The factors related to depressive symptoms in urban older adults in South Korea: a study based on the Seoul Aging Survey.

PURPOSE: This study aims to comprehensively examine the determinants of depression among urban older adults in Seoul, utilizing the social-ecological model to address multifaceted influences. METHODS: A comprehensive analysis was conducted using data from the 2022 Seoul Aging Survey, which surveyed 2,914 individuals aged 65 and above. A multiple logistic regression analysis was performed to identify factors contributing to depressive symptoms, including socio-demographic characteristics, health behaviors and status, research accessibility, social support, and environmental influences. RESULTS: This study revealed that poor subjective health (OR = 1.47) and the presence of multiple chronic diseases (OR = 1.59) significantly increased the risk of depressive symptoms among urban older adults. From a social support standpoint, living alone was associated with a higher risk of depression (OR = 1.66), low food security (OR = 2.56), and low digital competency (OR = 2.70) were all significant predictors of depressive symptoms. Additionally, a lack of engagement with cultural facilities (OR = 2.15) was identified as a critical environmental factor contributing to depression. CONCLUSIONS: The findings underscore the need for comprehensive policy and practical interventions aimed at preventing chronic disease, enhancing social support networks, improving digital literacy, ensuring food security, and expanding access to healthcare and cultural facilities. Such measures are crucial in mitigating depression among urban older adults, thereby enhancing their overall well-being and quality of life.

Arthrobacter horti sp. nov., isolated from mountain soil.

Gram-stain-positive, aerobic, rod-shaped strains, YJM1T and YJM12S, were isolated from Maebong Mountain, Dogok-dong, Gangnam-gu, Seoul, Republic of Korea. Strains YJM1T and YJM12S exhibited growth at 5-35 °C (optimum, 20-30 °C) and pH 6-9 (optimum, pH 7) and in 0-4 % (w/v) NaCl. Strains YJM1T and YJM12S showed highest 16S rRNA gene sequence similarity to the following members of the genus Arthrobacter: A. nanjingensis A33T (98.3 %/98.2 % similarity), A. woluwensis NBRC 107840T (98.2 %/98.1 %), A. humicola KV-653T (97.3 %), A. oryzae KV-651T (97.3 %), and A. globiformis NBRC 12137T (97.2 %). The strains grew well on Reasoner's 2A, nutrient, Mueller-Hinton, yeast-dextrose, and glucose-peptone-meat extract agars. The major polar lipids of strain YJM1T were phosphatidylglycerol, diphosphatidylglycerol, and phosphatidylinositol. The primary respiratory quinone of strain YJM1T was MK-9(H2), and the major fatty acids of strains YJM1T and YJM12S were anteiso-C15 : 0, anteiso-C17 : 0, iso-C15 : 0, and iso-C16 : 0. The DNA G+C content, based on the whole genome sequence of strain YJM1T, was 68.3 mol%. Average nucleotide identity values and digital DNA-DNA hybridization values between strain YJM1T and the reference strains ranged from 75.0 to 92.7 % and from 21.0 to 65.3 %, respectively. Strain YJM1T exhibited antimicrobial activity against Bacillus subtilis and Escherichia coli. Considering the chemotaxonomic, phenotypic, genotypic, and phylogenetic results, we propose the strain YJM1T represents a novel species in the genus Arthrobacter and suggest the name Arthrobacter horti sp. nov. (type strain YJM1T=KACC 23300T=JCM 36483T).

Alcohol Consumption Norms and the Favored Alcohol Consumption Policies of Citizens of Seoul.

The purpose of this study was to define the alcohol consumption norms and attitudes toward alcohol regulation policies among citizens of Seoul and the relationships between such norms and the favored regulatory policies. The study population consisted of 1001 adults aged 19-80 years living in Seoul. We collected demographic data and data on health behaviors, attitudes towards drinking, and preferred alcohol regulation policies. The correlations between drinking and the favored regulatory policies were analyzed. Male, as well as being employed, aged 19-39 years, single, a smoker, and a current or heavy episodic drinker were associated with more positive attitudes toward drinking (all p < 0.001) and less desire for alcohol regulation policies (all p < 0.001). We found a significant negative correlation between attitudes toward drinking and preferred alcohol regulation policies (p < 0.001). Participants who favored reduced or no alcohol consumption and a reduction in alcohol-related harm were more accepting of restrictive alcohol consumption policies. To establish alcohol control polices, differences in drinking norms within populations should be considered. Furthermore, for a successful alcohol control policy, efforts should be made to change drinking norms, as well as consider differences in regulatory policy preferences between population groups.

