Emissions of ozone precursors, EU15

Carbon monoxide has been included in the 2010 target lines assuming emissions remain constant from 1998. Weighting factors are used to derive tropospheric ozone-forming potentials (TOFP) so that emissions can be combined in terms of their contribution to tropospheric ozone: nitrogen oxides 1.22, non-methane volatile organic compounds 1.0, carbon monoxide 0.11 and methane 0.014.