HR: 13:40h
AN: A23D-01    [Abstracts]
TI: VARIABILITY OF AMBIENT AEROSOL IN THE MEXICO CITY METROPOLIAN AREA
AU: * Onasch, T B
EM: onacsh@aerodyne.com
AF: Aerodyne Research, Inc., 45 Manning Road , Billerica, MA 01821-3976 United States
AU: Worsnop, D R
AF: Aerodyne Research, Inc., 45 Manning Road , Billerica, MA 01821-3976 United States
AU: Canagaratna, M
AF: Aerodyne Research, Inc., 45 Manning Road , Billerica, MA 01821-3976 United States
AU: Jayne, J T
AF: Aerodyne Research, Inc., 45 Manning Road , Billerica, MA 01821-3976 United States
AU: Herndon, S
AF: Aerodyne Research, Inc., 45 Manning Road , Billerica, MA 01821-3976 United States
AU: Mortimer, P
AF: Aerodyne Research, Inc., 45 Manning Road , Billerica, MA 01821-3976 United States
AU: Kolb, C E
AF: Aerodyne Research, Inc., 45 Manning Road , Billerica, MA 01821-3976 United States
AU: Rogers, T
AF: Montana State University, Chemistry Department P.O. Box 173400 , Bozeman, MT 59717 United States
AU: Knighton, B
AF: Montana State University, Chemistry Department P.O. Box 173400 , Bozeman, MT 59717 United States
AU: Dunlea, E
AF: Massachusetts Institute of Technology, 77 Massachusetts Av., Cambridge, MA 02139 United States
AU: Marr, L
AF: Massachusetts Institute of Technology, 77 Massachusetts Av., Cambridge, MA 02139 United States
AU: De Foy, B
AF: Massachusetts Institute of Technology, 77 Massachusetts Av., Cambridge, MA 02139 United States
AU: Molina, M
AF: Massachusetts Institute of Technology, 77 Massachusetts Av., Cambridge, MA 02139 United States
AU: Molina, L
AF: Massachusetts Institute of Technology, 77 Massachusetts Av., Cambridge, MA 02139 United States
AU: Salcedo, D
AF: Universidad Aut¢noma del Estado de Morelos, Av. Universidad #1001 , Cuernavaca Morelos, 62210 Mexico
AU: Dzepina, K
AF: University of Colorado-Boulder, Dept. of Chemistry & Biochemistry and CIRES UCB 216, Boulder, CO 80309 United States
AU: Jimenez, J L
AF: University of Colorado-Boulder, Dept. of Chemistry & Biochemistry and CIRES UCB 216, Boulder, CO 80309 United States
AB: The spatial and temporal variations of the ambient aerosol in the Mexico City Metropolitan area was characterized during the springs of 2002 and 2003 using a mobile laboratory equipped with gas and particulate measurement instrumentation. The laboratory was operated at various fixed sites locations in and at the edge of the metropolitan area (Xalostoc, Merced, Cenica, Pedregal, and Santa Ana). Size-resolved aerosol mass and chemical composition was measured with an aerosol mass spectrometer and selected trace gas species (low mass organic compounds, NO, NO2, NOy, O3, SO2, CH2O, NH3, CO2) were measured using a proton transfer reaction mass spectrometer and various optical systems. The aerosol was predominantly organic in composition with lesser amounts of ammonium nitrate, sulfate, and chloride. The organic component was composed of mixed primary and secondary organic compounds. The mass loading and chemical composition of the aerosol was influenced by local and regional air pollution sources and the meteorology in Mexico City. Most urban sites were influenced by a strong diurnal particulate mass trend indicative of primary organic emissions from traffic during early morning and subsequently oxidized/processed organics and ammonium nitrate particles starting in the mid-morning (~9 AM) and continuing throughout the day. Morning traffic-related primary organic emissions were strongest at La Merced (center of Mexico City, located near a busy food market), more subdued at other fixed sites further from the city center, and varied depending upon the day of week and holiday schedules. Particle-bound polycyclic aromatic hydrocarbons were observed within Mexico City fixed sites and were correlated with traffic organic PM emissions. Oxidized organic and ammonium nitrate events occurred during mid-morning at all city sites and were well correlated with gas phase photochemical activity. The daily ammonium nitrate aerosol event occurred later at sites near the city limits, likely due to transported emissions from the city center. The sulfate particulate mass measured throughout most of the Mexico City area did not show a consistent diurnal pattern, characteristic of aged regional aerosol. Local refuse burns were observed to be a source of inorganic particulate chloride.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0345 Pollution--urban and regional (0305)
DE: 0365 Troposphere--composition and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting