Research Projects

Project at a Glance

Project Status: complete

Title: Measurement of ambient ammonia concentrations in Southern California

Principal Investigator / Author(s): Yoong, Matthias

Contractor: Rockwell International

Contract Number: A7-188-30

Research Program Area: Atmospheric Processes


For analytical methods for the determination of ambient ammonia concentrations were evaluated, both in the laboratory and in the field. One method was chosen for additional field study, improvements were made, and field measurements were conducted at five sites in the South Coast Air Basin over a one-year period. The improved method utilized a specially constructed sampling system containing a Teflon prefilter to remove particulates followed by oxalic acid impregnated filters to trap ammonia gas. The overall precision of the sampling and analytical method, including random error associated with the localized source, was found to be about Ī3ppb. During the course of the study, measured ammonia concentrations ranged from less than 1 ppb in West Los Angeles to more than 50 ppb in Riverside. Annual averages for West Los Angeles, El Monte, Long Beach, Santa Ana Canyon, and Riverside were 1.81, 4.00, 5.07, 8.23, and 12.11 ppb, respectively.


For questions regarding this research project, including available data and progress status, contact: Heather Choi at (916) 322-3893

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