SmogRank / Episodes / Czechia
Czechia and Austria, October 2023
For 2 days, from 19 to 20 October 2023, 20 cities in Czechia and Austria 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 20 in 2 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 Liberec Kroměříž Přerov Senica Karlova Ves Bratislava Zlín Kladno Steyr Trnava Valašské Meziříčí Wels Trenčín Graz Pilsen Frýdek-Místek Nitra Győr Litvínov Passau Partizánske Český Těšín 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 Starnberg Spišská Nová Ves Weimar Nuremberg Kazincbarcika Coburg Bamberg Erfurt Augsburg Ansbach Suhl Prešov Nordhausen Košice Meiningen Mühlhausen Eisenach Kempten (Allgäu) Vranov nad Topľou Würzburg Neu-Ulm Goslar Humenné Göttingen Lindau Znojmo Olomouc Havířov Beroun Prague České Budějovice Děčín Amstetten Traun Mladá Boleslav Most Linz Teplice Ústí nad Labem Kadaň Ansfelden Ostrava Bohumín Hradec Králové 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, 0.5× usual Bohumín, 17 October: 13.9 µg/m³, 1.1× usual Bohumín, 18 October: 32.7 µg/m³, 2.6× usual Bohumín, 19 October: 45.4 µg/m³, 3.7× usual Bohumín, 20 October: 24.7 µg/m³, 2.0× usual Bohumín, 21 October: 17.2 µg/m³, 1.4× usual Bohumín, 22 October: 9.0 µg/m³, 0.7× usual Bohumín, 23 October: 9.1 µg/m³, 0.7× usual Ostrava Ostrava, 16 October: 6.6 µg/m³, 0.6× usual Ostrava, 17 October: 17.2 µg/m³, 1.5× usual Ostrava, 18 October: 21.7 µg/m³, 1.9× usual Ostrava, 19 October: 40.0 µg/m³, 3.5× usual Ostrava, 20 October: 34.1 µg/m³, 3.0× usual Ostrava, 21 October: 15.1 µg/m³, 1.3× usual Ostrava, 22 October: 7.9 µg/m³, 0.7× usual Ostrava, 23 October: 9.0 µg/m³, 0.8× usual Hradec Králové Hradec Králové, 16 October: 4.2 µg/m³, 0.3× usual Hradec Králové, 17 October: 13.0 µg/m³, 1.1× usual Hradec Králové, 18 October: 17.2 µg/m³, 1.4× usual Hradec Králové, 19 October: 30.9 µg/m³, 2.6× usual Hradec Králové, 20 October: 45.0 µg/m³, 3.7× usual Hradec Králové, 21 October: no reading Hradec Králové, 22 October: no reading Hradec Králové, 23 October: 9.6 µg/m³, 0.8× usual Havířov Havířov, 16 October: 7.5 µg/m³, 0.6× usual Havířov, 17 October: 15.1 µg/m³, 1.1× usual Havířov, 18 October: 17.6 µg/m³, 1.3× usual Havířov, 19 October: 30.7 µg/m³, 2.3× usual Havířov, 20 October: 23.6 µg/m³, 1.8× usual Havířov, 21 October: 17.4 µg/m³, 1.3× usual Havířov, 22 October: 9.2 µg/m³, 0.7× usual Havířov, 23 October: 9.4 µg/m³, 0.7× usual Opava Opava, 16 October: 5.9 µg/m³, 0.8× usual Opava, 17 October: 7.4 µg/m³, 1.1× usual Opava, 18 October: 15.8 µg/m³, 2.3× usual Opava, 19 October: 28.6 µg/m³, 4.1× usual Opava, 20 October: 36.4 µg/m³, 5.2× usual Opava, 21 October: 19.6 µg/m³, 2.8× usual Opava, 22 October: 13.9 µg/m³, 2.0× usual Opava, 23 October: 8.6 µg/m³, 1.2× usual Ansfelden Ansfelden, 16 October: 8.8 µg/m³, 1.0× usual Ansfelden, 17 October: 11.9 µg/m³, 1.3× usual Ansfelden, 18 October: 18.5 µg/m³, 2.0× usual Ansfelden, 19 October: 28.3 µg/m³, 3.1× usual Ansfelden, 20 October: 21.3 µg/m³, 2.3× usual Ansfelden, 21 October: 10.3 µg/m³, 1.1× usual Ansfelden, 22 October: 2.9 µg/m³, 0.3× usual Ansfelden, 23 October: 8.5 µg/m³, 0.9× usual Traun Traun, 16 October: 12.9 µg/m³, 1.2× usual Traun, 17 October: 12.3 µg/m³, 1.2× usual Traun, 18 October: 18.9 µg/m³, 1.8× usual Traun, 19 October: 26.9 µg/m³, 2.5× usual Traun, 20 October: 20.7 µg/m³, 