Natural volatile organic compound emissions from plants and their roles in oxidant balance and particle formation

Numerous biogenic volatile organic compounds (VOC) species are released into the atmosphere from tropical forests. Measuring all those which are relevant for atmospheric chemistry or for the carbon budget is challenging. Large-Scale Biosphere-Atmosphere (LBA) Experiment field campaigns substantially increased the number of field studies of isoprene and monoterpene emissions, as well as of the exchange of several other VOC species. This chapter reports about the progress made within LBA from primary emission measurements at the plant species level up to discussions of the oxidative capacity of the atmosphere and formation of secondary organic aerosol particles and cloud condensation nuclei from biogenic hydrocarbons. VOC emission from Amazonian ecotypes has strong effects on atmospheric chemistry, which are obviously not fully understood in the case of the tropical atmosphere. Atmospheric flux studies within numerous field experiments resulted in new knowledge about local to regional scale biogenic VOC exchange and improved modeling. New data obtained from field as well as from laboratory studies helped to characterize VOC emissions from the Amazonian forest underlying seasonality within dry and wet seasons. Furthermore, first insight was obtained into the potential of floodplain areas affected by long-lasting flooding periods which can cause special emission adaptation. © Copyright 2009 by the American Geophysical Union