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Low-dose radiation exposure has received considerable attention because it reflects the general public’s type and level of exposure. Still, controversy remains due to the relatively unclear results and uncertainty in risk estimation compared to high-dose radiation. However, recent epidemiological studies report direct evidence of health effects for various types of low-dose radiation exposure. In particular, international nuclear workers’ studies, CT exposure studies, and children’s cancer studies on natural radiation showed significantly increased cancer risk among the study populations despite their low-dose radiation exposure. These studies showed similar results even when the cumulative radiation dose was limited to an exposure group of less than 100 mGy, demonstrating that the observed excess risk was not affected by high exposure. A linear dose-response relationship between radiation exposure and cancer incidence has been observed, even at the low-dose interval. These recent epidemiological studies include relatively large populations, and findings are broadly consistent with previous studies on Japanese atomic bomb survivors. However, the health effects of low-dose radiation are assumed to be small compared to the risks that may arise from other lifestyle factors; therefore, the benefits of radiation use should be considered at the individual level through a balanced interpretation. Further low-dose radiation studies are essential to accurately determining the benefits and risks of radiation.

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Background: The need to develop alternative chemicals is increasing worldwide due to the strengthening of global chemical regulations and consumer safety awareness in the marketplace.
Objectives: We aimed to review domestic and foreign technology trends for exploring alternative candidate algorithms that can be used to develop safer alternatives to strengthen global market competitiveness and protect public health in the future.
Methods: We searched the current status of research trends, companies related to the development of alternative chemicals in domestic and foreign countries. For this, we referred to research papers and websites by companies and institutes related to such alternatives.
Results: Among the domestic and foreign research trends, more studies in South Korea were focused on predicting molecular-based physicochemical properties and toxicity than were reporting on research exploring alternative candidates. Three web-based databases and six tools were being developed. More studies in other countries predicted information to consider in alternative development than reported on research exploring alternative candidates, and four web-based databases and three tools were being developed. Among the companies related to the development of alternative chemicals, 286 alternatives classified as ‘EVALUATED ALTERNATIVE’ in MARKETPLACE accounted for the most significant proportion in Europe on a continent basis, and the largest number in the United States (US) on a national basis. In South Korea, only significant companies were registered.
Conclusions: In this study, it was found to be necessary to provide public technology support platforms to explore alternative candidates considering various aspects in order to support alternative development. In conclusion, exploring alternative candidate algorithms could contribute to the response to the global trends in the chemical industry and to supporting companies and researchers developing safer alternatives in the future.

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Background: The existing research results on the combined toxicity of these pollutants using mammals, such as rodents, are insufficient, especially in relation to changes in the immune system.
Objectives: This study aims at evaluating the cellular immune response to PE-MPs solely or when combined with Pb, which possess excellent adsorption capacity with PE-MPs and is commonly co-exposed in our daily lives.
Methods: The study investigated the cellular immune function of 9-week ICR mice with 28 days exposure to PE-MPs (2 mg/mouse/day) and Pb (0.1 mM in distilled water) individually and in combination. PE-MPs were administered via gastric intubation while the lead intake was conducted via the oral drinking water route. Cellular immunity was evaluated by analyzing the production for T_H1 cytokines namely, TNF-α and IFN-γ and T_H2 cytokines, IL-4 and IL-6 in culture supernatants from polyclonally activated splenic mononuclear cells ex vivo.
Results: Both the PE-MPs only and the PE-MPs+Pb exposure group revealed an increased T_H1 response with elevated TNF-α and IFN-γ levels and downregulated T_H2 response with low IL-4, and IL-6 production levels compared to the control group. Furthermore, an increased IFN-γ/IL-4 ratio was found in the PE-MPs only and PE-MPs+Pb exposure groups, which indicated the skewedness to T_H1 response. Meanwhile, reduced blood hemoglobin levels and increased levels of IL-4, the dominant T_H2 cytokine in the Pb-only exposure group, were observed.
Conclusions: Our current findings on the predominance of T_H1 immune response in the PE-MPs and PE-MPs+Pb groups suggest that PE-MPs could be responsible for the predominant induction of the cellular immune changes. This finding could be used as an important landmark in research related to T_H1 predominance, such as autoimmune diseases. It suggests that additional research on immune modulation using longer exposure durations or the same exposure route is required to elucidate stronger findings.

