SmogRank / Episodes / Romania

Romania and Bulgaria, December 2023

For 2 days, from 1 to 2 December 2023, 8 cities in Romania, Bulgaria, Greece and 1 more countries had PM2.5 at least twice their usual for the time of year. The worst reading was Ruse, Ruse, Bulgaria: 48.2 µg/m³ on 2 December, about 2.8× its usual 17.5.

No cause namedWe have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached8in 4 countries
Days21 to 2 December 2023
Worst day1 December6 cities counted
Furthest above usual3.4×Sofia

Day by day

1 December 6 cities at twice their usual or more
SevlievoGabrovoBotevgradDimitrovgradNišCluj-NapocaDejPylaíaKavadarciVelesIlindenPristinaSkopjeTetovoBelgradeBitolaNovi SadThessaloníkiBucharestKochaniHaskovoIaşiRuseCraiovaSofia
28 Nov29301 Dec2345
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

SofiaSofia, 28 November: 11.9 µg/m³, 1.3× usualSofia, 29 November: 29.0 µg/m³, 3.2× usualSofia, 30 November: 34.4 µg/m³, 3.8× usualSofia, 1 December: 30.4 µg/m³, 3.4× usualSofia, 2 December: 4.4 µg/m³, 0.5× usualSofia, 3 December: 5.3 µg/m³, 0.6× usualSofia, 4 December: 7.8 µg/m³, 0.9× usualSofia, 5 December: 5.6 µg/m³, 0.6× usualKochaniKochani, 28 November: 14.2 µg/m³, 0.8× usualKochani, 29 November: 15.2 µg/m³, 0.8× usualKochani, 30 November: 22.5 µg/m³, 1.2× usualKochani, 1 December: 47.4 µg/m³, 2.5× usualKochani, 2 December: 19.0 µg/m³, 1.0× usualKochani, 3 December: 16.0 µg/m³, 0.8× usualKochani, 4 December: 17.9 µg/m³, 0.9× usualKochani, 5 December: 41.8 µg/m³, 2.2× usualRuseRuse, 28 November: 14.6 µg/m³, 0.8× usualRuse, 29 November: 11.6 µg/m³, 0.7× usualRuse, 30 November: 20.5 µg/m³, 1.2× usualRuse, 1 December: 46.5 µg/m³, 2.7× usualRuse, 2 December: 48.2 µg/m³, 2.8× usualRuse, 3 December: 15.4 µg/m³, 0.9× usualRuse, 4 December: 14.6 µg/m³, 0.8× usualRuse, 5 December: 27.9 µg/m³, 1.6× usualThessaloníkiThessaloníki, 28 November: 38.0 µg/m³, 1.7× usualThessaloníki, 29 November: 35.3 µg/m³, 1.6× usualThessaloníki, 30 November: 27.3 µg/m³, 1.2× usualThessaloníki, 1 December: 46.0 µg/m³, 2.0× usualThessaloníki, 2 December: 40.5 µg/m³, 1.8× usualThessaloníki, 3 December: 28.0 µg/m³, 1.2× usualThessaloníki, 4 December: 14.7 µg/m³, 0.7× usualThessaloníki, 5 December: 22.0 µg/m³, 1.0× usualCraiovaCraiova, 28 November: 10.1 µg/m³, 0.7× usualCraiova, 29 November: 8.3 µg/m³, 0.5× usualCraiova, 30 November: 20.1 µg/m³, 1.3× usualCraiova, 1 December: 45.7 µg/m³, 3.0× usualCraiova, 2 December: 47.2 µg/m³, 3.1× usualCraiova, 3 December: 18.8 µg/m³, 1.2× usualCraiova, 4 December: 11.5 µg/m³, 0.8× usualCraiova, 5 December: 18.4 µg/m³, 1.2× usualHaskovoHaskovo, 28 November: 14.5 µg/m³, 0.8× usualHaskovo, 29 November: 13.3 µg/m³, 0.7× usualHaskovo, 30 November: 20.3 µg/m³, 1.1× usualHaskovo, 1 December: 44.4 µg/m³, 2.5× usualHaskovo, 2 December: 23.3 µg/m³, 1.3× usualHaskovo, 3 December: no readingHaskovo, 4 December: 29.9 µg/m³, 1.7× usualHaskovo, 5 December: 27.8 µg/m³, 1.5× usualIaşiIaşi, 28 November: 14.5 µg/m³, 1.0× usualIaşi, 29 November: 13.3 µg/m³, 0.9× usualIaşi, 30 November: 17.0 µg/m³, 1.1× usualIaşi, 1 December: 22.4 µg/m³, 1.5× usualIaşi, 2 December: 42.4 µg/m³, 2.8× usualIaşi, 3 December: 22.2 µg/m³, 1.5× usualIaşi, 4 December: 34.4 µg/m³, 2.3× usualIaşi, 5 December: 16.9 µg/m³, 1.1× usualBucharestBucharest, 28 November: 11.7 µg/m³, 0.9× usualBucharest, 29 November: 8.1 µg/m³, 0.6× usualBucharest, 30 November: 19.3 µg/m³, 1.4× usualBucharest, 1 December: 23.1 µg/m³, 1.7× usualBucharest, 2 December: 31.8 µg/m³, 2.3× usualBucharest, 3 December: 14.7 µg/m³, 1.1× usualBucharest, 4 December: 12.1 µg/m³, 0.9× usualBucharest, 5 December: 14.5 µg/m³, 1.1× usual28 Nov29301 Dec2345
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
SofiaSofia-Capital, Bulgaria1 34.430 November9.03.8×
CraiovaDolj, Romania2 47.22 December15.23.1×
IaşiIași County, Romania1 42.42 December15.22.8×
RuseRuse, Bulgaria2 48.22 December17.52.8×
KochaniKochani, North Macedonia1 47.41 December18.92.5×
HaskovoHaskovo, Bulgaria1 44.41 December18.02.5×
BucharestBucharest, Romania1 31.82 December13.72.3×
ThessaloníkiCentral Macedonia, Greece1 46.01 December22.52.0×

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.

Use this page

SmogRank, Romania and Bulgaria, December 2023: 8 cities with PM2.5 at twice their usual or more, 1 to 2 December 2023, smogrank.com/episodes/2023-12-romania-and-bulgaria (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.