Research Projects

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 ±3ppb. 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.