SmogRank / Episodes / Czechia
Czechia, Austria and Poland, October 2023
For 2 days, from 19 to 20 October 2023, 21 cities in Czechia, Austria and Poland had PM2.5 at least twice their usual for the time of year. The worst reading was Bohumín, Moravian-Silesian Region, Czechia: 45.4 µg/m³ on 19 October, about 3.7× its usual 12.4.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 21 in 3 countries
Days 2 19 to 20 October 2023
Worst day 20 October 13 cities counted
Furthest above usual 5.2× Opava
Day by day
Play 20 October 13 cities at twice their usual or more
Pardubice Brno Židenice Klosterneuburg Sankt Pölten Vienna Perchtoldsdorf Mödling Baden Kroměříž Liberec Přerov Senica Karlova Ves Bratislava Zlín Kladno Steyr Trnava Valašské Meziříčí Wels Trenčín Graz Frýdek-Místek Nitra Győr Pilsen Litvínov Passau Partizánske Český Těšín Cieszyn Třinec Prievidza Žilina Handlová Martin Žiar nad Hronom Veszprém Salzburg Burghausen Sokolov Esztergom Banská Bystrica Zvolen Ružomberok Traunreut Saalfelden am Steinernen Meer Weiden Altenburg Schwandorf in Bayern Marktredwitz Greiz Gyál Kelheim Wittenberg Gera Poprad Munich Jena Saalfeld Spišská Nová Ves Starnberg Weimar Nuremberg Kazincbarcika Coburg Bamberg Erfurt Augsburg Ansbach Suhl Prešov Košice Nordhausen Meiningen Mühlhausen Eisenach Kempten (Allgäu) Vranov nad Topľou Würzburg Neu-Ulm Goslar Humenné Göttingen Lindau Znojmo Olomouc Havířov Prague Beroun Amstetten České Budějovice Traun Děčín Linz Mladá Boleslav Most Ansfelden Teplice Ústí nad Labem Kadaň Ostrava Hradec Králové Wodzisław Śląski Bohumín Opava 16 Oct 17 18 19 20 21 22 23 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
Bohumín Bohumín, 16 October: 5.6 µg/m³ Bohumín, 17 October: 13.9 µg/m³ Bohumín, 18 October: 32.7 µg/m³ Bohumín, 19 October: 45.4 µg/m³, 3.7× its usual 12.4 Bohumín, 20 October: 24.7 µg/m³ Bohumín, 21 October: 17.2 µg/m³ Bohumín, 22 October: 9.0 µg/m³ Bohumín, 23 October: 9.1 µg/m³ Wodzisław Śląski Wodzisław Śląski, 16 October: 5.6 µg/m³ Wodzisław Śląski, 17 October: 13.9 µg/m³ Wodzisław Śląski, 18 October: 32.7 µg/m³ Wodzisław Śląski, 19 October: 45.4 µg/m³, 3.7× its usual 12.4 Wodzisław Śląski, 20 October: 24.7 µg/m³ Wodzisław Śląski, 21 October: 17.2 µg/m³ Wodzisław Śląski, 22 October: 9.0 µg/m³ Wodzisław Śląski, 23 October: 9.1 µg/m³ Ostrava Ostrava, 16 October: 6.6 µg/m³ Ostrava, 17 October: 17.2 µg/m³ Ostrava, 18 October: 21.7 µg/m³ Ostrava, 19 October: 40.0 µg/m³, 3.5× its usual 11.4 Ostrava, 20 October: 34.1 µg/m³, 3.1× its usual 11.1 Ostrava, 21 October: 15.1 µg/m³ Ostrava, 22 October: 7.9 µg/m³ Ostrava, 23 October: 9.0 µg/m³ Hradec Králové Hradec Králové, 16 October: 4.2 µg/m³ Hradec Králové, 17 October: 13.0 µg/m³ Hradec Králové, 18 October: 17.2 µg/m³ Hradec Králové, 19 October: 30.9 µg/m³, 2.6× its usual 12.1 Hradec Králové, 20 October: 45.0 µg/m³, 3.7× its usual 12.1 Hradec Králové, 21 October: no reading Hradec Králové, 22 October: no reading Hradec Králové, 23 October: 9.6 µg/m³ Havířov Havířov, 16 October: 7.5 µg/m³ Havířov, 17 October: 15.1 µg/m³ Havířov, 18 October: 17.6 µg/m³ Havířov, 19 October: 30.7 µg/m³, 2.3× its usual 13.2 Havířov, 20 October: 23.6 µg/m³ Havířov, 21 October: 17.4 µg/m³ Havířov, 22 October: 9.2 µg/m³ Havířov, 23 October: 9.4 µg/m³ Opava Opava, 16 October: 5.9 µg/m³ Opava, 17 October: 7.4 µg/m³ Opava, 18 October: 15.8 µg/m³ Opava, 19 October: 28.6 µg/m³, 4.0× its usual 7.1 