• Journal of Korean Society for Atmospheric Environment
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• 제17권E2호
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• pp.43-51
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• 2001

A report by the national research council in the United States suggested that many lung cancer deaths each year be associated with breathing radon in indoor air. Most of the indoor radon comes directly from soil beneath the basement of foundations. Recently, radon released from groundwater is found to contribute to the total inhalation risk from indoor air. This study presents the quantitative assessment of human exposures to radon released from the groundwater into indoor air. At first, a three-compartment model is developed to describe the transfer and distribution of radon released from groundwater in a house through showering, washing clothes, and flushing toilets. Then, to estimate a daily human exposure through inhalation of such radon for an adult. a physiologically-based pharmacokinetic(PBPK) model is developed. The use of a PBPK model for the inhaled radon could provide useful information regarding the distribution of radon among the organs of the human body. Indoor exposure patterns as input to the PBPK model are a more realistic situation associated with indoor radon pollution generated from a three-compartment model describing volatilization of radon from domestic water into household air. Combining the two models for inhaled radon in indoor air can be used to estimate a quantitative human exposure through the inhalation of indoor radon for adults based on two sets of exposure scenarios. The results obtained from the present study would help increase the quantitative understanding of risk assessment issues associated with the indoor radon released from groundwater.

• 한국지하수토양환경학회지:지하수토양환경
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• 제20권4호
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• pp.51-65
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• 2015

Indoor inhalation of vapors intruded into buildings is an important exposure pathway in volatile organic compoundscontaminated sites. Site-specifically measured indoor air concentration is preferentially used for risk assessment. However, when indoor air concentration of VOC is not measured, the indoor air concentration needs to be estimated from soil concentration or measured soil gas concentration of the VOC. Some risk assessment guidance (e.g., Korea Ministry of Environment (KMOE) and American Society for Testing and Materials (ASTM) International guidance) estimate the indoor air concentration from soil concentration while other guidances (e.g., United States Environmental Protection Agency (USEPA) and Dutch National Institute for Public Health (RIVM)) estimate it from measured soil gas concentration. This study derived indoor inhalation risks of intruded benzene in two benzene-contaminated residential areas with four different risk assessment guidances (i.e., KMOE, USEPA, ASTM, and Dutch RIVM) and compared the derived risks. The risk assessment results revealed that indoor air estimation approach from soil concentration could either underestimate (when the contaminant is not detected in soil) or overestimate (when the contaminant is detected in soil even at negligible concentration) the indoor air inhalation risk. Hence, this paper recommends to estimate indoor air concentration from soil gas concentration, rather than soil concentration. Discussions about the various indoor air concentration estimation approaches are provided.

• 한국환경보건학회지
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• 제49권6호
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• pp.324-333
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• 2023

Background: Human exposure to phthalates in indoor environments occurs via dermal absorption, oral ingestion of indoor dust, and inhalation of indoor air. However, systematic studies to investigate the exposure rate to phthalates among the three exposure routes in indoor environments are currently limited. Objectives: A theoretical exposure ratio between inhalation and oral exposure was calculated based on the total amount of di(2-ethyl-hexyl) phthalate (DEHP) emitted into indoor air and deposited into floor dust in a test house. Methods: Flooring and wallpaper containing DEHP were installed in a test house and the concentration of DEHP in both indoor air and floor dust were monitored for five months. Based on the measured DEHP concentrations, the theoretical total amount ratio of DEHP that could be exposed through inhalation and oral ingestion was calculated. Results: Considering the period of operation in the test house, the theoretical total amount of DEHP through inhalation and oral ingestion exposures in the entire test house space was calculated to be 0.014 mg and 5.5 mg, respectively. The exposure ratio of the two routes between inhalation and oral exposure corresponding to the total DEHP amount in flooring and wallpaper was 6.0×10^-7% and 2.3×10^-4%, indicating that theoretical oral exposure to DEHP is approximately 380 times higher than inhalation. Conclusions: Monitoring results from a test house has shown that oral exposure is the main exposure route for DEHP in indoor environments. The experimental design employed in this study and theoretical exposure ratio obtained can be applied to investigate actual exposure to DEHP and to determine the exposure characteristics of various types of semi-volatile organic compounds.

• 한국대기환경학회지
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• 제17권3호
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• pp.241-249
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• 2001

A report by the National Research Council in the United States suggested that many lung cancer deaths each year are associated with breathing radon in indoor air. Most of the indoor radon comes directly from soil beneath the basement of foundation. Recently, radon released from groundwater is found to contribute to the total inhalation risk from indoor air. This study presents the assessment of a exposure to radon released from the groundwater into indoor air. At first, a 3-compartment model is describe the transfer and distribution if radon released from groundwater in a house through showering, washing clothes, and flushing toilets. The model is used to estimate a daily human exposure through inhalation of such radon for adults based on two sets of exposure scenarios, Finally, a sensitivity analysis is used to identify important parameters. The results obtained from the study would help to increase the understanding of risk assessment issues associated with the indoor radon released from groundwater.

• Environmental Analysis Health and Toxicology
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• 제17권2호
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• pp.125-133
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• 2002

Volatile disinfection by-products (DBPs) contained in chlorinated tap water are released into household air during indoor activities (showering, cooking, dish -washing, etc.) associated with tap water uses and may cause adverse health effects on humans. Twenty seven subjects were recruited and their homes were visited during the winter of 2002. Tap water, household air, and exhaled breath samples were collected and analyzed for five volatile DBPs (chloroform, bromodichloromethane, dichloroacetonitrile, 1,1 -dichloropropanone and 1,1,1 trichloropropanone). Chloroform was a major DBP found in most samples. Tap water chloroform concentrations were not statistically correlated with its household air concentrations, probably due to individual variability in indoor activities such as showering, cooking, and dish - washing as well as household ventilation. Correlation of breath chloroform concentration with household air chloroform concentration showed its possible use as a biomarker of exposure to household air chloroform. Exposure estimates suggested that inhalation during household stay be a major route of exposure to volatile DBPs and that ingestion of tap water be a trivial contributor to the total exposure in Koreans.

• 한국대기환경학회지
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• 제18권5호
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• pp.373-381
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• 2002

Benzene, Ethyl-benzene, Toluene and Xylene (BTEX) can be released to a groundwater in case of the oil leakage from underground storage tank of a gas station. These chemicals are found to contribute to the total inhalation risk from contaminated indoor air. This study presents the assessment of a human exposure to such chemicals released from the groundwater into indoor air. At first, a 2-compartment model is developed to describe the transfer and distribution of the chemicals released from groundwater in a house through showering, washing clothes, and flushing toilets. The model is used to estimate a daily human exposure through inhalation of such BTEX for adults based on two sets of exposure scenarios. Finally, a sensitivity analysis is used to identify important parameters. The results obtained from the study would help to increase the understanding of risk assessment issues associated with the indoor pollution by BTEX released from contaminated groundwater.

• 한국대기환경학회지
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• 제18권4호
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• pp.327-334
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• 2002

The work presents sensitivity and uncertainty analysis of 2-compartment model for the evaluation of indoor radon pollution in a house. Effort on the development of such model is directed towards the prediction of the generation and transfer of radon in indoor air released from groundwater. The model is used to estimate a quantitative daily human exposure through inhalation of such radon based on exposure scenarios. However, prediction from the model has uncertainty propagated from uncertainties in model parameters. In order to assess how model predictions are affected by the uncertainties of model inputs, the study performs a quantitative uncertainty analysis in conjunction with the developed model. An importance analysis is performed to rank input parameters with respect to their contribution to model prediction based on the uncertainty analysis. The results obtained from this study would be used to the evaluation of human risk by inhalation associated with the indoor pollution by radon released from groundwater.

