This study was undertaken to investigate whether HEPA filter-equipped air purifiers can remove aerosolized virus, whether the removed virus can re-scatter through the filter, and how long the removed virus keeps its infectivity in the filter. For this investigation, six HEPA filter-equipped air purifiers produced by different companies were tested against PhiX174 and MS2 phages aerosolized by nebulizers. For viral detection from the air, LB agar plates covered with Escherichia coli hosts and an Andersen air sampler were used, and from the surface, the swab method was used. Both the aerosolized PhiX174 and MS2 viruses absorbed by the HEPA filters in the air purifiers were not detected from the air through filters or the surface of the outlet of the air purifiers. During the operation of the air purifiers at medium mode, the infectious viral concentration of these viruses in the HEPA filters decreased to 0%~12.3% as the time period passed. These results regarding infectious viral concentration differences were assumed to be due to the different wind speed and air volume among the six air purifiers. Based on observations over 5 days, the infectious viral concentration of the PhiX174 phage was 8,600 times lower when the air purifier was operated than when it was not operated. Overall, our results demonstrate that HEPA filter-equipped air purifiers can efficiently remove the two aerosolized viruses and the removed viruses in the HEPA filter could not re-spread and maintain their infectivity.

The objective of this study was to investigate ELF-MF exposure levels in infant living environmental spaces at daycare centers. To achieve the objective of the study, we surveyed ELF-MF levels using EMDEX II at daycare centers from October 2013 to October 2014. The ELF-MF level of 53 daycare centers in terms of arithmetic mean (AM) and geometric mean (GM) were 0.59 ± 0.76 mG and 0.33 mG, respectively. And the ELF-MF level of 260 daycare center classrooms was 0.50 ± 0.71 mG (GM: 0.28 mG). The exposure levels of ELF-MF for all daycare centers were far below the recommended standards cited in guidelines in Korea (833 mG) and international reference levels proposed by WHO or ICNIRP (2,000 mG). Furthermore, we discovered out that as distance increased, ELF-MF emission levels decreased significantly in all electrical instruments. Below the 2 mG ELF-MF levels when an electrical instrument moved away stage 1 (Grade). Thus, these results will provide useful data for the determination of ELF-MF management and reduction methods at infant daycare centers.

The objective of this study was to assess RF-EMF exposure levels in indoor daycare centers in a Metropolitan city. RF-EMF measurements were collected and surveyed from 50 volunteer daycare centers in the Korea between October 2013 and October 2014. Through our research, it was found that the main exposure source for indoor daycare centers is the frequency bands for TV and Radio broadcasting (FM: 88.1~107.9 MHz), mobile phone (869~894 MHz, 1840~1870 MHz, 1885~2170 MHz), wireless LAN and home electronics, etc., including TRS, Wireless Data Communication. The RF-EMF exposure levels for all daycare centers were far below the recommended standards of EMF Guideline Korea and international reference levels proposed by ICNIRP (International Commission on Non-Ionizing Radiation Protection). However, in terms of long term health effects some uncertainty exists, and thus minimizing exposure may reduce this uncertainty. The data we collected will be useful data for determining RF-EMF management and risk communication at daycare centers.

The objective of this study is to investigate the effect of ELF (Extremely Low Frequency) exposure on the health of elementary school students. A total of 103 students 12~13 years old were chosen for the study. The experimental group consisted of 56 students who went to school near an overhead powerline. The ELF exposure and environmental hazard factors were evaluated during a 24-hour exposure period. The body and dwelling characteristics of the students as well as disease occurrence related to the respiratory system and allergies were investigated through a questionnaire. The brain wave and electrocardiogram were also inspected. The exposure of the group exposed while at a school located near a powerline was 6.8 mG (p<0.01). Based on the questionnaire results, neither the body or dwelling characteristics of the two groups were affected by the ELF emitted from powerline. There was no significant difference between the two groups in relation to the rate of occurrence of respiratory diseases such as wheezing, asthma and bronchitis. Although brain waves of the group exposed to ELF were lower than that of the group not exposed to it in terms of absolute power of gamma and beta, there is no significant difference between the health status of the two groups. According to our study, school students who lived near a power line were exposed to higher ELF levels than those away from a power line. The two groups have significant differences inBrain wave and ECG, but this change doesn't mean there is a difference in health status. Finally, our study has a limitation in terms of the number of study subjects and the restricted area examined.

