title: PM2.5source attribution for Seoul in May from 2009 to 2013 using GEOS-Chem and its adjoint model.
abstract: Enforcement of an air quality standard for PM2.5in the Seoul metropolitan area (SMA) was enacted in 2015. From May to June of 2016, an international airborne and surface measurement campaign took place to investigate air pollution mechanisms in the SMA. The total and speciated PM2.5concentrations since 2008 have been measured at an intensive monitoring site for the SMA operated by the National Institute of Environmental Research (NIER). To gain insight on the trends and sources of PM2.5in the SMA in May, we analyze PM2.5concentrations from 2009 to 2013 using the measurements and simulations from a 3-dimensional global chemical transport model, GEOS-Chem and its adjoint. The model is updated here with the latest regional emission inventory and diurnally varying NH3emissions. Monthly average PM2.5concentration measured by β-ray attenuation ranges from 28 (2010) to 45 (2013) μg/m3, decreased from 2009 to 2010, and then continuously increased until 2013. The model shows good agreement with the measurements for the daily average PM2.5concentrations (R ≥ 0.5), and reproduces 10 out of 17 measured episodes exceeding the daily air quality standard (50 μg/m3). Using the GEOS-Chem adjoint model, we find that anthropogenic emissions from the Shandong region have the largest modeled influence on PM2.5in Seoul in May. Average contributions to the high PM2.5episodes simulated by the model are 39% from the Shandong region, 16% from the Shanghai region, 14% from the Beijing region, and 15% from South Korea. Anthropogenic SO2emissions from South Korea are negligible with 90% of the total contribution originating from China. Findings from this study may guide interpretation of observations obtained in the KORUS-AQ measurement campaign.
authors.affiliation: Department of Civil, Environmental, and Architectural Engineering, University of Colorado, Boulder, CO, USA. Electronic address: hyungmin.lee@colorado.edu.
authors.forename: Hyung-Min
authors.initials: HM
authors.lastname: Lee
authors.affiliation: School of Earth and Environmental Sciences, Seoul National University, Seoul, Republic of Korea.
authors.forename: Rokjin J
authors.initials: RJ
authors.lastname: Park
authors.affiliation: Department of Mechanical Engineering, University of Colorado, Boulder, CO, USA.
authors.forename: Daven K
authors.initials: DK
authors.lastname: Henze
authors.affiliation: School of Earth and Environmental Sciences, Seoul National University, Seoul, Republic of Korea.
authors.forename: Seungun
authors.initials: S
authors.lastname: Lee
authors.affiliation: Korea Environment Institute, 370 Sicheong-daro, Sejong, Republic of Korea.
authors.forename: Changsub
authors.initials: C
authors.lastname: Shim
authors.affiliation: National Institute of Environmental Research, Incheon, Republic of Korea.
authors.forename: Hye-Jung
authors.initials: HJ
authors.lastname: Shin
authors.affiliation: National Institute of Environmental Research, Incheon, Republic of Korea.
authors.forename: Kwang-Joo
authors.initials: KJ
authors.lastname: Moon
authors.affiliation: Department of New Technology and Fusion, Konkuk University, Seoul, Republic of Korea.
authors.forename: Jung-Hun
authors.initials: JH
authors.lastname: Woo
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000032:analysis / Q000706:statistics & numerical data; D004784:Environmental Monitoring / Q000379:methods*; D008956:Models, Chemical; D008962:Models, Theoretical; D052638:Particulate Matter / Q000032:analysis*; D066106:Seoul
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter
keywords: Adjoint modeling; Atmospheric chemical transport model; PM2.5; Sensitivity analysis; Seoul metropolitan area; Source attribution