SmogRank / Episodes / Romania
Southern Europe, December 2025
For 2 days, from 10 to 11 December 2025, 19 cities in Romania, North Macedonia, Slovenia and 5 more countries had PM2.5 at least twice their usual for the time of year. The worst reading was Banja Luka, Srpska, Bosnia and Herzegovina: 171.0 µg/m³ on 10 December, about 3.2× its usual 53.7. Ended 11 December.
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 reached 19 in 8 countries
Days 2 10 to 11 December 2025
Worst day 10 December 10 cities counted
Furthest above usual 5.8× Koper
Day by day
Play 10 December 10 cities at twice their usual or more
Szeged Pljevlja Bijelo Polje Sarajevo Calafat Nikšić Podgorica Skopje Gostivar Bar Dunaújváros Travnik Veles Debrecen Gyál Kochani Sofia Budapest Veszprém Cluj-Napoca Dej Sevlievo Zagreb Murska Sobota Codlea Gabrovo Eisenzicken Buftea Maribor Bragadiru Ruse Jilava Baloteşti Leibnitz Popeşti-Leordeni Novo Mesto Celje Haskovo Weiz Cernica Graz Kostel Trbovlje Zagorje ob Savi Voitsberg Bruck an der Mur Wolfsberg Ljubljana Kranj Klagenfurt am Wörthersee Varna Holboca Lienz Saalfelden am Steinernen Meer Zell am See Kumanovo Tetovo Craiova Pécs Bucharest Ptuj Iaşi Otopeni Dimitrovgrad Târgu Mureş Nova Gorica Gorizia Bihać Livno Belgrade Voluntari Ilinden Banja Luka Koper 7 Dec 8 9 10 11 12 13 14 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, 7 December: 34.3 µg/m³ Banja Luka, 8 December: 50.0 µg/m³ Banja Luka, 9 December: 137.0 µg/m³ Banja Luka, 10 December: 171.0 µg/m³, 3.2× its usual 53.7 Banja Luka, 11 December: no reading Banja Luka, 12 December: no reading Banja Luka, 13 December: no reading Banja Luka, 14 December: no reading Kumanovo Kumanovo, 7 December: 8.1 µg/m³ Kumanovo, 8 December: 11.4 µg/m³ Kumanovo, 9 December: 29.0 µg/m³ Kumanovo, 10 December: 63.5 µg/m³, 2.0× its usual 31.0 Kumanovo, 11 December: 59.1 µg/m³ Kumanovo, 12 December: 22.6 µg/m³ Kumanovo, 13 December: 21.6 µg/m³ Kumanovo, 14 December: 34.8 µg/m³ Belgrade Belgrade, 7 December: 9.8 µg/m³ Belgrade, 8 December: 35.1 µg/m³ Belgrade, 9 December: 49.9 µg/m³ Belgrade, 10 December: 61.4 µg/m³, 2.2× its usual 27.5 Belgrade, 11 December: 43.4 µg/m³ Belgrade, 12 December: 23.1 µg/m³ Belgrade, 13 December: 16.1 µg/m³ Belgrade, 14 December: 22.4 µg/m³ Koper Koper, 7 December: 4.4 µg/m³ Koper, 8 December: 6.6 µg/m³ Koper, 9 December: 10.5 µg/m³ Koper, 10 December: 43.2 µg/m³, 5.8× its usual 7.5 Koper, 11 December: 33.4 µg/m³ Koper, 12 December: 26.7 µg/m³ Koper, 13 December: 4.6 µg/m³ Koper, 14 December: 12.6 µg/m³ Livno Livno, 7 December: 18.8 µg/m³ Livno, 8 December: 25.3 µg/m³ Livno, 9 December: 26.3 µg/m³ Livno, 10 December: 37.2 µg/m³, 2.2× its usual 16.8 Livno, 11 December: 30.5 µg/m³ Livno, 12 December: 48.5 µg/m³ Livno, 13 December: 41.3 µg/m³ Livno, 14 December: 26.1 µg/m³ Bihać Bihać, 7 December: 14.7 µg/m³ Bihać, 8 December: 20.2 µg/m³ Bihać, 9 December: 28.3 µg/m³ Bihać, 10 December: 35.2 µg/m³, 2.2× its usual 16.0 Bihać, 11 December: 43.2 µg/m³ Bihać, 12 December: 29.8 µg/m³ Bihać, 13 December: 23.8 µg/m³ Bihać, 14 December: 11.9 µg/m³ Gorizia Gorizia, 7 December: 12.5 µg/m³ Gorizia, 8 December: 13.2 µg/m³ Gorizia, 9 December: 17.1 µg/m³ Gorizia, 10 December: 33.4 µg/m³, 2.2× its usual 14.9 Gorizia, 11 December: 30.3 µg/m³ Gorizia, 12 December: 13.5 µg/m³ Gorizia, 13 December: 16.4 µg/m³ Gorizia, 14 December: 14.8 µg/m³ Nova Gorica Nova Gorica, 7 December: 12.5 µg/m³ Nova Gorica, 8 December: 13.2 µg/m³ Nova Gorica, 9 December: 17.1 µg/m³ Nova Gorica, 10 December: 33.4 µg/m³, 2.2× its usual 14.9 Nova Gorica, 11 December: 30.3 µg/m³ Nova Gorica, 12 December: 13.5 µg/m³ Nova Gorica, 13 December: 16.4 µg/m³ Nova Gorica, 14 December: 14.8 µg/m³ Ptuj Ptuj, 7 December: 24.9 µg/m³ Ptuj, 8 December: 17.8 µg/m³ Ptuj, 9 December: 26.8 µg/m³ Ptuj, 10 December: 32.6 µg/m³, 2.1× its usual 15.8 Ptuj, 11 December: 38.1 µg/m³ Ptuj, 12 December: no reading Ptuj, 13 December: 29.5 µg/m³ Ptuj, 14 December: 18.1 µg/m³ Pécs Pécs, 7 December: 11.0 µg/m³ Pécs, 8 December: 19.0 µg/m³ Pécs, 9 December: 26.9 µg/m³ Pécs, 10 December: 30.6 µg/m³, 2.1× its usual 14.7 Pécs, 11 December: 20.6 µg/m³ Pécs, 12 December: 16.8 µg/m³ Pécs, 13 December: 6.6 µg/m³ Pécs, 14 December: 4.1 µg/m³ Tetovo Tetovo, 7 December: 32.9 µg/m³ Tetovo, 8 December: 29.5 µg/m³ Tetovo, 9 December: 37.3 µg/m³ Tetovo, 10 December: 100.3 µg/m³ Tetovo, 11 December: 115.5 µg/m³, 2.0× its usual 57.5 Tetovo, 12 December: 66.3 µg/m³ Tetovo, 13 December: 40.4 µg/m³ Tetovo, 14 December: 79.1 µg/m³ Ilinden Ilinden, 7 December: 8.7 µg/m³ Ilinden, 8 December: 9.4 µg/m³ Ilinden, 9 December: 22.0 µg/m³ Ilinden, 10 December: 42.5 µg/m³ Ilinden, 11 December: 97.8 µg/m³, 2.6× its usual 37.0 Ilinden, 12 December: 37.3 µg/m³ Ilinden, 13 December: 33.0 µg/m³ Ilinden, 14 December: 46.1 µg/m³ Târgu Mureş Târgu Mureş, 7 December: 55.2 µg/m³ Târgu Mureş, 8 December: 79.7 µg/m³ Târgu Mureş, 9 December: 82.7 µg/m³ Târgu Mureş, 10 December: 92.1 µg/m³ Târgu Mureş, 11 December: 76.5 µg/m³, 2.1× its usual 37.2 Târgu Mureş, 12 December: 34.3 µg/m³ Târgu Mureş, 13 December: 24.2 µg/m³ Târgu Mureş, 14 December: 30.8 µg/m³ Voluntari Voluntari, 7 December: 12.4 µg/m³ Voluntari, 8 December: 15.1 µg/m³ Voluntari, 9 December: 16.4 µg/m³ Voluntari, 10 December: 43.4 µg/m³ Voluntari, 11 December: 45.5 µg/m³, 2.5× its usual 18.5 Voluntari, 12 December: 30.7 µg/m³ Voluntari, 13 December: 38.2 µg/m³ Voluntari, 14 December: 33.3 µg/m³ Dimitrovgrad Dimitrovgrad, 7 December: 4.2 µg/m³ Dimitrovgrad, 8 December: 6.0 µg/m³ Dimitrovgrad, 9 December: 15.5 µg/m³ Dimitrovgrad, 10 December: 21.8 µg/m³ Dimitrovgrad, 11 December: 38.6 µg/m³, 2.1× its usual 18.4 Dimitrovgrad, 12 December: 37.0 µg/m³ Dimitrovgrad, 13 December: 23.0 µg/m³ Dimitrovgrad, 14 December: 31.2 µg/m³ Otopeni Otopeni, 7 December: 10.4 µg/m³ Otopeni, 8 December: 13.6 µg/m³ Otopeni, 9 December: 16.9 µg/m³ Otopeni, 10 December: 30.3 µg/m³ Otopeni, 11 December: 38.2 µg/m³, 2.1× its usual 18.1 Otopeni, 12 December: 27.3 µg/m³ Otopeni, 13 December: 26.7 µg/m³ Otopeni, 14 December: 26.1 