Impact of urban aerosol properties on cloud condensation nuclei (CCN) activity during the KORUS-AQ field campaign

摘要: Abstract Ground measurements of physical, chemical and hygroscopic properties aerosols were made at the Olympic Park, Seoul, as part KORea-United States Air Quality study (KORUS-AQ) campaign in May–June 2016. The average number concentrations larger than 10 nm diameter cloud condensation nuclei (CCN) 0.6% supersaturation (S) 10800 c m − 3 3400 , respectively. geometric mean ( D g ) was 44 nm, size-resolved aerosol hygroscopicity (κ) from HTDMA ranged 0.11 to 0.24 for particle diameters range 30–150 nm. Aerosols classified into three types based on mixing state growth factor (GF): Type 1 (externally mixed aerosol), 2 (Internally aerosol) (internally non-growth aerosol). These showed distinct diurnal patterns. difference physical different air mass sources crucially impacted hygroscopicity. Using external mixture assumption with measured data improved results CCN prediction compared those simple internal because externally comprised a significant portion this urban area. Moreover, size distribution fixed composition sufficiently explained more 50 percent variation concentrations, although information still meaningful. Overall, consistency Megacity Pollution Studies (MAPS-Seoul) held during 2015, implying that these may represent spring/summer Korean Peninsula.