2.0× usual Traun, 21 October: 9.1 µg/m³, 0.9× usual Traun, 22 October: 3.6 µg/m³, 0.3× usual Traun, 23 October: 9.4 µg/m³, 0.9× usual Znojmo Znojmo, 16 October: 5.0 µg/m³, 0.4× usual Znojmo, 17 October: 9.9 µg/m³, 0.8× usual Znojmo, 18 October: 10.6 µg/m³, 0.8× usual Znojmo, 19 October: 26.0 µg/m³, 2.0× usual Znojmo, 20 October: 22.9 µg/m³, 1.8× usual Znojmo, 21 October: 15.5 µg/m³, 1.2× usual Znojmo, 22 October: 7.1 µg/m³, 0.6× usual Znojmo, 23 October: 8.8 µg/m³, 0.7× usual Linz Linz, 16 October: 13.5 µg/m³, 1.5× usual Linz, 17 October: 10.2 µg/m³, 1.1× usual Linz, 18 October: 14.5 µg/m³, 1.6× usual Linz, 19 October: 25.1 µg/m³, 2.7× usual Linz, 20 October: 19.6 µg/m³, 2.1× usual Linz, 21 October: 11.3 µg/m³, 1.2× usual Linz, 22 October: 3.5 µg/m³, 0.4× usual Linz, 23 October: 8.0 µg/m³, 0.9× usual Amstetten Amstetten, 16 October: 7.3 µg/m³, 0.7× usual Amstetten, 17 October: 10.1 µg/m³, 1.0× usual Amstetten, 18 October: 16.4 µg/m³, 1.6× usual Amstetten, 19 October: 25.0 µg/m³, 2.5× usual Amstetten, 20 October: 18.3 µg/m³, 1.8× usual Amstetten, 21 October: 9.9 µg/m³, 1.0× usual Amstetten, 22 October: 3.6 µg/m³, 0.4× usual Amstetten, 23 October: 8.0 µg/m³, 0.8× usual Děčín Děčín, 16 October: 8.0 µg/m³, 0.6× usual Děčín, 17 October: 16.2 µg/m³, 1.1× usual Děčín, 18 October: 23.3 µg/m³, 1.6× usual Děčín, 19 October: 22.1 µg/m³, 1.5× usual Děčín, 20 October: 35.2 µg/m³, 2.5× usual Děčín, 21 October: 28.0 µg/m³, 2.0× usual Děčín, 22 October: 14.9 µg/m³, 1.0× usual Děčín, 23 October: 12.3 µg/m³, 0.9× usual Teplice Teplice, 16 October: 3.4 µg/m³, 0.3× usual Teplice, 17 October: 12.3 µg/m³, 1.1× usual Teplice, 18 October: 14.7 µg/m³, 1.3× usual Teplice, 19 October: 18.2 µg/m³, 1.6× usual Teplice, 20 October: 32.0 µg/m³, 2.8× usual Teplice, 21 October: 14.9 µg/m³, 1.3× usual Teplice, 22 October: 7.2 µg/m³, 0.6× usual Teplice, 23 October: 10.5 µg/m³, 0.9× usual Beroun Beroun, 16 October: no reading Beroun, 17 October: 12.2 µg/m³, 0.9× usual Beroun, 18 October: 20.3 µg/m³, 1.5× usual Beroun, 19 October: 24.7 µg/m³, 1.8× usual Beroun, 20 October: 31.9 µg/m³, 2.4× usual Beroun, 21 October: 15.2 µg/m³, 1.1× usual Beroun, 22 October: no reading Beroun, 23 October: 13.0 µg/m³, 1.0× usual Kadaň Kadaň, 16 October: no reading Kadaň, 17 October: 8.7 µg/m³, 0.8× usual Kadaň, 18 October: 19.2 µg/m³, 1.9× usual Kadaň, 19 October: 21.6 µg/m³, 2.1× usual Kadaň, 20 October: 31.4 µg/m³, 3.0× usual Kadaň, 21 October: 12.6 µg/m³, 1.2× usual Kadaň, 22 October: 7.0 µg/m³, 0.7× usual Kadaň, 23 October: no reading Most Most, 16 October: 6.4 µg/m³, 0.6× usual Most, 17 October: 13.6 µg/m³, 1.2× usual Most, 18 October: 17.2 µg/m³, 1.5× usual Most, 19 October: 19.2 µg/m³, 1.7× usual Most, 20 October: 30.4 µg/m³, 2.7× usual Most, 21 October: 16.5 µg/m³, 1.5× usual Most, 22 October: 5.8 µg/m³, 0.5× usual Most, 23 October: 8.1 µg/m³, 0.7× usual Ústí nad Labem Ústí nad Labem, 16 October: 5.3 µg/m³, 0.5× usual Ústí nad Labem, 17 October: 11.8 µg/m³, 1.1× usual Ústí nad Labem, 18 October: 14.9 µg/m³, 1.4× usual Ústí nad Labem, 19 October: 20.4 µg/m³, 2.0× usual Ústí nad Labem, 20 October: 30.0 µg/m³, 2.9× usual Ústí nad Labem, 21 October: 17.6 µg/m³, 1.7× usual Ústí nad Labem, 22 October: 5.8 µg/m³, 0.6× usual Ústí nad Labem, 23 October: 9.4 µg/m³, 0.9× usual Mladá Boleslav Mladá Boleslav, 16 