A Case Study of a Springtime Ozone Episode in the North China Plain

Air quality has been steadily improving over most of the United States throughout the past several decades, but the progress in primary pollutant concentrations is less obvious in developing regions, such as eastern China. This work utilizes aircraft data collected over the North China Plain during Spring 2016 from the Air Chemistry Research in Asia (ARIAs) campaign. We will present a case study of an ozone episode on May 28, 2016 and the long-range transport across the Yellow Sea. Spirals over the North China Plain reveal a small stratospheric influence at altitudes above 2500 m, characterized by high ozone (~85 ppbv), low carbon monoxide (<100 ppbv), and low relative humidity (~20%). The National Oceanic and Atmospheric Administration (NOAA) Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT) forward trajectories indicate elevated ozone concentrations (90-97 ppbv) in the planetary boundary layer transported to South Korea whose air pollution was thoroughly studied by the National Aeronautics and Space Administration’s (NASA) Korea-United States Air Quality Study (KORUS-AQ) campaign. We compare profiles of trace gases and aerosol properties from ARIAs and KORUS-AQ to demonstrate an air pollution episode and uncommon transport event in Spring 2016.