The purpose of this study is to investigate the characteristics of asbestos containing materials in public facilities in Korea. We investigated 201 public facilities between January and December in 2009. PACM were collected according to EPA AHERA rules, and analyzed using the US EPA method 600/R/116. The air samples from public facilities were analyzed by PCM. For the survey on ACM risk assessment, we used both the ASTM rules and Korea ACM risk assessment(developed by the Korea ministry of employment and labor). Public facilities showed that ceiling textiles contained chrysolite/amosite(2 and 25%) and cement flat boards contained chrysolite(5 and 26%). Also, gaskets contained chrysolite(3 and 95%) and Floor tile & carpet contained chrysolite(less than 1 and 6%). PCM analysis was performed on all air samples, and it was found that the concentration of fiber did not exceed the Korean guideline(0.01f/cc). In this study, it was found that according to the ASTM rule of asbestos material, 70 materials were “Abatement” grade and 344 materials were “Q&M” grade when assessed by ASTM B-line. Furthermore, based on the adjusted Korea ACM risk assessment 22 materials rated as were “Fair” and 390 materials were “Good”.

It is important to develop the smart ventilation system in order to minimize a building energy consumption using ventilation. In this study, We evaluated the efficiency of the smart ventilation system being developed at the nursery. To evaluate the energy savings and carbon dioxide removal efficiency, two kinds of experimental conditions were compared. First, air conditioner and Smart HVAC system were operated. Second, air conditioner was operating and external air was put into the inside by rate of air circulation. It was more effective when working with air conditioning and ventilation system at the same time. If the Smart HVAC system is applied in a multi-use facility, indoor air quality will be comfortable and the social cost will be reduced.

In order to minimize a building energy consumption with ventilation, a development of smart ventilation system is very important. In this study, a dry adsorbent that is main element of smart ventilation system was developed for removing indoor CO2, and evaluate the adsorption performance. Specific surface area, pore characteristic and crystal structure of the modified sorbent was measured to analyze physical properties. From this analysis, it was found that the developed absorbent has a low specific surface area, due to mesopores of substrate was filled with metal contained raw material. Additionally, through analysis of the adsorption properties, the developed adsorbent was shown a adsorption form of mesopore (type Ⅳ), which means adsorption amount was rapidly increased at the part of high-pressure. Order to applying for the field, chamber test was performed. Continuous column tests (2,500 ppm) and batch chamber tests (4 m3, 5,000 ppm) showed CO2 removal efficiency of 95% and 88% within 1 hour, respectively.

This study was conducted to analyze dust mite allergen and bacterial endotoxin concentrations in the subwaycabins. For this aim, we sampled dust using a vacuum cleaner on cabin seats of subway trains operating in threeSeoul Metro Lines from April to May in 2011. The concentration of dust mite allergen and endotoxin were1,137.51±806.26ng/g and 5,742.1(4.68)EU/g, respectively. While, the concentration of dust mite allergen washigher on cabin seats of subway trains in Line B(1,487.61±930.59ng/g) than on those of trains in Lines A andC(641.9±398.3 and 1,344.9±822.4ng/g). All measurements did not exceed the National Workshop Guidelineof 2,000ng/g. While, bacterial endotoxin concentration [GM (GSD)] was higher on cabin seats of subway trainsin Line A [12,373.21(4.97EU/g)] than on those of trains in Line B and C8,520.77(3.98) and 1,631.43(1.88)EU/g. Dust mite allergen concentrations were strongly influenced by the portion of underground (on the subway line)and endotoxin concentrations were significantly correlated with the number of passengers using the subway lines.Seats for seniors and the week showed relatively higher concentrations compared to seats for general passengers.But, no significant difference of dust mite allergen and endotoxin concentrations in the subway cabins was foundrelating to seat type (p=0.451, p=0.564). There was no correlation between the dust mite allergen levels andendotoxin levels in the subway cabins (p=0.439).

The purpose of this study was designed to identify the health care condition aggressively to urban and semi-urban seniors and to inform the importance of prevention prior to treatment for better old age. A total of 200 seniors who were over the age of 65 and lived specific area of Seoul and Daeboo-island Ansan-city, from 7 September to 4 October 2012, and used self-developed questionnaire. The result of relevance analysis for oral health care demands shows that seniors from Ansan-city had higher dental prosthesis demands(the average 4.43) than seniors from Seoul(3.96) and the difference was statistically significant(p<0.01). Analysis of the correlation between items represented positive(+) relation in all items and same age distribution. Dental prosthesis has high correlation in every items, but fluorine treatment has low correlation relatively. Correlation between independent variables and dependent variables was slightly high, R=0.356(35.6%). However daily activity, oral heath care and anxiety times showed statistical significances. The result of this study shows that there are significant differences between urban area and semi-urban area. Therefore, authorities need to offer oral health education.

