Understanding the paths of surface ozone abatement in the Los Angeles Basin: long-term pollution controls versus the COVID-19 impacts

Ozone in the urban atmosphere can accumulate from photochemistry involving nitrogen oxides, carbon monoxide, and volatile organic compounds predominantly emitted from fossil fuel combustions. Concentrated ozone near the earth's surface has had a detrimental impact on the ecosystem and public health. The Los Angeles Basin is a prototypical example of an urban region with long-standing ozone pollution, frequently in violation of air quality standard set by the US Environmental Protection Agency. In this study, we utilize a chemical transport modeling approach to reproduce historical ozone trends and to project the future following emission scenarios. To model emission trends, we include the fuel-use based bottom-up emission inventory in harmony with top-down estimations from the satellite and in-situ monitor data. In this presentation, we will highlight the impacts of the long-term emission controls and the recent effects of the COVID-19 pandemic on ozone trends. The current status of ozone pollution in the Los Angeles Basin and prospective abatement strategies will also be discussed.