Part 2 Assessment thresholds for Group B pollutants
| Upper assessment threshold | 60% of target value (3.6 ng/m3) |
| Lower assessment threshold | 40% of target value (2.4 ng/m3) |
| Upper assessment threshold | 60% of target value (3.6 ng/m3) |
| Lower assessment threshold | 40% of target value (2.4 ng/m3) |