Developing proper reduction strategies of indoor radon which have been an important issue in Korea requires proper information on source characteristics a phosphate gypsum board which is a common building material used for inter-wall thermal protection in Korea could be a major source of indoor radon level. This study evaluated the correlation between indoor radon concentration and the attribution of gypsum board content in building materials. In this study we valuated indoor/outdoor radon from 58 facilities selected based on the information availability of gypsum content in the building material across 8 different cities in Korea. Our results showed that indoor radon concentrations were 2 to 3 times higher than outdoor but those results were not significantly attributed from gypsum contents in the building material. Indeed, phosphate content in gypsum board did not significantly play a role in indoor radon level variations. It is concluded that physical environmental condition such as temperature, relative humidity, radon exhalation rate out of each building materials, as well as pathway from external sources (e.g., soil) needs to be identified to develop indoor radon reduction strategies.

The aim of this study was to investigate the perception of government's asbestos management policy for asbestos managers in school and asbestos industries, who are stakeholders related to asbestos, and the general public. The purpose is to suggest preliminary data for the establishment of communication methodology of asbestos risk, fit for the features of each audiences, by grasping the features of risk communication by each element for each group survey. For this study, a questionnaire survey has been conducted from May to August in 2012 and the responses of 617 people including 214 school asbestos managers, 95 managers related to asbestos industry and 308 the general people have been analyzed. As a result of the measurement of asbestos risk, the perception degree of general asbestos risk is higher in general public than the expert group's one, women than men, and nonsmokers than smokers. For the reliability of government's asbestos risk management, it was shown that it is the highest in school asbestos managers with public official personalities, who are a quasi-expert group for asbestos, than any other groups, the expert group of managers related to asbestos industry is in the middle level and general public group is in the lowest level. For trust in of government policy, it was shown that it is higher in school asbestos managers, than in group of managers related to asbestos industry, and the general public has a similar level of reliability with the group of managers related to asbestos industry. After consideration of path coefficient by structural equation modeling in order to investigate the relation between factors that the trust affects of asbestos management policy among the variables of awareness of asbestos management policy, it has been shown that the main factor in reliability of asbestos policy in all investigated groups was an awareness of information sharing for asbestos policy, and the second factor was reliability in government's asbestos risk management.

Recently, airborne fungi as indoor air pollutant have attention due to its health related problems such as asthma, rhinitis, sinusitis, atopy, pneumonia, building syndrome and etc.. However, it is considered that current laws and policies in Korea are not efficient to deal with these problems. Our research investigated influential factors and species distribution on the basis of previous research related to airborne fungi issue conduced in Korea by applying meta analysis technique. We selected 15 articles containing variables affecting fungi population such as outdoor air characteristics, temperature, location, and ventilation to evaluate significant factors. It was confirmed that airborne fungi level has partial correlation to those factors despite of limited sample size. It is required that the consistent and systematic research effort should be extended to characterize health effect caused by these fungi as well as to control them efficiently.

We estimated decreasing rate of indoor air pollutants with are airborne bacteria, airborne fungi, formaldehyde, total volatile organic compounds, PM10, and PM2.5 in 10 children’s hospitals and 6 childbirth houses located in Seoul and Gyeonggi-do from November to December in 2012. Sectional period was respectively divided for operating and non-operating the air cleaners. There was a trend that concentration of surveyed pollutants in children’s hospitals and childbirth houses during operating period decreased among indoor air. We used Monte-Calro simulation to remove uncertainty and identify efficiency of eliminated pollutants such as surveyed pollutants by the air cleaners. Average efficiency of removal were 61.39 ± 21.42% for airborne bacteria, 71.77 ± 19.65% for airborne fungi, 73.37 ± 24.62% for formaldehyde, 71.20 ± 25.96% for total volatile organic compounds, 65.16 ± 23.80% for PM10, and 71.06 ± 23.97% for PM2.5.

The objective of this study is to offer basic scientific data to support policy decision-making for the improved control of nitrogen dioxide(NO₂) and nitrous acid(HONO) in residence. The survey on concentration of NO₂and HONO in 20 houses in Seoul and Daegu was performed from January to February, 2013. Average NO₂concentrations in the kitchen, living room, and room were 25.7 ± 7.7 ppb, 24.3 ± 8.5 ppb, and 19.6 ± 5.6 ppb, respectively. Also, average HONO concentration were 3.6 ± 1.0 ppb, 3.1 ± 0.9 ppb, and 3.1 ± 0.9 ppb, respectively. NO₂and HONO concentration in kitchen were significantly higher than the concentration in the living room and room(p<0.05). Concentration ratios of HONO/NO2 were ranged to 0.070 0.277 for indoor air and 0.004 0.161 for outdoor air. Indoor HONO/NO2 ratios were higher than the outdoor HONO/NO₂ratios.

