Air Quality index, 11/04/2004 - 25/04/2004
| 11/04 | 12/04 | 13/04 | 14/04 | 15/04 | 16/04 | 17/04 | 18/04 | 19/04 | 20/04 | 21/04 | 22/04 | 23/04 | 24/04 | 25/04 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Conurbation | |||||||||||||||
| Brussels | 4 | 5 | 4 | 6 | 6 | 6 | 5 | 4 | 4 | 4 | 4 | 4 | 5 | 5 | 5 |
| Antwerp | 4 | 5 | 4 | 5 | 6 | 6 | 5 | 4 | 4 | 4 | 4 | 4 | 5 | 5 | 6 |
| Ghent | 4 | 5 | 4 | 5 | 5 | 6 | 5 | 4 | 4 | 4 | 3 | 4 | 5 | 5 | 6 |
| Liège | 4 | 7 | 5 | 7 | 6 | 7 | 6 | 5 | 6 | 5 | NA | NA | 4 | 5 | 5 |
| Charleroi | 4 | 6 | 4 | 6 | 6 | 7 | 5 | 5 | 5 | 4 | NA | NA | 4 | 5 | 6 |
| Area | |||||||||||||||
| Coast | 5 | 5 | 4 | 6 | 6 | 6 | 5 | 5 | 5 | 5 | 3 | 5 | 5 | 6 | 6 |
| West-Vlaanderen (south) | 4 | 5 | 5 | 6 | 6 | 6 | 5 | 1 | 3 | 4 | 4 | 4 | 5 | 5 | 6 |
| Ghent canal area | 4 | 5 | 4 | 5 | 6 | 6 | 5 | 4 | 4 | 4 | 3 | 5 | 5 | 5 | 6 |
| Oost-Vlaanderen (south) | 4 | 5 | 4 | 4 | 6 | 7 | 5 | 5 | 5 | 5 | 4 | 4 | 5 | 4 | 6 |
| Antwerp harbour area | 4 | 5 | 4 | 6 | 6 | 6 | 5 | 4 | 4 | 4 | 5 | 4 | 5 | 5 | 5 |
| Kempen - Vlaams-Brabant (east) | 4 | 6 | 5 | 5 | 6 | 7 | 7 | 5 | 6 | 4 | 4 | 3 | 5 | 5 | 6 |
| Limburg | 2 | 5 | 4 | 4 | 7 | 7 | 7 | 5 | 5 | 4 | 3 | 4 | 5 | 5 | 6 |
| Region | |||||||||||||||
| Brussels | 4 | 5 | 4 | 6 | 6 | 6 | 5 | 4 | 4 | 4 | 4 | 4 | 5 | 5 | 5 |
| Flanders | 4 | 5 | 4 | 5 | 6 | 6 | 5 | 5 | 4 | 4 | 4 | 4 | 5 | 4 | 6 |
| Wallonia | 4 | 6 | 4 | 6 | 6 | 7 | 6 | 5 | 5 | 4 | NA | NA | 5 | 5 | 6 |
| Country | |||||||||||||||
| Belgium | 4 | 5 | 4 | 5 | 6 | 6 | 6 | 5 | 4 | 4 | 4 | 4 | 5 | 4 | 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 |