Opava, 20 October: 36.4 µg/m³, 5.2× its usual 7.0 Opava, 21 October: 19.6 µg/m³ Opava, 22 October: 13.9 µg/m³ Opava, 23 October: 8.6 µg/m³ Ansfelden Ansfelden, 16 October: 8.8 µg/m³ Ansfelden, 17 October: 11.9 µg/m³ Ansfelden, 18 October: 18.5 µg/m³ Ansfelden, 19 October: 28.3 µg/m³, 2.8× its usual 10.0 Ansfelden, 20 October: 21.3 µg/m³ Ansfelden, 21 October: 10.3 µg/m³ Ansfelden, 22 October: 2.9 µg/m³ Ansfelden, 23 October: 8.5 µg/m³ Traun Traun, 16 October: 12.9 µg/m³ Traun, 17 October: 12.3 µg/m³ Traun, 18 October: 18.9 µg/m³ Traun, 19 October: 26.9 µg/m³, 2.5× its usual 10.7 Traun, 20 October: 20.7 µg/m³ Traun, 21 October: 9.1 µg/m³ Traun, 22 October: 3.6 µg/m³ Traun, 23 October: 9.4 µg/m³ Znojmo Znojmo, 16 October: 5.0 µg/m³ Znojmo, 17 October: 9.9 µg/m³ Znojmo, 18 October: 10.6 µg/m³ Znojmo, 19 October: 26.0 µg/m³, 2.0× its usual 12.7 Znojmo, 20 October: 22.9 µg/m³ Znojmo, 21 October: 15.5 µg/m³ Znojmo, 22 October: 7.1 µg/m³ Znojmo, 23 October: 8.8 µg/m³ Linz Linz, 16 October: 13.5 µg/m³ Linz, 17 October: 10.2 µg/m³ Linz, 18 October: 14.5 µg/m³ Linz, 19 October: 25.1 µg/m³, 2.6× its usual 9.6 Linz, 20 October: 19.6 µg/m³ Linz, 21 October: 11.3 µg/m³ Linz, 22 October: 3.5 µg/m³ Linz, 23 October: 8.0 µg/m³ Amstetten Amstetten, 16 October: 7.3 µg/m³ Amstetten, 17 October: 10.1 µg/m³ Amstetten, 18 October: 16.4 µg/m³ Amstetten, 19 October: 25.0 µg/m³, 2.5× its usual 10.0 Amstetten, 20 October: 18.3 µg/m³ Amstetten, 21 October: 9.9 µg/m³ Amstetten, 22 October: 3.6 µg/m³ Amstetten, 23 October: 8.0 µg/m³ Děčín Děčín, 16 October: 8.0 µg/m³ Děčín, 17 October: 16.2 µg/m³ Děčín, 18 October: 23.3 µg/m³ Děčín, 19 October: 22.1 µg/m³ Děčín, 20 October: 35.2 µg/m³, 2.5× its usual 14.3 Děčín, 21 October: 28.0 µg/m³ Děčín, 22 October: 14.9 µg/m³ Děčín, 23 October: 12.3 µg/m³ Teplice Teplice, 16 October: 3.4 µg/m³ Teplice, 17 October: 12.3 µg/m³ Teplice, 18 October: 14.7 µg/m³ Teplice, 19 October: 18.2 µg/m³ Teplice, 20 October: 32.0 µg/m³, 2.8× its usual 11.6 Teplice, 21 October: 14.9 µg/m³ Teplice, 22 October: 7.2 µg/m³ Teplice, 23 October: 10.5 µg/m³ Beroun Beroun, 16 October: no reading Beroun, 17 October: 12.2 µg/m³ Beroun, 18 October: 20.3 µg/m³ Beroun, 19 October: 24.7 µg/m³ Beroun, 20 October: 31.9 µg/m³, 2.4× its usual 13.5 Beroun, 21 October: 15.2 µg/m³ Beroun, 22 October: no reading Beroun, 23 October: 13.0 µg/m³ Kadaň Kadaň, 16 October: no reading Kadaň, 17 October: 8.7 µg/m³ Kadaň, 18 October: 19.2 µg/m³ Kadaň, 19 October: 21.6 µg/m³ Kadaň, 20 October: 31.4 µg/m³, 3.0× its usual 10.3 Kadaň, 21 October: 12.6 µg/m³ Kadaň, 22 October: 7.0 µg/m³ Kadaň, 23 October: no reading Most Most, 16 October: 6.4 µg/m³ Most, 17 October: 13.6 µg/m³ Most, 18 October: 17.2 µg/m³ Most, 19 October: 19.2 µg/m³ Most, 20 October: 30.4 µg/m³, 2.7× its usual 11.1 Most, 21 October: 16.5 µg/m³ Most, 22 October: 5.8 µg/m³ Most, 23 October: 8.1 µg/m³ Ústí nad Labem Ústí nad Labem, 16 October: 5.3 µg/m³ Ústí nad Labem, 17 October: 11.8 µg/m³ Ústí nad Labem, 18 October: 14.9 µg/m³ Ústí nad Labem, 19 October: 20.4 µg/m³ Ústí nad Labem, 20 October: 30.0 µg/m³, 2.9× its usual 10.4 Ústí nad Labem, 21 October: 17.6 µg/m³ Ústí nad Labem, 22 October: 5.8 µg/m³ Ústí nad Labem, 23 October: 9.4 µg/m³ Mladá Boleslav Mladá Boleslav, 16 October: 4.8 µg/m³ Mladá Boleslav, 17 October: 15.6 µg/m³ Mladá Boleslav, 18 October: 15.1 µg/m³ Mladá Boleslav, 19 October: 20.4 µg/m³ Mladá Boleslav, 