SmogRank / Episodes / United Kingdom
United Kingdom, Belgium and 2 more countries, September 2023
For 4 days, from 7 to 10 September 2023, 42 cities in the United Kingdom, Belgium, France and 1 more countries had PM2.5 at least twice their usual for the time of year. The worst reading was Canvey Island, England, United Kingdom: 53.0 µg/m³ on 10 September, about 11× its usual 4.9.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 42 in 4 countries
Days 4 7 to 10 September 2023
Worst day 9 September 29 cities counted
Furthest above usual 11× Canvey Island
Day by day
Play 9 September 29 cities at twice their usual or more
Biggleswade Royal Leamington Spa Oxford Hayes Chesterfield Reading Newmarket Sheffield Barnsley Kingston upon Hull Andover York Southampton Portsmouth Brighton Seaford Irlam Warrington Bristol Middlesbrough Wigan Newport Cardiff Briton Ferry Newton Abbot Barnstaple Lille Kortrijk Douai Tournai Denain Valenciennes 's-Gravenzande Maassluis The Hague Mons Stabroek Rotterdam Hillegom Ridderkerk Velsen-Zuid Velserbroek Badhoevedorp Zaanstad Charleroi Breda Amsterdam Purmerend Maarssen IJsselstein Medemblik Utrecht Tilburg Mol Andenne Eindhoven Barneveld Flémalle-Haute Marche-en-Famenne Liège Nijmegen Venray Waregem Izegem Grays Roubaix Menen Birmingham Leeds Manchester Preston Gent Belfast Canterbury Liverpool Kapellen Speke Lochristi Brussels Dublin Nottingham Banbridge London Plymouth Stoke-on-Trent Grimbergen Evergem Norwich Maldegem Willebroek Dún Laoghaire Roeselare Aarschot Koksijde Saltash Beveren Dagenham Dartford Bexley Antwerp Clacton-on-Sea Zwijndrecht Dunkirk Canvey Island 4 Sep 5 6 7 8 9 10 11 12 13 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
Dartford Dartford, 4 September: no reading Dartford, 5 September: no reading Dartford, 6 September: no reading Dartford, 7 September: 38.3 µg/m³, 6.8× its usual 5.6 Dartford, 8 September: 13.6 µg/m³ Dartford, 9 September: 15.9 µg/m³ Dartford, 10 September: 39.2 µg/m³, 7.4× its usual 5.3 Dartford, 11 September: 10.7 µg/m³ Dartford, 12 September: 6.5 µg/m³ Dartford, 13 September: 6.5 µg/m³ Canvey Island Canvey Island, 4 September: no reading Canvey Island, 5 September: 21.5 µg/m³ Canvey Island, 6 September: 27.3 µg/m³ Canvey Island, 7 September: 36.1 µg/m³, 7.2× its usual 5.0 Canvey Island, 8 September: 38.7 µg/m³, 7.7× its usual 4.9 Canvey Island, 9 September: 23.5 µg/m³ Canvey Island, 10 September: 53.0 µg/m³, 11× its usual 4.9 Canvey Island, 11 September: 22.7 µg/m³ Canvey Island, 12 September: 8.1 µg/m³ Canvey Island, 13 September: 4.6 µg/m³ Bexley Bexley, 4 September: 23.0 µg/m³ Bexley, 5 September: 18.2 µg/m³ Bexley, 6 September: 20.6 µg/m³ Bexley, 7 September: 33.4 µg/m³, 6.7× its usual 5.0 Bexley, 8 September: 25.9 µg/m³, 5.2× its usual 4.9 Bexley, 9 September: 16.3 µg/m³ Bexley, 10 September: 38.9 µg/m³, 7.8× its usual 4.9 Bexley, 11 September: 18.7 µg/m³ Bexley, 12 September: 6.5 µg/m³ Bexley, 13 September: 4.1 µg/m³ Dagenham Dagenham, 4 September: 15.8 µg/m³ Dagenham, 5 September: 15.9 µg/m³ Dagenham, 6 September: 22.1 µg/m³ Dagenham, 7 September: 32.7 µg/m³, 6.2× its usual 5.3 Dagenham, 8 September: 29.5 µg/m³, 5.9× its usual 4.7 Dagenham, 9 September: no reading Dagenham, 10 September: 36.6 µg/m³, 7.3× its usual 4.6 Dagenham, 11 September: 11.1 µg/m³ Dagenham, 12 September: 5.6 µg/m³ Dagenham, 13 September: 2.8 µg/m³ Grays Grays, 4 September: 15.3 µg/m³ Grays, 5 September: 18.0 µg/m³ Grays, 6 September: 24.8 µg/m³ Grays, 7 September: 32.5 µg/m³, 4.3× its usual 7.6 Grays, 8 September: 20.3 µg/m³ Grays, 9 September: no reading Grays, 10 September: 32.5 µg/m³, 4.3× its usual 7.5 Grays, 11 September: 9.5 µg/m³ Grays, 12 September: 5.6 µg/m³ Grays, 13 September: 5.3 µg/m³ Clacton-on-Sea Clacton-on-Sea, 4 September: no reading Clacton-on-Sea, 5 September: 15.0 µg/m³ Clacton-on-Sea, 6 September: 17.1 µg/m³ Clacton-on-Sea, 7 September: 31.6 µg/m³, 6.3× its usual 4.6 Clacton-on-Sea, 8 September: 41.8 µg/m³, 8.4× its usual 4.6 Clacton-on-Sea, 9 September: 28.9 µg/m³, 5.8× its usual 4.6 Clacton-on-Sea, 10 September: 35.7 µg/m³, 7.1× its usual 4.5 Clacton-on-Sea, 11 September: 19.6 µg/m³ Clacton-on-Sea, 12 September: 7.1 µg/m³ Clacton-on-Sea, 13 September: 5.0 µg/m³ London London, 4 September: 18.1 µg/m³ London, 5 September: 17.4 µg/m³ London, 6 September: 20.8 µg/m³ London, 7 September: 31.5 µg/m³, 5.0× its usual 6.3 London, 8 September: 18.8 µg/m³ London, 9 September: 20.7 µg/m³ London, 10 September: 33.9 µg/m³, 5.6× its usual 6.1 London, 11 September: 10.5 µg/m³ London, 12 September: 6.1 µg/m³ London, 13 September: 5.2 µg/m³ Dunkirk Dunkirk, 4 September: 15.9 µg/m³ Dunkirk, 5 September: 12.8 µg/m³ Dunkirk, 6 September: 28.0 µg/m³ Dunkirk, 7 September: 27.3 µg/m³, 4.9× its usual 5.6 Dunkirk, 8 September: 29.9 µg/m³, 5.3× its usual 5.6 Dunkirk, 9 September: 48.5 µg/m³, 8.8× its usual 5.5 Dunkirk, 10 September: 27.2 µg/m³, 4.9× its usual 5.5 Dunkirk, 11 September: 13.9 µg/m³ Dunkirk, 12 September: 12.3 µg/m³ Dunkirk, 13 September: 6.5 µg/m³ Canterbury Canterbury, 4 September: no reading Canterbury, 5 September: 15.6 µg/m³ Canterbury, 6 September: 17.8 µg/m³ Canterbury, 7 September: 26.5 µg/m³, 4.1× its usual 6.4 Canterbury, 8 September: 20.5 µg/m³ Canterbury, 9 September: 16.8 µg/m³ Canterbury, 10 September: 27.8 µg/m³, 5.1× its usual 5.5 Canterbury, 11 