Parameter

Time-weighted averageμg/Nm³ (ppm)

Averaging time

Number of allowable exceedances

Carbon Monoxide

10,000 (8.1)

8 hours

None

40,000 (32)

1 hour

Lead

0.5 (0.00005)

Annual

N/A

Nitrogen Dioxide

660 (0.35)

1 hour

2 times per 30 days

100 (0.05)

Annual

N/A

Sulphur Dioxide

730 (0.28)

1 hour

2 times per annum

365 (0.14)

24 hours

1 time per annum

80 (0.03)

Annual

N/A

Benzene

5 (0.0015)

Annual

N/A

Particulate Matter (PM 10)

340 (variable)

24 hours

24 times per annum^b

80 (variable)

Annual

N/A

Particulate Matter (PM 2.5)

35

24 hours

24 times per annum^c

15

Annual

N/A

Ozone

235 (0.12)

1 hour

2 times per 30 days

157 (0.08)

8 hours

2 times per 7 days

Hydrogen Sulphide

150 (0.1)

24 hours

10 times per annum

40 (0.03)

Annual

N/A