Surface ozone (O 3 ) is formed from photochemical reactions of nitrogen oxides (NO x = NO + NO 2 ) and volatile organic compounds (VOCs). O 3 has serious health impacts up to and including premature mortality (Bell et al., 2004;Di et al., 2017). In the U.S., reductions in NO x and VOCs over the past several decades have reduced peak O 3 concentrations considerably (Simon et al., 2015), but at present, there are still more than 100 million Americans living in areas that do not meet the O 3 standard (American Lung Association (ALA), 2020). For O 3 , the U.S. National Ambient Air Quality Standards (NAAQS) is based on the annual fourth highest maximum daily 8-hr average (MDA8) concentration. To be in compliance with the 2015 8-hr O 3 standard, each monitor in a region must have a 3-year average of the fourth highest MDA8 of 70 ppb or less. Using data from 2018 to 2020, the U.S. Environmental Protection Agency (EPA) reports that there are 52 regions in the U.S. that are considered non-attainment areas (NAAs) for the 2015 standard (https://www.epa.gov/air-trends/air-quality-design-values). Most of these NAAs are in large metropolitan areas. However, some areas have relatively low emissions but are downwind of a major metropolitan area. Simon et al. (2015) report downward trends for U.S. anthropogenic NO x and VOCs emissions of 39% and 14%, respectively, for 2002-2011. Hidy and Blanchard (2015) report a near linear relationship between peak