Air Quality index, 07/05/2023 - 21/05/2023
| 07/05 | 08/05 | 09/05 | 10/05 | 11/05 | 12/05 | 13/05 | 14/05 | 15/05 | 16/05 | 17/05 | 18/05 | 19/05 | 20/05 | 21/05 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Conurbation | |||||||||||||||
| Brussels | 3 | 3 | 2 | 3 | 4 | 3 | 5 | 5 | 4 | 4 | 5 | 5 | 5 | 5 | 5 |
| Antwerp | 4 | 4 | 2 | 3 | 4 | 5 | 6 | 5 | 4 | 4 | 5 | 5 | 6 | 5 | 5 |
| Ghent | 3 | 3 | 3 | 3 | 3 | 4 | 5 | 5 | 4 | 4 | 5 | 5 | 5 | 6 | 5 |
| Liège | 4 | 4 | 3 | 4 | 4 | 3 | 6 | 5 | 4 | 4 | 5 | 5 | 5 | 5 | 5 |
| Charleroi | 2 | 3 | 2 | 2 | 4 | 3 | 6 | 5 | 4 | 4 | 5 | 5 | 5 | 5 | 5 |
| Area | |||||||||||||||
| Coast | 4 | 4 | 3 | 4 | 4 | 4 | 6 | 6 | 4 | 4 | 5 | 5 | 5 | 5 | 4 |
| West-Vlaanderen (south) | 4 | 3 | 3 | 4 | 3 | 3 | 5 | 5 | 4 | 4 | 4 | 5 | 5 | 5 | 4 |
| Ghent canal area | 4 | 3 | 2 | 3 | 3 | 4 | 4 | 5 | 4 | 4 | 4 | 5 | 5 | 5 | 4 |
| Oost-Vlaanderen (south) | 3 | 3 | 3 | 3 | 4 | 4 | 5 | 5 | 4 | 4 | 5 | 5 | 5 | 5 | 5 |
| Antwerp harbour area | 4 | 4 | 3 | 3 | 4 | 5 | 6 | 5 | 4 | 4 | 5 | 5 | 5 | 5 | 5 |
| Kempen - Vlaams-Brabant (east) | 3 | 4 | 3 | 4 | 4 | 4 | 7 | 5 | 4 | 4 | 5 | 5 | 6 | 5 | 5 |
| Limburg | 4 | 4 | 3 | 4 | 4 | 4 | 6 | 6 | 4 | 4 | 5 | 5 | 6 | 5 | 5 |
| Region | |||||||||||||||
| Brussels | 3 | 3 | 2 | 3 | 4 | 3 | 5 | 5 | 4 | 4 | 5 | 5 | 5 | 5 | 5 |
| Flanders | 4 | 3 | 2 | 3 | 4 | 4 | 6 | 5 | 4 | 4 | 5 | 5 | 5 | 5 | 5 |
| Wallonia | 3 | 4 | 3 | 3 | 4 | 3 | 6 | 5 | 5 | 4 | 5 | 5 | 5 | 5 | 5 |
| Country | |||||||||||||||
| Belgium | 3 | 3 | 2 | 3 | 4 | 4 | 6 | 5 | 4 | 4 | 5 | 5 | 5 | 5 | 5 |
| 1 | exellent |
| 2 | very good |
| 3 | good |
| 4 | fairly good |
| 5 | moderate |
| 6 | poor |
| 7 | very poor |
| 8 | bad |
| 9 | very bad |
| 10 | horrible |