• 한국환경과학회지
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• 제29권1호
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• pp.109-117
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• 2020

Asthmatics are more susceptible to fine particulate matters (PM_2.5), compared to the general population. It has been reported that indoor PM_2.5 is mainly generated by combustion of fossil fuels, meat or fish In particular, asthmatics are known to be more susceptible to indoor PM_2.5 because 65~95% of child or adult asthmatics stay inside the house. Thus, understanding the association between indoor activity patterns and variations in indoor PM_2.5 levels is important. The purpose of this study is to determine the distribution of hourly indoor PM_2.5 concentrations in asthmatics' homes, and to evaluate its association with pan-frying cooking activity patterns, the most common PM_2.5 emission related activity. From November 2017 to February 2018, real-time PM_2.5 concentrations were measured in the living room of each asthmatic's house (n = 35) for three weeks at 1 minute intervals. At the same time, self-reported daily activity patterns, hourly proportion (%) of cooking activities, were also recorded every hour over three weeks for each patient. In this study, we provided quantitative evidence that the distribution patterns of indoor hourly PM_2.5 concentrations were associated with indoor cooking activities, especially in the homes of adult asthmatics. In addition, we observed that PM_2.5 emitted by pan-frying could maintain even over up to 2 hour lagtime.

• 한국환경보건학회지
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• 제50권3호
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• pp.181-190
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• 2024

Background: Air pollutants have been reported to have harmful effects on human health. Busan is a vulnerable area in terms of air quality due to the installation of various industrial complexes, particularly the port industry. However there is limited research data on the ambient air quality of residential areas near ports and industrial complexes. Objectives: This study aimed to determine the quarterly levels of air pollutants near industrial complexes and ports and to identify trends and characteristics of air pollutant exceedances. Methods: Air measurements were conducted quarterly. The measured air pollutants included O₃, SO₂, CO, NO₂, PM₁₀, and PM_2.5. PM₁₀ and PM_2.5 were measured using BAM-1020 equipment, while O₃, SO₂, CO, and NO₂ were measured using AP-370 Series equipment. The quarterly concentration levels of air pollutants were determined, and the influence of precipitation and commuting hours on fine particulate matter was examined. Analysis of variance (ANOVA) was conducted to determine if there was significance between the concentrations of fine particulate matter during commuting hours and non-commuting hours. Results: The concentrations of air pollutants were generally higher in the first and second quarters. Furthermore, the concentrations of PM₁₀ and PM_2.5 tended to decrease continuously following consecutive rainfall, with concentrations at the end of rainfall periods lower than those observed at the beginning. The frequency of exceeding average concentrations of PM₁₀ and PM_2.5 was higher on weekdays. Moreover, the average concentrations of PM₁₀ and PM_2.5 during weekday commuting hours were higher compared to non-commuting hours. Conclusions: The concentrations of air pollutants in the survey area were found to be higher than the overall average in Busan. Based on this study, continuous air quality monitoring is necessary for residential areas near industrial complexes and ports. For further research, health biomonitoring of residents in these areas should be conducted to assess their exposure levels.

• 한국환경보건학회지
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• 제49권3호
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• pp.149-158
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• 2023

Background: Injury is one of the major health problems in South Korea. Few studies have evaluated both intentional and unintentional injury when investigating the association between exposure to air pollutants and injury. Objectives: We aimed to explore the association between short-term exposure to ambient air pollution and years of life lost (YLLs) due to injury. Methods: Data on daily YLLs for 2002~2019 were obtained from the the Death Statistics Database of the Korean National Statistical Office. This study estimated short-term exposure to particulate matter with an aerodynamic diameter of <10 ㎛ (PM₁₀), particulate matter with an aerodynamic diameter of <2.5 ㎛ (PM_2.5), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), carbon monoxide (CO), and ozone (O₃). This time series study was conducted using a generalized additive model (GAM) assuming a Gaussian distribution. We also evaluated a delayed effect of ambient air pollution by constructing a lag structure up to seven days. The best-fitting lag was selected based on smallest generalized cross validation (GCV) value. To explore effect modification by intentionality of injury (i.e., intentional injury [self-harm, assault] and unintentional injury), we conducted stratified subgroup analyses. Additionally, we stratified unintentional injury by mechanism (traffic accident, fall, etc.). Results: During the study period, the average daily YLLs due to injury was 307.5 years. In the intentional injury, YLLs due to self-harm and assault showed positive association with air pollutants. In the unintentional injury, YLLs due to fall, electric current, fire and poisoning showed positive association with air pollutants, whereas YLLs due to traffic accident, mechanical force and drowning/submersion showed negative associations with air pollutants. Conclusions: Injury is recognized as preventable, and effective strategies to create a safe society are important. Therefore, we need to establish strategies to prevent injury and consider air pollutants in this regard.

