Air Quality index, 25/03/2003 - 08/04/2003
| 25/03 | 26/03 | 27/03 | 28/03 | 29/03 | 30/03 | 31/03 | 01/04 | 02/04 | 03/04 | 04/04 | 05/04 | 06/04 | 07/04 | 08/04 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Conurbation | |||||||||||||||
| Brussels | 7 | 7 | 7 | 7 | 6 | 6 | 5 | 6 | 4 | 4 | 6 | 4 | NA | 4 | 5 |
| Antwerp | 8 | NA | 7 | 7 | 7 | 7 | 5 | 6 | 3 | 4 | 6 | 4 | 5 | 4 | 4 |
| Ghent | 8 | 7 | 7 | 7 | 7 | 7 | 6 | 6 | 4 | 4 | 6 | 5 | 5 | 4 | 4 |
| Liège | 8 | 6 | 7 | 7 | 6 | 6 | 4 | 6 | 2 | 3 | 5 | 4 | 5 | 4 | 4 |
| Charleroi | 8 | 8 | 7 | 7 | 6 | 6 | 5 | 6 | 3 | 4 | 5 | 4 | 3 | 4 | 5 |
| Area | |||||||||||||||
| Coast | 7 | 7 | 6 | 7 | 8 | 5 | 5 | 5 | 5 | 5 | 4 | 5 | 5 | 4 | 4 |
| West-Vlaanderen (south) | NA | NA | NA | NA | NA | NA | 5 | 6 | 4 | 4 | 5 | 5 | 5 | 4 | 4 |
| Ghent canal area | 8 | 8 | 8 | 8 | 8 | 7 | 7 | 6 | 4 | 5 | 6 | 6 | 5 | 5 | 6 |
| Oost-Vlaanderen (south) | 7 | 7 | 6 | 6 | 5 | 6 | 4 | 6 | 4 | 5 | 5 | 4 | 5 | 4 | 4 |
| Antwerp harbour area | NA | NA | NA | NA | NA | NA | NA | NA | NA | NA | NA | NA | NA | NA | NA |
| Kempen - Vlaams-Brabant (east) | NA | NA | NA | NA | NA | NA | NA | NA | NA | NA | NA | NA | NA | NA | NA |
| Limburg | 7 | NA | 6 | 6 | 6 | 7 | 4 | 5 | NA | 4 | 4 | 4 | 5 | 4 | 4 |
| Region | |||||||||||||||
| Brussels | 7 | 7 | 7 | 7 | 6 | 6 | 5 | 6 | 4 | 4 | 6 | 4 | NA | 4 | 5 |
| Flanders | NA | NA | 7 | 7 | 7 | NA | 5 | 6 | 4 | 4 | 5 | 4 | 5 | 4 | 4 |
| Wallonia | 8 | 8 | 7 | 7 | 6 | 6 | 4 | 6 | 4 | 4 | 5 | 4 | 5 | 4 | 5 |
| Country | |||||||||||||||
| Belgium | 8 | NA | 7 | 7 | 7 | 6 | 5 | 6 | 4 | 4 | 5 | 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 |