Biogenic volatile organic compounds (VOC): An overview on emission, physiology and ecology

This overview compiles the actual knowledge of the biogenic emissions of so me volatile organic compounds (VOCs), i.e., isoprene, terpenes, alkanes, al kenes, alcohols, esters, carbonyls, and acids. We discuss VOC biosynthesis, emission inventories, relations between emission and plant physiology as w ell as temperature and radiation, and ecophysiological functions. For isopr ene and monoterpenes, an extended summary of standard emission factors, wit h data related to the plant genus and species, is included. The data compil ation shows that we have quite a substantial knowledge of the emission of i soprene and monoterpenes, including emission rates, emission regulation, an d biosynthesis. The situation is worse in the case of numerous other compou nds (other VOCs or OVOCs) being emitted by the biosphere. This is reflected in the insufficient knowledge of emission rates and biological functions. Except for the terpenoids, only a limited number of studies of OVOCs are av ailable; data are summarized for alkanes, alkenes, carbonyls, alcohols, aci ds, and esters. In addition to closing these gaps of knowledge, one of the major objectives for future VOC research is improving our knowledge of the fate of organic carbon in the atmosphere, ending up in oxidation products a nd/or as aerosol particles.