HR: 10:20h
AN: A52B-01 INVITED     [Abstracts]
TI: Emissions of highly reactive BVOCs are an order of magnitude larger than above canopy terpene flux
AU: * Goldstein, A H
EM: ahg@nature.berkeley.edu
AF: University of Calfornia, Department of Environmental Science, Policy, and Management 151 Hilgard Hall, Berkeley, CA 94563 United States
AU: Holzinger, R
EM: holzing@nature.berkeley.edu
AF: University of Calfornia, Department of Environmental Science, Policy, and Management 151 Hilgard Hall, Berkeley, CA 94563 United States
AU: Lee, A
EM: alee@nature.berkeley.edu
AF: University of Calfornia, Department of Environmental Science, Policy, and Management 151 Hilgard Hall, Berkeley, CA 94563 United States
AU: McKay, M
EM: megan@nature.berkeley.edu
AF: University of Calfornia, Department of Environmental Science, Policy, and Management 151 Hilgard Hall, Berkeley, CA 94563 United States
AU: Lunden, M M
EM: MMLunden@lbl.gov
AF: Lawrence Berkeley National Laboratory, Department of Energy, Berkeley, CA 94702 United States
AU: Rasmussen, R A
EM: rei@ebs.ogi.edu
AF: Oregon Graduate Institute, Department of Environmental and Biomolecular Systems, Beaverton, OR 97006 United States
AB: Biogenic emissions of VOCs play important roles in the chemistry of the atmosphere, with terpenes and isoprene affecting regional air quality, atmospheric radiation, and global climate through secondary organic aerosol formation. In 2002 we began field and laboratory measurements with a fast response Proton-Transfer-Reaction Mass Spectrometer (PTR-MS) of biogenic terpenes, and their oxidation products. Measurements were made in a California pine forest at the Blodgett Forest Research Station. Field measurements of vertical concentration profiles through the forest canopy of terpene oxidation products revealed the presence of large amounts of previously unreported compounds consistent with those recently observed in smog chamber studies. In addition, we have recently shown that about half the ecosystem scale ozone flux in summer is actually due to chemical reactions occurring between terpenoid compounds and ozone within the forest canopy. Taken together, this new information suggests that the flux of terpenes leaving the forest canopy represents at most 10% of the terpenoid compounds actually emitted, and the rest is chemically processed within the forest canopy. Branch enclosure measurements confirm more than 100 BVOCs are emitted but not typically observed above the forest. The implication is that the source of secondary aerosols from biogenic terpene oxidation is likely much larger than previously estimated. We have also consistently observed fine aerosol growth events at the Blodgett Forest site, which we believe are related to the terpene oxidation occurring in the forest canopy. Similar observations of aerosol growth events, non-stomatal ozone deposition, and missing OH reactivity at forested sites around the world suggest unmeasured reactive BVOC emission is common. The unmeasured BVOCs represent a previously unquantified carbon loss from ecosystems and a potentially major source of secondary organic aerosols, oxygenated VOCs (OVOCs), and OH radicals.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0315 Biosphere/atmosphere interactions
DE: 0365 Troposphere--composition and chemistry
DE: 0368 Troposphere--constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting