Los Angeles Smog

LOS ANGELES SMOG John W. Reith University of Southern California, Los Angeles The annoyance caused by smoke, soot and other foreign matter in the air over cities is not simply a recent situation. Some seven hundred years ago, in 1307, Edward I of England was so annoyed he instructed his commissioners to "assess great fines and ransoms" against the Londoners who ignored his pioneering anti-smoke ordinance. But only in the past 150 years, since the start of intensive industrialization, with its voluminous use of mineral fuels has the annoyance become really serious. The "Black Countries " of England derived their name from its effects, and the Donora incident of November 1948 pointed up the disasters which it may cause in areas of heavy industrial concentration. Several American cities have suffered this problem and some of them have at least partially cured their problems. Los Angeles, with its claim to sunny weather, currently is embarrassed by a volume and a frequency of foreign matter in the atmosphere that is proving difficult to eradicate totally. Our local climate may become permanently changed if eradication proves impractical. In most industrial areas the problem of cleaning up the air is relatively simple. It is a case of installing devices that will completely burn the fuel and facilities that will remove the large particles, so that a prevailing wind drift will disperse the reduced amounts of air pollutants until the concentration is negligible. St. Louis and Pittsburgh solved their problems relatively easily. But the situation in Los Angeles is unlike that in most other industrialized areas. This difference is owing in variable parts to the topography, to the climate, to the meteorology, to the type of industrial installations and fuels and to the sprawling expanse of and type of settlement pattern of the area. The purpose of this paper is to survey these causes of the smog in Los Angeles, to investigate some of the effects of the smog, and to tell what is being done to solve our smog problem. Definition of Smog The words smoke and fog, from which the term smog was coined, do not adequately define the problem in Los Angeles. Although smog is the term most frequently used, the Los Angeles County Air Pollution Control District is correctly named. Air pollution is more correct because analysis has shown the air here to contain not only water vapor and smoke, but also a complex and variable mixture of gases, solid particles, and droplets of other liquids. Nevertheless, the term smog is well implanted in the local vocabulary and has definite connotation. A day is arbitrarily defined as smoggy by the Air Pollution Control District when at least four complaints are received. The complaints are classified under four headings: (1) crop or plant damage, (2) eye smarting, (3) obscuring of sun and visibility, and (4) local nuisance such as dirty wash or heavy dust fall. Of these, local nuisances and obscuring of sun and visibility are most common, eye smarting is most annoying, and crop or plant damage is of most economic importance. Causes of Smog Too often the causes of smog are oversimplified. Actually the problem is comDlex because of the natural Conditions nrnmntino emno formation 25 and also because of the sources of the air pollution. The natural conditions which are important to smog formation in the Los Angeles area are the local basin topography, the climate, and the meteorology. These are, of course, interrelated. The Los Angeles Basin is a lowland surrounded on the north and east by hills and mountains and on the south and west by the Pacific Ocean. The hills and mountains are not continuous but the few low passes are not of sufficient size to permit large scale transfer of air through them. However, the hills are sufficiently high to block passage of air when climatic or meteorological inversions persist over the area. (Figure 1.) Although smog conditions may develop in any season, the smog season, when more days of smog normally occur, is the period from June through November. At this time the northward migration of the Hawaiian High dominates the climate of the Southern California coast. The air within the Los Angeles Basin...