September: 15.8 µg/m³ Canterbury, 12 September: 8.1 µg/m³ Canterbury, 13 September: 5.0 µg/m³ Koksijde Koksijde, 4 September: 13.0 µg/m³ Koksijde, 5 September: 12.8 µg/m³ Koksijde, 6 September: 17.5 µg/m³ Koksijde, 7 September: 25.0 µg/m³, 5.0× its usual 4.6 Koksijde, 8 September: 26.6 µg/m³, 5.3× its usual 4.6 Koksijde, 9 September: 35.0 µg/m³, 7.0× its usual 4.6 Koksijde, 10 September: 23.0 µg/m³ Koksijde, 11 September: 12.6 µg/m³ Koksijde, 12 September: 11.1 µg/m³ Koksijde, 13 September: 5.5 µg/m³ Plymouth Plymouth, 4 September: no reading Plymouth, 5 September: 8.6 µg/m³ Plymouth, 6 September: 14.5 µg/m³ Plymouth, 7 September: 16.5 µg/m³ Plymouth, 8 September: 36.7 µg/m³, 5.6× its usual 6.5 Plymouth, 9 September: 21.1 µg/m³ Plymouth, 10 September: 14.6 µg/m³ Plymouth, 11 September: 9.6 µg/m³ Plymouth, 12 September: 5.1 µg/m³ Plymouth, 13 September: 4.2 µg/m³ Saltash Saltash, 4 September: no reading Saltash, 5 September: 7.8 µg/m³ Saltash, 6 September: 14.7 µg/m³ Saltash, 7 September: 17.2 µg/m³ Saltash, 8 September: 36.2 µg/m³, 7.2× its usual 3.1 Saltash, 9 September: 19.4 µg/m³ Saltash, 10 September: 12.4 µg/m³ Saltash, 11 September: 9.5 µg/m³ Saltash, 12 September: 5.6 µg/m³ Saltash, 13 September: 3.1 µg/m³ Nottingham Nottingham, 4 September: no reading Nottingham, 5 September: 14.7 µg/m³ Nottingham, 6 September: 21.4 µg/m³ Nottingham, 7 September: 21.0 µg/m³ Nottingham, 8 September: 32.2 µg/m³, 5.5× its usual 5.9 Nottingham, 9 September: 33.0 µg/m³, 5.5× its usual 6.0 Nottingham, 10 September: 22.7 µg/m³ Nottingham, 11 September: 16.0 µg/m³ Nottingham, 12 September: 6.1 µg/m³ Nottingham, 13 September: 4.1 µg/m³ Dún Laoghaire Dún Laoghaire, 4 September: 5.8 µg/m³ Dún Laoghaire, 5 September: 15.6 µg/m³ Dún Laoghaire, 6 September: 11.1 µg/m³ Dún Laoghaire, 7 September: 13.8 µg/m³ Dún Laoghaire, 8 September: 31.5 µg/m³, 6.3× its usual 4.4 Dún Laoghaire, 9 September: 10.6 µg/m³ Dún Laoghaire, 10 September: 15.1 µg/m³ Dún Laoghaire, 11 September: 3.8 µg/m³ Dún Laoghaire, 12 September: 3.4 µg/m³ Dún Laoghaire, 13 September: 4.6 µg/m³ Speke Speke, 4 September: no reading Speke, 5 September: 17.7 µg/m³ Speke, 6 September: 15.6 µg/m³ Speke, 7 September: 22.0 µg/m³ Speke, 8 September: 29.8 µg/m³, 5.2× its usual 5.7 Speke, 9 September: 30.6 µg/m³, 5.3× its usual 5.8 Speke, 10 September: no reading Speke, 11 September: no reading Speke, 12 September: no reading Speke, 13 September: no reading Banbridge Banbridge, 4 September: 6.0 µg/m³ Banbridge, 5 September: 11.2 µg/m³ Banbridge, 6 September: 10.6 µg/m³ Banbridge, 7 September: 13.3 µg/m³ Banbridge, 8 September: 28.1 µg/m³, 5.6× its usual 3.9 Banbridge, 9 September: 10.5 µg/m³ Banbridge, 10 September: 14.0 µg/m³ Banbridge, 11 September: 3.5 µg/m³ Banbridge, 12 September: 3.1 µg/m³ Banbridge, 13 September: 6.1 µg/m³ Dublin Dublin, 4 September: 6.0 µg/m³ Dublin, 5 September: 11.6 µg/m³ Dublin, 6 September: 10.2 µg/m³ Dublin, 7 September: 13.2 µg/m³ Dublin, 8 September: 27.2 µg/m³, 5.4× its usual 4.5 Dublin, 9 September: 10.0 µg/m³ Dublin, 10 September: 14.5 µg/m³ Dublin, 11 September: 3.4 µg/m³ Dublin, 12 September: 3.1 µg/m³ Dublin, 13 September: 5.5 µg/m³ Belfast Belfast, 4 September: no reading Belfast, 5 September: 10.6 µg/m³ Belfast, 6 September: 10.6 µg/m³ Belfast, 7 September: 13.4 µg/m³ Belfast, 8 September: 26.4 µg/m³, 5.1× its usual 5.2 Belfast, 9 September: 23.4 µg/m³ Belfast, 10 September: 7.0 µg/m³ Belfast, 11 September: 7.2 µg/m³ Belfast, 12 September: 3.1 µg/m³ Belfast, 13 September: 4.9 µg/m³ Zwijndrecht Zwijndrecht, 4 September: 11.0 µg/m³ Zwijndrecht, 5 September: 7.9 µg/m³ Zwijndrecht, 6 September: 8.0 µg/m³ Zwijndrecht, 7 September: 11.1 µg/m³ Zwijndrecht, 8 September: 21.6 µg/m³ Zwijndrecht, 9 September: 43.8 µg/m³, 8.4× its usual 5.2 Zwijndrecht, 10 September: 18.7 µg/m³ Zwijndrecht, 11 September: 15.9 µg/m³ Zwijndrecht, 12 September: 26.2 µg/m³ Zwijndrecht, 13 September: 9.9 µg/m³ Antwerp Antwerp, 4 September: 9.8 µg/m³ Antwerp, 5 September: 7.2 µg/m³ Antwerp, 6 September: 7.0 µg/m³ Antwerp, 7 September: 10.9 µg/m³ Antwerp, 8 September: 19.2 µg/m³ Antwerp, 9 September: 40.5 µg/m³, 7.8× its usual 5.2 Antwerp, 10 September: 18.7 µg/m³ Antwerp, 11 September: 15.3 µg/m³ Antwerp, 12 September: 24.2 µg/m³ Antwerp, 13 September: 10.7 µg/m³ Beveren Beveren, 4 September: 10.5 µg/m³ Beveren, 5 September: no reading Beveren, 6 September: 8.1 µg/m³ Beveren, 7 September: 11.0 µg/m³ Beveren, 8 September: 21.2 µg/m³ Beveren, 9 September: 36.3 µg/m³, 7.3× its usual 5.0 Beveren, 10 September: 18.6 µg/m³ Beveren, 11 September: 16.5 µg/m³ Beveren, 12 September: 24.1 µg/m³ Beveren, 13 September: 9.6 µg/m³ Roeselare Roeselare, 4 September: 13.3 µg/m³ Roeselare, 5 September: 12.5 µg/m³ Roeselare, 6 September: 11.0 µg/m³ Roeselare, 7 September: 18.8 µg/m³ Roeselare, 8 September: 22.6 µg/m³ Roeselare, 9 September: 35.2 µg/m³, 6.6× its usual 5.3 Roeselare, 10 September: 16.6 µg/m³ Roeselare, 11 September: 17.0 µg/m³ Roeselare, 12 September: 18.2 µg/m³ Roeselare, 13 September: 6.7 µg/m³ Aarschot Aarschot, 4 September: 9.6 µg/m³ Aarschot, 5 September: 5.9 µg/m³ Aarschot, 6 September: 6.0 µg/m³ Aarschot, 7 September: 10.5 µg/m³ Aarschot, 8 September: 13.8 µg/m³ Aarschot, 9 September: 35.0 µg/m³, 7.0× its usual 4.4 Aarschot, 10 September: 14.4 µg/m³ Aarschot, 11 September: 11.8 µg/m³ Aarschot, 12 