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Emissions of Size-Segregated Aerosols from On-Road Vehicles in the Caldecott Tunnel

Allen, Jonathan O. and Mayo, Paul R. and Hughes, Lara S. and Salmon, Lynn G. and Cass, Glen R. (2001) Emissions of Size-Segregated Aerosols from On-Road Vehicles in the Caldecott Tunnel. Environmental Science and Technology, 35 (21). pp. 4189-4197. ISSN 0013-936X. doi:10.1021/es0015545.

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Particulate matter emissions from the California in-use vehicle fleet were measured as 37 500 vehicles traveled through two bores of the Caldecott Tunnel located in the San Francisco Bay area. Microorifice cascade impactors and filter-based samplers were used to determine the particle chemical composition as a function of particle size. Ammonia emissions from the vehicle fleet were measured as well. Concentrations of aerosol mass, organic carbon, elemental carbon, sulfate ion, nitrate ion, and ammonium ion, as well as 13 elements are reported. The particle mass distribution peaks in the particle size range 0.1−0.18 μm aerodynamic diameter (D_a). Elemental carbon and organic matter were the largest components of particle mass in all the size ranges studied. The Caldecott Tunnel bores studied include one which carries light-duty vehicle traffic and one which carries a mixture of light- and heavy-duty vehicle traffic. From experiments conducted in both bores, estimates are made of the size distribution and chemical composition of particulate matter emissions extrapolated to the 100% light-duty and 100% heavy-duty vehicle fleets. The heavy-duty vehicle fleet emitted 1285 ± 237 mg of fine particulate matter (D_a < 1.9 μm)/kg of C contained in the fuel burned (corresponding to approximately 430 ± 79 mg/km driven). Light-duty vehicles emitted less than 85 ± 6 mg/kg of C in the fuel burned (corresponding to less than approximately 5.5 ± 0.4 mg/km driven). Emissions of gas-phase ammonia in the Caldecott Tunnel were measured to be 194 and 267 mg/L of gasoline-equivalent fuel burned in the tunnel. The ammonia emissions are attributed to automobiles that were equipped with 3-way catalysts and operating fuel rich.

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Additional Information:© 2001 American Chemical Society. Received for review August 3, 2000. Revised manuscript received June 27, 2001. Accepted June 27, 2001. This project was supported by the Coordinating Research Council, Inc., and the U.S. DOE Office of Heavy Vehicle Technologies through the National Renewable Energy Laboratory under CRC Project No. A-22. Thanks are due to CalTrans and the Caldecott Tunnel staff. VOC canister analyses were performed by Dr. Barbara Zielinska of the Desert Research Institute. Traffic counts were performed by Prof. Deborah Niemeir's research group at the University of California, Davis. INAA analyses were performed by Dr. Michael Ames and Dr. Jec Gone at the Nuclear Reactor Laboratory, Massachusetts Institute of Technology.
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Department of Energy (DOE)CRC Project No. A-22
Issue or Number:21
Record Number:CaltechAUTHORS:20160607-145727632
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Official Citation:Emissions of Size-Segregated Aerosols from On-Road Vehicles in the Caldecott Tunnel Jonathan O. Allen, Paul R. Mayo, Lara S. Hughes, Lynn G. Salmon, and Glen R. Cass Environmental Science & Technology 2001 35 (21), 4189-4197 DOI: 10.1021/es0015545
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:67751
Deposited By: George Porter
Deposited On:08 Jun 2016 14:36
Last Modified:11 Nov 2021 03:54

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