HR: 0800h
AN: A11A-0015    [Abstracts]
TI: Mobile Laboratory Measurements of Black Carbon and Polycyclic Aromatic Hydrocarbon Emissions in Mexico City: A New Method for Motor Vehicle Emission Inventory Calculations
AU: * Jiang, M
EM: meij@vt.edu
AF: Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, 411 Durham Hall, Blacksburg, VA 24061
AU: Marr, L C
EM: lmarr@vt.edu
AF: Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, 411 Durham Hall, Blacksburg, VA 24061
AU: Marr, L C
EM: lmarr@vt.edu
AF: Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139
AU: Dunlea, E
EM: dunlea@post.harvard.edu
AF: Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139
AU: Dunlea, E
EM: dunlea@post.harvard.edu
AF: Cooperative Institute for Research in Environmental Sciences, University of Colorado, UCB 216, Boulder, CO 80309
AU: Herndon, S
EM: herndon@aerodyne.com
AF: Center for Atmospheric and Environmental Chemistry, Aerodyne Research, Inc., 45 Manning Road, Billerica, MA 01821
AU: Jayne, J
EM: jayne@aerodyne.com
AF: Center for Atmospheric and Environmental Chemistry, Aerodyne Research, Inc., 45 Manning Road, Billerica, MA 01821
AU: Rogers, T
EM: trogers@chemistry.montana.edu
AF: Department of Chemistry and Biochemistry, Montana State University, P.O. Box 173400, Bozeman, MT 59717
AU: Knighton, B
EM: bknighton@chemistry.montana.edu
AF: Department of Chemistry and Biochemistry, Montana State University, P.O. Box 173400, Bozeman, MT 59717
AU: Zavala, M
EM: miguelz@mit.edu
AF: Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139
AU: Molina, L T
EM: ltmolina@mit.edu
AF: Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139
AU: Molina, M J
EM: mmolina@mit.edu
AF: Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139
AB: Aerosol black carbon (BC) and polycyclic aromatic hydrocarbons (PAHs) are two products of carbonaceous fuel combustion that are of major concern for urban air quality and global climate change. As part of the Mexico City Metropolitan Area field campaign in April 2003 (MCMA-2003), a mobile laboratory drove throughout the city and chased vehicles to measure pollutants in their exhaust emissions. The laboratory is a van designed and built by Aerodyne Research, Inc. and is equipped with a suite of gas and particle analyzers, including an aethalometer that measures BC and a photoemission aerosol sensor that measures particle-bound PAHs. The main goal of this research is to determine fuel-based emission factors, or the mass of BC and PAH emitted per volume of fuel burned, for Mexico City­_s vehicle fleet. We can then calculate the megacity­_s emission inventory of these compounds, which is important on both the urban and global scales. In previous analyses, the mobile laboratory has been used to target emissions from specific vehicles. While chasing events can be analyzed to obtain emission factors for specific vehicles, data from the entire time period while the lab is driving through the streets, whether chasing individual vehicles or not, can also provide valuable information about mobile source emissions. The laboratory continuously samples ambient air from an inlet at the front of the van, and it is always ­øseeing­ñ exhaust plumes from the vehicles around it. This ­ømacroscopic­ñ approach that considers all vehicles on the road, similar to tunnel and remote sensing studies, complements the ­ømicroscopic­ñ approach that focuses on individual vehicles. We have developed a method that automatically identifies exhaust plumes and quantifies emission factors from data collected by the mobile lab. While 200 individual chasing events were identified during the field campaign, over 40,000 exhaust plume points were identified using the macroscopic approach. The large sample size enables us to estimate fleet-average emission factors and thus the emission inventory. This method is applicable not only to BC and PAH concentrations, but also to other pollutants measured by the mobile lab. For comparison, we also estimate total emissions using an alternative method: multiplying ambient concentration ratios of BC to carbon monoxide by official estimates of carbon monoxide emissions. Results of the two methods agree reasonably well, adding confidence to our estimates.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0345 Pollution--urban and regional (0305)
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting