SmogRank / Episodes / Belgium
Belgium, Germany and 2 more countries, May 2023
For 1 day, on 22 May 2023, 26 cities in Belgium, Germany, The Netherlands and 1 more countries had PM2.5 at least twice their usual for the time of year. The worst reading was Andenne, Wallonia, Belgium: 38.1 µg/m³ on 22 May, about 7.5× its usual 5.1.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 26 in 4 countries
Days 1 22 May 2023
Worst day 22 May 26 cities counted
Furthest above usual 7.5× Andenne
Day by day
Play 22 May 26 cities at twice their usual or more
Flémalle-Haute Esch-sur-Alzette Luxembourg Verdun Eindhoven Trier Mönchengladbach Tilburg Venray Metz Willebroek Kapellen Breda Zwijndrecht Krefeld Stabroek Beveren Nijmegen Leverkusen Ratingen Duisburg Saint-Dizier Nancy Reims IJsselstein Forbach Ridderkerk Oberhausen Utrecht Lochristi Barneveld Saarbrücken Maarssen Rotterdam Essen Wuppertal Gent Épernay Lunéville Gelsenkirchen Hattingen Maassluis Borken Denain Waregem The Hague 's-Gravenzande Badhoevedorp Amsterdam Hillegom Maldegem Saint-Quentin Hagen Zaanstad Purmerend Kortrijk Velserbroek Datteln Velsen-Zuid Dortmund Lüdenscheid Roubaix Izegem Schwerte Enschede Douai Menen Bad Kreuznach Troyes Kaiserslautern Roeselare Lille Unna Limburg an der Lahn Netphen Münster Wiesbaden Mainz Coulommiers Béthune Lingen Kehl Soest Worms Rüsselsheim am Main Koksijde Lampertheim Ludwigshafen am Rhein Warstein Mannheim Eschborn Speyer Baden-Baden Eggenstein-Leopoldshafen Creil Karlsruhe Bensheim Darmstadt Dunkirk Frankfurt am Main Gießen Amiens Osnabrück Freiburg Melun Heidelberg Marburg an der Lahn Fontainebleau Sarcelles Wiesloch Domont Paris Beauvais Pforzheim Bielefeld Marsberg Sainte-Geneviève-des-Bois Großostheim Aschaffenburg Calais Villingen-Schwenningen Herrenberg Étampes Heilbronn Ludwigsburg Tübingen Stuttgart Rambouillet Rinteln Filderstadt Reutlingen Kassel Fulda Lauda-Königshofen Olivet Chartres Dreux Dieppe Rouen Würzburg Canterbury Évreux Clacton-on-Sea Göttingen Hannover Norwich Aalen Biberach an der Riß Hildesheim Eisenach Ulm Neu-Ulm Meiningen Mühlhausen Canvey Island Gillingham Goslar Ansbach Salzgitter Grays Lisieux Seaford Braunschweig Bamberg Le Havre Newmarket Nordhausen Dagenham Coburg Erfurt Brighton Nuremberg Alençon London Augsburg Le Mans Halberstadt Weimar Saalfeld Caen Biggleswade Hayes Starnberg Munich Evergem Solingen Thionville Antwerp Düsseldorf Mol Bergheim Jüchen Brussels Jülich Köln Grimbergen Aachen Bonn Mons Neuwied Tournai Aarschot Marche-en-Famenne Koblenz Heerlen Bendorf Charleroi Liège Eupen Andenne 19 May 20 21 22 23 24 25 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