µg/m³ Iaşi Iaşi, 7 December: 13.3 µg/m³ Iaşi, 8 December: 13.8 µg/m³ Iaşi, 9 December: 13.0 µg/m³ Iaşi, 10 December: 22.7 µg/m³ Iaşi, 11 December: 33.0 µg/m³, 2.1× its usual 15.8 Iaşi, 12 December: 16.3 µg/m³ Iaşi, 13 December: 15.8 µg/m³ Iaşi, 14 December: 14.9 µg/m³ Bucharest Bucharest, 7 December: 11.0 µg/m³ Bucharest, 8 December: 10.9 µg/m³ Bucharest, 9 December: 14.2 µg/m³ Bucharest, 10 December: 26.7 µg/m³ Bucharest, 11 December: 31.6 µg/m³, 2.1× its usual 14.9 Bucharest, 12 December: 21.8 µg/m³ Bucharest, 13 December: 24.2 µg/m³ Bucharest, 14 December: 23.3 µg/m³ Craiova Craiova, 7 December: 8.8 µg/m³ Craiova, 8 December: 10.9 µg/m³ Craiova, 9 December: 13.8 µg/m³ Craiova, 10 December: 23.2 µg/m³ Craiova, 11 December: 30.0 µg/m³, 2.1× its usual 14.1 Craiova, 12 December: 24.9 µg/m³ Craiova, 13 December: 19.8 µg/m³ Craiova, 14 December: 13.7 µg/m³ 7 Dec 8 9 10 11 12 13 14 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
Koper Urban Municipality of Koper, Slovenia 1 10 December 7.5 5.8× Banja Luka Srpska, Bosnia and Herzegovina 1 10 December 53.7 3.2× Ilinden Ilinden, North Macedonia 1 11 December 37.0 2.6× Voluntari Ilfov, Romania 1 11 December 18.5 2.5× Belgrade Central Serbia, Serbia 1 10 December 27.5 2.2× Livno Federation of B&H, Bosnia and Herzegovina 1 10 December 16.8 2.2× Bihać Federation of B&H, Bosnia and Herzegovina 1 10 December 16.0 2.2× Gorizia Friuli Venezia Giulia, Italy 1 10 December 14.9 2.2× Nova Gorica Urban Municipality of Nova Gorica, Slovenia 1 10 December 14.9 2.2× Târgu Mureş Mureș County, Romania 1 11 December 37.2 2.1× Dimitrovgrad Haskovo, Bulgaria 1 11 December 18.4 2.1× Otopeni Ilfov, Romania 1 11 December 18.1 2.1× Iaşi Iași County, Romania 1 11 December 15.8 2.1× Ptuj Urban Municipality of Ptuj, Slovenia 1 10 December 15.8 2.1× Bucharest Bucharest, Romania 1 11 December 14.9 2.1× Pécs Baranya, Hungary 1 10 December 14.7 2.1× Craiova Dolj, Romania 1 11 December 14.1 2.1× Tetovo Tetovo, North Macedonia 1 11 December 57.5 2.0× Kumanovo Kumanovo, North Macedonia 1 10 December 31.0 2.0×
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 Romania and North Macedonia
The largest of 10 episodes in Romania and North Macedonia since our records began, by cities reached.
Southern Europe, December 2025 19 South-eastern Europe, February 2024 18 Romania and Bulgaria, March 2026 12 Romania, February 2026 10 Romania, Bulgaria and 2 more countries, December 2023 10 South-eastern Europe, November 2023 10 North Macedonia, Bulgaria and 2 more countries, December 2025 9 Romania, Hungary and Serbia, March 2025 9 Romania and Slovakia, October 2025 8 Romania, Bulgaria and Serbia, January 2025 8 Bars: cities reached; colour: the level of the episode's highest daily reading.
Use this page SmogRank, Southern Europe, December 2025: 19 cities with PM2.5 at twice their usual or more, 10 to 11 December 2025, smogrank.com/episodes/2025-12-southern-europe (accessed 5 October 2026).
Copy citation 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.
