• Journal of Environmental Health Sciences
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• v.48 no.1
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• pp.52-58
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• 2022

Background: Few studies have evaluated the exposure to phthalates via inhalation of floor dust in children's living areas. Objectives: This study evaluated the concentration and exposure level of phthalates emitted from indoor floor dust in children's living areas. Methods: This study utilized the results of a survey conducted by the Ministry of Environment in 2019. Indoor dust was collected from 150 households with children aged 3~7 and 67 daycare centers or local children's centers by using vacuum cleaners. It was analyzed by gas chromatography mass spectrometry. Six types of phthalates were analyzed: Bis (2-ethylhexyl) phthalate (DEHP), Dibutyl phthalate (DBP), Benzyl butyl phthalate (BBP), Di-N-octyl phthalate (DNOP), Diisononyl phthalate (DINP), Di -isodecyl phthalate (DIDP). Results: The medians of DEHP concentrations were 1,028 and 1,937 mg/kg in homes and daycare centers, respectively. The median and maximum values of daily intake were calculated by applying the median and 95th percentile values (the upper 5% of the total concentration) in dust measured in the homes. The DEHP median value was 1.6 ㎍/kg/bw/day, and a maximum A value of 7.8 ㎍/kg/bw/day was calculated. When the childcare center values were applied, the median daily intake of DEHP was 3.1 ㎍/kg/bw/day and the maximum value was 29.2 ㎍/kg/bw/day. As a result of calculating the daily intake by integrating the values of home and childcare facilities, the median and maximum values of daily intake were 1.9 and 10.9 ㎍/kg/bw/day, respectively. Conclusions: This study derives phthalate concentrations among the floor dust in homes and childcare facilities where children mainly spend time, and suggests their intake of phthalates through this. In particular, it was newly suggested that the phthalate concentrations in homes and childcare facilities are different, resulting in differences in intake.

• Journal of Radiation Protection and Research
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• v.48 no.2
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• pp.59-67
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• 2023

Background: This study aims to reevaluate natural radiation exposure, following up on our previous study conducted in 2019, and to assess the associated risk of lung cancer to the public residing in the gold mining areas of Betare-Oya, east Cameroon, and its vicinity. Materials and Methods: Gamma-ray spectra collected using a 7.62 cm×7.62 cm in NaI(Tl) scintillation spectrometer during a car-borne survey, in situ measurements and laboratory measurements performed in previous studies were used to determine the outdoor absorbed dose rate in air to evaluate the annual external dose inhaled by the public. For determining internal exposure, radon gas concentrations were measured and used to estimate the inhalation dose while considering the inhalation of radon and its decay products. Results and Discussion: The mean value of the laboratory-measured outdoor gamma dose rate was 47 nGy/hr, which agrees with our previous results (44 nGy/hr) recorded through direct measurements (in situ and car-borne survey). The resulting annual external dose (0.29±0.09 mSv/yr) obtained is similar to that of the previous study (0.33±0.03 mSv/yr). The total inhalation dose resulting from radon isotopes and their decay products ranged between 1.96 and 9.63 mSv/yr with an arithmetic mean of 3.95±1.65 mSv/yr. The resulting excess lung cancer risk was estimated; it ranged from 62 to 216 excess deaths per million persons per year (MPY), 81 to 243 excess deaths per MPY, or 135 excess deaths per MPY, based on whether risk factors reported by the U.S. Environmental Protection Agency, United Nations Scientific Committee on the effects of Atomic Radiation, or International Commission on Radiological Protection were used, respectively. These values are more than double the world average values reported by the same agencies. Conclusion: There is an elevated level of risk of lung cancer from indoor radon in locations close to the Betare-Oya gold mining region in east Cameroon. Therefore, educating the public on the harmful effects of radon exposure and considering some remedial actions for protection against radon and its progenies is necessary.

• Biomedical Science Letters
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• v.19 no.4
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• pp.315-329
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• 2013

This study was conducted to evaluate the distribution, frequency, sensitization rate, and types of specific allergen in allergic patients. We analyzed allergens of 12,882 allergic patient's serum referred for Medical Laboratory using MAST Allergy Screen Test (Inhalation/food panel) from April, 2010 to March, 2011. Allergen reactivity were not detected in 833/12,882 (6.5%) allergic patients and the other allergic patients had two or more types of allergens of food and inhalant, respectively. In the distribution of the allergen food 73.4% (9,450/12,882 patients) was much higher than the pollen 26.6% (3,432/12,882 patients). The sensitization rate to each allergen showed garlic 26.7%, egg white 21.5% of food allergens, mugwort 24.9%, ragweed short 19.6% of pollen allergens, Candida albicans 10.5%, Alternaria spp. 7.9% of fungus allergens, and showed high sensitized rate to Dermatophagoides farinae 90.2%, Dermatophagoides pteronyssinus 77.8%, house dust 57% of indoor allergens, respectively. The specific allergens of food allergen, fungus allergen, and indoor allergen were more frequent in young child than adult, but pollen allergens were frequent in adult than young child. In seasonal distribution, the food allergen were frequent in summer and autumn, the pollen allergen in autumn, fungus allergen in spring and in winter, and indoor allergen in autumn and in winter. In conclusion, the mite of Dermatophagoides farinae and Dermatophagoides pteronyssinus, and house dust showed the highest sensitization rate in specific allergen of allergic patients. The allergens showed difference feature according to the age, region, and types of allergen.