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Background: Among various pollutants, fine particle (PM_2.5, defined as particle less than 2.5 nm in aerodynamic diameter) shows the most consistent association with adverse health effects. There is scientific evidence documenting a variety of adverse health outcomes due to exposure to PM_2.5.
Objectives: This study aims to assess the health benefits of that would be achieved by meeting the World Health Organization’s air quality guidelines for PM_2.5 using AirQ+ and BenMAP.
Methods: We estimated PM_2.5 related health benefits in Korea from implementing the World Health Organization’s air quality guidelines (annual average 5 μg/m³ and 10 μg/m³) and Korea’s National Ambient Air Quality Standard (annual average 15 μg/m³). We used World Health Organization’s AirQ+ and U.S. Environmental Protection Agency’s Environmental Benefits Mapping and Analysis Program.
Results: The annual number of avoided PM_2.5 related premature deaths exceeding WHO guideline levels was assessed using both AirQ+ and BenMAP. We estimated that the health benefits of attaining the World Health Organization’s air quality guidelines for PM_2.5 (annual average 5 μg/m³) would suggest an annual reduction of 26,128 (95% confidence interval [CI]: 17,363~34,024) and 26,853 (95% CI: 18,527~34,944) premature deaths.
Conclusions: Our study provided useful information to policy makers and confirms that the reduction of PM_2.5 concentration would result in significant health benefits in Korea.

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Background: Paraben is a widely used substance with a preservative effect found in various materials such as food, medicine, personal care products, and cosmetics.
Objectives: This study was conducted to identify the level of urinary paraben concentrations (i.e., methyl-, ethyl-, and propyl-) among Korean adults and to explore the factors related with the exposure levels.
Methods: We analyzed the third period (2015~2017) of the Korean National Environmental Health Survey (KoNEHS). R statistical software (version 4.1.1) was used to estimate representative values for the whole population with weight variables to reflect sampling design. Whether urinary concentrations tended to increase as the level of paraben exposure-related characteristics increased was tested and P_trend was calculated using general linear models.
Results: Urinary concentrations of all three parabens (i.e., methyl-, ethyl- and propyl-) were higher in women than in men (P_trend<0.0001, 0.008, and <0.0001), and the values of methylparaben and propylparaben tended to increase as the age of subjects increased (P_trend<0.0001, and <0.0001). Urinary concentrations of methylparaben and propylparaben were associated with intensity of exercise (P_trend<0.001, and 0.004), and that of propylparaben was higher in non-smokers (P_trend=0.01). In terms of paraben exposure-related variables, urinary concentrations of parabens (i.e., methyl-, ethyl- and propyl-) increased as the daily average frequency of teeth-brushing (P_trend<0.0001, 0.03 and 0.0001), the frequency of use of hair products (P_trend=0.005, 0.05 and 0.04), the frequency of use of makeup products (P_trend<0.001, 0.001 and <0.001), and the frequency of use of antibacterial products (P_trend=0.005, 0.02 and 0.02) increased.
Conclusions: In our study, urinary concentrations of all three parabens are associated with gender, teethbrushing, hair products, make-up products, and antibacterial products. Methyl- and proyl-parabens were associated with age and intensity of exercise, and propyl-paraben was associated with smoking.

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Background: Few studies have assessed exposure to chemicals in the context of environmental vulnerability with a focus on exposure among populations living in certain geographical areas.
Objectives: This study aimed to investigate cadmium exposure levels and kidney damage indices in environmentally and socioeconomically vulnerable populations, with further subgrouping according to economic status.
Methods: Four areas were selected to represent geographical vulnerability (two environmentally vulnerable populations and two socioeconomically vulnerable populations). Among them, population groups with lower socioeconomic status (SES) were separately classified. Urinary cadmium (UCd), beta₂-microglobulin (β₂-MG), and N-acetyl-β-D-glucosaminidase (NAG) levels were analyzed in samples from 245 residents of these four areas.
Results: Geometric means of concentrations of UCd (0.97~2.02 μg/g creatinine) in all selected populations (N, 245; mean age, 67.8~70.9 years old) were higher than the national reference values (0.39 for adults and 0.78 μg/g creatinine for people in their 60s). Participants with a lower SES had higher UCd and NAG concentrations than did non-low SES participants. In the lower SES group, there was a significant association between UCd and NAG concentrations; however, there was no such correlation in the non-low SES group.
Conclusions: Consistent with the findings of previous studies evaluating chemical exposure and associated health effects in specific populations, the findings of this study suggest that individuals with a low SES may be more vulnerable to exposure and related health effects.

