Industrial Dusts and Fumes in the Los Angeles Area

Abstract

Meteorological and topographical conditions in the LosAngeles basin cause the retention of dusts and fumes, frequently for several days. Eye irritation and limited visibility are characteristic of the resultant smog. Studies of the aerosols in this area have been undertaken by government and private laboratories. Methods and equipment used by the Los Angeles County Air Pollution Control District in identification of industrial contaminants are described. The roles of sulfuric acid mist and metallurgical dusts in smog formation are discussed. INTHE Los Angeles basin the term smog is applied to the complex blue haze of air pollution which limits visibility and on 53 days of 1948 caused reports of eye, nose, and throat irritation. Natural gas is used for domestic heating, and natural and refinery gas and fuel oils are the principal fuels of industry.

Gas Damage to Plants

“…Fog is not a necessary component of the smog ; in fact, more often than not, it is absent. Smog is generally distributed in urban and industrial areas, but economic plant damage due to smog has been reported only in the Los Angeles area, where, owing to the recent greatly increased industrialization, together with the low wind velocities of summer and autumn and large-scale, semi-permanent, non-diurnal temperature inversions (86), the industrial and urban wastes discharged into the atmos phere can sometimes reach concentrations sufficient to cause injury to vege tation (24, p. 148 ; 46, 82a, 83, 87). The injury has economic significance only in "heavy" smog when the inversion layer and the wind velocity are low and the concentration of the toxicants is raised materially above the us ual "smog" level.…”

“…Swain (28) has reviewed the outstanding periodic developments of this century. The Donora incident (18) of October 1948, coupled with the investigation of atmospheric pollution which was already in progress at that time in the Los Angeles area (84,85,86,88,89) and a rather widespread concern over fluorine emanations, has resulted in another period of heightened interest in this subject and many new studies are being made and published cur· rently. Also, a number of reviews of older work (13; 24, pp.…”

Artificial Surface Dirts for Detergency Studies with Painted Surfaces

“…The Pittsburgh, Pa., region has contributed to the atmosphere much soot from coal combustion and metallic oxides from iron and zinc production (7). The Los Angeles region, where coal consumption and smoke are relatively unimportant, contributes dusts, fumes, and liquid aerosols predominantly on heavy smog days (9). Atmospheric pollutants may comprise aerosols which have undergone spontaneous modification or modification by the chemical and physical conditions of the atmosphere, as well as unmodified aerosols.…”

“…McCabe and coworkers (9) reported that solid particles are capable of acting as nuclei of hygroscopic aerosols and these particles, as well as atmospheric and toxic gases such as sulfur dioxide, tend to dissolve in the condensed moisture. Johnstone (5,9) pointed out that an increase in relative humidity causes an increase in the particle size of a hygroscopic aerosol and stabilizes the aerosol. Chemical reactions may occur between the component parts of an aerosol or between the aerosol and the atmosphere.…”

“…McCabe and coworkers (9) reported the presence of both liquid and solid material on cascade impactor slides exposed in Los Angeles; immediately following rain, only solids were collected.…”