The KORUS-AQ (Korea and United States Air Quality) field experiment in May-June 2016 provided a comprehensive dataset of air quality measurements over Seoul and across South Korea and its surrounding seas. This international collaboration, led by the National Institute of Environmental Research (NIER) in South Korea and the National Aeronautics and Space Administration (NASA), continues to analyze the observations from aircraft, ships, ground sites and satellites to help understand the factors controlling air quality in the region. One set of simulations with CESM(CAM-chem) has provided an estimate of the source contributions to the carbon monoxide (CO) distributions observed during KORUS-AQ. Model simulations performed with standard emissions inventories significantly underestimated the CO observations, and adjustment of the emissions was required to reproduce the observations. To determine the contributions of emissions from Korea as opposed to other regions (Japan, China, etc.), additional tracers were used in the model to track emissions from various regions in East Asia. The figure below summarizes the contributions from Korea and other regions to the CO profiles over Seoul and Busan, South Korea. Near the surface, local sources are very important to the concentrations, but aloft emissions from other regions are dominant. This means that South Korea can make some improvements to their air quality through local control measures, but they will still be affected by upwind sources of pollution. 

Figure 1. Community Atmosphere Model with chemistry source contributions to CO concentrations at different altitudes over Seoul and Busan during the Korea United States Air Quality campaign for (a, e) 40‐day averaged profiles and (b–d, f–h) daily averages of 3 days (20160513, 20160531, and 20160605). The shaded area corresponds to the range of estimates from top 50% of Taylor scores across the ensemble of simulations. [Figure 7 of Tang et al., 2019]

Reference

Tang, W., Emmons, L. K., Arellano Jr, A. F., Gaubert, B., Knote, C., Tilmes, S., et al. (2019). Source contributions to carbon monoxide concentrations during KORUS‐AQ based on CAM‐chem model applications. Journal of Geophysical Research: Atmospheres, 124, 2796–2822. https://doi.org/10.1029/2018JD029151