FORECAST DISTRIBUTIONS OF SPECIES AND THEIR ATMOSPHERIC REACTIVITIES FOR THE UK VOC EMISSION INVENTORY

The planned reductions of volatile organic compound (VOC) emissions in the U.K, will have an influence on both the total mass and species di stribution of emissions. Different organic compound species vary in th eir ability to react and produce ground level ozone and reactivity sca les can be used to link primary VOC pollutant species quantitatively w ith ground level ozone formation. This report examines the changes in emission inventory species distributions based on sector-specific redu ction forecasts and compares the reactivities of these distributions u sing photochemical ozone creating potentials (POCP). Despite the varia bility in compound distributions and planned reductions from different sectors, reductions are forecast to change the fractional distributio ns of species and their reactivities for the overall U.K. emission inv entory only slightly by the end of the century. The distribution of na tional emissions based on an atmospheric reactivity scale remains rela tively stable because the largest mass reductions are made from sector s with distributions estimated to be similar to the overall distributi on. There is also a balancing effect of making simultaneous reductions from source sectors with average ozone creating potentials which are higher and lower than that for the current national distribution.