• 한국환경보건학회지
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• 제46권5호
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• pp.532-538
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• 2020

Objectives: The study evaluated correlations among monthly PM_2.5, PM₁₀, Cd, Pb concentrations and the number of Asian dust days. Methods: Based on data from 'The annual report on air quality in Korea from 1999 to 2017', concentrations of PM₁₀, PM_2.5, Cd, Pb, and the number of Asian dust days were recalculated to mean, standard deviation, minimum, and maximum. Correlation coefficients were calculated among PM_2.5, PM₁₀, Cd, Pb, and Asian dust days. Results: Asian dust days were correlated only with PM₁₀ among the four factors of PM₁₀, PM_2.5, Cd, and Pb. The four factors of PM₁₀, PM_2.5, Cd, and Pb were very significantly correlated with each other (p<0.01). Their correlation coefficients for PM₁₀ were 0.800 for PM_2.5, 0.823 for Cd, and 0.892 for Pb. PM_2.5 was also correlated strongly with Cd (0.845) and Pb (0.830). Cd had a correlation with Pb of 0.971. The maximums of PM_2.5, PM₁₀, and Pb were shown to exceed the atmospheric environmental standard of Korea, which necessitates national continuous exposure control. Based on exposure data, Asian dust days were thought to be an exposure factor for Cd and Pb. Conclusion: Asian dust might be a factor in Cd and Pb exposure. National exposure controls are required for exposure to PM_2.5, PM₁₀, Cd, and Pb.

• Nuclear Engineering and Technology
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• 제54권12호
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• pp.4693-4697
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• 2022

Parylene coating was adopted on CdZnTe (CZT) detector as a mechanical protection layer after wet passivation with hydrogen peroxide (H₂O₂) and ammonium fluoride (NH₄F). Wet chemical passivant lose their effectiveness when exposed to the ambient conditions for a long time. Parylene coating could protect the effectiveness of passivation, by mechanically blocking the exposure to the ambient conditions. Stability of CZT detector was tested with the measurement of leakage current density and response to radio-isotopes. When the enough thickness of parylene (>100 ㎛) is adopted, parylene is a promising protection layer thereby ensuring the performance and long-term stability of CZT detectors.

• 상하수도학회지
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• 제36권2호
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• pp.81-95
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• 2022

The present study was performed to investigate the effects of NH₃-N and nitrifying microorganisms on the increased BOD of downstream of the Yeongsan river in Gwangju. Water samples were collected periodically from the 13 sampling sites of rivers from April to October 2021 to monitor water qualities. In addition, the trends of nitrogenous biochemical oxygen demand (NBOD) and microbial clusters were analyzed by adding different NH₃-N concentrations to the water samples. The monitoring results showed that NH₃-N concentration in the Yeongsan river was 22 times increased after the inflow of discharged water from the Gwangju 1st public sewage treatment plant (G-1-PSTP). Increased NH₃-N elevated NBOD levels through the nitrification process in the river, consequently, it would attribute to the increase of BOD in the Yeongsan river. Meanwhile, there was no proportional relation between NBOD and NH₃-N concentrations. However, there was a significant difference in NBOD occurrence by sampling sites. Specifically, when 5 mg/L NH₃-N was added, NBOD of the river sample showed 2-4 times higher values after the inflow of discharged water from G-1-PSTP. Therefore, it could be thought other factors such as microorganisms influence the elevated NBOD levels. Through next-generation sequencing analysis, nitrifying microorganisms such as Nitrosomonas, Nitroga, and Nitrospira (Genus) were detected in rivers samples, especially, the proportion of them was the highest in river samples after the inflow of discharged water from G-1-PSTP. These results indicated the effects of nitrifying microorganisms and NH₃-N concentrations as important limiting factors on the increased NBOD levels in the rivers. Taken together, comprehensive strategies are needed not only to reduce the NH₃-N concentration of discharged water but also to control discharged nitrifying microorganisms to effectively reduce the NBOD levels in the downstream of the Yeongsan river where discharged water from G-1-PSTP flows.

• 한국환경보건학회지
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• 제49권2호
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• pp.108-117
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• 2023

