HR: 1400h
AN: A33A-08    [Abstracts]
TI: Mobile Emission Trends in the MCMA: Effects on Photochemistry
AU: * Zavala, M
EM: miguelz@mit.edu
AF: Massachussetts Institute of Technology, 77 Mass. Av., Cambridge, MA 02139, United States
AU: * Zavala, M
EM: miguelz@mit.edu
AF: Molina Center for Energy and the Environment, 3262 Holiday Court, Suite 201, La Jolla, CA 92037, United States
AU: Herndon, S
AF: Aerodyne Research Inc., 45 Manning Road, Billerica, MA 01821, United States
AU: Wood, E
AF: Aerodyne Research Inc., 45 Manning Road, Billerica, MA 01821, United States
AU: Knighton, B
AF: Montana State University, Department of Chemistry & Biochemistry, 108 Gaines Hall , Bozeman, MT 59717, United States
AU: Molina, M J
AF: University of California, San Diego, Department of Chemistry and Biochemistry 2040 Urey Hall Addition, 500 Gilman Drive, La Jolla, CA 92093, United States
AU: Kolb, C
AF: Aerodyne Research Inc., 45 Manning Road, Billerica, MA 01821, United States
AU: Molina, L T
AF: Massachussetts Institute of Technology, 77 Mass. Av., Cambridge, MA 02139, United States
AU: Molina, L T
AF: Molina Center for Energy and the Environment, 3262 Holiday Court, Suite 201, La Jolla, CA 92037, United States
AB: Emissions from mobile sources have a strong influence on the photochemical levels and other pollutants of an urban area. Mobile emissions in the Mexico City Metropolitan Area (MCMA) have been studied for the period 1991- 2006 with several measurement techniques that include remote sensing, dynamometer and tunnel studies and - more recently- with the chasing technique. During the same time period, several factors that directly affect the emission characteristics of the vehicle fleet have occurred. These factors include the implementation of more stringent emission standards, emission control technologies and changes in fuel composition, among others. Along with these changes, concurrent non-linear changes in photochemical levels as well as in toxic and criteria pollutants have been observed. In this study we compare the historical trends of CO, NOx and VOCs from mobile emission sources in the MCMA from 1991 to 2006 with pollutant trends of hourly data of CO, NO_X, and the CO/NO_X ratio during peak traffic. Using the historical trends comparison and the on-road emission data obtained with the Aerodyne Research Inc. (ARI) Mobile Laboratory during the 2002/2003-MCMA and the MCMA-2006/MILAGRO field campaigns (see http:www.mce2.org), we derive historical changes on the VOC/NO_X ratio from mobile sources. The inferred trend is in turn compared with observed trends of O3 to quantify the induced changes on photochemical levels in the MCMA by mobile sources. Finally, the effect of the perturbed VOC/NO_X ratio on simulated historical ozone levels is investigated in a companion modeling study.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
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: 2007 Joint Assembly