Three-Dimensional Distribution of Air Pollutants in the Los Angeles Basin

Abstract

Data from a three-dimensional pollutant mapping program, conducted in the Los Angeles basin, wereanalyzed to obtain "grand average" vertical profiles sampled on 24 summer days in 1973. Morning andafternoon profiles at four locations show an erosion of the nighttime radiation inversion, increased temperatures, more intense mixing in the inland areas, and a semi-permanent subsidence inversion at higher levels.High values of primary pollutant parameters (NO, and condensation nuclei) are seen in the western part ofthe basin at Hawthorne. Secondary pollutant parameters (Os and light scattering coefficient) were dominating at the inland receptor site, Riverside. Ozone concentrations in the morning were consistently higheraloft. The deficit near the surface is attributed to ozone scavenging by primary emissions.

Aerosol Science and Technology: History and Reviews

“…Detailed analyses of the 3-D Study data from the July 24-26, 1973, pollutant episode illuminated the general characteristics of the SoCAB episodes of the time (Blumenthal et al, 1974;Blumenthal et al, 1978;Hidy et al, 1980;Husar et al, 1977). From these analyses, it was clear that emissions accumulated in the urban/industrial areas of the western SoCAB in the night and morning hours and were subsequently transported with the sea breeze to the more rural, eastern areas of the SoCAB in the afternoon.…”

“…Although the data shown here are from one episode, certain phenomena on episode days were so characteristic that they survived averaging over numerous episodes. Husar et al (1977) prepared grand average profiles for 24 episode days for spirals over the cities of Hawthorne (coastal), El Monte (north-central SoCAB), Ontario (eastern SoCAB), and Riverside (eastern SoCAB downwind receptor area). Comparison of early-morning and afternoon average profiles showed the erosion of the nighttime radiation inversion at all locations, increased temperatures and more intense mixing in the inland areas, and a semi-permanent subsidence inversion covering the whole SoCAB at higher altitudes.…”

“…The results of the 3-D Study are presented in Blumenthal et al (1974), Blumenthal et al (1978), Blumenthal et al (1980), and Husar et al (1977). Hidy et al (1980) presents an extensive digest of the background and results of both ACHEX and the 3-D Study, with contributions by all the investigators.…”

“…Because California has a visibility standard, the visibility component was important, so the investigators included measurement of the light extinction coefficient, along with human observations of visual range. As noted by Hidy and colleagues (1980), the study included a number of ancillary experiments, perhaps most important of which was the aircraft over-flight program to obtain vertical distributions (Blumenthal, 2011;Blumenthal et al, , 1977Husar et al, 1977).…”

Aircraft Measurements of Medium-Range Transport of Air Pollutants over Complex Terrain

“…To support this investigation, aircraft measurements * Present affiliation: Meteorological Satellite Center , Kiyose, Tokyo 204, Japan of meteorological elements and air pollutants were carried out in addition to surface and upper air observations. Three-dimensional pollution studies by instrumented aircraft have been done by Edinger (1973), Gloria et al (1974), Husar et al (1977) and Blumenthal et al (1978) in the Los Angeles air basin on smoggy days. Blumenthal et al mapped out the three-dimensional distribution of air pollutants in the basin and related the movement of the polluted air to the sea breeze.…”