Real-time monitoring of radon background level at Gosan site, Jeju Island

The real-time monitoring of radon () concentrations has been carried out to evaluate the background concentration level of atmospheric radon in Gosan site, Jeju Island. The mean concentration of radon for the recent 10 years was 2831 (0.077 pCi/L), which was 19.5 time lower than that of indoor radon in Korea. The seasonal concentrations were 2657, 2071, 3249, 3384 respectively for spring, summer, fall, and winter seasons. In monthly comparison, the radon concentrations were high in October and low in July. The hourly concentrations have increased during the nighttime, showing 3666 at 7 a.m., and decreased relatively during the daytime, showing 2755 at 2~3 p.m. From the back trajectory analysis, the radon concentrations showed higher values when the air mass was moved from the Asia continent to Jeju area, on the other hand, it showed low values when it was moved from the North Pacific Ocean.