동북아 오염물질 장거리이동 분석을 위한 서울시 대기 중 라돈농도의 시계열적 특성에 관한 연구

Time Series Observations of Atmospheric Radon Concentration in Seoul, Korea for an Analysis of Long-Range Transportation of Air Pollutants in the North-East Asia

Atmospheric concentrations of radon had been continuously observed in Seoul, Korea since December 1999, as a tracer for long-range transport of air pollutants from China continent to Korea. In order to study radon as a tracer of long-range transport, it is important to know information about the atmospheric distribution and variation of radon concentration and its time variation. Atmospheric radon concentration are measured with electrostatic radon monitor(ERM) at Hanyang University located in Eastern area of Seoul. Air sample is taken into a vessel of ERM, and alpha particles emitted by radon daughters Po218 are detected with ZnS(Ag) scintillation counter. Hourly mean concentrations and hourly alpha counts are recorded automatically. The major results obtained from time series observation of atmospheric radon were as follows : (1) The mean of airborne radon concentration in Seoul was found to be 7.624.11Bq/m3 during December 1999~January 2002. (2) The hourly variation of radon concentrations showed the highest in 8:00AM (8.66 4.22 Bq/m3) and the lowest in 3:00AM (6.623.70 Bq/m3) and 5:00AM (6.623.39 Bq/m3). (3) the seasonal variation of radon concentrations showed higher during winter-to-fall and lower during summer-to-spring. (4) Correlation between airborne radon concentration and the meteorological factors were0.21 for temperature, 0.09 for humidity, 0.20 for wind speed, and 0.04 for pressure. (5) The mean difference of airborne radon concentration between Asian dust (5.361.28 Bq/m3) and non-Asian dust (4.951.49 Bq/m3) phenomenon was significant (p=0.08). We could identify time series distribution of radon concentration related meteorological factors. In addition, radon can be considered a good natural tracer of vertical dispersion and long-range transport.