Andenne Andenne, 19 May: 13.4 µg/m³ Andenne, 20 May: 11.9 µg/m³ Andenne, 21 May: 15.9 µg/m³ Andenne, 22 May: 38.1 µg/m³, 7.5× its usual 5.1 Andenne, 23 May: 15.7 µg/m³ Andenne, 24 May: 6.2 µg/m³ Andenne, 25 May: 10.6 µg/m³ Koblenz Koblenz, 19 May: 5.7 µg/m³ Koblenz, 20 May: 10.2 µg/m³ Koblenz, 21 May: 19.3 µg/m³ Koblenz, 22 May: 38.1 µg/m³, 5.3× its usual 7.2 Koblenz, 23 May: 13.9 µg/m³ Koblenz, 24 May: 7.1 µg/m³ Koblenz, 25 May: 7.5 µg/m³ Aarschot Aarschot, 19 May: 10.0 µg/m³ Aarschot, 20 May: 7.7 µg/m³ Aarschot, 21 May: 13.3 µg/m³ Aarschot, 22 May: 32.5 µg/m³, 4.4× its usual 7.4 Aarschot, 23 May: 12.2 µg/m³ Aarschot, 24 May: 10.0 µg/m³ Aarschot, 25 May: 10.1 µg/m³ Grimbergen Grimbergen, 19 May: 10.3 µg/m³ Grimbergen, 20 May: 7.5 µg/m³ Grimbergen, 21 May: 11.9 µg/m³ Grimbergen, 22 May: 31.7 µg/m³, 3.8× its usual 8.4 Grimbergen, 23 May: 13.4 µg/m³ Grimbergen, 24 May: 9.9 µg/m³ Grimbergen, 25 May: 9.0 µg/m³ Liège Liège, 19 May: 8.0 µg/m³ Liège, 20 May: 6.6 µg/m³ Liège, 21 May: 15.9 µg/m³ Liège, 22 May: 31.3 µg/m³, 5.7× its usual 5.5 Liège, 23 May: 13.4 µg/m³ Liège, 24 May: 7.9 µg/m³ Liège, 25 May: 11.2 µg/m³ Bendorf Bendorf, 19 May: 5.6 µg/m³ Bendorf, 20 May: 11.3 µg/m³ Bendorf, 21 May: 18.0 µg/m³ Bendorf, 22 May: 30.0 µg/m³, 5.4× its usual 5.6 Bendorf, 23 May: 12.6 µg/m³ Bendorf, 24 May: 5.7 µg/m³ Bendorf, 25 May: 7.6 µg/m³ Bergheim Bergheim, 19 May: 7.2 µg/m³ Bergheim, 20 May: 7.4 µg/m³ Bergheim, 21 May: 15.6 µg/m³ Bergheim, 22 May: 30.0 µg/m³, 3.1× its usual 9.8 Bergheim, 23 May: 9.0 µg/m³ Bergheim, 24 May: 9.2 µg/m³ Bergheim, 25 May: 12.5 µg/m³ Charleroi Charleroi, 19 May: 8.9 µg/m³ Charleroi, 20 May: 7.4 µg/m³ Charleroi, 21 May: 12.9 µg/m³ Charleroi, 22 May: 29.8 µg/m³, 5.5× its usual 5.4 Charleroi, 23 May: 14.1 µg/m³ Charleroi, 24 May: 7.2 µg/m³ Charleroi, 25 May: 10.4 µg/m³ Eupen Eupen, 19 May: 4.9 µg/m³ Eupen, 20 May: 6.6 µg/m³ Eupen, 21 May: 16.4 µg/m³ Eupen, 22 May: 29.7 µg/m³, 5.9× its usual 4.1 Eupen, 23 May: 13.8 µg/m³ Eupen, 24 May: 6.1 µg/m³ Eupen, 25 May: 14.5 µg/m³ Bonn Bonn, 19 May: 5.6 µg/m³ Bonn, 20 May: 6.9 µg/m³ Bonn, 21 May: 14.5 µg/m³ Bonn, 22 May: 29.6 µg/m³, 4.1× its usual 7.2 Bonn, 23 May: 11.3 µg/m³ Bonn, 24 May: 9.4 µg/m³ Bonn, 25 May: 10.6 µg/m³ Neuwied Neuwied, 19 May: 5.2 µg/m³ Neuwied, 20 May: 10.3 µg/m³ Neuwied, 21 May: 17.1 µg/m³ Neuwied, 22 May: 29.0 µg/m³, 4.3× its usual 6.8 Neuwied, 23 May: 13.9 µg/m³ Neuwied, 24 May: 6.5 µg/m³ Neuwied, 25 May: 7.3 µg/m³ Köln Köln, 19 May: 6.0 µg/m³ Köln, 20 May: 6.6 µg/m³ Köln, 21 May: 16.1 µg/m³ Köln, 22 May: 29.0 µg/m³, 3.8× its usual 7.7 Köln, 23 May: 11.4 µg/m³ Köln, 24 May: 10.2 µg/m³ Köln, 25 May: 11.9 µg/m³ Jülich Jülich, 19 May: 10.1 µg/m³ Jülich, 20 May: 9.9 µg/m³ Jülich, 21 May: 16.8 µg/m³ Jülich, 22 May: 28.7 µg/m³, 3.7× its usual 7.8 