ABSTRACT
This chapter looks at what happened to air quality in Southern California. Insofar as visibility reduction can be used as indicator of air quality, numbers indicate that air quality has improved. One of the air quality problems is how to measure air quality in a way that will allow for an analysis of institutional change. The major difficulty in finding such an indicator is that the systematic measurement of pollutants is a fairly recent development. The selected indicator must be one that has been measured in a consistent, uniform way for the period covered. The air quality indicator that most closely satisfies these criteria is the measurement of visibility reduction at various locations within the South Coast Air Basin. The Los Angeles Air Pollution Control District and subsequently the South Coast Air Quality Management District collected Federal Aviation Administration data and published several reports under the authorship of Ralph Keith, the chief meteorologist for these agencies.
