Appendix 4 — The Air Quality Objectives as detailed in the Air Quality (Scotland) Regulations and 2002 (Scotland) (Amendment) Regulations 2002.

Benzene

16.25 micrograms per cubic metre or less, when expressed as a running annual mean

31 December 2003

5 micrograms per cubic metre or less, when expressed as an annual mean

31 December 2010

1,3 —Butadiene

2.25 micrograms per cubic metre or less, when expressed as a running annual mean

31 December 2003

Carbon monoxide

10 milligrams per cubic metre or less, when expressed as a running 8 hour mean

31 December 2003

Nitrogen dioxide

200 micrograms per cubic metre, when expressed as an hourly mean, not to be exceeded more than 18 times a year

31 December 2005

40 micrograms per cubic metre, when expressed as an annual mean

31 December 2005

PM₁₀

50 micrograms per cubic metre or less, when expressed as a 24 hour mean, not to be exceeded more than 7 times a year

31 December 2010

18 micrograms per cubic metre or less, when expressed as an annual mean

31 December 2010

Sulphur dioxide

125 micrograms per cubic metre or less, when expressed as a 24 hour mean, not to be exceeded more than 3 times a year

31^st December 2004

350 micrograms per cubic metre or less, when expressed as an hourly mean, not to be exceeded more than 24 times a year

31^st December 2004

266 micrograms per cubic metre or less, when expressed as a 15 minute mean, not to be exceeded more than 35 times a year

31^st December 2005