• 한국환경과학회지
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• 제13권7호
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• pp.627-635
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• 2004

Evaluated were household THMs exposure associated with the use of municipal tap water treated with chlorine and with ozone-chlorine. The current study measured the THMs concentrations in the tap water and indoor and outdoor air in the two types of household, along with an estimation of THMs exposure from water ingestion, showering, and the inhalation of indoor air. Chloroform was the most abundant THMs in all three media, yet no bromoform was detected in any sample. Contrary to previous findings, the fall water THMs concentrations exhibited no significant difference between the chlorine and ozone-chlorine treated water. However, the spring median chloroform concentration in the tap water treated with chlorine (17.6 ppb) was 1.3 times higher than that in the tap water treated with ozone-chlorine (13.4 ppb). It is suggested that the effects of the water parameters should be considered when evaluating the advantage of ozone-chlorine disinfection for THMs formation over chlorine disinfection. The indoor air THMs concentration trend was also consistent with the water concentration trend, yet the outdoor air THMs concentrations did not differ significantly between the two types of household. The indoor to outdoor air concentration ratios were comparable with previous studies. The THMs exposure estimates from water ingestion, showering, and the inhalation of indoor air suggested that, for the residents living in the surveyed households, their exposure to THMs in the home was mostly associated with their household water use, rather than the indoor air. The THMs exposure estimates from tap water ingestion were similar to those from showering.

• Journal of Radiation Protection and Research
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• 제26권2호
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• pp.79-86
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• 2001

본 연구는 지하수로부터 방출되는 라돈에 의한 실내오염시 정량적인 인체노출량을 평가하였다. 실내에 존재하는 라돈은 대부분 건물의 지하층에 존재하는 토양층으로부터 발생하는 것으로 알려져 왔다. 그러나, 최근 지하수내에 존재하는 라돈은 물사용으로 인해 실내공기로 휘발하여 실내오염을 야기하고 호흡에 의한 인체위해를 증가시키는 것으로 밝혀졌다. 본 연구는 주택내의 라돈의 이동 및 분포를 정량적으로 평가하기 위해 수학적 모델을 개발하였다. 그리고, 실내에서 예상되는 인체노출패턴과 이런 수학적 모델을 사용하여 성인의 경우, 실내 라돈오염에 의한 호흡노출을 통한 인체축적량을 계산하였다. 이러한 연구의 결과는 지하수로부터의 발생되는 라돈의 실내오염시 인체노출에 의한 위해도 평가시 도움을 주리라고 판단된다.

• 한국환경보건학회지
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• 제48권2호
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• pp.75-85
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• 2022

Background: Various types of semi-volatile organic compounds (SVOCs) exist in the public's living environment. They occur in different forms in terms of their physical and chemical properties and partition coefficients. As a consequence, indoor exposure to SVOCs occurs via various routes, including inhalation of air and airborne particles, skin contact, and dust intake. Objectives: To propose a method for assessing human exposure to the SVOCs occurring in the air of an indoor environment, the concentrations of SVOCs in house dust and organic films measured in a real residential environment were estimated in terms of gas-phase concentration using the partition coefficient. Assessment of inhalation exposure to SVOCs was performed using this method. Methods: Phthalates were collected from samples of house dust and organic films from 110 households in a real residential environment. To perform an exposures assessment of the phthalates present in organic films, gas-phase concentration was calculated using the partition coefficient. The airborne gas-phase concentrations of phthalates from the house dust and organic films were estimated and exposure assessment was performed based on the assumption of inhalation exposure from air. Results: As a result of the exposure assessment for gas-phase phthalates from house dust and organic films, preschool children showed the highest level of inhalation of phthalates, followed by school children, adults, and adolescents. Conclusions: This study includes the limitation of not considering different SVOCs exposure pathways in the health impact assessment, including those of phthalates in the indoor living environment. However, this study has the significance of performing exposure assessment based on exposure to SVOCs present in indoor air that originated from organic films in the indoor residential environment. Therefore, the results of this study should be useful as basic data for exposure and health risk assessments of SVOCs associated with organic films in the indoor environment.