| 1 | Other pollutants, such as sulphur, increase the burden. | |
| 2 | It also avoids the release of the pollutants sulphur dioxide and nitrogen dioxide. | |
| 3 | These contaminants, I think, are threatening the human food supply. | |
| 4 | But not all air pollution starts out as soot. | |
| 5 | In Europe it is currently one of the air pollutants of most concern. |