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/m 3 , and the exposure concentration was 15.21±23.28 µg/m 3 . 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.

Background:The coronavirus disease (COVID-19) has caused changes in human activity, and these changes may possibly increase or decrease exposure to fine dust (PM 2.5 ). Therefore, it is necessary to evaluate the exposure to PM 2.5 in relation to the outbreak of COVID-19. Objectives:The purpose of this study was to compare and evaluate the exposure to PM 2.5 concentrations by the variation of dynamic populations before and after the outbreak of COVID-19.Methods: This study evaluated exposure to PM 2.5 concentrations by changes in the dynamic population distribution in Guro-gu, Seoul, before and after the outbreak of COVID-19 between Jan and Feb, 2020. Gurogu was divided into 2,204 scale standard grids of 100 m×100 m. Hourly PM 2.5 concentrations were modeled by the inverse distance weight method using 24 sensor-based air monitoring instruments. Hourly dynamic population distribution was evaluated according to gender and age using mobile phone network data and time-activity patterns.Results: Compared to before, the population exposure to PM 2.5 decreased after the outbreak of COVID-19.The concentration of PM 2.5 after the outbreak of COVID-19 decreased by about 41% on average. The variation of dynamic population before and after the outbreak of COVID-19 decreased by about 18% on average. Conclusions:Comparing before and after the outbreak of COVID-19, the population exposures to PM 2.5 decreased by about 40%. This can be explained to suggest that changes in people's activity patterns due to the outbreak of COVID-19 resulted in a decrease in exposure to PM 2.5 .

No abstract

Background: Exposure to volatile organic compounds (VOCs) can have acute and chronic health effects on human beings in general and in working environments. In particular, VOCs are often emitted in large quantities in industrial settings. In such circumstances, there is a need to improve the indoor air quality at workplaces. Objectives:The purposes of this study were to verify the effectiveness of air cleaning devices in workplaces and provide alternative solutions for improving working environments. Methods:Personal exposure and area level of VOCs for workers were evaluated in a car-part adhesive process before and after installing an air cleaning device with a TiO 2 -coated filter. Passive samplers and direct reading instruments were used to collect and analyze the VOCs, and the removal efficiency and improvement of air quality were evaluated. We also calculated the exposure index (EI) to assess the risk level in the workplace. Results:The removal efficiency for VOCs through the installation of the air cleaning device was approximately 26.9~69.0% as determined by the concentration levels before and after installation. The measured substances did not exceed the exposure limits for the work environment and the EI was less than 1.However, carcinogenic substances such as benzene, formaldehyde, carbon tetrachloride, and trichloroethylene were detected. Conclusions:The application of an air cleaning device can be a solution for controlling the indoor air quality in a workplace, particularly in cases where ventilation systems cannot be installed due to process limitations.

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.