September: 14.2 µg/m³ Aarschot, 13 September: 10.0 µg/m³ Evergem Evergem, 4 September: 12.8 µg/m³ Evergem, 5 September: 11.8 µg/m³ Evergem, 6 September: 11.3 µg/m³ Evergem, 7 September: 15.9 µg/m³ Evergem, 8 September: 20.4 µg/m³ Evergem, 9 September: 33.5 µg/m³, 5.9× its usual 5.7 Evergem, 10 September: 20.6 µg/m³ Evergem, 11 September: 16.8 µg/m³ Evergem, 12 September: 22.7 µg/m³ Evergem, 13 September: 9.1 µg/m³ Maldegem Maldegem, 4 September: 13.8 µg/m³ Maldegem, 5 September: 12.4 µg/m³ Maldegem, 6 September: 12.1 µg/m³ Maldegem, 7 September: 18.0 µg/m³ Maldegem, 8 September: 24.1 µg/m³ Maldegem, 9 September: 31.6 µg/m³, 6.0× its usual 5.3 Maldegem, 10 September: 20.1 µg/m³ Maldegem, 11 September: 19.0 µg/m³ Maldegem, 12 September: 20.5 µg/m³ Maldegem, 13 September: 6.4 µg/m³ Willebroek Willebroek, 4 September: 9.2 µg/m³ Willebroek, 5 September: 5.6 µg/m³ Willebroek, 6 September: 5.9 µg/m³ Willebroek, 7 September: 9.7 µg/m³ Willebroek, 8 September: 15.4 µg/m³ Willebroek, 9 September: 31.5 µg/m³, 6.3× its usual 4.7 Willebroek, 10 September: 14.6 µg/m³ Willebroek, 11 September: 12.8 µg/m³ Willebroek, 12 September: 20.9 µg/m³ Willebroek, 13 September: 9.6 µg/m³ Lochristi Lochristi, 4 September: 9.4 µg/m³ Lochristi, 5 September: 7.8 µg/m³ Lochristi, 6 September: 7.4 µg/m³ Lochristi, 7 September: 11.8 µg/m³ Lochristi, 8 September: 17.7 µg/m³ Lochristi, 9 September: 31.0 µg/m³, 5.3× its usual 5.9 Lochristi, 10 September: 16.2 µg/m³ Lochristi, 11 September: 15.4 µg/m³ Lochristi, 12 September: 22.2 µg/m³ Lochristi, 13 September: 7.8 µg/m³ Izegem Izegem, 4 September: 11.8 µg/m³ Izegem, 5 September: 12.2 µg/m³ Izegem, 6 September: 10.6 µg/m³ Izegem, 7 September: 16.0 µg/m³ Izegem, 8 September: 20.2 µg/m³ Izegem, 9 September: 30.5 µg/m³, 4.1× its usual 7.4 Izegem, 10 September: 15.4 µg/m³ Izegem, 11 September: 17.1 µg/m³ Izegem, 12 September: 21.3 µg/m³ Izegem, 13 September: 7.4 µg/m³ Norwich Norwich, 4 September: no reading Norwich, 5 September: 12.3 µg/m³ Norwich, 6 September: no reading Norwich, 7 September: no reading Norwich, 8 September: 23.7 µg/m³ Norwich, 9 September: 30.1 µg/m³, 6.0× its usual 4.7 Norwich, 10 September: 23.0 µg/m³ Norwich, 11 September: 17.8 µg/m³ Norwich, 12 September: 6.9 µg/m³ Norwich, 13 September: 4.1 µg/m³ Manchester Manchester, 4 September: no reading Manchester, 5 September: 11.9 µg/m³ Manchester, 6 September: 13.0 µg/m³ Manchester, 7 September: 18.9 µg/m³ Manchester, 8 September: 22.9 µg/m³ Manchester, 9 September: 29.3 µg/m³, 4.9× its usual 6.0 Manchester, 10 September: 17.0 µg/m³ Manchester, 11 September: 14.9 µg/m³ Manchester, 12 September: 5.1 µg/m³ Manchester, 13 September: 4.6 µg/m³ Grimbergen