During this three-year program, the atmospheric chemistry of selected organic compounds emitted into the atmosphte from vegetation will be experimentally investigated. On regional and global scales, the emissions of non-methane organic compounds from vegetation will be expermentally investigated. On regional and global scales, the emissions of non-methane organic compounds from vegetation, which are largely comprised of isoprene (2-methyl-1,3- butadiene and C10H16 monoterpenes, are comparable to or exceed the emissions of non-methane organic compounds from anthropogenic sources. The chemistry of the planetary boundary layer may well be dominated by these biogenic emissions. Additionally, the emissions of isoprene and monoterpenes from vegetation have been implicated in the formation of ozone and other manifestations of photochemical air pollutiion in rural and urban areas. Sine the rate constants fro the atmosphereically-important gas-phase reactions of isoprene and the monoterpenes with hydrozyl (NO3) radicals and ozone (O3) are now reliably known, this project will focus on the products formed from the OH radical, NO3 radical and O3 reactions with these biogenic organic compounds and the elecidation of the reaction mechanisms. Experiments to identify and quantify the products of the gas-phase reactions of OH radicals, NO3 radicals and O