Jülich, 23 May: 11.2 µg/m³ Jülich, 24 May: 7.6 µg/m³ Jülich, 25 May: 11.6 µg/m³ Aachen Aachen, 19 May: 8.3 µg/m³ Aachen, 20 May: 8.5 µg/m³ Aachen, 21 May: 19.2 µg/m³ Aachen, 22 May: 28.4 µg/m³, 4.0× its usual 7.1 Aachen, 23 May: 13.3 µg/m³ Aachen, 24 May: 9.1 µg/m³ Aachen, 25 May: 14.5 µg/m³ Heerlen Heerlen, 19 May: no reading Heerlen, 20 May: 6.9 µg/m³ Heerlen, 21 May: 12.6 µg/m³ Heerlen, 22 May: 28.0 µg/m³, 5.4× its usual 5.2 Heerlen, 23 May: no reading Heerlen, 24 May: no reading Heerlen, 25 May: 8.6 µg/m³ Mons Mons, 19 May: 10.9 µg/m³ Mons, 20 May: 8.1 µg/m³ Mons, 21 May: 12.9 µg/m³ Mons, 22 May: 28.0 µg/m³, 4.2× its usual 6.6 Mons, 23 May: 12.2 µg/m³ Mons, 24 May: 6.8 µg/m³ Mons, 25 May: 8.5 µg/m³ Antwerp Antwerp, 19 May: 10.8 µg/m³ Antwerp, 20 May: 9.0 µg/m³ Antwerp, 21 May: 12.4 µg/m³ Antwerp, 22 May: 26.7 µg/m³, 3.0× its usual 9.0 Antwerp, 23 May: 12.9 µg/m³ Antwerp, 24 May: 9.9 µg/m³ Antwerp, 25 May: 10.4 µg/m³ Mol Mol, 19 May: 9.8 µg/m³ Mol, 20 May: 7.2 µg/m³ Mol, 21 May: 12.7 µg/m³ Mol, 22 May: 26.6 µg/m³, 3.1× its usual 8.5 Mol, 23 May: 10.7 µg/m³ Mol, 24 May: 9.1 µg/m³ Mol, 25 May: 9.5 µg/m³ Jüchen Jüchen, 19 May: 9.4 µg/m³ Jüchen, 20 May: 8.5 µg/m³ Jüchen, 21 May: 14.7 µg/m³ Jüchen, 22 May: 26.2 µg/m³, 3.4× its usual 7.7 Jüchen, 23 May: 8.2 µg/m³ Jüchen, 24 May: 9.1 µg/m³ Jüchen, 25 May: 14.8 µg/m³ Solingen Solingen, 19 May: 6.4 µg/m³ Solingen, 20 May: 7.7 µg/m³ Solingen, 21 May: 15.9 µg/m³ Solingen, 22 May: 25.9 µg/m³, 2.6× its usual 10.0 Solingen, 23 May: 12.2 µg/m³ Solingen, 24 May: 11.5 µg/m³ Solingen, 25 May: 13.3 µg/m³ Brussels Brussels, 19 May: 10.8 µg/m³ Brussels, 20 May: 9.3 µg/m³ Brussels, 21 May: 11.9 µg/m³ Brussels, 22 May: 25.6 µg/m³, 3.5× its usual 7.4 Brussels, 23 May: 10.4 µg/m³ Brussels, 24 May: 7.6 µg/m³ Brussels, 25 May: 8.4 µg/m³ Düsseldorf Düsseldorf, 19 May: 10.0 µg/m³ Düsseldorf, 20 May: 10.4 µg/m³ Düsseldorf, 21 May: 16.8 µg/m³ Düsseldorf, 22 May: 25.4 µg/m³, 3.1× its usual 8.3 Düsseldorf, 23 May: 9.6 µg/m³ Düsseldorf, 24 May: 10.2 µg/m³ Düsseldorf, 25 May: 12.4 µg/m³ Thionville Thionville, 19 May: 11.6 µg/m³ Thionville, 20 May: 10.8 µg/m³ Thionville, 21 May: 17.3 µg/m³ Thionville, 22 May: 25.3 µg/m³, 2.8× its usual 9.0 Thionville, 23 May: 17.8 µg/m³ Thionville, 24 May: 11.9 µg/m³ Thionville, 25 May: 11.7 µg/m³ Evergem Evergem, 19 May: 14.9 µg/m³ Evergem, 20 May: 12.0 µg/m³ Evergem, 21 May: 13.9 µg/m³ Evergem, 22 May: 25.1 µg/m³, 2.5× its usual 10.0 Evergem, 23 May: 13.4 µg/m³ Evergem, 24 May: 9.1 µg/m³ Evergem, 25 May: 12.3 µg/m³ Marche-en-Famenne Marche-en-Famenne, 19 May: 5.1 µg/m³ Marche-en-Famenne, 20 May: 5.8 µg/m³ Marche-en-Famenne, 21 May: 17.4 µg/m³ Marche-en-Famenne, 22 May: 25.0 µg/m³, 5.0× its usual 4.2 Marche-en-Famenne, 23 May: 12.5 µg/m³ Marche-en-Famenne, 24 May: 4.2 µg/m³ Marche-en-Famenne, 25 May: 10.8 µg/m³ Tournai Tournai, 19 May: 13.6 µg/m³ Tournai, 20 May: 8.5 µg/m³ Tournai, 21 May: 15.7 µg/m³ Tournai, 22 May: 25.0 µg/m³, 4.4× its usual 5.7 Tournai, 23 May: 9.7 µg/m³ Tournai, 24 May: 6.6 µg/m³ Tournai, 25 May: 9.2 µg/m³ 19 May 20 21 22 23 24 25 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