Grimbergen, 4 September: 8.7 µg/m³ Grimbergen, 5 September: 5.9 µg/m³ Grimbergen, 6 September: 5.8 µg/m³ Grimbergen, 7 September: 9.6 µg/m³ Grimbergen, 8 September: 15.1 µg/m³ Grimbergen, 9 September: 29.1 µg/m³, 5.8× its usual 5.0 Grimbergen, 10 September: 14.0 µg/m³ Grimbergen, 11 September: 12.6 µg/m³ Grimbergen, 12 September: 16.2 µg/m³ Grimbergen, 13 September: 9.9 µg/m³ Stoke-on-Trent Stoke-on-Trent, 4 September: no reading Stoke-on-Trent, 5 September: 11.3 µg/m³ Stoke-on-Trent, 6 September: 13.7 µg/m³ Stoke-on-Trent, 7 September: 15.0 µg/m³ Stoke-on-Trent, 8 September: 21.6 µg/m³ Stoke-on-Trent, 9 September: 28.7 µg/m³, 5.7× its usual 4.7 Stoke-on-Trent, 10 September: 17.8 µg/m³ Stoke-on-Trent, 11 September: 15.3 µg/m³ Stoke-on-Trent, 12 September: 5.2 µg/m³ Stoke-on-Trent, 13 September: no reading Leeds Leeds, 4 September: no reading Leeds, 5 September: 15.5 µg/m³ Leeds, 6 September: 16.8 µg/m³ Leeds, 7 September: 24.5 µg/m³ Leeds, 8 September: 21.4 µg/m³ Leeds, 9 September: 28.3 µg/m³, 4.8× its usual 5.9 Leeds, 10 September: 15.2 µg/m³ Leeds, 11 September: 16.3 µg/m³ Leeds, 12 September: 5.1 µg/m³ Leeds, 13 September: 4.5 µg/m³ Brussels Brussels, 4 September: 12.1 µg/m³ Brussels, 5 September: 9.2 µg/m³ Brussels, 6 September: 9.1 µg/m³ Brussels, 7 September: 10.9 µg/m³ Brussels, 8 September: 15.8 µg/m³ Brussels, 9 September: 26.9 µg/m³, 5.4× its usual 4.4 Brussels, 10 September: 12.5 µg/m³ Brussels, 11 September: 11.5 µg/m³ Brussels, 12 September: 14.5 µg/m³ Brussels, 13 September: 4.6 µg/m³ Roubaix Roubaix, 4 September: 12.1 µg/m³ Roubaix, 5 September: 14.0 µg/m³ Roubaix, 6 September: 14.7 µg/m³ Roubaix, 7 September: 17.4 µg/m³ Roubaix, 8 September: 19.7 µg/m³ Roubaix, 9 September: 26.8 µg/m³, 4.4× its usual 6.1 Roubaix, 10 September: 14.0 µg/m³ Roubaix, 11 September: no reading Roubaix, 12 September: no reading Roubaix, 13 September: 7.5 µg/m³ Kapellen Kapellen, 4 September: 9.0 µg/m³ Kapellen, 5 September: 6.8 µg/m³ Kapellen, 6 September: 6.5 µg/m³ Kapellen, 7 September: 9.6 µg/m³ Kapellen, 8 September: 20.1 µg/m³ Kapellen, 9 September: 26.7 µg/m³, 5.3× its usual 5.0 Kapellen, 10 September: 17.9 µg/m³ Kapellen, 11 September: 14.5 µg/m³ Kapellen, 12 September: 23.2 µg/m³ Kapellen, 13 September: 8.4 µg/m³ Liverpool Liverpool, 4 September: no reading Liverpool, 5 September: 11.8 µg/m³ Liverpool, 6 September: 10.7 µg/m³ Liverpool, 7 September: 16.3 µg/m³ Liverpool, 8 September: 24.0 µg/m³ Liverpool, 9 September: 26.5 µg/m³, 5.3× its usual 4.5 Liverpool, 10 September: 20.0 µg/m³ Liverpool, 11 September: 12.4 µg/m³ Liverpool, 12 September: 2.8 µg/m³ Liverpool, 13 September: 3.0 µg/m³ Birmingham Birmingham, 4 