Air pollution in Los Angeles

Trends in air pollutant concentrations can be predicted with simple empirical models based on atmospheric and laboratoiy data. Concentrations of nonreactive pollutants from point sources can be predicted vfith accuracy well within a factor of 2 predictions are more likely to be too high than too low, especially predictions of concentration peaks. Concentrations of reactive pollutants, such as ozone and other photochemical oxidants, can be predicted reasonably well with photochemical-diffusion models when detailed emission, air quality, and meteorolc c measurements are available most such predictions of air pollution in Los Angeles, California, have been accurate to within approximately 50% for ozone. Detailed performance analyses are found elsewhere in this chapter. 

Technology, the Franklin Institute in Philadelphia, and finally at SRI. The chemical perpetrators of air pollution in Los Angeles had been found. Scientific controversy around the cause of Los Angeles smog was at an end the debate over what to do about it would continue for decades to come.18... 

In 1966, the Los Angeles Air Pollution Control Board designated trichloroethylene as a photochemically reactive solvent that decomposes in the lower atmosphere, contributing to air pollution. In 1970 all states were requited to submit pollution control plans to EPA to meet national air quaUty standards. These plans, known as State Implementation Plans (SIPS), controlled trichloroethylene as a volatile organic compound (VOC). They were designed to have each state achieve the National Ambient Air QuaUty Standard (NAAQS) for ozone. The regulations were estabUshed to control the emission of precursors for ozone, of which trichloroethylene is one. 

Figure 7-12 depicts the main physical pathways by which aerosol particles are introduced into and removed from the air. Processes that occur within the atmosphere also transform particles as they age and are transported. This form of distribution of mass with size was originally discovered in polluted air in Los Angeles, but it is now known to hold for remote unpolluted locations as well (Whitby and Sverdrup, 1980). In the latter case, the... 

McMillan, R. S., D. H. Wiseman, B. Hanes, and P. F. Wehrle. Effect of oxidant air pollution on peak expiratory flow rates in Los Angeles school children. Arch. Environ. Health 18 941-949, 1%9. 

Haagen-Smit, A. J., E. F. Darley, M. Zaitlin, H. Hull, and W. Noble. Investigation on injury to plants from air pollution in the Los Angeles area. Plant Physiol. 27 18-34, 1952. 

To verify this hypothesis, low volume samplers have been operated in parallel with the air pollution control district s Km samplers. The samples collected were analyzed optically for elemental carbon and by the Gamma Ray Analysis of Light Elements (GRALE) technique for total carbon. These data were used to assess the concentration of elemental and total carbon aerosols present during the winter months in Los Angeles. It was established that the Km samplers can be calibrated to read elemental carbon concentrations. This calibration can be used to reconstruct historical elemental carbon levels at seven sites in Los Angeles. 

Nordsieck, R.A., "Air Quality Impacts of Electric Cars in Los Angeles, Appendix A, Pollutant Emissions Estimates and Projections for the South Coast Air Basin " document RM-1905-A General Research Corporation Santa Barbara, California, 1974. 

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