HR: 0800h
AN: A11A-0003    [Abstracts]
TI: Open-path Emission Factors Derived from DOAS and FTIR Measurements in the Mexico City Metropolitan Area
AU: * Flores, E
AF: Centro de Ciencias de la Atmosfera, Universidad Nacional Aut¢noma de M‚xico (UNAM), Circuito Exterior s/n, Ciudad Universitaria, Delegaci¢n Coyoac n, Mexico City, 04510 Mexico
AU: Grutter, M
AF: Centro de Ciencias de la Atmosfera, Universidad Nacional Aut¢noma de M‚xico (UNAM), Circuito Exterior s/n, Ciudad Universitaria, Delegaci¢n Coyoac n, Mexico City, 04510 Mexico
AU: Galle, B
AF: Department of Radio and Space Science, Chalmers University of Technology, SE-412, Goteborg, 96 Sweden
AU: Mellqvist, J
AF: Department of Radio and Space Science, Chalmers University of Technology, SE-412, Goteborg, 96 Sweden
AU: Samuelsson, J
AF: Department of Radio and Space Science, Chalmers University of Technology, SE-412, Goteborg, 96 Sweden
AU: Knighton, B
AF: Montana State University, Department of Chemistry, P.O. Box 173400, Bozeman, MT 59717 United States
AU: Jobson, B T
AF: Pacific Northwest National Laboratory, P.O. Box 999, MSIN K9-30, Richland, WA 99352 United States
AU: Volkamer, R
AF: Departments of Earth, Atmospheric and Planetary Sciences and of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139 United States
AU: Molina, L T
AF: Departments of Earth, Atmospheric and Planetary Sciences and of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139 United States
AU: Molina, M J
AF: Departments of Earth, Atmospheric and Planetary Sciences and of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139 United States
AB: Mobile sources are responsible for about 50% of VOC (volatile organic compounds) and about 70% of NOx emissions in the Mexico City Metropolitan Area (MCMA). A novel approach has been developed to derive emission factors for mobile sources that are representative of the overall vehicle fleet, using collocated open-path Differential Optical Absorption Spectroscopy (DOAS) and Fourier Transform Infrared (FTIR) spectroscopic measurements. Measurements were recorded at two sites within the MCMA: (1) research-grade DOAS and FTIR systems were operated at the Mexican National Research and Training Center (CENICA) in Iztapalapa, (2) a research grade FTIR was operated at La Merced. In addition, point-sampling with a proton transfer reaction mass spectrometer (PTR-MS) was performed on the same location and the calibration standards for the PTR-MS and the DOAS instruments were cross-calibrated. The DOAS measured speciated aromatic hydrocarbons, including benzene, toluene, m-xylene, p-xylene, ethylbenzene (and mono-substituted alkylbenzenes), benzaldehyde, phenol, and p-cresol. The DOAS detection of aromatic hydrocarbons in the UV/vis spectral range between 250 to 310 nm suffers from the interference of molecular oxygen, and a novel approach is being presented that enables measurement of absolute concentrations of the above species. Further, HONO, NO2, SO2 and HCHO were measured at longer wavelengths. In combination with FTIR measurements of CO, CO2, NO, HCHO, ethylene, ethene, and total alkane, average emission factors for NOx, SO2 and numerous hydrocarbons were derived and scaled with fuel sales data to estimate total emissions of the vehicle fleet in the MCMA. The advantages and limitations of this low-cost emission inventory for mobile sources are decsribed.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0317 Chemical kinetic and photochemical properties
DE: 0345 Pollution--urban and regional (0305)
DE: 0365 Troposphere--composition and chemistry
DE: 0394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting