Meteorological and Emission Drivers of Compound Heat and Ozone Pollution Episodes in Oklahoma City During Periods Influenced by Atlantic Tropical Cyclones

Abstract

Compound heat and ozone (O3) pollution events are widespread and pose significant health risks in urban areas. In the Southern Great Plains (SGP), where heat waves are becoming more frequent and intense, these compound events represent a growing environmental and public health concern, underscoring the need for improved process‐based understanding to support effective risk assessment and mitigation. This study investigates the three severe O3 pollution episodes recorded in Oklahoma City (OKC) since 2014–19 July 2018 (106 ppb), 15 June 2021 (93 ppb), and 6–7 August 2024 (86 ppb)—with a particular focus on the June 2021 event that coincided with a pronounced heat wave. Using high‐resolution WRF‐Chem simulations, we examine the formation mechanisms and identify key meteorological and emission‐related contributors to the episode. The episode developed under atypical summer conditions over the SGP, characterized by a frontal passage coincided with the evolution of a tropical storm over the Atlantic Ocean. TROPOMI‐based satellite observations reveal substantial power plant emissions in addition to urban emissions in the Tulsa region. Under persistent northeasterly winds, southwestward transport of pollutants from Tulsa on 14–15 June supplied additional pollutants to OKC. Meanwhile, the weak‐wind zone over OKC on 15 June, ahead of the advancing front, further favored pollutant accumulation and O3 production. WRF‐Chem sensitivity experiments illustrate that total NOx emissions from the Tulsa area contributed ∼4–15 ppbv of surface O3 in OKC on 15 June 2021, while power plants alone accounted for ∼2–6 ppbv, with contributions varying by location.