Air Quality index, 11/07/2021 - 25/07/2021
| 11/07 | 12/07 | 13/07 | 14/07 | 15/07 | 16/07 | 17/07 | 18/07 | 19/07 | 20/07 | 21/07 | 22/07 | 23/07 | 24/07 | 25/07 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Conurbation | |||||||||||||||
| Brussels | 4 | 3 | 4 | 4 | 4 | 3 | 4 | 4 | 4 | 5 | 6 | 5 | 6 | 5 | 4 |
| Antwerp | 3 | 4 | 4 | 4 | 3 | 3 | 3 | 4 | 4 | 4 | 5 | 5 | 5 | 4 | 3 |
| Ghent | 4 | 3 | 4 | 4 | 4 | 4 | 3 | 4 | 4 | 5 | 6 | 5 | 6 | 5 | 4 |
| Liège | 3 | 3 | 3 | 4 | 4 | 3 | 4 | 4 | 5 | 5 | 6 | 6 | 6 | 4 | 3 |
| Charleroi | 3 | 3 | 3 | 3 | 3 | 3 | 4 | 5 | 4 | 5 | 6 | 6 | 7 | 5 | 4 |
| Area | |||||||||||||||
| Coast | 3 | 3 | 5 | 4 | 4 | 4 | 3 | 4 | 4 | 5 | 6 | 5 | 4 | 5 | 4 |
| West-Vlaanderen (south) | 4 | 3 | 4 | 4 | 4 | 3 | 3 | 4 | 4 | 5 | 6 | 5 | 5 | 5 | 4 |
| Ghent canal area | 4 | 3 | 4 | 4 | 4 | 3 | 3 | 4 | 4 | 5 | 6 | 5 | 5 | 4 | 4 |
| Oost-Vlaanderen (south) | 4 | 3 | 4 | 4 | 4 | 4 | 4 | 5 | 5 | 5 | 6 | 5 | 6 | 5 | 4 |
| Antwerp harbour area | 4 | 4 | 4 | 4 | 4 | 3 | 4 | 4 | 4 | 5 | 6 | 5 | 5 | 4 | 3 |
| Kempen - Vlaams-Brabant (east) | 3 | 4 | 3 | 3 | 3 | 3 | 4 | 4 | 4 | 5 | 6 | 5 | 6 | 4 | 3 |
| Limburg | 4 | 4 | 4 | 4 | 4 | 3 | 4 | 4 | 4 | 5 | 6 | 5 | 6 | 4 | 4 |
| Region | |||||||||||||||
| Brussels | 4 | 3 | 4 | 4 | 4 | 3 | 4 | 4 | 4 | 5 | 6 | 5 | 6 | 5 | 4 |
| Flanders | 4 | 3 | 4 | 4 | 4 | 3 | 4 | 4 | 4 | 5 | 6 | 5 | 5 | 4 | 4 |
| Wallonia | 3 | 3 | 3 | 4 | 4 | 3 | 4 | 4 | 4 | 5 | 6 | 6 | 6 | 5 | 3 |
| Country | |||||||||||||||
| Belgium | 3 | 3 | 3 | 4 | 4 | 3 | 4 | 4 | 4 | 5 | 6 | 5 | 6 | 4 | 4 |
| 1 | exellent |
| 2 | very good |
| 3 | good |
| 4 | fairly good |
| 5 | moderate |
| 6 | poor |
| 7 | very poor |
| 8 | bad |
| 9 | very bad |
| 10 | horrible |