ANNEX XMEASUREMENTS OF OZONE PRECURSOR SUBSTANCES

A.Objectives

The main objectives of such measurements are to analyse any trend in ozone precursors, to check the efficiency of emission reduction strategies, to check the consistency of emission inventories and to help attribute emission sources to observed pollution concentrations.

An additional aim is to support the understanding of ozone formation and precursor dispersion processes, as well as the application of photochemical models.

B.Substances

Measurement of ozone precursor substances shall include at least nitrogen oxides (NO and NO2), and appropriate volatile organic compounds (VOC). A list of volatile organic compounds recommended for measurement is given below:

1-Butene

Isoprene

Ethyl benzene

Ethane

Trans-2-Butene

n-Hexane

m + p-Xylene

Ethylene

cis-2-Butene

i-Hexane

o-Xylene

Acetylene

1,3-Butadiene

n-Heptane

1,2,4-Trimethylebenzene

Propane

n-Pentane

n-Octane

1,2,3-Trimethylebenzene

Propene

i-Pentane

i-Octane

1,3,5-Trimethylebenzene

n-Butane

1-Pentene

Benzene

Formaldehyde

i-Butane

2-Pentene

Toluene

Total non-methane hydrocarbons

C.Siting

Measurements shall be taken in particular in urban or suburban areas at any monitoring site set up in accordance with the requirements of this Directive and considered appropriate with regard to the monitoring objectives referred to in Section A.