HR: 08:52h
AN: A31E-04 INVITED [Abstracts]
TI: Efficient Transport of Nitric Acid in Urban Plumes Observed Over the North Atlantic Ocean
AU: * Neuman, J
EM: andy.neuman@noaa.gov
AF: Cooperative Institute for Research in Environmental Sciences, University of Colorado at Boulder,
Boulder, CO 80309
United States
AU: * Neuman, J
EM: andy.neuman@noaa.gov
AF: NOAA Aeronomy Laboratory, 325 Broadway, Boulder, CO 80305
United States
AU: Parrish, D
EM: David.D.Parrish@noaa.gov
AF: NOAA Aeronomy Laboratory, 325 Broadway, Boulder, CO 80305
United States
AU: Trainer, M
EM: Michael.K.Trainer@noaa.gov
AF: NOAA Aeronomy Laboratory, 325 Broadway, Boulder, CO 80305
United States
AU: Brown, S
EM: Steven.S.Brown@noaa.gov
AF: Cooperative Institute for Research in Environmental Sciences, University of Colorado at Boulder,
Boulder, CO 80309
United States
AU: Brown, S
EM: Steven.S.Brown@noaa.gov
AF: NOAA Aeronomy Laboratory, 325 Broadway, Boulder, CO 80305
United States
AU: Fehsenfeld, F
EM: Fred.c.Fehsenfeld@noaa.gov
AF: Cooperative Institute for Research in Environmental Sciences, University of Colorado at Boulder,
Boulder, CO 80309
United States
AU: Fehsenfeld, F
EM: Fred.c.Fehsenfeld@noaa.gov
AF: NOAA Aeronomy Laboratory, 325 Broadway, Boulder, CO 80305
United States
AU: Flocke, F
EM: ffl@ucar.edu
AF: National Center for Atmospheric Research, 1850 Table Mesa Drive, Boulder, CO 80305
United States
AU: Holloway, J
EM: Holloway@al.noaa.gov
AF: Cooperative Institute for Research in Environmental Sciences, University of Colorado at Boulder,
Boulder, CO 80309
United States
AU: Holloway, J
EM: Holloway@al.noaa.gov
AF: NOAA Aeronomy Laboratory, 325 Broadway, Boulder, CO 80305
United States
AU: Nowak, J
EM: jnowak@al.noaa.gov
AF: Cooperative Institute for Research in Environmental Sciences, University of Colorado at Boulder,
Boulder, CO 80309
United States
AU: Nowak, J
EM: jnowak@al.noaa.gov
AF: NOAA Aeronomy Laboratory, 325 Broadway, Boulder, CO 80305
United States
AU: Ryerson, T
EM: tryerson@al.noaa.gov
AF: NOAA Aeronomy Laboratory, 325 Broadway, Boulder, CO 80305
United States
AU: Stark, H
EM: hstark@al.noaa.gov
AF: Cooperative Institute for Research in Environmental Sciences, University of Colorado at Boulder,
Boulder, CO 80309
United States
AU: Stark, H
EM: hstark@al.noaa.gov
AF: NOAA Aeronomy Laboratory, 325 Broadway, Boulder, CO 80305
United States
AU: Swanson, A
EM: aswanson@ucar.edu
AF: Cooperative Institute for Research in Environmental Sciences, University of Colorado at Boulder,
Boulder, CO 80309
United States
AU: Swanson, A
EM: aswanson@ucar.edu
AF: NOAA Aeronomy Laboratory, 325 Broadway, Boulder, CO 80305
United States
AU: Swanson, A
EM: aswanson@ucar.edu
AF: National Center for Atmospheric Research, 1850 Table Mesa Drive, Boulder, CO 80305
United States
AB:
The processing of anthropogenic NOx emissions from urban and industrial sources was studied using data collected from an
instrumented aircraft flying over the east coast of the United States and over the North Atlantic Ocean. Pollutants were
sampled from the National Oceanic and Atmospheric Administration WP-3 aircraft during the International Consortium for
Atmospheric Research on Transport and Transformation study in July and August, 2004. Fast response measurements of reactive
nitrogen compounds and carbon monoxide (CO) were obtained in crosswind transects of urban plumes in the New York City and
Boston source regions and up to 1600 km downwind.
The magnitude and geographical extent of the effects of NOx and its oxidation products depend on the NOx oxidation rates and
pathways and on the atmospheric lifetime and loss mechanisms of the resulting secondary products. In urban plumes that were
sampled further than 200 km from New York City and Boston, nitric acid was always the most abundant reactive nitrogen species
and usually accounted for over 80% of the sum of NOx and its oxidation products. During this study, frequently plumes were
transported above the marine boundary layer at a few hundred meters altitude and were decoupled from the surface, which
allowed efficient transport of nitric acid that is not commonly observed at the surface, in the continental boundary layer,
or in the free troposphere. In plumes observed over the remote North Atlantic Ocean, nitric acid mixing ratios were high (up
to 50 ppbv) and the ratio of CO to reactive nitrogen changed little with plume age, reflecting the small depositional loss
of nitric acid. Many of the photochemically aged urban plumes were characterized by the presence of tens of ppbv of nitric
acid for several days. As a consequence of the slow removal of nitric acid from these air masses, NOx can be reformed from
nitric acid photolysis and OH oxidation. The efficient transport of nitric acid may also allow for episodic deposition of
high levels of nitrate to the remote ocean.
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0365 Troposphere: composition and chemistry
DE: 0368 Troposphere: constituent transport and chemistry
DE: 0478 Pollution: urban, regional and global (0345, 4251)
DE: 4251 Marine pollution (0345, 0478)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005