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Background: PM_2.5 and black carbon (BC) can be generated from cooking and from vehicle operation. Street vendors may be exposed to PM_2.5 and BC due to their proximity both to roads and to cooking activities.
Objectives: The objectives of this study were to evaluate the PM_2.5 and BC concentrations in cooking stalls and to determine the effects of cooking activity and of types of cooking.
Methods: Indoor and outdoor PM_2.5 and BC concentrations, temperature, and relative humidity were measured in 32 stalls in April and May 2022. Behavioral factors such as the presence of cooking activity and types of cooking were observed. Student’s T-test was performed using the difference of indoor and outdoor PM_2.5 and BC concentrations to compare the effects of cooking activity and to compare types of cooking.
Results: One-hour averages of the difference in indoor and outdoor PM_2.5 concentrations for cooking stalls and non-cooking stalls were 9.7±15.7 μg/m³ (n=22) and –0.5±0.4 μg/m³ (n=10), respectively. The difference in indoor and outdoor PM_2.5 concentrations in cooking stalls was significantly higher than in non-cooking stalls (p<0.05). The indoor PM_2.5 concentration for stalls for Chinese pancakes and teokbokki exceeded the standards for indoor air quality in South Korea (50 μg/m³). The indoor PM_2.5 concentration for Korean pancake stalls exceeded the standards for outdoor air quality in South Korea (35 μg/m³ for 24 hours).
Conclusions: The PM_2.5 concentrations in stalls with cooking activity was significantly higher than those in stalls without cooking activity. Some stalls with certain types of foods exceeded standards for indoor and outdoor air quality in South Korea. Better management of indoor air quality in stalls with cooking activities is necessary.

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Background: The concentration of air pollutants as measured by the Air Quality Monitoring System (AQMS) is not an accurate population exposure level since actual human activities and temporal and spatial variability need to be considered. Therefore, to increase the accuracy of exposure assessment, the population should be considered. However, it is difficult to obtain population data due to limitations such as personal information.
Objectives: The existing population defined in this study is the number of people in each region's grid. The purpose is to provide a methodology for evaluating exposure to PM_2.5 through existing population data provided by the National Geographic Information Institute.
Methods: The selected study period was from October 26 to October 28, 2021. Using PM_2.5 concentration data measured at the Sensor-based Air Monitoring Station (SAMS) installed in Guro-gu and Wonju-si, the concentration for each grid was estimated by applying inverse distance weights through QGIS version 3.22. Considering the existing population, population-weighted average concentration (PWAC) was calculated and the exposure level of the population was compared by region.
Results: The outdoor PM_2.5 concentration as measured through the SAMS was high in Wonju-si on all three days. Wonju-si showed an average 22% higher PWAC than Guro-gu. As a result of comparing the PWAC and outdoor PM_2.5 concentration by region, the PWAC in Guro-gu was 1~2% higher than the observed value, but it was almost the same. Conversely, observations of Wonju-si were 10.1%, 11.3%, and 8.2% higher than PWAC.
Conclusions: It is expected that the Geographic Information System (GIS) method and the existing population will be used to evaluate the exposure level of a population with a narrow activity radius in further research. In addition, based on this study, it is judged that research on exposure to environmental pollutants and risk assessment methods should be expanded.

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Background: Due to the rapid aging of the South Korean population, neurological diseases such as dementia are increasing. Many studies have reported that the incidence of dementia is associated with environmental factors along with age.
Objectives: This study analyzed the association between cognitive function and ten heavy metals in the body: arsenic, aluminum, chromium, manganese, cobalt, nickel, iron, copper, zinc, and lead.
Methods: From 2018 to 2019, a total of 120 participants who suffered from cognitive impairment were recruited for this study. Blood and urine samples were collected and analyzed for heavy metal concentrations using an inductively coupled plasma mass spectrometer. Demographic information was obtained through face-to-face questionnaires completed by a trained investigator. Cognitive function was evaluated with the Korean version of the Mini-Mental State Examination and the Korean version of the Boston Name Waiting Test. The associations between cognitive function scores and heavy metal concentrations were analyzed using multiple logistic regression analysis.
Results: The average age of the 120 participants was 72.7 years, and 69.2% were female. The mean of the MMSE-K and K-BNT scores were 22.9 and 37.9, respectively. The geometric mean of aluminum (Al) was 8.42 μg/L. MMSE-K was associated with iron (Fe), but the significance was removed in the logistic regression based on 24 points. K-BNT was significantly associated with aluminum and the odds ratio for K-BNT above 38 decreased by 45% as the aluminum concentration increased.
Conclusions: The association between aluminum and the K-BNT score indicated that aluminum is associated with language-related cognitive decline. Based on this result, further study will be conducted by considering co-exposure effects of heavy metals including aluminum.

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Background: Socioeconomical disadvantaged communities are more vulnerable to environmental chemical exposure and associated health effects. However, there is limited information on chemical exposure among vulnerable populations in Korea.
Objectives: This study investigated chemical exposure among underprivileged populations. We measured urinary metabolites of phthalates in urban disadvantaged communities and investigated their correlations with residential environment factors and relative socioeconomic vulnerability.
Methods: Urine samples were collected from 64 residents in a disadvantaged community in Seoul. A total of eight phthalate metabolites were analyzed by liquid chromatography-mass spectroscopy. Analytical method used by the Korean National Environmental Health Survey (KoNEHS) was employed. Covariate variance analysis and general linear regression adjusted with age, sex and smoking were performed.
Results: Several phthalate metabolites, namely monomethyl phthalate (MMP), monoethyl phthalate (MEP), mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), and mono-n-butyl phthalate (MnBP) had higher levels than those reported in the adults of 4th KoNEHS. Notably, the MnBP level was higher in the lower socioeconomic group (geometric mean [GM]=47.3 μg/g creatinine) compared to non-recipients (GM=31.9 μg/ g creatinine) and the national reference level (GM=22.0, 28.2 and 32.2 μg/g creatinine for adults, 60’s and 70’s, respectively.). When age, sex and smoking were adjusted, MEP and MnBP were significantly increased the lower socioeconomic group than non-recipients (p=0.014, p=0.023). The lower socioeconomic group’s age of flooring were higher than non-recipients, not statistically significant.
Conclusions: These results suggest that a relatively low income and aged flooring could be considered as risk factors for increased levels of phthalate metabolites in socioeconomic vulnerable populations.

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Background: Lung injuries due to exposure to humidifier disinfectants (HDs) were reported in 2011 in South Korea. As a result of the government’s epidemiological investigation and toxicity test study, it was found that HDs caused health damage such as lung disease.
Objectives: The purpose of this study was to classify HD exposure ratings and analyze the affecting factors that could identify the relationship with lung disease.
Methods: Exposure assessment for HDs was conducted using a questionnaire during face-to-face interviews with the applicants. Ratings of high exposure (Class 1) and low exposure (Class 2) were cross-tabulated with clinical ratings (acceptable and unacceptable). Logistic regression analysis was carried out by setting the clinical rating of lung disease as a dependent variable and the socio-demographic and exposure characteristics obtained through the questionnaire as independent variables.
Results: The concentration in air of polyhexamethylene guanidine (PHMG) was 71.96±107.47 μg/m³, and the exposure concentration was 15.21±23.28 μg/m³. The exposure rating was overestimated with 97.1% of affected subjects having high exposure using margin of exposure (MOE), but only 9.9% matching the clinical class. In the overestimated group, it could be explained by the fact that the exposure time was long and the subjects had already recovered from damage symptoms. As a result of logistic regression analysis, ten variables were found to be significant influencing factors.
Conclusions: A new exposure rating could be calculated based on the MOE, and factors affecting lung disease could be estimated through comparative evaluation with the clinical rating.