Division Definition for certain air pollutants
United Kingdom
| Term used | Definition |
|---|---|
| NOx expressed as NO2 | The sum of nitrogen oxide (NO) and nitrogen dioxide (NO2) expressed as NO2 |
| SOx expressed as SO2 | The sum of sulphur dioxide (SO2) and sulphur trioxide (SO3) expressed as SO2 |
| Hydrogen chloride expressed as HCl | All gaseous chlorides expressed as HCl |
| Hydrogen fluoride expressed as HF | All gaseous fluorides expressed as HF |