Long Term (2004-2010) Measurement of Submicron Aerosol Size Distribution and CCN Concentration in the Mega City of Seoul, Korea

摘要

As an effort to characterize the physical properties of anthropogenic aerosols, we measured total aerosol(CN) number concentration, cloud condensation nuclei(CCN) number concentration and aerosol size distribution(10NM < particle diameter < 500 NM) in the mega city of Seoul, Korea for the period of 2004-2010. The average CN number concentration was 18517 ± 8880 cm-3 while CCN number concentration at 0.6 % supersaturation was 5227 ± 3142 cm-3. The average of CCN/CN ratio was approximately 0.30 ± 0.15. The diurnal variation of CN number concentration in Seoul showed minima around 4 a.m. and the highest peaks around 8 ~ 10 a.m. regardless of the season of the year. The average CN and CCN number concentrations were higher in winter than in summer. The correlation between CN number concentration and traffic was high (R2 =0.84). Out of the 891days of size distribution measurement particle formation and growth (PFG) events were observed in 83days. Thus the PFG events occurred during 10 % of the measurement days and appeared to be associated with cloudiness and precipitation.