 15 16 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. Good 0–50
Moderate 51–100
Sensitive groups 101–150
Unhealthy 151–200
Very unhealthy 201–300
Hazardous 301+
Every city it reached
City Days Highest Usual Above usual
Handlová Trenčín Region, Slovakia 1 16 December 11.5 3.3× Sarajevo Federation of B&H, Bosnia and Herzegovina 2 10 December 51.1 3.2× Haskovo Haskovo, Bulgaria 3 14 December 19.6 3.1× Ruse Ruse, Bulgaria 1 11 December 17.4 2.9× Trnava Trnava Region, Slovakia 1 12 December 11.4 2.7× Kochani Kochani, North Macedonia 1 13 December 30.9 2.6× Partizánske Trenčín Region, Slovakia 1 12 December 14.1 2.6× Banská Bystrica Banská Bystrica Region, Slovakia 1 12 December 12.1 2.4× Banja Luka Srpska, Bosnia and Herzegovina 1 12 December 53.5 2.4× Prievidza Trenčín Region, Slovakia 1 16 December 13.7 2.2× Niš Central Serbia, Serbia 2 12 December 36.5 2.2× Falconara Marittima The Marches, Italy 1 12 December 16.5 2.2× Graz Styria, Austria 1 12 December 21.5 2.1× Craiova Dolj, Romania 1 12 December 14.0 2.1× Volos Thessaly, Greece 1 13 December 29.8 2.1× Kavadarci Kavadarci, North Macedonia 2 13 December 46.1 2.1×
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 Slovakia and Bulgaria
Number 4 of 6 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, December 2023: 16 cities with PM2.5 at twice their usual or more, 11 to 13 December 2023, smogrank.com/episodes/2023-12-south-eastern-europe (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.
