MEASUREMENTS OF OZONE PRECURSOR SUBSTANCES
ANNEX XSupplementary provisions
ANNEX X MEASUREMENTS 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 NO 2 ), 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.