September: no reading Birmingham, 5 September: 12.2 µg/m³ Birmingham, 6 September: 13.7 µg/m³ Birmingham, 7 September: 16.2 µg/m³ Birmingham, 8 September: 20.5 µg/m³ Birmingham, 9 September: 25.8 µg/m³, 4.7× its usual 5.5 Birmingham, 10 September: 23.2 µg/m³ Birmingham, 11 September: 14.8 µg/m³ Birmingham, 12 September: 4.9 µg/m³ Birmingham, 13 September: 4.3 µg/m³ Gent Gent, 4 September: 9.4 µg/m³ Gent, 5 September: 7.8 µg/m³ Gent, 6 September: 7.9 µg/m³ Gent, 7 September: 11.5 µg/m³ Gent, 8 September: 14.4 µg/m³ Gent, 9 September: 25.7 µg/m³, 5.0× its usual 5.1 Gent, 10 September: 14.6 µg/m³ Gent, 11 September: 13.1 µg/m³ Gent, 12 September: 17.7 µg/m³ Gent, 13 September: 8.0 µg/m³ Preston Preston, 4 September: no reading Preston, 5 September: 10.3 µg/m³ Preston, 6 September: 10.0 µg/m³ Preston, 7 September: 19.0 µg/m³ Preston, 8 September: 20.2 µg/m³ Preston, 9 September: 25.1 µg/m³, 5.0× its usual 4.8 Preston, 10 September: 15.5 µg/m³ Preston, 11 September: 10.6 µg/m³ Preston, 12 September: 3.7 µg/m³ Preston, 13 September: 3.3 µg/m³ Menen Menen, 4 September: 10.4 µg/m³ Menen, 5 September: 11.6 µg/m³ Menen, 6 September: 9.4 µg/m³ Menen, 7 September: 15.3 µg/m³ Menen, 8 September: 19.3 µg/m³ Menen, 9 September: 25.0 µg/m³, 4.5× its usual 5.6 Menen, 10 September: 13.9 µg/m³ Menen, 11 September: 14.5 µg/m³ Menen, 12 September: 15.7 µg/m³ Menen, 13 September: 7.4 µg/m³ Waregem Waregem, 4 September: 10.9 µg/m³ Waregem, 5 September: 10.4 µg/m³ Waregem, 6 September: 9.4 µg/m³ Waregem, 7 September: 14.8 µg/m³ Waregem, 8 September: 18.9 µg/m³ Waregem, 9 September: 25.0 µg/m³, 3.7× its usual 6.8 Waregem, 10 September: 15.3 µg/m³ Waregem, 11 September: 16.2 µg/m³ Waregem, 12 September: 21.0 µg/m³ Waregem, 13 September: 7.4 µg/m³ 4 Sep 5 6 7 8 9 10 11 12 13 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
Canvey Island England, United Kingdom 3 10 September 4.9 11× Dunkirk Hauts-de-France, France 4 9 September 5.5 8.8× Zwijndrecht Flanders, Belgium 1 9 September 5.2 8.4× Clacton-on-Sea England, United Kingdom 4 8 September 4.6 8.4× Antwerp Flanders, Belgium 1 9 September 5.2 7.8× Bexley England, United Kingdom 3 10 September 4.9 7.8× Dartford England, United Kingdom 2 10 September 5.3 7.4× Dagenham England, United Kingdom 3 10 September 4.6 7.3× Beveren Flanders, Belgium 1 9 September 5.0 7.3× Saltash England, United Kingdom 1 8 September 3.1 7.2× Koksijde Flanders, Belgium 3 9 September 4.6 7.0× Aarschot Flanders, Belgium 1 9 September 4.4 7.0× Roeselare Flanders, Belgium 1 9 September 5.3 6.6× Dún Laoghaire Leinster, Ireland 1 8 September 4.4 6.3× Willebroek Flanders, Belgium 1 9 September 4.7 6.3× Maldegem Flanders, Belgium 