TY - JOUR
T1 - Biogenic hydrocarbon chemistry within and above a mixed deciduous forest
AU - Fuentes, Jose D.
AU - Wang, Daniel
AU - Bowling, Dave R.
AU - Potosnak, Mark
AU - Monson, Russell K.
AU - Goliff, Wendy S.
AU - Stockwell, William R.
N1 - Funding Information:
Acknowledgments Fuentes received support from the University of Virginia to carry out the field research of this study. Fuentes also received support from the U.S. National Science foundation (grant ATM-0445012). James Kathilankal of the University of Virginia provided assistance to perform the air parcel trajectory analyses. Tony Delany of the National Center for Atmospheric Research (NCAR) is acknowledged for his able assistance with the NOX measurements. Kell Wilson from the Atmospheric and Turbulence Diffusion Laboratory, National Oceanic and Atmospheric Administration is thanked for sharing the meteorological data included in this manuscript. Monson and Bowling were supported by a grant from the National Science Foundation and funds from the University of Colorado and the NCAR. Potosnak received support from a National Science Foundation Graduate Research Fellowship. Steve Hoskins provided assisted with the field studies. Stockwell was supported by the NOAA Educational Partnership Program with Minority Serving Institutions (EPP/MSI) under cooperative agreements NA17AE1625 and NA17AE1623. Stockwell and Goliff were supported by the National Aeronautics and 362 Space Administration under the Experimental Program to Stimulate Competitive 363 Research (EPSCoR), grant number NCC5-583. Two anonymous journal reviewers are acknowledged for providing excellent comments to improve the manuscript.
PY - 2007/3
Y1 - 2007/3
N2 - This manuscript includes findings from field and numerical modeling investigations designed to quantify the degree and rates of biogenic hydrocarbon chemical processing within and above a mixed deciduous forest in the southeastern United States. The study site was under the influences of nitrogen oxide and hydrocarbon emissions from suburban automobile traffic. The most common ambient biogenic hydrocarbons measured within and above the forest included isoprene, α-pinene, and d-limonene. Isoprene was the most abundantly produced biogenic hydrocarbon, with maximum isoprene flux densities reaching 50 nmol m-2 s-1. Isoprene and its reaction products (methyl vinyl ketone and methacrolein) comprised over 75% of the measured hydrocarbon mass. Substantial nitrate (NO3) and hydroxyl (HO) radical formation occurred within the forest canopy, with maximum NO 3 and HO levels approaching 1 part per trillion on a volume basis (pptv) and 0.05 pptv, respectively. These NO3 and HO levels, combined with within-canopy ozone (O3) mixing ratios of 60 parts per billion (ppbv), reacted with biogenic hydrocarbons and produced substantial amounts (0.6 ppbv) of peroxy radicals. The main conclusion from this investigation is that forested ecosystems capable of high rates (>50 nmol m-2 s -1) of biogenic hydrocarbon emissions, and in the vicinity of modest rates of nitrogen oxide emissions from suburban automobile traffic, can support a unique and active photochemistry within the forest canopy. In these areas it may not be valid to use biogenic emissions estimated from measurements made at the foliage level for regional-scale air quality modeling because the underlying processes are nonlinear. Regional-scale air quality models should include chemical preprocessing of biogenic hydrocarbons before they are emitted to the full regional modeling grid in order to accurately represent the photochemical production of pollutants on the wider scale.
AB - This manuscript includes findings from field and numerical modeling investigations designed to quantify the degree and rates of biogenic hydrocarbon chemical processing within and above a mixed deciduous forest in the southeastern United States. The study site was under the influences of nitrogen oxide and hydrocarbon emissions from suburban automobile traffic. The most common ambient biogenic hydrocarbons measured within and above the forest included isoprene, α-pinene, and d-limonene. Isoprene was the most abundantly produced biogenic hydrocarbon, with maximum isoprene flux densities reaching 50 nmol m-2 s-1. Isoprene and its reaction products (methyl vinyl ketone and methacrolein) comprised over 75% of the measured hydrocarbon mass. Substantial nitrate (NO3) and hydroxyl (HO) radical formation occurred within the forest canopy, with maximum NO 3 and HO levels approaching 1 part per trillion on a volume basis (pptv) and 0.05 pptv, respectively. These NO3 and HO levels, combined with within-canopy ozone (O3) mixing ratios of 60 parts per billion (ppbv), reacted with biogenic hydrocarbons and produced substantial amounts (0.6 ppbv) of peroxy radicals. The main conclusion from this investigation is that forested ecosystems capable of high rates (>50 nmol m-2 s -1) of biogenic hydrocarbon emissions, and in the vicinity of modest rates of nitrogen oxide emissions from suburban automobile traffic, can support a unique and active photochemistry within the forest canopy. In these areas it may not be valid to use biogenic emissions estimated from measurements made at the foliage level for regional-scale air quality modeling because the underlying processes are nonlinear. Regional-scale air quality models should include chemical preprocessing of biogenic hydrocarbons before they are emitted to the full regional modeling grid in order to accurately represent the photochemical production of pollutants on the wider scale.
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U2 - 10.1007/s10874-006-9048-4
DO - 10.1007/s10874-006-9048-4
M3 - Article
AN - SCOPUS:34250651313
SN - 0167-7764
VL - 56
SP - 165
EP - 185
JO - Journal of Atmospheric Chemistry
JF - Journal of Atmospheric Chemistry
IS - 2
ER -