O3, last 14 days

O₃ concentrations per day (µg/m³), 11/05/2026 - 24/05/2026

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 11/05 12/05 13/05 14/05 15/05 16/05 17/05 18/05 19/05 20/05 21/05 22/05 23/05 24/05

41B011 Sint-Agatha-Berchem 90.5 85.5 80 71 85.5 92 67.5 77.5 69.5 83.5 88 119 116.5 126

41MEU1 Neder-Over-Heembeek 89.5 84.5 73.5 79.5 84.5 88 63.5 71.5 65 74.5 88 129.5 119 123.5

41N043 Voorhaven (Haren) 84.5 81 72.5 75 79 84.5 59.5 69 59 74.5 80 120 112 119

41R001 Sint-Jans-Molenbeek 78 76 71.5 67.5 75.5 84.5 64.5 59.5 NA 77.5 84 113 125.5 124

41R012 Ukkel 91.5 87 78 78.5 87 89 67 75.5 69 80 86 116 118 123

42N016 Dessel NA 68 74 84 90 93 73.5 78.5 71 84 98 126.5 129 121

42N027 Bree 94.5 96.5 84.5 83.5 90.5 98.5 77 93 77 89.5 106 135.5 125.5 124.5

42N035 Aarschot 97 96 78.5 83.5 90.5 97.5 76.5 86.5 70 88 103.5 123 147 132.5

42N040 Sint-Pieters-Leeuw 87 86 78.5 74.5 84 90 69.5 77.5 68.5 79.5 92 115 117.5 121.5

42N046 Gellik 91.5 97.5 82 88 94 99.5 73.5 89.5 68.5 87.5 92.5 127.5 120.5 129

42N047 Hasselt 90 97 80 82 86.5 97.5 72 84.5 72 84.5 95 119 122.5 128

42R801 Borgerhout 91.5 91.5 79.5 75 86.5 89 68 77 67 81 87 126.5 132 124

42R811 Schoten 97 92 75.5 76 91 95 73 82.5 71.5 86.5 93.5 135.5 138 123.5

42R842 Mechelen (Hendrik Speecqvest) 90 87.5 71.5 78.5 83.5 90 68 70 66.5 74.5 82.5 119.5 117.5 116

44M705 Roeselare (Haven) 96.5 85.5 82.5 84.5 90.5 93.5 87.5 86.5 69 89 91 128.5 130 148

44N012 Moerkerke 94 97 78.5 83 89.5 94 77.5 86.5 73 90 92 136.5 131 146

44N029 Houtem (Veurne) 93.5 96 77.5 84 92 92 80.5 87 76.5 83 93.5 128.5 124 140.5

44R701 Gent (Baudelopark) 92.5 91 76 78.5 90.5 90.5 73 81.5 71.5 85.5 99 126.5 141 148.5

44R710 Destelbergen 93 94 78 72.5 85 90.5 72 78.5 72 86.5 98 123.5 142 143

43N060 Havinnes 84 83.5 68 77 80.5 85 60 72 60.5 69.5 85 103 117.5 117

43N064 Rixensart 92 94.5 85 90 91 93 78.5 82 73.5 89.5 100.5 118 125.5 114.5

43N066 Eupen 81.5 89 78 72.5 80 87 71 75.5 67 79.5 93.5 115.5 122 117.5

43N070 Mons 85 76 61.5 80 77.5 76.5 59.5 59.5 57.5 57.5 85 93.5 97 34.5

43N073 Vezin 85 88.5 76.5 70.5 84 87.5 64 73 65.5 81 94 113 116.5 124

43N085 Vielsalm 70.5 77.5 71 72.5 77.5 84.5 68.5 66.5 63.5 64.5 81.5 109 114.5 109

43N093 Sinsin 85.5 87.5 79.5 81.5 88.5 91 67.5 77.5 66 79 87.5 111.5 106.5 126

43N100 Dourbes 92.5 95.5 80.5 79 91.5 90.5 67.5 83 77 84 91.5 110.5 108.5 127

43N113 Saint-Ode 82 84.5 84 78.5 85 87.5 75 84 72 75 84 112 119.5 109

43N121 Offagne 69 79.5 71.5 58 63.5 76.5 58 60 59.5 65.5 42.5 70 68.5 74.5

43N132 Habay-La-Neuve 79.5 84 81 74 80.5 82 69.5 76 71.5 75.5 87 115.5 121 110.5

43R221 Herstal 90.5 93.5 79.5 79 81 93.5 74.5 84.5 69 85 93 122 123.5 134.5

43R222 Liège (ISSeP) 85 90 79 77.5 84 92 74 77 67 82.5 98 118 121 136.5

43R240 Engis 84.5 88 71.5 69 74 79 62 67 62.5 80.5 88 107.5 106.5 130.5

43R401 Namur 87 91 81.5 73.5 86.5 89.5 68.5 78 66.5 82.5 93.5 108 119 118.5

45R502 Lodelinsart 83.5 78.5 69 73.5 79.5 81.5 62 65.5 64.5 67 89.5 96 96 123

Interpolated spatial average in :