• Journal of the Korean Society of Radiology
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• v.14 no.3
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• pp.313-318
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• 2020

Since radon is an inert gas and is a monoatomic molecule, the size of one particle represents the size of an atom, which means that it has a radius of approximately 1 to 100 nm. Therefore, if the mask has a radius smaller than the size of general fine dust and ultra fine dust, but it is possible to block the inhalation of radon more than a certain amount, it is considered that the exposure through the inhalation of radon can be reduced through normal indoor wear. Accordingly, we would like to find out the radon blocking effect of a mask worn in everyday life. Looking at the reduction rate of radon for each mask, cotton masks decreased by 33.45%, medical masks by 33.50%, KF 80 masks by 35.12%, and KF 94 masks by 37.72%. It was found that the radon blocking effect of the cotton and medical masks was somewhat inferior to that of the KF mask, but the difference was not so great that the introduction of radon into the air could be blocked to a certain level by wearing a mask.

• Journal of Environmental Health Sciences
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• v.49 no.3
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• pp.169-177
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• 2023

Background: The Korea Centers for Disease Control and Prevention (KCDC) has identified cases of people suspected of suffering lung disease potentially caused by chloromethylisothiazolinone/methylisothiazolinone (CMIT/MIT) used in humidifier disinfectants (HDs). The Korean Ministry of Environment (MoE) epidemiological investigation and toxicity test study found that HDs caused health damage such as asthma and lung disease. Objectives: The main purposes of this study were to classify the HD exposure rating and to analyze the exposure characteristics that affect exposure to CMIT/MIT HDs. Methods: The exposure characteristics and socio-demographic characteristics of victim participants using CMIT/MIT HDs were investigated through questionnaires. An inhalation no observed adverse effect level (NOAEL) for CMIT/MIT was produced based on inhalation toxicity values. Exposure ratings (class 1~class 2) were cross-tabulated with clinical ratings (acceptable~unacceptable). A correlation analysis was conducted with the main exposure characteristics that affect the exposure concentration of CMIT/MIT HDs. Results: The concentration in indoor air of CMIT/MIT was 8.75±25.40 ㎍/m³, and the exposure concentration was 2.30±6.29 ㎍/m³. The CMIT/MIT exposure rating of 67 participants with high exposures of not more than MOE 100 were evaluated as 14.5%, while the damage participants who matched the clinical rating made up 4.5%. The exposure concentration of CMIT/MIT showed a positive correlation with the daily usage amount and usage frequency, and a negative correlation with volume of the indoor environment. Conclusions: A new exposure rating could be suggested and calculated based on the MOE, and the factors affecting the exposure concentration could be identified.

• Archives of design research
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• v.18 no.3 s.61
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• pp.219-222
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• 2005

This study is for the design developement of wall mount air purification device used for pleasant and clean resident environment. As more people have the high standard of living, they are interested in the air quality of indoor environment, since it is believed its relationship with human health. Now the social demand of air purifier is increasing. Its market is growing and there are various design products in the market. However, dominant current products are floor-based standing type, it needs much spaces to install for the air inhalation and exhaust. Therefore, this product provides the space-saved design. Its concept comes from existing wall mount type air conditioners. The effect of wall decoration is another merit of this proposal. It has an easy filtering change and cleaning system and a simple operation of multiple functions. This product also has the perfect-matched slim design that is consist of natural curves with rectangle for any indoor spaces.

• Nuclear Engineering and Technology
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• v.54 no.4
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• pp.1431-1438
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• 2022

In this study, natural radioactivity concentrations and dosimetric values of fly ash samples were evaluated for the landfill area of the coal-fired power plant (CFPP) complex at Binh Thuan, Vietnam. The average activity concentrations of ²³⁸U, ²²⁶Ra, ²³²Th and ⁴⁰K were 93, 77, 92 and 938 Bq kg^-1, respectively. The average results for radon dose, indoor external, internal, and total effective dose equivalent (TEDE) were 5.27, 1.22, 0.16, and 6.65 mSv y^-1, respectively. The average emanation fraction for fly ash were 0.028. The excess lifetime cancer risks (ELCR) were recorded as 20.30×10^-3, 4.26×10^-3, 0.62×10^-3, and 25.61×10^-3 for radon, indoor, outdoor exposures, and total ELCR, respectively. The results indicated that the cover of shielding materials above the landfill area significantly decreased the gamma radiation from the ash and slag in the ascending order: Zeolite < PVC < Soil < Concrete. Total dose of all radionuclides in the landfill site reached its peak at 19.8 years. The obtained data are useful for evaluation of radiation safety when fly ash is used for building material as well as the radiation risk and the overload of the landfill area from operation of these plants for population and workers.

