# The Air Quality Standards (Wales) Regulations 2007, Paragraph 4: Substances


A list of volatile organic compounds recommended for measurement by Directive 2002/3/EC is given in the table below—
Ethane
1-Butene
Isoprene
Ethyl benzene
Ethylene
trans-2-Butene
n-Hexane
m+p-Xylene
Acetylene
cis-2-Butene
i-Hexane
o-Xylene
Propane
1.3-Butadiene
n-Heptane
1,2,4-Trimeth. Benzene
Propene
n-Pentane
n-Octane
1,2,3-Trimeth. Benzene
n-Butane
i-Pentane
i-Octane
1,3,5-Trimeth. Benzene
i-Butane
1-Pentene
Benzene
Formaldehyde
2-Pentene
Toluene
Total non-methane hydrocarbons

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Source: https://www.legislation.gov.uk/wsi/2007/717/schedule/10/paragraph/4 (the official version)
Page: https://openlegislation.uk/air-quality-standards-wales-regulations-2007/schedule-10/paragraph-4
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.