Air Quality index, 26/02/2011 - 12/03/2011
| 26/02 | 27/02 | 28/02 | 01/03 | 02/03 | 03/03 | 04/03 | 05/03 | 06/03 | 07/03 | 08/03 | 09/03 | 10/03 | 11/03 | 12/03 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Conurbation | |||||||||||||||
| Brussels | 3 | 3 | 6 | 7 | 7 | 7 | 7 | 5 | 4 | 4 | 6 | 5 | 3 | 4 | 4 |
| Antwerp | 4 | 3 | 6 | 7 | 8 | 7 | 7 | 4 | 5 | 4 | 6 | 5 | 4 | 5 | 5 |
| Ghent | 3 | 4 | 7 | 7 | 8 | 7 | 7 | 5 | 5 | 4 | 6 | 5 | 4 | 5 | 4 |
| Liège | 3 | 4 | 5 | 7 | 7 | 7 | 7 | 6 | 4 | 4 | 5 | 5 | 3 | 4 | 5 |
| Charleroi | 3 | 3 | 5 | 7 | 7 | 7 | 7 | 6 | 4 | 4 | 5 | 4 | 3 | 4 | 4 |
| Area | |||||||||||||||
| Coast | 4 | 4 | 7 | 6 | 8 | 7 | 7 | 4 | 4 | 3 | 6 | 4 | 4 | 4 | 4 |
| West-Vlaanderen (south) | 2 | 2 | 6 | 7 | 7 | 7 | 7 | 4 | 5 | 4 | 6 | 4 | 4 | 4 | 4 |
| Ghent canal area | 4 | 4 | 7 | 7 | 8 | 7 | 8 | 4 | 4 | 4 | 6 | 5 | 4 | 4 | 4 |
| Oost-Vlaanderen (south) | NA | NA | NA | NA | NA | NA | NA | NA | NA | NA | NA | NA | NA | NA | NA |
| Antwerp harbour area | 2 | 2 | 6 | 6 | 7 | NA | 6 | 4 | 5 | 4 | 6 | 4 | 4 | 4 | 4 |
| Kempen - Vlaams-Brabant (east) | 4 | 4 | 6 | 7 | 8 | 7 | 7 | 5 | 5 | 4 | 5 | 5 | 4 | 4 | 4 |
| Limburg | 3 | 4 | 6 | 7 | 7 | 7 | 7 | 5 | 4 | 4 | 4 | 4 | 4 | 4 | 4 |
| Region | |||||||||||||||
| Brussels | 3 | 3 | 6 | 7 | 7 | 7 | 7 | 5 | 4 | 4 | 6 | 5 | 3 | 4 | 4 |
| Flanders | 3 | 4 | 6 | 7 | 7 | 7 | 7 | 4 | 4 | 3 | 6 | 5 | 4 | 4 | 4 |
| Wallonia | 3 | 4 | 4 | 6 | 7 | 7 | 7 | 6 | 4 | 4 | 5 | 4 | 4 | 4 | 5 |
| Country | |||||||||||||||
| Belgium | 3 | 4 | 6 | 7 | 7 | 7 | 7 | 5 | 4 | 3 | 5 | 5 | 4 | 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 |