Emissions and photochemistry of oxygenated VOCs in urban plumes in the Northeastern United States R. Sommariva1,2,*, J. A. de Gouw1,2, M. Trainer1, E. Atlas3, P. D. Goldan2, W. C. Kuster1, C. Warneke1,2, and F. C. Fehsenfeld2 1Earth System Research Laboratory, NOAA, Boulder, CO, USA 2CIRES, University of Colorado, Boulder, CO, USA 3Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USA *now at: School of Environmental Sciences, University of East Anglia, Norwich, UK
Abstract. Photochemical processes inside urban plumes in the Northeast of the United
States have been studied using a highly detailed chemical model, based upon
the Master Chemical Mechanism (MCM). The model results have been compared to
measurements of oxygenated VOCs (acetone, methyl ethyl ketone, acetaldehyde,
acetic acid and methanol) obtained during several flights of the NOAA WP-3D
aircraft, which sampled plumes from the New York City area during the ICARTT
campaign in 2004. The agreement between the model and the measurements was
within 40–60 % for all species, except acetic acid.
The model results have been used to study the formation and photochemical
evolution of acetone, methyl ethyl ketone and acetaldehyde. Under the
conditions encountered during the ICARTT campaign, acetone is produced from
the oxidation of propane (24–28 %) and i-propanol (<15 %) and
from a number of products of i-pentane oxidation. Methyl ethyl ketone (MEK)
is mostly produced from the oxidation of n-butane (20–30 %) and
3-methylpentane (<40 %). Acetaldehyde is formed from several
precursors, mostly small alkenes, >C5 alkanes, propanal and MEK. Ethane
and ethanol oxidation account, respectively, for 6–23 % and
5–25 % of acetaldehyde photochemical formation. The results
highlight the importance of alkanes for the photochemical production of
ketones and the role of hydroperoxides in sustaining their formation far from
the emission sources.
Citation: Sommariva, R., de Gouw, J. A., Trainer, M., Atlas, E., Goldan, P. D., Kuster, W. C., Warneke, C., and Fehsenfeld, F. C.: Emissions and photochemistry of oxygenated VOCs in urban plumes in the Northeastern United States, Atmos. Chem. Phys., 11, 7081-7096, doi:10.5194/acp-11-7081-2011, 2011.