Regulation 13(5)
SCHEDULE 4Assessment thresholds
PART 1Assessment thresholds for Group A pollutants
Benzene
| Annual average |
|---|
| Upper assessment threshold | 70% of limit value (3.5 μg/m3) |
| Lower assessment threshold | 40% of limit value (2 μg/m3) |
Carbon monoxide
| Eight-hour average |
|---|
| Upper assessment threshold | 70% of limit value (7 mg/m3) |
| Lower assessment threshold | 50% of limit value (5 mg/m3) |
Lead
| Annual average |
|---|
| Upper assessment threshold | 70% of limit value (0.35 μg/m3) |
| Lower assessment threshold | 50% of limit value (0.25 μg/m3) |
Nitrogen dioxide (NO2) and oxides of nitrogen (NOx)
| Hourly limit value for the protection of human health (NO2) | Annual limit value for the protection of human health (NO2) | Annual limit value for the protection of vegetation (NOx) |
|---|
| Upper assessment threshold | 70% of limit value (140 μg/m3), not to be exceeded more than 18 times in any calendar year | 80% of limit value (32 μg/m3) | 80% of limit value (24 μg/m3) |
| Lower assessment threshold | 50% of limit value (100 μg/m3), not to be exceeded more than 18 times in any calendar year | 65% of limit value (26 μg/m3) | 65% of limit value (19.5 μg/m3) |
PM10
| 24-hour average | Annual average |
|---|
| Upper assessment threshold | 60% of limit value (30 μg/m3), not to be exceeded more than 7 times in any calendar year | 70% of limit value (14 μg/m3) |
| Lower assessment threshold | 40% of limit value (20 μg/m3), not to be exceeded more than 7 times in any calendar year | 50% of limit value (10 μg/m3) |
Sulphur dioxide
| Health protection | Ecosystem protection |
|---|
| Upper assessment threshold | 60% of 24-hour limit value (75 μg/m3), not to be exceeded more than 3 times in any calendar year | 60% of winter limit value (12 μg/m3) |
| Lower assessment threshold | 40% of 24-hour limit value (50 μg/m3), not to be exceeded more than 3 times in any calendar year | 40% of winter limit value (8 μg/m3) |
PART 2Assessment thresholds for Group B pollutants
Arsenic
| Upper assessment threshold | 60% of target value (3.6 ng/m3) |
| Lower assessment threshold | 40% of target value (2.4 ng/m3) |
Benzo(a)pyrene
| Upper assessment threshold | 60% of target value (0.6 ng/m3) |
| Lower assessment threshold | 40% of target value (0.4 ng/m3) |
Cadmium
| Upper assessment threshold | 60% of target value (3 ng/m3) |
| Lower assessment threshold | 40% of target value (2 ng/m3) |
Nickel
| Upper assessment threshold | 70% of target value (14 ng/m3) |
| Lower assessment threshold | 50% of target value (10 ng/m3) |
PART 3Determination of when assessment thresholds are exceeded
1. Exceedances of upper and lower assessment thresholds must be determined on the basis of concentrations during the previous five years where sufficient data are available. An assessment threshold will be deemed to have been exceeded if it has been exceeded during at least three separate years out of the previous five years.
2. Where fewer than five years' data are available, measurement campaigns of short duration during the period of the year and at locations likely to be typical of the highest concentrations may be combined with results obtained from emission inventories and modelling to determine exceedances of the upper and lower assessment thresholds.