• Journal of Digital Policy
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• v.2 no.4
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• pp.11-15
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• 2023

Recently, a fire suddenly broke out in a crowded theater, and many people were unable to find an escape route, becoming entangled, injured, and suffocating from smoke inhalation, resulting in a large-scale fire accident. Even though most of the people were young, they were unable to evacuate. If they had been elderly, it could have resulted in greater casualties. In particular, since it is difficult to receive accurate location information from GPS indoor, there is an urgent need for location-based services using beacons and an emergency evacuation system that intuitively shows evacuation routes in augmented reality using smart-phones. In this paper, an augmented reality-based emergency evacuation smartphone app was developed based on identifying fire locations and evacuation routes using beacons and fire sensors (IoT). In the future, if the proposed system is applied to indoor spaces where people are crowded, rapid evacuation will be possible even in a sudden fire accident, minimizing human damage.

• Asian Journal of Atmospheric Environment
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• v.8 no.1
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• pp.35-47
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• 2014

The purpose of the study is to evaluate the pollution level (gaseous and particle phase) in the public facilities for the PAHs, non-regulated materials, forecast the risk level by the health risk assessment (HRA) and propose the guideline level. PAH assessments through sampling of particulate matter of diameter < 2.5 ${\mu}m$ ($PM_{2.5}$). The user and worker exposure scenario for the PAHs consists of 24-hour exposure scenario (WIES) assuming the worst case and the normal exposure scenario (MIES) based on the survey. This study investigated 20 PAH substances selected out of 32 substances known to be carcinogenic or potentially carcinogenic. The risk assessment applies major toxic equivalency factor (TEF) proposed from existing studies and estaimates individual Excess Cancer Risk (ECR). The study assesses the fine dusts ($PM_{2.5}$) and the exposure levels of the gaseous and particle PAH materials for 6 spots in each 8 facility, e.g. underground subway stations, child-care facilities, elderly care facilities, super market, indoor parking lot, terminal waiting room, internet caf$\acute{e}$ (PC-rooms), movie theater. For internet caf$\acute{e}$ (PC-rooms) in particular, that marks the highest $PM_{2.5}$ concentration and the average concentration of 10 spots (2 spots for each cafe) is 73.3 ${\mu}g/m^3$ (range: 6.8-185.2 ${\mu}g/m^3$). The high level of $PM_{2.5}$ seen in internet cafes was likely due to indoor smoking in most cases. For the gaseous PAHs, the detection frequency for 4-5 rings shows high and the elements with 6 rings shows low frequency. For the particle PAHs, the detection frequency for 2-3 rings shows low and the elements with 6 rings show high frequency. As a result, it is investigated that the most important PAHs are the naphthalene, acenaphthene and phenanthrene from the study of Kim et al. (2013) and this annual study. The health risk assessment demonstrates that each facility shows the level of $10^{-6}-10^{-4}$. Considering standards and local source of pollution levels, it is judged that the management standard of the benzo (a)pyrene, one of the PAHs, shall be managed with the range of 0.5-1.2 $ng/m^3$. Smoking and ventilation were considered as the most important PAHs exposure associated with public facility $PM_{2.5}$. This study only estimated for inhalation health risk of PAHs and focused on the associated cancer risk, while multiple measurements would be necessary for public health and policy.

• Journal of Environmental Science International
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• v.16 no.5
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• pp.665-670
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• 2007

In this study, we evaluated the property change and relationship between hematological and biochemical parameters in exposure group and control group by multiple inhalation exposure, of $NO_2$. In case of leukocyte, change of hematological property increased significantly in statistics (p<0.05) in mice experiment. in case of hematocrit of exposure group, it was of decreased significantly in statistics. the tendency of hemoglobin and hematocrit was similar to all for three case. in case of methmoglobin that of the exposure group in mice experiment was meaning increased(p<0.05). For the $NO_2$ influence in biochemical property, total protein and triglyceride was decreased but not significant in statistics, albumin was decreased in the exposure group in the animal experiments, blood urea nitrogen and creatinine increased significantly in statistics in the animal experiments. uric acid and lactate dehydrogenase in serum increased significantly in the exposure group. We have to evaluate risk assessment for the $NO_2$ of indoor air pollutant in low concentration and long time.