Air Quality index, 03/05/2011 - 17/05/2011
| 03/05 | 04/05 | 05/05 | 06/05 | 07/05 | 08/05 | 09/05 | 10/05 | 11/05 | 12/05 | 13/05 | 14/05 | 15/05 | 16/05 | 17/05 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Conurbation | |||||||||||||||
| Brussels | 5 | 5 | 5 | 6 | 6 | 6 | 5 | 5 | 4 | 5 | 5 | 5 | 4 | 4 | 4 |
| Antwerp | 5 | 5 | 5 | 6 | 6 | 6 | 4 | 5 | 4 | 5 | 5 | 5 | 4 | 4 | 4 |
| Ghent | 5 | 5 | 6 | 6 | 6 | 6 | 5 | 4 | 5 | 5 | 5 | 5 | 5 | 4 | 4 |
| Liège | 4 | 5 | 6 | 7 | 7 | 7 | 5 | 6 | 5 | 5 | 6 | 5 | 4 | 4 | 5 |
| Charleroi | 4 | 5 | 6 | 7 | 6 | 6 | 4 | 6 | 4 | 4 | 5 | 5 | 4 | 4 | 4 |
| Area | |||||||||||||||
| Coast | 5 | 5 | 6 | 7 | 6 | 5 | 5 | 5 | 4 | 5 | 4 | 5 | 5 | 4 | 4 |
| West-Vlaanderen (south) | 4 | 4 | 5 | 6 | 6 | 5 | 5 | 4 | 5 | 5 | 5 | 5 | 5 | 4 | 4 |
| Ghent canal area | 5 | 5 | 5 | 7 | 6 | 6 | 5 | 4 | 4 | 5 | 4 | 5 | 5 | 4 | 4 |
| Oost-Vlaanderen (south) | 5 | 5 | 6 | 7 | 6 | 6 | 5 | 5 | 5 | 5 | 6 | 5 | 5 | 4 | 5 |
| Antwerp harbour area | 5 | 5 | 5 | 6 | 6 | 6 | 4 | 5 | 5 | 4 | 4 | 5 | 4 | 4 | 3 |
| Kempen - Vlaams-Brabant (east) | 5 | 5 | 6 | 7 | 7 | 6 | 5 | 6 | 5 | 5 | 5 | 5 | 4 | 4 | 4 |
| Limburg | 4 | 5 | 6 | 7 | 7 | 7 | 5 | 7 | 6 | 5 | 6 | 5 | 5 | 4 | 4 |
| Region | |||||||||||||||
| Brussels | 5 | 5 | 5 | 6 | 6 | 6 | 5 | 5 | 4 | 5 | 5 | 5 | 4 | 4 | 4 |
| Flanders | 5 | 5 | 6 | 6 | 7 | 6 | 4 | 5 | 5 | 5 | 5 | 5 | 5 | 4 | 4 |
| Wallonia | 5 | 5 | 6 | 7 | 7 | 6 | 5 | 5 | 5 | 5 | 6 | 5 | 4 | 4 | 5 |
| Country | |||||||||||||||
| Belgium | 5 | 5 | 6 | 6 | 7 | 6 | 4 | 5 | 5 | 5 | 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 |