20 October: 30.0 µg/m³, 2.6× its usual 11.4 Mladá Boleslav, 21 October: 19.2 µg/m³ Mladá Boleslav, 22 October: 7.3 µg/m³ Mladá Boleslav, 23 October: 8.4 µg/m³ Olomouc Olomouc, 16 October: 9.1 µg/m³ Olomouc, 17 October: 16.4 µg/m³ Olomouc, 18 October: 17.0 µg/m³ Olomouc, 19 October: 24.7 µg/m³ Olomouc, 20 October: 28.9 µg/m³, 2.2× its usual 12.9 Olomouc, 21 October: 19.0 µg/m³ Olomouc, 22 October: 9.2 µg/m³ Olomouc, 23 October: 15.0 µg/m³ Prague Prague, 16 October: 5.8 µg/m³ Prague, 17 October: 13.6 µg/m³ Prague, 18 October: 15.1 µg/m³ Prague, 19 October: 20.6 µg/m³ Prague, 20 October: 27.5 µg/m³, 2.4× its usual 11.6 Prague, 21 October: 15.2 µg/m³ Prague, 22 October: 8.3 µg/m³ Prague, 23 October: 8.7 µg/m³ České Budějovice České Budějovice, 16 October: 6.0 µg/m³ České Budějovice, 17 October: 11.2 µg/m³ České Budějovice, 18 October: 18.9 µg/m³ České Budějovice, 19 October: 21.2 µg/m³ České Budějovice, 20 October: 25.1 µg/m³, 2.5× its usual 10.2 České Budějovice, 21 October: 17.2 µg/m³ České Budějovice, 22 October: 8.2 µg/m³ České Budějovice, 23 October: 8.8 µg/m³ 16 Oct 17 18 19 20 21 22 23 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
Opava Moravian-Silesian Region, Czechia 2 20 October 7.0 5.2× Bohumín Moravian-Silesian Region, Czechia 1 19 October 12.4 3.7× Wodzisław Śląski Silesia, Poland 1 19 October 12.4 3.7× Hradec Králové Hradec Králové Region, Czechia 2 20 October 12.1 3.7× Ostrava Moravian-Silesian Region, Czechia 2 19 October 11.4 3.5× Kadaň Ústí nad Labem Region, Czechia 1 20 October 10.3 3.0× Ústí nad Labem Ústí nad Labem Region, Czechia 1 20 October 10.4 2.9× Teplice Ústí nad Labem Region, Czechia 1 20 October 11.6 2.8× Ansfelden Upper Austria, Austria 1 19 October 10.0 2.8× Most Ústí nad Labem Region, Czechia 1 20 October 11.1 2.7× Mladá Boleslav Central Bohemia, Czechia 1 20 October 11.4 2.6× Linz Upper Austria, Austria 1 19 October 9.6 2.6× Děčín Ústí nad Labem Region, Czechia 1 20 October 14.3 2.5× Traun Upper Austria, Austria 1 19 October 10.7 2.5× České Budějovice South Bohemian Region, Czechia 1 20 October 10.2 2.5× Amstetten Lower Austria, Austria 1 19 October 10.0 2.5× Beroun Central Bohemia, Czechia 1 20 October 13.5 2.4× Prague Prague, Czechia 1 20 October 11.6 2.4× Havířov Moravian-Silesian Region, Czechia 1 19 October 13.2 2.3× Olomouc Olomouc Region, Czechia 1 20 October 12.9 2.2× Znojmo South Moravian, Czechia 1 19 October 12.7 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 Czechia and Austria
Number 6 of 15 episodes in Czechia and Austria since our records began, by cities reached.
Eastern Europe, 4 to 9 December 2023 110 Eastern Europe, March 2023 59 Eastern Europe, November and December 2023 43 Eastern Europe, January 2025 27 Eastern Europe, January 2024 26 Czechia, Austria and Poland, October 2023 21 Czechia, Poland and Slovakia, November 2025 19 Czechia, Slovakia and 2 more countries, December 2023 18 Germany, Czechia and 2 more countries, January 2024 17 Poland and Czechia, January 2023 17 Poland and Czechia, April 2023 16 Czechia and Poland, April 2023 11 Bars: cities reached; colour: the level of the episode's highest daily reading. All 15 .
Use this page SmogRank, Czechia, Austria and Poland, October 2023: 21 cities with PM2.5 at twice their usual or more, 19 to 20 October 2023, smogrank.com/episodes/2023-10-czechia-austria-and-poland (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.
