Effects of the Motor Vehicle Control Program On Hydrocarbon Concentrations in The Central Los Angeles Atmosphere

Abstract

The body of information presented in this paper is directed to those individuals concerned with the effect of the motor vehicle control program on ambient hydrocarbon concentrations in a metropolitan area during peak traffic hours. The data used in this study are from gas chromatographic analyses of air samples taken in 1963-65, before implementation of the exhaust control program for new motor vehicles, and in 1971 and 1973, after several years' application of this program. A brief history of the motor vehicle program in California together with emission standards for hydrocarbons are discussed and certain automobile-related hydrocarbons are identified and characterized. Frequency distributions were constructed for total hydrocarbons, non-methane hydrocarbons, methane, acetylene, and isopentane for 1963-65, 1971, and 1973 and the standard deviation (1 sigma) concentration limits are discussed for each of the subgroups mentioned above. The average concentration and relative percent comparisons for methane, ethane, n-butane, isopentane, C 3+ paraffin, ethene, propene, C 4+ olefin, acetylene, benzene, and toluene are shown and discussed in detail. These studies: 1) show hydrocarbon emissions from motor vehicles were reduced 47.6% during this time period; 2) indicate selective reduction of compounds; and 3) reveal a 51.8% reduction in the 1973 ambient total hydrocarbon concentration since 1963-65.

Trends in ozone, its precursors, and related secondary oxidation products in Los Angeles, California: A synthesis of measurements from 1960 to 2010

“…Our historical analysis of precursor emissions begins with ground‐based measurements of VOCs and NO x in downtown Los Angeles in 1960 by Neligan []. This study was followed with additional measurements by the California Air Pollution Control District in 1963 [ Leonard et al ., ], Lonneman et al . [] in 1966, Altshuller et al .…”

Certain regularities in the composition of volatile organic pollutants in the urban atmosphere

“…Data reported by Leonard et al (14) provide an idea as to the possible scope of this source of pollutants: in such a large city as Los Angeles, in 1965, the total loss of gasoline due only to evaporation was 350 tons per day.…”

Specific nonmethane hydrocarbons and their relationship to ozone in an eastern urban area, Manhattan

“…Therefore the butene values presented in Table 1 Table 3 were obtained by multiplying the given mean acetylene concentration for the site and time period by the mean hydrocarbon to acetylene ratio for individual or groups of hydrocarbon species. Leonard et al [1976] presented data for downtown Los Angeles for the years 1963-1965, 1971, and 1973. A summary of mean concentrations and percentages of total aliphatics for olefms, paraffins, and certain specific hydrocarbons is given in [Mayrsohn et al, 1977] for Los Angeles in 1976.…”