Comprehensive Analysis of Ground-Level Ozone Pollution in Arizona: Source Attribution, Dynamics, and Cross-Border Transport

Ground-level ozone (O3) pollution is a persistent environmental concern despite substantial reductions in anthropogenic emissions over the past decade. This study delves into the specific case of Arizona, United States, a region marked by elevated O3 concentrations and designated non-attainment areas by the U.S. Environmental Protection Agency. Additionally, we explore the contributions of distinct O3 sources to overall levels, employing a tagging technique within the WRF-Chem model and the MOZART gas chemistry mechanism. This methodology allows us to attribute the sources of nitrogen oxides (NOx), with a particular emphasis on contributions from anthropogenic, fire, and biogenic emissions. Furthermore, our investigation employs the model to trace the transport of O3 and its precursors (NO2, VOC) from surrounding states and Mexico, contributing valuable insights into the complex dynamics of O3 pollution in the region.