Andenne Wallonia, Belgium 1 22 May 5.1 7.5× Eupen Wallonia, Belgium 1 22 May 4.1 5.9× Liège Wallonia, Belgium 1 22 May 5.5 5.7× Charleroi Wallonia, Belgium 1 22 May 5.4 5.5× Bendorf Rheinland-Pfalz, Germany 1 22 May 5.6 5.4× Heerlen Limburg, The Netherlands 1 22 May 5.2 5.4× Koblenz Rheinland-Pfalz, Germany 1 22 May 7.2 5.3× Marche-en-Famenne Wallonia, Belgium 1 22 May 4.2 5.0× Aarschot Flanders, Belgium 1 22 May 7.4 4.4× Tournai Wallonia, Belgium 1 22 May 5.7 4.4× Neuwied Rheinland-Pfalz, Germany 1 22 May 6.8 4.3× Mons Wallonia, Belgium 1 22 May 6.6 4.2× Bonn North Rhine-Westphalia, Germany 1 22 May 7.2 4.1× Aachen North Rhine-Westphalia, Germany 1 22 May 7.1 4.0× Grimbergen Flanders, Belgium 1 22 May 8.4 3.8× Köln North Rhine-Westphalia, Germany 1 22 May 7.7 3.8× Jülich North Rhine-Westphalia, Germany 1 22 May 7.8 3.7× Brussels Brussels Capital, Belgium 1 22 May 7.4 3.5× Jüchen North Rhine-Westphalia, Germany 1 22 May 7.7 3.4× Bergheim North Rhine-Westphalia, Germany 1 22 May 9.8 3.1× Mol Flanders, Belgium 1 22 May 8.5 3.1× Düsseldorf North Rhine-Westphalia, Germany 1 22 May 8.3 3.1× Antwerp Flanders, Belgium 1 22 May 9.0 3.0× Thionville Grand Est, France 1 22 May 9.0 2.8× Solingen North Rhine-Westphalia, Germany 1 22 May 10.0 2.6× Evergem Flanders, Belgium 1 22 May 10.0 2.5×
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 Belgium and Germany
Number 29 of 47 episodes in Belgium and Germany since our records began, by cities reached.
Europe, 6 to 25 February 2023 608 Europe, 14 February to 1 March 2025 517 Europe, 1 to 14 February 2025 506 Europe, January and February 2026 502 Germany, Poland and 25 more countries, March 2025 463 Europe, 8 to 27 January 2024 449 Europe, 1 to 12 March 2026 444 Germany, France and 18 more countries, January 2025 381 Europe, 18 to 25 March 2026 362 Europe, March 2025 335 Europe, February and March 2024 264 Europe, November 2024 260 Belgium, Germany and 2 more countries, May 2023 26 Bars: cities reached; colour: the level of the episode's highest daily reading. All 47 .
Use this page SmogRank, Belgium, Germany and 2 more countries, May 2023: 26 cities with PM2.5 at twice their usual or more, 22 May 2023, smogrank.com/episodes/2023-05-belgium-germany-and-2-more-countries (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.
