A Box-Model Simulation of the Formation of Inorganic Ionic Particulate Species and Their Air Quality Implications in Republic of Korea

Abstract

The Observation-Constrained Atmospheric BOX model (OCABOX) was used to analyze the formation of secondary inorganic PM species in the Seoul Metropolitan Area (SMA), South Korea. The measurement data of the ionic components of PM_2.5 and their gaseous precursors made at the Olympic Park ground site (37.53°N, 127.12°E) during the Korea-United States Air Quality field campaign were used to run OCABOX in observation-based mode and compare the simulation results. The use of the HNO₃ concentrations measured at a marine background site as the boundary conditions appeared to increase the accuracy of the model prediction of HNO₃ and particulate NO₃⁻ concentrations. For the primary precursors emitted considerably throughout the SMA, such as NO_x and NH₃, using the data measured inside the SMA as the boundary conditions could lead to more accurate predictions. OCABOX was shown to be a reliable tool to analyze the formation of secondary inorganic aerosol in the SMA if used with appropriate regional background concentrations and observation-based constraints