HR: 1340h
AN: A43C-0065    [Abstracts]
TI: Emission Measurements of Mono and Sequiterpenes From Loblolly Pine ({\it Pinus taeda}) Using a Dynamic Branch Enclosure Technique
AU: * Herrick, J D
EM: herrick.jeffrey@epa.gov
AF: USEPA, NRMRL, Research Triangle Park, 109 TW Alexander Drive, RTP, NC 27711 United States
AU: Geron, C
EM: geron.chris@epa.gov
AF: USEPA, NRMRL, Research Triangle Park, 109 TW Alexander Drive, RTP, NC 27711 United States
AU: Arnts, R R
EM: arnts.robert@epa.gov
AF: USEPA, NERL, Research Triangle Park, 109 TW Alexander Drive, RTP, NC 27711 United States
AU: Helmig, D
EM: Detlev.Helmig@colorado.edu
AF: Institute of Arctic and Alpine Research, 1560, 30th St, Boulder, CO 80303 United States
AU: Pollmann, J
EM: Jan.Pollmann@colorado.edu
AF: Institute of Arctic and Alpine Research, 1560, 30th St, Boulder, CO 80303 United States
AU: Ortega, J
EM: John.Ortega@Colorado.EDU
AF: Institute of Arctic and Alpine Research, 1560, 30th St, Boulder, CO 80303 United States
AU: Rasmussen, R A
EM: rei@ebs.ogi.edu
AF: Oregon Graduate Institute, Environmental and Biomoleculr Systems, 20000 NW Walker Rd., Beaverton, OR 97006 United States
AB: Biogenic VOC's such as monoterpenes and sequiterpenes are emitted from forest vegetation and are known precursors for secondary organic aerosols. However, there is very little information quantifying the emission rates of these VOC's and the changes in emission rate due to environmental and physiological factors, especially for oxygenated terpenes and sesquiterpenes. The goal of our research to quantify mono and sesquiterpene emissions from loblolly pine growing the Duke Forest in Chapel Hill, NC. FEP Teflon film enclosures were carefully placed on rapidly growing full sun branches throughout the year. Ambient air was scrubbed of ozone and purged through the enclosure at approximately 25 liters per minute. The incoming air was also cooled using an ice bath and water condensation was trapped and taken out of the air stream. Air temperatures inside of the enclosure stayed within 4 degrees C of the ambient air when in the full sunlight. Tenax filled tubes were used to sample the outflow from the branch enclosure. Compounds were quantified and identified by thermally desorbing the tubes on to a GC/MS system. The most abundant compounds found were alpha-pinene, beta-pinene, limonene, beta-phellandrene, longifolene, beta-caryophylene, and alpha-humulene. Our measurements in the fall and winter indicated substantially more sesquiterpenes (primarily beta-caryophylene) than monoterpenes (primarily alpha-pinene). These results indicate sesquiterpene emissions may be a large part of VOC emissions from Loblolly pine. Sequiterpenes may be missed in ambient air studies due to their rapid reaction with ozone. Therefore, a large quantity of high aerosol forming VOCs may be missed in biogenic VOC emission inventories.
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