The levels of Indoor radon can increase in newly built apartments that mainly use construction materials such as concrete. However, radon measurement in newly built buildings has only been implemented recently, and there is a lack of sufficient data for radon management purposes. This study aimed to determine the levels of indoor radon in newly built apartments by regions, sizes of household, and floor (lower, middle, upper floor), and to explore the trend of radon reduction by time according to ventilation methods. Indoor radon was measured in 48 households in four regions (Gyeonggi-do and Gangwon-do). Measurements were performed for 48 hours and 24 hours under closed and ventilated conditions using real-time measurement devices FRD400 and RAD7, respectively. To analyze changes in radon concentration by floors, data were collected by dividing households into lower, middle, and upper floors according to their vertical height. The concentrations of indoor radon ranged from 12.1 Bq/m3 to 559.0 Bq/m3 when windows were closed and 12.0 Bq/m3~500.0 Bq/m3 when ventilated (including both mechanical and natural ventilation). On average, the concentration of closed conditions of household when sealed (arithmetic average 185.3 Bq/m3) was 1.5 times higher than the concentration during ventilation (including mechanical and natural ventilation: 123.8 Bq/m3), and around three times higher than the average for mechanical ventilation (65.7 Bq/m3). It was found that the indoor radon concentration statistically increased as the height increased and the size of the house became smaller. Typically, it took 7 to 8 hours to exceed the standard of 148 Bq/m3 after windows were closed. It decreased to less than 148 Bq/m3 within 3 to 4 hours after operating the mechanical ventilation system. However, in the case of natural ventilation, it takes more than 24 hours to reach below the standard value, and the concentrations stagnated after 24 hours. In conclusion, radon concentration in narrow spaces can be relatively high if ventilation is not sufficient due to the nature of apartments with wall-type structures. Therefore, it is necessary to prepare various radon reduction measures according to floor, size, and ventilation methods.

This study was undertaken to investigate the concentration of VOCs from newly built apartments in three cities (Suncheon, Yeosu, and Gwangyang) of Honam province in Korea. VOCs were sampled using canister and analyzed by GC/MSD. The result of the canister blank test showed that, most VOCs were not detected when 5 ppb was cleaned once and 10 ppb was cleaned with two times. In case of the replicate alalysis to check for the precision of GC/MSD, RSD values were found to be excellent at 6%. The upper floor of C apartment (25 pyong) showed the highest concentration of TVOCs at 3,235 ㎍/㎥. The average concentration of TVOCs was the highest in C apartment (25 pyong) as 1,833±1,217 ㎍/㎥. The average concentration of TVOCs in K (52 pyong) and S apartment (16 pyong) were 1,820±1,035 ㎍/㎥ and 498±71 ㎍/㎥, respectively. The I/O ratio of TVOCs were 8.99∼35.90 (mean : 25.99), 11.51∼35.43 (mean : 20.07) and 6.03∼7.90 (mean : 6.92) in K, C and S apartment, respectively. From these results, it is believed that the concentration of TVOCs was comparatively high in new apartment. Therefore, it is important to use low VOC emission materials to reduce the emission concentration of VOCs from in new apartment. It is hence necessary that a scientific study is performed to secure clean indoor air quality.