The biosphere is the major source and sink of non methane volatile organic compounds (VOC) in the atmosphere. Gas phase chemical reactions initiate the removal of these compounds from the atmosphere, which ultimately proceeds via deposition at the surface or direct oxidation to CO or CO 2 . We performed ecosystem scale flux measurements that show the removal of oxygenated VOC (oVOC) via dry deposition is substantially larger than currently assumed for deciduous ecosystems. Laboratory

more »

... indicate efficient enzymatic conversion and potential upregulation of various stress related genes leading to enhanced uptake rates as a response to ozone and methyl vinyl ketone exposure or mechanical wounding. A revised scheme for the uptake of oxygenated VOCs, incorporated into a global chemistry-transport model, predicts appreciable regional changes in annual dry deposition fluxes. Large quantities of non methane volatile organic compounds (NMVOC) enter the atmosphere via biogenic, pyrogenic and anthropogenic sources. The annual production of NMVOC (~ 1200-1350 TgC/a) likely exceeds that of methane and CO (~500 TgC/a each) (1, 2). Together these gases fuel tropospheric chemistry. Oxidation of NMVOC leads to the formation of aerosols (3-5) and modulates the oxidation capacity of the atmosphere (6) creating important climate feedbacks (7). One large uncertainty in constraining budgets of NMVOC is the amount of deposition to vegetation, which acts as a major source and sink for organic trace gases on a global scale. This has consequences for constraining secondary species produced in the gas phase, which will either oxidize to