HR: 0800h
AN: A11A-0021    [Abstracts]
TI: Characterization of Particle and Gas Phase Pollutant Emissions from Heavy- and Light-Duty Vehicles in a California Roadway Tunnel
AU: * Kirchstetter, T
EM: twkirchstetter@lbl.gov
AF: Lawrence Berkeley National Lab, 1 Cyclotron Rd, Berkeley, CA 94720
AU: Strawa, A
EM: astrawa@mail.arc.nasa.gov
AF: NASA, Ames Research Center, Moffett Field, CA 94035
AU: Hallar, G
EM: ahallar@mail.arc.nasa.gov
AF: NASA, Ames Research Center, Moffett Field, CA 94035
AU: Harley, R
EM: harley@ce.berkeley.edu
AF: UC Berkeley, Civil and Environmental Engineering , Berkeley, CA 94720
AU: Kendall, G
EM: GKendall@baaqmd.gov
AF: Bay Area Air Quality Management District, 939 Ellis St, San Francisco, CA 94109
AU: Hesson, J
EM: JHesson@baaqmd.gov
AF: Bay Area Air Quality Management District, 939 Ellis St, San Francisco, CA 94109
AU: Stevenson, E
EM: estevenson@baaqmd.gov
AF: Bay Area Air Quality Management District, 939 Ellis St, San Francisco, CA 94109
AU: Miguel, A
EM: ahmiguel@ucla.edu
AF: Southern California Particle Center and Supersite, UCLA, Los Angeles, CA 90095
AB: In summer 2004, particle and gas phase pollutant emissions from heavy-duty diesel and light-duty gasoline vehicles were characterized in the Caldecott tunnel, located east of San Francisco Bay. This measurement campaign was the latest of many in the tunnel. In addition to assessing temporal trends in pollutant emission rates, the study is of interest due to recent changes to gasoline composition in California - methyl tertiary butyl ether (MTBE) has been phased out and replaced in part with ethanol. The current study determined mass emission rates (in g of pollutant emitted per kg of fuel burned) of PM2.5, particulate black and organic carbon (BC and OC), and carbon monoxide (CO). The hygroscopicity and optical properties of PM2.5 emissions were also measured: optical absorption was measured using filter-based photometer methods and optical extinction and scattering were simultaneously measured in-situ with a new cavity ring-down instrument. Initial results of the study indicate substantial decreases in mass emission rates of PM2.5, BC, OC, and CO from both heavy-duty diesel and light duty-gasoline vehicles since 1997, when emission rates were previously measured at the tunnel. The decreases were greater for heavy-duty vehicles than for light-duty vehicles, but emission rates of the particulate species are, nonetheless, 10-20 times greater from heavy-duty vehicles. Hygroscopic growth was not evident when particulate matter was humidified from 40 to 80 percent relative humidity, indicating the hydrophobic nature of freshly emitted gasoline and diesel particles, which contained comparable amounts of OC and BC. Other results will be presented, including those pertaining to the measurement of aerosol optical absorption.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0345 Pollution--urban and regional (0305)
DE: 0399 General or miscellaneous
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting