Evolution of Nitrogen Species Air Pollutants along Trajectories Crossing the Los Angeles Area
Abstract
Ambient aerosol sampling was conducted in Diamond Bar, Mira Loma, and Riverside, CA, to observe at close range the effects of ammonia emissions on air quality. These sites are located upwind, within, and downwind, respectively, of the Chino dairy area, the largest single source of ammonia emissions in the Los Angeles area. Inertial impactors and bulk filter samplers provided 4−7-h measurements of aerosol chemical composition and size distribution. Daily average fine particle mass concentrations were in the range 22.4−143.0 μg m^(-3). On some days the fine particulate matter concentrations were more than two times greater than the proposed 24-h Federal standard of 65 μg m^(-3). Ammonium nitrate was the largest component of fine particle mass at all three sites; 24-h average fine particulate ammonium plus nitrate concentrations ranged from 11.7 to 75.4 μg m^(-3). A single air mass was studied as it passed the Diamond Bar air monitoring site in the morning and stagnated near Mira Loma in the evening of the same day. Between these two sites NO was oxidized to NO_2, and the ammonia concentration increased by a factor of 5. A second air parcel trajectory, which stagnated near Mira Loma during the early morning and passed near the Riverside site approximately 24 h later, showed a decrease in ammonia concentration over time that is consistent with dilution as the air mass moved downwind from the source of ammonia in the dairy area. Particulate NH_4NO_3 concentration in that air parcel remained approximately constant over time, consistent with a continued excess of NH_3 relative to HNO_3 downwind of the dairy area.
Additional Information
© 2002 American Chemical Society. Received for review June 13, 2001. Revised manuscript received May 30, 2002. Accepted July 8, 2002. This work 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. Neutron activation analyses were performed by Dr. Michael Ames at the Nuclear Reactor Laboratory, Massachusetts Institute of Technology. NO and NO2 concentrations at Diamond Bar and Riverside were measured by the South Coast Air Quality Management District (SCAQMD). We thank Prakash Bhave at Caltech for calculating backward trajectories and Kevin Durkee of the SCAQMD for help in obtaining the data. NO and NO2 concentrations at Mira Loma were measured by the California Air Resources Board as part of the Children's Health Study, and thanks are due to Leon Dosilager and Clinton Taylor for providing those data. Meteorological data were provided by Leon Dosilager of the California Air Resources Board. We especially thank Rudy Eden of the SCAQMD and Tony Van Curen of the CARB for help in obtaining access to the Diamond Bar and Mira Loma air monitoring sites.Additional details
- Eprint ID
- 67736
- Resolver ID
- CaltechAUTHORS:20160607-125104945
- Coordinating Research Council
- CRC Project No. A-22
- Department of Energy (DOE)
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2016-06-07Created from EPrint's datestamp field
- Updated
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2021-11-11Created from EPrint's last_modified field