October: 4.8 µg/m³, 0.4× usual Mladá Boleslav, 17 October: 15.6 µg/m³, 1.4× usual Mladá Boleslav, 18 October: 15.1 µg/m³, 1.3× usual Mladá Boleslav, 19 October: 20.4 µg/m³, 1.8× usual Mladá Boleslav, 20 October: 30.0 µg/m³, 2.6× usual Mladá Boleslav, 21 October: 19.2 µg/m³, 1.7× usual Mladá Boleslav, 22 October: 7.3 µg/m³, 0.6× usual Mladá Boleslav, 23 October: 8.4 µg/m³, 0.7× usual Olomouc Olomouc, 16 October: 9.1 µg/m³, 0.7× usual Olomouc, 17 October: 16.4 µg/m³, 1.3× usual Olomouc, 18 October: 17.0 µg/m³, 1.3× usual Olomouc, 19 October: 24.7 µg/m³, 1.9× usual Olomouc, 20 October: 28.9 µg/m³, 2.2× usual Olomouc, 21 October: 19.0 µg/m³, 1.5× usual Olomouc, 22 October: 9.2 µg/m³, 0.7× usual Olomouc, 23 October: 15.0 µg/m³, 1.2× usual Prague Prague, 16 October: 5.8 µg/m³, 0.5× usual Prague, 17 October: 13.6 µg/m³, 1.2× usual Prague, 18 October: 15.1 µg/m³, 1.3× usual Prague, 19 October: 20.6 µg/m³, 1.8× usual Prague, 20 October: 27.5 µg/m³, 2.4× usual Prague, 21 October: 15.2 µg/m³, 1.3× usual Prague, 22 October: 8.3 µg/m³, 0.7× usual Prague, 23 October: 8.7 µg/m³, 0.8× usual České Budějovice České Budějovice, 16 October: 6.0 µg/m³, 0.6× usual České Budějovice, 17 October: 11.2 µg/m³, 1.1× usual České Budějovice, 18 October: 18.9 µg/m³, 1.9× usual České Budějovice, 19 October: 21.2 µg/m³, 2.1× usual České Budějovice, 20 October: 25.1 µg/m³, 2.5× usual České Budějovice, 21 October: 17.2 µg/m³, 1.7× usual České Budějovice, 22 October: 8.2 µg/m³, 0.8× usual České Budějovice, 23 October: 8.8 µg/m³, 0.9× usual 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× Hradec Králové Hradec Králové Region, Czechia 2 20 October 12.1 3.7× Bohumín Moravian-Silesian Region, Czechia 1 19 October 12.4 3.7× Ostrava Moravian-Silesian Region, Czechia 2 19 October 11.4 3.5× Ansfelden Upper Austria, Austria 1 19 October 9.1 3.1× 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× Most Ústí nad Labem Region, Czechia 1 20 October 11.1 2.7× Linz Upper Austria, Austria 1 19 October 9.3 2.7× Mladá Boleslav Central Bohemia, Czechia 1 20 October 11.4 2.6× Traun Upper Austria, Austria 1 19 October 10.6 2.5× Amstetten Lower Austria, Austria 1 19 October 10.0 2.5× Děčín Ústí nad Labem Region, Czechia 1 20 October 14.3 2.5× České Budějovice South Bohemian Region, Czechia 1 20 October 10.2 2.5× Prague Prague, Czechia 1 20 October 11.6 2.4× Beroun Central Bohemia, Czechia 1 20 October 13.5 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. 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 Czechia and Austria
Number 4 of 10 episodes in Czechia and Austria since our records began, by cities reached.
Eastern Europe, December 2023 107 Eastern Europe, March 2023 56 Czechia and Slovakia, November and December 2023 41 Czechia and Austria, October 2023 20 Czechia, Slovakia and Austria, December 2023 16 Poland and Czechia, April 2023 15 Poland and Czechia, January 2023 15 Czechia and Poland, April 2023 9 Czechia and Slovakia, January 2023 9 Czechia and Germany, May 2023 8 Bars: cities reached; colour: the level of the episode's highest daily reading.
Use this page SmogRank, Czechia and Austria, October 2023: 20 cities with PM2.5 at twice their usual or more, 19 to 20 October 2023, smogrank.com/episodes/2023-10-czechia-and-austria (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.
