HR: 16:45h
AN: A14A-04    [Abstracts]
TI: Ambient Concentrations and Mobile Sources of Ammonia in Mexico City
AU: * Shorter, J H
EM: shorter@aerodyne.com
AF: Aerodyne Research, Inc., 45 Manning Road, Billerica, MA 01821 United States
AU: Herndon, S C
EM: herndon@aerodyne.com
AF: Aerodyne Research, Inc., 45 Manning Road, Billerica, MA 01821 United States
AU: Zahniser, M S
EM: mz@aerodyne.com
AF: Aerodyne Research, Inc., 45 Manning Road, Billerica, MA 01821 United States
AU: Wormhoudt, J
EM: jody@aerodyne.com
AF: Aerodyne Research, Inc., 45 Manning Road, Billerica, MA 01821 United States
AU: Zavala, M
EM: miguelz@MIT.EDU
AF: Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139 United States
AU: Dunlea, E J
EM: edward.dunlea@colorado.edu
AF: Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139 United States
AU: Molina, L T
EM: ltmolina@MIT.EDU
AF: Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139 United States
AU: Molina, M J
EM: mmolina@MIT.EDU
AF: Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139 United States
AU: Kolb, C E
EM: kolb@aerodyne.com
AF: Aerodyne Research, Inc., 45 Manning Road, Billerica, MA 01821 United States
AB: Emission of ammonia (NH$_{3}$) to the atmosphere is a major environmental concern and a potential health hazard. As the dominant gaseous alkaline species in the atmosphere, ammonia plays an important role in the dynamics of the atmospheric environment and on air quality. Ammonia is a major source of secondary PM-2.5 particulates including ammonium nitrate and ammonium sulfates. These important constituents of airborne PM-2.5 can contribute significantly to regional haze and visibility problems. They are also regulated under the U.S. "National Ambient Air Quality Standard for Particulate Matter" as a human health hazard. Models of the formation of these particulates are being developed but they depend on both detailed inventories of NH$_{3}$ emissions and on comparison of model results with ambient ammonia measurements. A real time tunable infrared laser differential absorption spectroscopy (TILDAS) instrument was deployed on the Aerodyne Research, Inc. Mobile Laboratory in the Mexico City Metropolitan Area (MCMA) in spring 2003. The Quantum Cascade laser (QCL) based instrument collected ammonia concentration data to characterize fleet average and individual vehicle emissions. Ambient concentration data at several stationary sites were also studied. Gas phase ammonia data will be used to elucidate the formation of ammonium particles in Mexico City. Implications of the results on air quality modeling will be discussed.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0322 Constituent sources and sinks
DE: 0345 Pollution--urban and regional (0305)
DE: 0365 Troposphere--composition and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting