Plants Make A Big Grab For VOCs

Leaves from deciduous trees might take up significantly greater quantities of volatile organic compounds (VOCs) from the atmosphere than previously recognized, a finding that could prompt revisions of atmospheric chemistry and climate models (Science, DOI: 10.1126/science.1192534). Climate scientists have assumed that plants don’t absorb significant amounts of VOCs, which have many sources including other plants, fossil-fuel burning, and industrial and household solvent use. VOCs are readily oxidized to form aerosols and ozone, which are atmospheric species that are important in moderating global climate cycles. But Thomas Karl at the National Center for Atmospheric Research and colleagues observed in field experiments that forests readily take up oxygenated VOCs such as hydroxyacetone, nopinone, and glycoaldehyde. Lab experiments with poplar leaves showed that enzymes readily metabolize the oxygenated VOCs. The researchers included this additional sink of oxygenated VOCs in a global atmospheric chemistry and transport model. This revised model predicted that vegetation in areas with higher ozone concentrations, such as the tropics, takes up oxygenated VOCs at higher rates than in previous models.