Background: When particles are absorbed into the human body, they penetrate deep into the lungs and interact with the tissues of the body. Heavy metals in PM_2.5 can cause various diseases. The main source of PM_2.5 emissions in South Korea's atmosphere has been surveyed to be places of business. Objectives: The concentration of heavy metals in PM_2.5 near the Ulsan Industrial Complex was measured and a health risk assessment was performed for residents near the industrial complex for exposure to heavy metals in PM_2.5. Methods: Concentrations of heavy metals in PM_2.5 were measured at four measurement sites (Ulsan, Mipo, Onsan, Maegok) near the industrial complexes. Heavy metals were analyzed according to the Air Pollution Monitoring Network Installation and Operation Guidelines presented by the National Institute of Environmental Research. Among them, only five substances (Mn, Ni, As, Cd, Cr⁶⁺) were targeted. The risk assessment was conducted on inhalation exposure for five age groups, and the excess cancer risk and hazard quotient were calculated. Results: In the risk assessment of exposure to heavy metals in PM_2.5, As, Cd, and Cr⁶⁺ exceeded the risk tolerance standard of 10^-6 for carcinogenic hazards. The highest hazard levels were observed in Onsan and Mipo industrial complexes. In the case of non-carcinogenic hazards, Mn was identified as exceeding the hazard tolerance of 1, and it showed the highest hazard in the Ulsan Industrial Complex. Conclusions: This study presented a detailed health risk from exposure to heavy metals in PM_2.5 by industrial complexes located in Ulsan among five age groups. It is expected to be utilized as the basis for preparing damage control and industrial emission reduction measures against PM_2.5 exposure at the Ulsan Industrial Complex.

• Biomolecules & Therapeutics
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• 제31권1호
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• pp.59-67
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• 2023

Thrombin is a serine protease that participates in a variety of biological signaling through protease-activated receptors. Intestinal myofibroblasts play central roles in maintaining intestinal homeostasis. In this study, we found that thrombin-induced apoptosis is mediated by the calcium-mediated activation of cytosolic phospholipase A₂ in the CCD-18Co cell. Thrombin reduced cell viability by inducing apoptosis and proteinase-activated receptor-1 antagonist attenuated thrombin-induced cell death. Endogenous ceramide did not affect the cell viability itself, but a ceramide-mediated pathway was involved in thrombin-induced cell death. Thrombin increased intracellular calcium levels and cytosolic phospholipase A₂ activity. The ceramide synthase inhibitor Fumonisin B1, intracellular calcium chelator BAPTA-AM, and cytosolic phospholipase A₂ inhibitor AACOCF₃ inhibited thrombin-induced cell death. Thrombin stimulated arachidonic acid release and reactive oxygen species generation, which was blocked by AACOCF₃, BAPTA-AM, and the antioxidant reagent Trolox. Taken together, thrombin triggered apoptosis through calcium-mediated activation of cytosolic phospholipase A₂ in intestinal myofibroblasts.

• 한국환경보건학회지
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• 제35권6호
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• pp.454-460
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• 2009

The subway is the major public transportation system in Seoul with 2.2 million people using it everyday. Indoor air pollution in the subway can be a significant part of population exposure because of the number of people using the subway, time spent in transit and potentially high exposure for certain pollutants. The Korea Ministry of Environment has established the level 2 of recommended standards of $PM_{10}$ and $CO_2$ in subway trains. The aims of this study were to determine the airborne levels of $PM_{10}$, $CO_2$ and any correlation between pollutant levels and number of passenger in a subway train. The airborne $PM_{10}$ and $CO_2$ were measured on the inside of trains on line #4 for 4 different days from October to November in 2008. Average $PM_{10}$ and $CO_2$ levels were $113{\pm}25{\mu}g/m^3$ and $1402{\pm}442$ ppm, respectively. These levels did not exceed the level 2 of recommended standards of $250{\mu}g/m^3$ for $PM_{10}$ and 3500 ppm for $CO_2$. $PM_{10}$ level was not correlated with the number of passengers, while $CO_2$ levels were positively correlated with the number of passengers. The findings suggested that $PM_{10}$ in subway trains may have sources other than those directly associated with the number of passengers.

• 한국환경보건학회지
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• 제39권2호
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• pp.144-150
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• 2013

Objectives: Cooking activity in indoor environments can generate particulate matter. The objective of this study was to determine the concentrations of ultrafine particles (UFP), $PM_{2.5}$, and $PM_{10}$ in cooking and non-cooking areas of major department stores in Seoul. Methods: Eighteen department stores in Seoul, Korea were measured for concentrations of particulate matter. Using real-time monitors, concentrations of UFP, $PM_{2.5}$ and $PM_{10}$ were simultaneously measured in cooking and non-cooking areas on the floor with a food court and a non-cooking floor. Results: The concentrations of UFP, $PM_{2.5}$ and $PM_{10}$ were significantly higher in cooking areas than in noncooking areas and non-cooking floors (p<0.05). UFP and $PM_{2.5}$ were significantly correlated in cooking areas and non-cooking areas but not in non-cooking floors. $PM_{2.5}$ were consisted of approximately 81% in $PM_{10}$ and highly correlated with $PM_{10}$ in all places. Conclusion: A higher correlation between UFP and $PM_{2.5}$ was shown on cooking floor than on non-cooking floor in department stores. High levels of fine particles were caused by cooking activities at food courts. The further management of PM is needed to improve the indoor PM levels at food courts in department stores.