O3, last 14 days

O₃ concentrations per day (µg/m³), 14/09/2026 - 27/09/2026

Highest hourly meanHighest 8-hourly mean

- Click on the figures in the table cells to get an evolution graph of daily concentrations
- Click on the date to get an interpolation map
- "NA" means no or not enough data were available

Code city 14/09 15/09 16/09 17/09 18/09 19/09 20/09 21/09 22/09 23/09 24/09 25/09 26/09 27/09

41B011 Sint-Agatha-Berchem 37.5 99.5 64.5 66.5 71.5 67 70 79.5 69 90.5 79.5 97 77 98

41MEU1 Neder-Over-Heembeek 38 95.5 65.5 62.5 69 61.5 73.5 83.5 68.5 89.5 73 96.5 76 94.5

41N043 Voorhaven (Haren) 35.5 92 60.5 59.5 65 62.5 68 77.5 60.5 88 64 86.5 67.5 86.5

41R001 Sint-Jans-Molenbeek 37 92.5 59.5 61 64 63 69 69.5 61.5 82 71 91 67 91.5

41R012 Ukkel 40.5 100.5 65 65 69 68 69.5 82 66.5 90 79 94.5 74.5 91.5

42N016 Dessel 40.5 99.5 65.5 63 71.5 65 71.5 77 76 88 78.5 95 79 97

42N027 Bree 60.5 105.5 76.5 72.5 75 78.5 81 82.5 79 97 83.5 100 90.5 102.5

42N035 Aarschot 45 112 73.5 72 77.5 75.5 77.5 82 73.5 100.5 85.5 109.5 83.5 114

42N040 Sint-Pieters-Leeuw 45 104.5 65.5 67.5 71.5 68 67.5 86.5 67.5 48.5 83 99 80.5 96

42N046 Gellik 59.5 100 77 72 72.5 80.5 76 85.5 80 96.5 83 101 109.5 98

42N047 Hasselt 56 101.5 73.5 72.5 75 76 70 78.5 76.5 97 80.5 98.5 97 99.5

42R801 Borgerhout 31.5 96 69 62.5 67.5 63.5 71.5 72.5 67.5 90.5 76.5 93 81 106.5

42R811 Schoten 34.5 101 64.5 65.5 75 66 76.5 77 66 94 75 105 79.5 115

42R842 Mechelen (Hendrik Speecqvest) 26.5 83 61 63 69.5 65 72 75.5 64.5 78.5 62.5 85 73.5 99

44M705 Roeselare (Haven) 55.5 91 73.5 70 83.5 72 81.5 91 68.5 98 79.5 112 86 118.5

44N012 Moerkerke 43.5 81.5 69.5 63 80.5 75 76 83.5 75 88 84 106.5 93.5 115

44N029 Houtem (Veurne) 43.5 72 68 58.5 73.5 69.5 75.5 89.5 83.5 86.5 78 105 95 105.5

44R701 Gent (Baudelopark) 51.5 89 67.5 65 74.5 65.5 75.5 84 70 91 75 105.5 82.5 115.5

44R710 Destelbergen 52.5 95 70.5 68 79 67.5 76.5 87.5 73.5 93 81.5 108.5 83.5 115

