Air Quality index, 19/04/2011 - 03/05/2011
| 19/04 | 20/04 | 21/04 | 22/04 | 23/04 | 24/04 | 25/04 | 26/04 | 27/04 | 28/04 | 29/04 | 30/04 | 01/05 | 02/05 | 03/05 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Conurbation | |||||||||||||||
| Brussels | 6 | 7 | 6 | 7 | 7 | 7 | 7 | 6 | 5 | 4 | 5 | 6 | 6 | 5 | 5 |
| Antwerp | 6 | 7 | 7 | 7 | 7 | 8 | 7 | 6 | 5 | 4 | 5 | 6 | 6 | 5 | 5 |
| Ghent | 7 | 7 | 7 | 8 | 7 | 8 | 7 | 6 | 5 | 5 | 6 | 6 | 6 | 5 | 5 |
| Liège | 7 | 7 | 7 | 7 | 6 | 8 | 7 | 6 | 5 | 4 | 5 | 5 | 5 | 5 | 4 |
| Charleroi | 7 | 7 | 7 | 7 | 7 | 8 | 7 | 7 | 5 | 5 | 6 | 6 | 6 | 5 | 4 |
| Area | |||||||||||||||
| Coast | 6 | 7 | 7 | 7 | 7 | 7 | 7 | 6 | 5 | 5 | 6 | 6 | 5 | 5 | 5 |
| West-Vlaanderen (south) | 6 | 7 | 7 | NA | NA | NA | NA | NA | 6 | 5 | 6 | 6 | 6 | 5 | 4 |
| Ghent canal area | 6 | 7 | 7 | 8 | 7 | 7 | 6 | 7 | 6 | 7 | 6 | NA | NA | 5 | 5 |
| Oost-Vlaanderen (south) | 7 | 7 | 7 | 7 | 7 | 7 | 7 | 7 | 5 | 4 | 6 | 6 | 6 | 5 | 5 |
| Antwerp harbour area | 6 | 7 | 7 | 7 | 7 | 8 | 7 | 6 | 5 | 4 | 6 | 6 | 6 | 5 | 5 |
| Kempen - Vlaams-Brabant (east) | 7 | 8 | 7 | 7 | 7 | 8 | 7 | 7 | 6 | 4 | 6 | 6 | 6 | 5 | 5 |
| Limburg | 7 | 7 | 7 | 7 | 7 | 8 | 7 | 7 | 6 | 5 | 6 | 6 | 6 | 5 | 4 |
| Region | |||||||||||||||
| Brussels | 6 | 7 | 6 | 7 | 7 | 7 | 7 | 6 | 5 | 4 | 5 | 6 | 6 | 5 | 5 |
| Flanders | 6 | 7 | 7 | 7 | 7 | 7 | 7 | 6 | 5 | 5 | 5 | 6 | 6 | 5 | 5 |
| Wallonia | 7 | 7 | 7 | 7 | 7 | 7 | 7 | 6 | 5 | 4 | 6 | 6 | 6 | 5 | 5 |
| Country | |||||||||||||||
| Belgium | 6 | 7 | 7 | 7 | 7 | 7 | 7 | 6 | 5 | 5 | 5 | 6 | 6 | 5 | 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 |