| Value | Category | Cases | |
|---|---|---|---|
| 1 | Industrial activities | 5 |
0.2%
|
| 2 | Waste burning | 7 |
0.2%
|
| 3 | Transportation | 66 |
2.2%
|
| 4 | Construction | 7 |
0.2%
|
| 5 | others | 4 |
0.1%
|
| 6 | furnaces | 0 |
0%
|
| Sysmiss | 2882 |