Ozone is a gas which has an irritant effect on the surface tissues of the body, such as eyes, nose and lungs and can damage vegitation and materials. Consequently near the earths surface ozone and ozone precursors are important pollutants. Ozone emissions are not estimated by the NAEI as the direct emissions are not significant compared with photochemical formation of ozone in the air from ozone precursor pollutants (NOx, CO and NMVOC). Estimating ozone concentrations in the troposphere requires modelling, and information on emissions of ozone precursors. Consequently there is a need for emission estimates of ozone precursors.