43N060 Havinnes 47 104 67.5 68.5 78.5 63.5 70.5 89 71.5 89.5 84.5 93 78.5 97.5

43N064 Rixensart 51 107 73 71 78 78 74.5 89.5 78 94 75 101.5 89.5 101

43N066 Eupen 50.5 84.5 64.5 72.5 64.5 78 63.5 78 78 82 76.5 94.5 101 98.5

43N070 Mons 36 81 57 56 52.5 60.5 61.5 84.5 70 75.5 77 75.5 75 68

43N073 Vezin 47.5 97 71.5 73 72 87 66.5 86.5 78 91 76.5 96.5 107.5 91

43N085 Vielsalm 24.5 71.5 65 65.5 55 75.5 48 69 59 72.5 75.5 92 90 99.5

43N093 Sinsin 48.5 96 74.5 80.5 74.5 87.5 69 94 87 91.5 81 102.5 113.5 95

43N100 Dourbes 59 119.5 83 84.5 84.5 105 75.5 103.5 90.5 98 89.5 108 127 103.5

43N113 Saint-Ode 50.5 93 84 84.5 72.5 89 68 92 85 88 82 105 104.5 99

43N121 Offagne 54 99.5 80 83 73 87.5 58.5 93.5 84.5 101.5 84 99.5 104 97

43N132 Habay-La-Neuve 51.5 90.5 84.5 76 63 79 47 85 83 84 78.5 99 103 94.5

43R221 Herstal 48.5 90 73 73 70.5 82 69 83 85.5 89.5 82 93 99 94

43R222 Liège (ISSeP) 49.5 93 70 76 74.5 84 70.5 75 65 69 63 74 90.5 73

43R240 Engis 38.5 84 59.5 63.5 66.5 74 56.5 70 68.5 82 72 92.5 99.5 85.5

43R401 Namur 50 96.5 72 73.5 73.5 87 65 87.5 74 88.5 73 94.5 103 92.5

45R502 Lodelinsart 43 92 48.5 67 64 79 69 84 75 81 84 91.5 100.5 91

Interpolated spatial average in :

Brussels 40 97 65 65 70 67 70 80 66 88 74 95 74 93

Flanders 47 94 70 67 75 70 75 83 72 91 80 102 84 104

Wallonia 46 92 71 73 69 79 62 85 77 85 80 95 97 92

Belgium 46 93 71 70 72 75 68 84 75 88 80 98 91 97

% of the population exposed to O₃ concentrations > 180 μg/m³ in:

Brussels 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0%

Flanders 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0%

Wallonia 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0%

Belgium 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0%

% of the population exposed to O₃ concentrations > 240 μg/m³ in:

Brussels 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0%

Flanders 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0%

Wallonia 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0%

Belgium 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0%

Code	city	14/09	15/09	16/09	17/09	18/09	19/09	20/09	21/09	22/09	23/09	24/09	25/09	26/09	27/09
41B011	Sint-Agatha-Berchem	37.5	99.5	64.5	66.5	71.5	67	70	79.5	69	90.5	79.5	97	77	98
41MEU1	Neder-Over-Heembeek	38	95.5	65.5	62.5	69	61.5	73.5	83.5	68.5	89.5	73	96.5	76	94.5
41N043	Voorhaven (Haren)	35.5	92	60.5	59.5	65	62.5	68	77.5	60.5	88	64	86.5	67.5	86.5
41R001	Sint-Jans-Molenbeek	37	92.5	59.5	61	64	63	69	69.5	61.5	82	71	91	67	91.5
41R012	Ukkel	40.5	100.5	65	65	69	68	69.5	82	66.5	90	79	94.5	74.5	91.5
42N016	Dessel	40.5	99.5	65.5	63	71.5	65	71.5	77	76	88	78.5	95	79	97
42N027	Bree	60.5	105.5	76.5	72.5	75	78.5	81	82.5	79	97	83.5	100	90.5	102.5
42N035	Aarschot	45	112	73.5	72	77.5	75.5	77.5	82	73.5	100.5	85.5	109.5	83.5	114
42N040	Sint-Pieters-Leeuw	45	104.5	65.5	67.5	71.5	68	67.5	86.5	67.5	48.5	83	99	80.5	96
42N046	Gellik	59.5	100	77	72	72.5	80.5	76	85.5	80	96.5	83	101	109.5	98
42N047	Hasselt	56	101.5	73.5	72.5	75	76	70	78.5	76.5	97	80.5	98.5	97	99.5
42R801	Borgerhout	31.5	96	69	62.5	67.5	63.5	71.5	72.5	67.5	90.5	76.5	93	81	106.5
42R811	Schoten	34.5	101	64.5	65.5	75	66	76.5	77	66	94	75	105	79.5	115
42R842	Mechelen (Hendrik Speecqvest)	26.5	83	61	63	69.5	65	72	75.5	64.5	78.5	62.5	85	73.5	99
44M705	Roeselare (Haven)	55.5	91	73.5	70	83.5	72	81.5	91	68.5	98	79.5	112	86	118.5
44N012	Moerkerke	43.5	81.5	69.5	63	80.5	75	76	83.5	75	88	84	106.5	93.5	115
44N029	Houtem (Veurne)	43.5	72	68	58.5	73.5	69.5	75.5	89.5	83.5	86.5	78	105	95	105.5
44R701	Gent (Baudelopark)	51.5	89	67.5	65	74.5	65.5	75.5	84	70	91	75	105.5	82.5	115.5
44R710	Destelbergen	52.5	95	70.5	68	79	67.5	76.5	87.5	73.5	93	81.5	108.5	83.5	115
43N060	Havinnes	47	104	67.5	68.5	78.5	63.5	70.5	89	71.5	89.5	84.5	93	78.5	97.5
43N064	Rixensart	51	107	73	71	78	78	74.5	89.5	78	94	75	101.5	89.5	101
43N066	Eupen	50.5	84.5	64.5	72.5	64.5	78	63.5	78	78	82	76.5	94.5	101	98.5
43N070	Mons	36	81	57	56	52.5	60.5	61.5	84.5	70	75.5	77	75.5	75	68
43N073	Vezin	47.5	97	71.5	73	72	87	66.5	86.5	78	91	76.5	96.5	107.5	91
43N085	Vielsalm	24.5	71.5	65	65.5	55	75.5	48	69	59	72.5	75.5	92	90	99.5
43N093	Sinsin	48.5	96	74.5	80.5	74.5	87.5	69	94	87	91.5	81	102.5	113.5	95
43N100	Dourbes	59	119.5	83	84.5	84.5	105	75.5	103.5	90.5	98	89.5	108	127	103.5
43N113	Saint-Ode	50.5	93	84	84.5	72.5	89	68	92	85	88	82	105	104.5	99
43N121	Offagne	54	99.5	80	83	73	87.5	58.5	93.5	84.5	101.5	84	99.5	104	97
43N132	Habay-La-Neuve	51.5	90.5	84.5	76	63	79	47	85	83	84	78.5	99	103	94.5
43R221	Herstal	48.5	90	73	73	70.5	82	69	83	85.5	89.5	82	93	99	94
43R222	Liège (ISSeP)	49.5	93	70	76	74.5	84	70.5	75	65	69	63	74	90.5	73
43R240	Engis	38.5	84	59.5	63.5	66.5	74	56.5	70	68.5	82	72	92.5	99.5	85.5
43R401	Namur	50	96.5	72	73.5	73.5	87	65	87.5	74	88.5	73	94.5	103	92.5
45R502	Lodelinsart	43	92	48.5	67	64	79	69	84	75	81	84	91.5	100.5	91

Interpolated spatial average in :
Brussels	40	97	65	65	70	67	70	80	66	88	74	95	74	93
Flanders	47	94	70	67	75	70	75	83	72	91	80	102	84	104
Wallonia	46	92	71	73	69	79	62	85	77	85	80	95	97	92
Belgium	46	93	71	70	72	75	68	84	75	88	80	98	91	97

% of the population exposed to O₃ concentrations > 180 μg/m³ in:
Brussels	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%
Flanders	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%
Wallonia	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%
Belgium	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%

% of the population exposed to O₃ concentrations > 240 μg/m³ in:
Brussels	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%
Flanders	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%
Wallonia	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%
Belgium	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%	0%

Color legend: Kleurlegende

These data are not validated : they should not be used for any study whatsoever
The use or publication of the data is allowed only when the source (www.irceline.be) is acknowledged