04/06/2009
Climate-Relevant Isoprene Chemical Pathways Uncovered
Summary
In spite of their many positive attributes, including removing carbon from the atmosphere, some trees also contribute to the challenges of climate change. Many deciduous trees emit isoprene (2-methyl-1,3-butadiene, C5H8) during daylight hours, a major organic carbon compound accounting for up to 2% of the carbon fixed by those plants and about one third of total volatile organic compounds (VOC) emissions. DOE research has previously demonstrated that isoprene oxidation may contribute significantly to the global aerosol burden with impacts on climate forcing and ozone production. A recent study by this same group described isoprene photooxidation and developed a detailed mechanism, including branching ratios and yields, for the compounds identified. The authors summarize the most important features of this mechanism in a scheme appropriate for use in global chemical transport models. The impact of this chemistry is important in the light of the potential for significant changes in isoprene emissions caused by climate change and changes in land use.
References
F. Paulot, J. D. Crounse, H. G. Kjaergaard, J. H. Kroll, J. H. Seinfeld, and P. O. Wennberg (2009), Isoprene photooxidation: new insights into the production of acids and organic nitrates, Atmos. Chem. Phys., 9, 1479-1501.