SmogRank / Episodes / Belgium
Europe, May 2023
For 1 day, on 22 May 2023, 32 cities in Belgium, Germany, The Netherlands and 2 more countries had PM2.5 at least twice their usual for the time of year. The worst reading was Champion, Wallonia, Belgium: 38.1 µg/m³ on 22 May, about 7.5× its usual 5.1. Ended 22 May.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 32 in 5 countries
Days 1 22 May 2023
Worst day 22 May 32 cities counted
Furthest above usual 7.5× Champion
Day by day
Play 22 May 32 cities at twice their usual or more
Flémalle-Haute Bertrix Habay-la-Vieille Luxembourg Esch-sur-Alzette Revin Couvin Waalre Verdun Eindhoven Trier Mönchengladbach Venray Metz Tilburg Willebroek Krefeld Kapellen Breda Zwijndrecht Melsele Stabroek Beveren Nijmegen Leverkusen Ratingen Duisburg Nancy Saint-Dizier Forbach Lopik Oberhausen IJsselstein Lunteren Reims Saarbrücken Ridderkerk Utrecht Barneveld Lochristi Wuppertal Essen Maarssen Rotterdam Zelzate Lunéville Breukelen Gent Gelsenkirchen Hattingen Evergem Épernay Borken Maassluis Denain The Hague Badhoevedorp Amsterdam Waregem 's-Gravenzande Hillegom Hagen Noordwijkerhout Datteln Maldegem Zaanstad Saint-Quentin Purmerend Dortmund Lüdenscheid Velserbroek Wormer Kortrijk Meulebeke Velsen-Zuid Schwerte Enschede Bad Kreuznach Roubaix Izegem Kaiserslautern Damme Douai Menen Troyes Roeselare Unna Lille Limburg an der Lahn Netphen Münster Wiesbaden Mainz Coulommiers Kehl Lingen Soest Béthune Worms Rüsselsheim am Main Veurne Sulzbach Koksijde Lampertheim Ludwigshafen am Rhein Mannheim Eschborn Warstein Speyer Eggenstein-Leopoldshafen Baden-Baden Karlsruhe Bensheim Darmstadt Frankfurt am Main Gießen Osnabrück Creil Dunkirk Amiens Freiburg Marburg an der Lahn Heidelberg Wiesloch Melun Fontainebleau Sarcelles Domont Pforzheim Bielefeld Paris Marsberg Beauvais Großostheim Sainte-Geneviève-des-Bois Aschaffenburg Villingen-Schwenningen Calais Herrenberg Étampes Heilbronn Ludwigsburg Tübingen Stuttgart Rinteln Filderstadt Rambouillet Reutlingen Kassel Fulda Lauda-Königshofen Olivet Chartres Dreux Würzburg Dieppe Rouen Canterbury Évreux Göttingen Clacton-on-Sea Hannover Brightlingsea Le Trait Aalen Biberach an der Riß Hildesheim Norwich Eisenach Ulm Neu-Ulm Meiningen Bad Windsheim Mühlhausen Hoo Canvey Island Gillingham Goslar Ansbach Salzgitter Oettingen in Bayern Grays Braunschweig Bamberg Nordhausen Lisieux Coburg Seaford Le Havre Newmarket Dagenham Erfurt Burwell Nuremberg Brighton Augsburg Alençon Halberstadt London Le Mans Weimar Saalfeld Caen Biggleswade Hayes Jena La Ferté-Macé Starnberg Magdeburg Munich Solingen Thionville Antwerp Düsseldorf Mol Bergheim Titz Brussels Jülich Niederzier Köln Grimbergen Grevenmacher Aachen Bonn Mons Neuwied Tournai Aarschot Gingelom Roetgen Hamois Marche-en-Famenne Koblenz Heerlen Bendorf Höhr-Grenzhausen Charleroi Liège Eupen Andenne Champion 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
