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Indoor radon measurements of the multi-storey buildings in Seoul, Korea

Most people are exposed to various kinds of indoor pollutants due to spending most of their time indoors. Unlike other anthropogenic pollutants of the indoor environment, radon gas is a naturally formed radioactive pollutant and it has been known as a second major contributor to lung cancer. However, most radon studies have focused on underground facilities and one-story buildings because the dominant source of indoor radon was known as the soil gas which was emitted from cracks or pores of the wall on the ground. Three study areas were selected for this research: the first and the second floor of a two-storey building (area A), the third floor of a newly built four-storey building (area B), and the 11th floor of a 15-storey apartment house (area C). Radon concentrations were measured by means of etched-track detectors (passive method) and by continuous measurements (active method). The active method was only used in area B because of continuous pump noise of the measuring device. Radon concentrations were monitored by the passive method for 3 or 4 months according to the study area. Continuous measurements were conducted for 3 months using the radon monitoring instrument (RAD7). The measuring protocol for the active method was ‘sniff’. The average radon concentrations determined by the passive and the active methods in area B were 2.9 and 1.8 pCi/L, respectively. The radon concentration measured by the passive method was 1.6 times higher than that measured by the active method. The average radon concentration in area C was 1.7 pCi/L (range 1.3–2.1 pCi/L) and slightly higher than that in area A (average 1.3 pCi/L with a range of 0.6–2.1 pCi/L). The results suggest that more detailed studies on the sources and rates of radon emissions are needed for multi-storey buildings.