This study investigated the effect of smoking on Indoor Air Quality in smoking allowed buildings. Total 26 buildings(Restaurants 3, Billiards 4, Karaokes 6, Golfs 7, Pubs 6) were surveyed for nicotine, PM₁₀, CO₂, CO, NO₂, HCHO, TVOCs, benzene, toluene, ethylbenzene, styrene and xylene at quiet and busy time, respectively. The concentrations of nicotine, PM₁₀, CO₂ and benzene were significantly higher(p<0.05) at busy time compared to the quiet time. Some buildings exceeded Indoor Air Quality Standards for PM₁₀, CO₂, HCHO and TVOCs. Our results show that smoking-ban legistration should be introduced to improve Indoor Air Quality.

This case study carried out to improve the situation of large gap between scientific evidence and public perception on Extremely Low Frequency-Electric and Magnetic Fields (ELF-EMFs) problems in Korea. According to literature review on techniques and applications for EMF risk communication (RC) in Korea and other countries, the program which is appropriate for Korean society for RC was developed and the questionnaire to survey on perceptional level on ELF-EMFs based on this program was also developed. As some results of survey the perceptional levels on ELF-EMFs problems from some primary-school students and adults according to the educational tools (a presentation, a brochure, and a VOD) and protocols which were developed for RC, we identified in this study that the educational programs for RC have some effects to supply the right information and to improve the perceptional level on ELF-EMF problems to the general population such as the primary-school students and adults in Korea.

This study was performed to investigate the exposure levels of magnetic field (MF) in residences near electrical transformer rooms in apartment buildings in Korea. We determined that the location of transformer rooms in apartment buildings in Korea is not same as in other countries. In particular, in Korea, the transformer on the pole near buildings serves residential buildings of less than 5 floors. In the buildings taller than 5 floors transformers are often placed below the parking lots in the basement. We estimated that there were, however, about 85,000 with transformer room adjacent to an apartment and had identified about 1,600 apartment buildings with transformers that can be included in the TransExpos study. The mean value of measured MFs was 1.17 mG in apartments above transformer room and 0.97 mG in other floors from transformer room. This study was concluded that apartments in building with transformer room can be classified into high-exposure category based on their location in relation to transformer room.

The purpose of this study were to investigate the state of indoor environmental factors and energy consumption during winter in residential houses and to analyze factors which influenced this environment. Energy consumptions and indoor environmental factors of this survey were conducted in 21 houses(apartment, 11 and detached houses,10) between December, 2010 and February, 2011 which measured energy consumptions and indoor environmental factors as well as kept records of interviews with residents and other related factors. The results obtained were as follows. Indoor environmental factors which were found to influence apartment houses higher than detached houses. The average gas consumption of detached houses(90.98³) was higher than that of apartment houses(76.33³). Gas consumption showed positive correlations to temperature and carbon dioxide in the residential houses. The mean concentration of PM₁₀, and CO₂ in large family were higher than those of small family. We found that the more gas consumption, the higher concentration of PM₁₀, CO₂ and temperature(p<0.01).

This study was performed in the 175 selected child-care facilities in the urban area (Seoul, Suwon, Daejeon, and Busan) and the industrial complex area (Sihwa and Yeosu) to measure of the characteristics of VOCs in the indoor air from August, 2007 to April, 2008. All samples were collected at the indoor and outdoor places to the child-care facilities in spring, summer, and winter seasons using the Tenex absorption trap and were analyzed through the GC/MSD. The mean concentration of VOCs in the 175 child-card facilities showed the highest levels of 73.68 ㎍/m³in the toluene and the lowest levels of 0.28 ㎍/m³in the chlorobenzene. In the concentration of the TVOC, it exceeded 2.5 times more as the indoor air quality guideline in Korea. The result of this study was found that the concentration of VOCs in the child-care facilities in Korea may influenced from the some factors such as the constructional period, traffic density, and ventilation rate. These findings may expected to imply that effective risk management strategies should be applied to minimize the public health effects for children in the child-care facilities in Korea.

The purpose of this study is to estimate concentration and emission unit of ammonia and hydrogen sulfide released from domestic chicken buildings by field investigation. Mean concentrations of ammonia and hydrogen sulfide emitted from chicken buildings were 18.25(±4.78)ppm and 807.53(±526.17)ppb for caged layer house, 14.48(±4.13)ppm and 644.82(±312.48)ppb for broiler house, and 6.16(±2.02)ppm and 284.75(±232.08)ppb for layer house with manure belt, respectively. Mean emission coefficients of ammonia and hydrogen sulfide were 0.951(±0.131) g hen^-1h^-1 and 2.956(±0.968) mg hen^-1h^-1 based on head whereas they were 0.575(±0.082) g m^-2h^-1 and 12.44(±3.536) mg m^-2h^-1 based on time. In conclusion indoor concentration and emission coefficient of ammonia and hydrogen sulfide were highest in caged layer housed, followed by broiler house and layer house with manure belt.