1 9 September 5.3 6.0× Norwich England, United Kingdom 1 9 September 4.7 6.0× Evergem Flanders, Belgium 1 9 September 5.7 5.9× Grimbergen Flanders, Belgium 1 9 September 5.0 5.8× Stoke-on-Trent England, United Kingdom 1 9 September 4.7 5.7× Plymouth England, United Kingdom 1 8 September 6.5 5.6× London England, United Kingdom 2 10 September 6.1 5.6× Banbridge Northern Ireland, United Kingdom 1 8 September 3.9 5.6× Nottingham England, United Kingdom 2 9 September 6.0 5.5× Dublin Leinster, Ireland 1 8 September 4.5 5.4× Brussels Brussels Capital, Belgium 1 9 September 4.4 5.4× Lochristi Flanders, Belgium 1 9 September 5.9 5.3× Speke England, United Kingdom 2 9 September 5.8 5.3× Kapellen Flanders, Belgium 1 9 September 5.0 5.3× Liverpool England, United Kingdom 1 9 September 4.5 5.3× Canterbury England, United Kingdom 2 10 September 5.5 5.1× Belfast Northern Ireland, United Kingdom 1 8 September 5.2 5.1× Gent Flanders, Belgium 1 9 September 5.1 5.0× Preston England, United Kingdom 1 9 September 4.8 5.0× Manchester England, United Kingdom 1 9 September 6.0 4.9× Leeds England, United Kingdom 1 9 September 5.9 4.8× Birmingham England, United Kingdom 1 9 September 5.5 4.7× Menen Flanders, Belgium 1 9 September 5.6 4.5× Roubaix Hauts-de-France, France 1 9 September 6.1 4.4× Grays England, United Kingdom 2 7 September 7.6 4.3× Izegem Flanders, Belgium 1 9 September 7.4 4.1× Waregem Flanders, Belgium 1 9 September 6.8 3.7×
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 the United Kingdom and Belgium
Number 6 of 24 episodes in the United Kingdom and Belgium since our records began, by cities reached.
Europe, 14 to 15 January 2025 90 Western Europe, December 2024 75 France, The Netherlands and United Kingdom, January 2023 66 Western Europe, January 2025 50 France, Belgium and 2 more countries, November and December 2023 43 United Kingdom, Belgium and 2 more countries, September 2023 42 Western Europe, November 2024 38 France, Belgium and Germany, April 2023 36 Belgium, Germany and 2 more countries, May 2023 26 Belgium, The Netherlands and United Kingdom, May 2024 24 Belgium, France and 2 more countries, August 2024 23 United Kingdom and The Netherlands, March 2024 20 Bars: cities reached; colour: the level of the episode's highest daily reading. All 24 .
Use this page SmogRank, United Kingdom, Belgium and 2 more countries, September 2023: 42 cities with PM2.5 at twice their usual or more, 7 to 10 September 2023, smogrank.com/episodes/2023-09-united-kingdom-belgium-and-2-more-countries (accessed 4 October 2026).
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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.
