The objective of this study is to investigate indoor radon concentrations and identify influencing factors for one of the representative house type in South Korea. We surveyed 3,000 detached houses using alpha track (raduet) between November 2013 and March 2014. The Arithmetic mean radon concentration of the houses studied was 147.9 Bq/m3 (GM=106.4 Bq/m3), and the range was 11.8 to 1,936.6 Bq/m3. The Arithmetic mean radon concentration in living rooms was 134.2 Bq/m3 (GM=98.8 Bq/m3), much higher value compar with the Arithmetic mean radon concentration in bedrooms (153.0 Bq/m3). The year of constructon, basement status, ventilation frequency and heating period in a house were identified as major factors influencing indoor radon concentrations. The indoor radon concentrations in houses that were constructed prior to 1990 and that had basements were higher than those in the comparison groups. On the other hand, houses that were frequently ventilated and had a short heating period showed a tendency toward lower indoor radon concentration.
This study has intended to analyze the impact of odor perception of residents, who currently live in Ochang industrial complex, on their subjective odor sensitiveness. In addition to the relationship between the perception and the sensitiveness, odor acceptance was considered as moderating variable in a research model. Korean governments has experienced even great and small civil complaints regarding bad smells throughout the country especially around the industrial complex. The residential areas are getting much closer to industrial complex due to major cities’ expansion. The closer cities are to industrial areas, the bigger the conflicts are growing due to the odor. According to the research results, it was proven that residents’ concerns on an bad image due to odor, their perception on an administrative agency’s responsibilities and economical values of their living places have a significant effect on the odor sensitiveness. Moreover, odor acceptance perceived by them has a negative moderating effect between odor perception and odor sensitiveness. Based on such results, implications and suggestions are included in the research to support the research objectives.
This study aimed at providing fundamental information for development of governmental policy on radon management, investigated the radon levels of residential homes nationwide. It also suggested the necessity for policy development which focuses on management of the degree of harm through the installation of radon alarm devices and radon reduction consulting for homes with radon readings in excess of recommended threshold. Results showed that the radon level of the subjects of this study, 1,167 houses, was 97.3 ± 65.8 Bq/m3. Regionally, Seoul had the highest level, while Jeju had the lowest. In the first round of the investigation, the number of houses, with radon level which exceeded the recommended threshold, 148 Bq/m3, was 171. However, as a result of the radon alarm installation and radon reduction consultation, the indoor radon level of 137 households decreased to less than the recommended threshold. In the second round of the investigation, 80% of the households, the radon concentration of which exceeded the current recommended threshold in the first round, appeared to maintain their radon concentration below the recommended threshold. As a result of the communication about radon's harmfulness and the installation of the radon alarm device for recognition of harmful environments. It could be deduced from this result that the communication about harm contributes to the reduction of radon.
This paper presents the results of a human health effect for H2S emission standard of incinerators in Seoul, Korea. The four selected incinerators of Gangnam, Mapo, Nowon and Yangcheon were chosen as the domains of study. Air dispersion modelling (AERMOD) was used to predict the ground level concentration within 3 km distance of the emission source. The emissions at the incinerators studied ranged from 0.0721 (Yangcheon) to 0.3007 g/s (Gangnam). These values were about three orders of magnitude smaller than that of Canadian geothermal power plants. Based on the health risk assessment, different health risks were identified for short-term and long-term dispersion of the studied areas. The short-term hazard quotient (HQ) for H2S of Gangnam and Nowon incinerators were greater than the acceptable limit (i.e., 1.0) in some locations. However the long-term HQ for H2S of all incinerators were lower than the acceptable limit.
This study measured the particulate matter (PM) in a subway tunnel using a dust spectrometer and estimated the PM10 and PM2.5 using a Kriging method. For the hourly measurement, a probe was attached inside the cabin and put through the window to collect data from the outside. The Kriging method is a spatial analysis method, and time and spatial data were applied in the subway tunnel along with a PM concentration map. The result of the measurement shows that PM10 is 31.9~271.3 μg/m3 and PM2.5 is 30.9~209.5 μg/m3. In addition, The pollutant map shows that some sections have a higher concentration than other sections because of the depth and curvature of tunnel and traffic volume on the section and local construction. Also, the results show that differences concentration at different times of sampling could be distinguished. The highest concentration was found at 3 pm while the lowest was at 12 pm. We expect to use the pollutant map in planning air quality improvements for the tunnel.
Carcasses of pigs were trench buried using either general soil or mature compost as a cover material and the malodorous substances discharged were observed about a year. With the soil burial method, the speed of decay was shown to be dominantly affected by the ambient air temperature. However the compost burial method’s decaying process took place quickly, even ambient air temperature was dropped; it holds the temperature of 40oC or higher. With the compost burial method, there was a period where, the temperature inside the pig carcasses and the temperature of cover-material layer were strongly reversed. From this discovery, level of decay process could be speculated. With the soil burial method there was a trend when malodorous substances concentration was high, the level of concentration in the cover soil was also tends to be high. However, the compost burial method had different result. When malodorous substances concentration was high the level of concentration in the compost cover layer was observed to be lower. This indicates compost burial method shown to intercept and absorb malodorous substances. Furthermore, the compost burial method appears to be able to contribute to deactivate the pathogens by quickly decompose the carcasses at a high temperature.
