Monitoring Data

Monitoring data for ozone concentrations across the study area were collected by the USEPA Air Quality System (AQS). There were 1,877 monitoring sites available within the study area during the study period, but some of them reported data for a subset of the study period or reported data intermittently. Monitoring sites were densely located in the Eastern United States and the Western Coast, while the Mountain Region and other remote areas had fewer monitoring sites (Fig. 1). We calibrated the model to the 8-hour daily maximum ozone (daily 8hr-max ozone). In this paper, unless specified otherwise, the term “ozone” refers to daily 8hr-max ozone at ground level.

Ozone monitoring sites in the United States.