Date of Award
Bachelor of Science (BS)
College of Science
Ozone (O3) occurs naturally as a protective, ultraviolet radiation-shielding “Ozone Layer” in the Stratosphere and as a photochemically produced pollutant in the Troposphere. The Clean Air Act (CAA) of 1970 regulates the emission and concentration of O3 and five other atmospheric pollutants. Since the signing of the CAA, the ongoing question has been whether or not the National Ambient Air Quality Standards (NAAQS) and regulatory policies have had an effect on decreasing O3 concentration. The Los Angeles metropolitan area is a prime example of how O3 can be a public health hazard, and taint a city’s aesthetics and quality of life through photochemical smog. I chose LA for this study in attempt to contribute to the conversation regarding the effectiveness of the CAA. I explored daily maximum O3 concentrations from 1980 to the present of three air quality monitoring stations in metropolitan LA from the AirData database of the U.S. Environmental Protection Agency. Various statistical metrics of this dataset were compared to the established NAAQS during this period. The NAAQS themselves were only exceeded twice at one station throughout the data available. While the average O3 concentrations have been well below the NAAQS during this period, they have remained relatively constant. In contrast, variance about these averages have been steadily declining. It can be concluded that the CAA has had a positive impact on O3 concentration from this more controlled, predictable range. Yet, the fight against air pollution will not be over until the concentration falls to natural levels.
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Ford, Rebecca G., "The Clean Air Act and Its Impact on Ground Level Ozone Pollution Levels in Los Angeles, California" (2017). Honors Theses. 384.