To obtain information on the sanitary condition of indoor environment in greenhouses used for shiitake cultivation, bacteria associated with larvae and imagoes of Sciaridae flies, a pest to shiitake mushroom, were isolated and identified. A total of 1,048 bacterial colonies were isolated from the flies’ larvae and 984 bacterial colonies were isolated from the flies’ imagoes. Based on the molecular analysis of the 16S rDNA sequence, Achromobacter xylosoxidans and Tetrathiobacter kashmirensis of betaproteobacteria, Enterobacter asburiae and Raoultella ornithinolytica of gammaproteobacteria, Curtobacterium sp. and Microbacterium thalassium of Actinobacteria, and Penibacillus taichungensis of Firmicutes were identified from the colonies of the flies’ larvae. On the other hand, Bacillus megaterium, B. thuringiensis, Lysinbacillus sphaericus and L. fusifomis of Firmicutes, Microbacterium thalassium and Citricoccus parietis of Actinobacteria, and Enterobacter asburiae of gammaproteobacteria were identified from the flies’ imagoes. Some of the isolated bacterial species were known to be human pathogens. Overall, the results of this study suggested that mushroom fly carrying human pathogenic bacteria is one of factors affecting the sanitary of indoor environment of greenhouses used for shiitake cultivation.
The following study aims to estimate the configuration ratio of the ion compounds that identifies the cause of fine dust and ways to reduce it. In this study, the physical and chemical properties of fine particles in a tunnel and the configuration form of ionic composition were interpreted to establish reasonable measurement for air quality management. Seasonal measurements were performed by collecting samples from the Mia sageori subway station. Chemical Mass Balance (CMB) model was used to estimate the configuration ratio of ions in this study. The results showed that the test performed outside showed about 56.4% of total ion, with (NH4)2SO4, NH4NO3, CaCO3 and NaCl showing concentrations of 2.138 μg/m3, 1.957 μg/m3, 1.697 μg/m3 and 1.600 μg/m3, respectively, while the results indoor had CaCO3, NH4NO3, (NH4)2SO4 and NaCl showing concentrations of 2.272 μg/m3, 2.204 μg/m3, 1.656 μg/m3 and 1.342 μg/m3, respectively, about 65.1% of total ion. During the usage of tunnel, it was found that CaCO3, NH4NO3, (NH4)2SO4 and MgCO3 showed concentrations of 3.464 μg/m3, 1.732 μg/m3, 1.698 μg/m3 and 0.582 μg/m3, respectively, total ion of 70.2% was presented.
This study was conducted to investigate the influence of moisture removal using a moisture condensation tube on the odor concentration, when sampling a malodorous substance from an odor discharge facility’s emission sites. For high-temperature and humid gas streams, the odor concentration was decreased through the use of a moisture condensation tube. The multiple odor concentration of the high-temperature and humid gas streams emitted from boiler-burning equipment decreased from a 3,000 to a 1,221 dilution factor when using one or two moisture condensation tube. This multiple odor concentration was further decreased to a 1,000 dilution factor by using two moisture condensation tubes and glass beads, and also was decreased to a 374 dilution factor by using two moisture condensation tubes and silicagel. Among the designated offensive odorous substances, ammonia, trimethylamine and acetaldehyde that have high solubility in water showed high reduction rate of their concentration. Compared to the result using a sampling tube only, the concentration was decreased by 94.8% ~ 97.7% for ammonia, by 87.5% ~ 95.9% for trimethylamine and by 100% for acetaldehyde. The findings of this study indicate that sampling using a moisture condensation tube affects the concentration of multiple odors. Therefore, it is considered that using a sampling tube only for emissions sampling enhances analytical accuracy and precision rather than using moisture condensation tube with sampling tube, even for the emissions containing moisture.
A single-stage electrostatic precipitator (ESP) was evaluated in terms of its performance in removing dust in subway tunnels. A wire-to-plate type ESP was tested in a small-scale wind tunnel. The effects of wire-to-wire spacing (2040 mm) and the material connecting wire-to-wire on the performance of ESP were investigated, with varying applied voltage and airflow velocity. A narrower wire-to-wire spacing showed higher collection efficiency at the same applied voltage. Lower electrical resistivity of material connecting wire to wire was more effective. Ozone generation in subway tunnel applications was insignificant.
The purpose of this study is to investigate the level of ELF-MF emissions from underground cable lines near daycare centers in the metropolitan city of Seoul. We investigated 143 daycare centers from June to September of 2015. In addition, the rate of reduction of ELF-MF levels according to the distance from the line was calculated using simulations. The ELF-MF emission level of 143 daycare centers at boundary point was 1.37 ± 1.75 mG (GM: 0.75 mG) and at direct point was 11.14 ± 17.99 mG (GM:6.05 mG). ELF-MF levels at direct point were 8.13 (arithmetic mean) and 8.06 (geometric mean) times higher, respectively, than that at the boundary point. By analyzing the relationship between ELF-MF and electricity current (A) and operating depth (m), a significant correlation was found between ELF-MF and current (A) and depth (m), at 0.360 (p<0.01) and -0.303 (p<0.05), respectively. The results of the simulation showed that appropriate separation distances showing below 4 mG was 8m and 14m, adjusted mean current (A) and maximum current (A), respectively. The results of the study suggest that a plan should be implemented for the management of ELF-MF in High voltage power-line and Underground cable line areas, through a broad and detailed survey and risk communication.