Champion Champion, 19 May: 13.4 µg/m³ Champion, 20 May: 11.9 µg/m³ Champion, 21 May: 15.9 µg/m³ Champion, 22 May: 38.1 µg/m³, 7.5× its usual 5.1 Champion, 23 May: 15.7 µg/m³ Champion, 24 May: 6.2 µg/m³ Champion, 25 May: 10.6 µg/m³ 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 Gingelom Gingelom, 19 May: 10.3 µg/m³ Gingelom, 20 May: 9.5 µg/m³ Gingelom, 21 May: 14.5 µg/m³ Gingelom, 22 May: 33.0 µg/m³, 4.8× its usual 6.9 Gingelom, 23 May: 13.8 µg/m³ Gingelom, 24 May: 9.4 µg/m³ Gingelom, 25 May: 11.1 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 Höhr-Grenzhausen Höhr-Grenzhausen, 19 May: 5.6 µg/m³ Höhr-Grenzhausen, 20 May: 11.3 µg/m³ Höhr-Grenzhausen, 21 May: 18.0 µg/m³ Höhr-Grenzhausen, 22 May: 30.0 µg/m³, 5.4× its usual 5.6 Höhr-Grenzhausen, 23 May: 12.6 µg/m³ Höhr-Grenzhausen, 24 May: 5.7 µg/m³ Höhr-Grenzhausen, 25 May: 7.6 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 Niederzier Niederzier, 19 May: 10.1 µg/m³ Niederzier, 20 May: 9.9 µg/m³ Niederzier, 21 May: 16.8 µg/m³ Niederzier, 22 May: 28.7 µg/m³, 3.7× its usual 7.8 Niederzier, 23 May: 11.2 µg/m³ Niederzier, 24 May: 7.6 µg/m³ Niederzier, 25 May: 11.6 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 Titz Titz, 19 May: 9.4 µg/m³ Titz, 20 May: 8.5 µg/m³ Titz, 21 May: 14.7 µg/m³ Titz, 22 May: 26.2 µg/m³, 3.4× its usual 7.7 Titz, 23 May: 8.2 µg/m³ Titz, 24 May: 9.1 µg/m³ Titz, 25 May: 14.8 µg/m³ Roetgen Roetgen, 19 May: 6.0 µg/m³ Roetgen, 20 May: 7.1 µg/m³ Roetgen, 21 May: 16.4 µg/m³ Roetgen, 22 May: 26.1 µg/m³, 4.9× its usual 5.3 Roetgen, 23 May: 10.9 µg/m³ Roetgen, 24 May: 8.6 µg/m³ Roetgen, 25 May: 12.1 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 Grevenmacher Grevenmacher, 19 May: 7.9 µg/m³ Grevenmacher, 20 May: 7.8 µg/m³ Grevenmacher, 21 May: 13.5 µg/m³ Grevenmacher, 22 May: 25.2 µg/m³, 3.9× its usual 6.5 Grevenmacher, 23 May: 15.8 µg/m³ Grevenmacher, 24 May: 8.3 µg/m³ Grevenmacher, 25 May: 9.2 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 Hamois Hamois, 19 May: 5.1 µg/m³ Hamois, 20 May: 5.8 µg/m³ Hamois, 21 May: 17.4 µg/m³ Hamois, 22 May: 25.0 µg/m³, 5.0× its usual 4.2 Hamois, 23 May: 12.5 µg/m³ Hamois, 24 May: 4.2 µg/m³ Hamois, 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
Champion Wallonia, Belgium 1 22 May 5.1 7.5× 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× Höhr-Grenzhausen Rheinland-Pfalz, Germany 1 22 May 5.6 5.4× 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× Hamois Wallonia, Belgium 1 22 May 4.2 5.0× Roetgen North Rhine-Westphalia, Germany 1 22 May 5.3 4.9× Gingelom Flanders, Belgium 1 22 May 6.9 4.8× 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× Grevenmacher Grevenmacher, Luxembourg 1 22 May 6.5 3.9× Grimbergen Flanders, Belgium 1 22 May 8.4 3.8× Köln North Rhine-Westphalia, Germany 1 22 May 7.7 3.8× Niederzier North Rhine-Westphalia, Germany 1 22 May 7.8 3.7× Jülich North Rhine-Westphalia, Germany 1 22 May 7.8 3.7× Brussels Brussels Capital, Belgium 1 22 May 7.4 3.5× Titz 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×
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 25 of 45 episodes in Belgium and Germany since our records began, by cities reached.
Europe, 1 to 14 February 2025 628 Europe, January and February 2026 625 Europe, 14 February to 1 March 2025 619 Germany, Poland and 25 more countries, March 2025 553 Europe, 1 to 12 March 2026 532 Europe, 8 to 27 January 2024 519 Germany, France and 19 more countries, January 2025 446 Europe, 18 to 25 March 2026 430 Europe, March 2025 401 Europe, November 2024 365 Europe, February and March 2024 303 Europe, March and April 2024 282 Europe, May 2023 32 Bars: cities reached; colour: the level of the episode's highest daily reading. All 45 .
Use this page SmogRank, Europe, May 2023: 32 cities with PM2.5 at twice their usual or more, 22 May 2023, smogrank.com/episodes/2023-05-europe (accessed 5 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.
