Efficient Atmospheric Cleansing of Oxidized Organic Trace Gases by Vegetation

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Science  21 Oct 2010:
DOI: 10.1126/science.1192534


The biosphere is the major source and sink of nonmethane 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 CO2. We performed ecosystem-scale flux measurements that show the removal of oxygenated VOC via dry deposition is substantially larger than currently assumed for deciduous ecosystems. Laboratory experiments 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.