SCHEDULE 3UPPER AND LOWER ASSESSMENT THRESHOLDS AND EXCEEDANCES

Regulations 7(8), 8(1)

PART IUpper and lower assessment thresholds

The following upper and lower assessment thresholds will apply:

(a) 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)

(b) NITROGEN DIOXIDE AND OXIDES OF NITROGEN

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)

(c) PARTICULATE MATTER

24-hour average

Annual average

Upper assessment threshold

60% of limit value (30 µg/m3), not to be exceeded more than seven 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 seven times in any calendar year

50% of limit value (10 µg/m3)

(d) 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)

(e) BENZENE

Annual Average

Upper assessment threshold

70% of limit value (3.5 µg/m3)

Lower assessment threshold

40% of limit value (2 µg/m3)

(f) CARBON MONOXIDE

Eight-hour average

Upper assessment threshold

70% of limit value (7mg/m3)

Lower assessment threshold

50% of limit value (5mg/m3)

PART IIDetermination of exceedances of upper and lower assessment thresholds

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.

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 pollution levels may be combined with results obtained from emission inventories and modelling to determine exceedances of the upper and lower assessment thresholds.