Brussels 87 85 76 77 83 88 66 76 69 81 87 116 116 119

Flanders 93 93 78 80 88 91 73 81 70 85 94 124 125 128

Wallonia 82 83 74 73 82 84 65 72 66 76 86 102 107 110

Belgium 87 88 76 76 85 87 69 76 68 80 89 112 115 118

% 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	11/05	12/05	13/05	14/05	15/05	16/05	17/05	18/05	19/05	20/05	21/05	22/05	23/05	24/05
41B011	Sint-Agatha-Berchem	90.5	85.5	80	71	85.5	92	67.5	77.5	69.5	83.5	88	119	116.5	126
41MEU1	Neder-Over-Heembeek	89.5	84.5	73.5	79.5	84.5	88	63.5	71.5	65	74.5	88	129.5	119	123.5
41N043	Voorhaven (Haren)	84.5	81	72.5	75	79	84.5	59.5	69	59	74.5	80	120	112	119
41R001	Sint-Jans-Molenbeek	78	76	71.5	67.5	75.5	84.5	64.5	59.5	NA	77.5	84	113	125.5	124
41R012	Ukkel	91.5	87	78	78.5	87	89	67	75.5	69	80	86	116	118	123
42N016	Dessel	NA	68	74	84	90	93	73.5	78.5	71	84	98	126.5	129	121
42N027	Bree	94.5	96.5	84.5	83.5	90.5	98.5	77	93	77	89.5	106	135.5	125.5	124.5
42N035	Aarschot	97	96	78.5	83.5	90.5	97.5	76.5	86.5	70	88	103.5	123	147	132.5
42N040	Sint-Pieters-Leeuw	87	86	78.5	74.5	84	90	69.5	77.5	68.5	79.5	92	115	117.5	121.5
42N046	Gellik	91.5	97.5	82	88	94	99.5	73.5	89.5	68.5	87.5	92.5	127.5	120.5	129
42N047	Hasselt	90	97	80	82	86.5	97.5	72	84.5	72	84.5	95	119	122.5	128
42R801	Borgerhout	91.5	91.5	79.5	75	86.5	89	68	77	67	81	87	126.5	132	124
42R811	Schoten	97	92	75.5	76	91	95	73	82.5	71.5	86.5	93.5	135.5	138	123.5
42R842	Mechelen (Hendrik Speecqvest)	90	87.5	71.5	78.5	83.5	90	68	70	66.5	74.5	82.5	119.5	117.5	116
44M705	Roeselare (Haven)	96.5	85.5	82.5	84.5	90.5	93.5	87.5	86.5	69	89	91	128.5	130	148
44N012	Moerkerke	94	97	78.5	83	89.5	94	77.5	86.5	73	90	92	136.5	131	146
44N029	Houtem (Veurne)	93.5	96	77.5	84	92	92	80.5	87	76.5	83	93.5	128.5	124	140.5
44R701	Gent (Baudelopark)	92.5	91	76	78.5	90.5	90.5	73	81.5	71.5	85.5	99	126.5	141	148.5
44R710	Destelbergen	93	94	78	72.5	85	90.5	72	78.5	72	86.5	98	123.5	142	143
43N060	Havinnes	84	83.5	68	77	80.5	85	60	72	60.5	69.5	85	103	117.5	117
43N064	Rixensart	92	94.5	85	90	91	93	78.5	82	73.5	89.5	100.5	118	125.5	114.5
43N066	Eupen	81.5	89	78	72.5	80	87	71	75.5	67	79.5	93.5	115.5	122	117.5
43N070	Mons	85	76	61.5	80	77.5	76.5	59.5	59.5	57.5	57.5	85	93.5	97	34.5
43N073	Vezin	85	88.5	76.5	70.5	84	87.5	64	73	65.5	81	94	113	116.5	124
43N085	Vielsalm	70.5	77.5	71	72.5	77.5	84.5	68.5	66.5	63.5	64.5	81.5	109	114.5	109
43N093	Sinsin	85.5	87.5	79.5	81.5	88.5	91	67.5	77.5	66	79	87.5	111.5	106.5	126
43N100	Dourbes	92.5	95.5	80.5	79	91.5	90.5	67.5	83	77	84	91.5	110.5	108.5	127
43N113	Saint-Ode	82	84.5	84	78.5	85	87.5	75	84	72	75	84	112	119.5	109
43N121	Offagne	69	79.5	71.5	58	63.5	76.5	58	60	59.5	65.5	42.5	70	68.5	74.5
43N132	Habay-La-Neuve	79.5	84	81	74	80.5	82	69.5	76	71.5	75.5	87	115.5	121	110.5
43R221	Herstal	90.5	93.5	79.5	79	81	93.5	74.5	84.5	69	85	93	122	123.5	134.5
43R222	Liège (ISSeP)	85	90	79	77.5	84	92	74	77	67	82.5	98	118	121	136.5
43R240	Engis	84.5	88	71.5	69	74	79	62	67	62.5	80.5	88	107.5	106.5	130.5
43R401	Namur	87	91	81.5	73.5	86.5	89.5	68.5	78	66.5	82.5	93.5	108	119	118.5
45R502	Lodelinsart	83.5	78.5	69	73.5	79.5	81.5	62	65.5	64.5	67	89.5	96	96	123

Interpolated spatial average in :
Brussels	87	85	76	77	83	88	66	76	69	81	87	116	116	119
Flanders	93	93	78	80	88	91	73	81	70	85	94	124	125	128
Wallonia	82	83	74	73	82	84	65	72	66	76	86	102	107	110
Belgium	87	88	76	76	85	87	69	76	68	80	89	112	115	118

% 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