Unraveling the causes of the Seoul Halloween crowd-crush disaster.

As the world steadily recovers from the COVID-19 pandemic, managing large gatherings becomes a critical concern for ensuring crowd safety. The crowd-crush disaster in Seoul in 2022 highlights the need for effective predictive crowd management techniques. In this study, an empirical analysis of this incident is conducted using data from various sources, and model-based simulations are created to replicate hazardous crowd conditions in high-risk areas. In the empirical analysis, mobile device data indicates a significant increase in population above normal levels in the disaster area just hours before the incident occurred. In the simulations, a hydrodynamic model is employed to simulate a bidirectional collision, which quantitatively demonstrates that the average density during the crush reached 7.57 ped/m2 (with a maximum of (9.95)ped/m2). Additionally, the average crowd pressure peaked at 1,063 N/m (with a maximum of 1,961 N/m), and the maximum velocity entropy was 10.99. Based on these findings, it can be concluded that the primary causes of the disaster were the substantial population, bidirectional collision, and escalating panic. The results of controlled simulations under various management strategies are then presented. By implementing effective crowd management techniques, crowd safety can be enhanced through quantitative comparisons of these key indicators.

Uneven geography of health opportunities among subsidized households: Illustrating healthcare accessibility and walkability for public rental housing in Seoul, Korea.

Planners and policymakers significantly consider providing suitable living environments for marginalized households, beyond creating affordable homes. Previous studies have explored various socioeconomic attributes of neighborhoods with public rental housing (PRH), particularly regarding education, job, and transportation opportunities; however, we have a limited understanding of health opportunities among such subsidized households. This study, therefore, explores the accessibility and spatial equity of emergency medical services (EMS) and primary health care (PHC) for PRH residents in Seoul, Korea. The findings show that neighborhoods with PRHs are associated with lower odds ratios for EMS and PHC accessibility. In particular, the relationships between the locations of PRHs and medical services accessibility in neighborhoods varied across the types of PRHs. While neighborhoods with large-scale PRHs are associated with lower PHC access, those with small-scale PRHs are associated with lower EMS access. In addition, our findings show that PRHs tend to be located in neighborhoods with lower walkability. These results may help in empirically determining the spatial accessibility of PHC and EMS, as well as neighborhood walkability, which may affect the health status of individuals in subsidized households.

Cycling safely: Examining the factors associated with bicycle accidents in Seoul, South Korea.

This study investigates the factors contributing to bicycle accidents, focusing on four types of bicycle lanes and other exposure and built environment characteristics of census blocks. Using Seoul as a case study, three years of bicycle accident spot data from 2018 to 2020 was collected, resulting in 1,330 bicycle accident spots and a total of 2,072 accidents. The geographically weighted Poisson regression (GWPR) model was used as a methodological approach to investigate the spatially varying relationships between the accident frequency and explanatory variables across the space, as opposed to the Poisson regression model. The results indicated that the GWPR model outperforms the global Poisson regression model in capturing unobserved spatial heterogeneity. For example, the value of deviance that determines the goodness of fit for a model was 0.244 for the Poisson regression model and 0.500 for the far better-fitting GWPR model. Further findings revealed that the factors affecting bicycle accidents have varying impacts depending on the location and distribution of accidents. For example, despite the presence of bicycle lanes, some census blocks, particularly in the northeast part of the city, still pose a risk for bicycle accidents. These findings can provide valuable insights for urban planners and policymakers in developing bicycle safety measures and regulations.

Delayed effects of air pollution on public bike-sharing system use in Seoul, South Korea: A time series analysis.

BACKGROUND: As a complementary means to urban public transit systems, public bike-sharing provides a green and active mode of sustainable mobility, while reducing carbon-dioxide emissions and promoting health. There has been increasing interest in factors affecting bike-sharing usage, but little is known about the effect of ambient air pollution. METHOD: To assess the short-term impact of daily exposure to multiple air pollutants (PM2.5, PM10, NO2, and O3) on the public bike-sharing system (PBS) usage in Seoul, South Korea (2018-2021), we applied a quasi-Poisson generalized linear model combined with a distributed lag nonlinear model (DLNM). The model was adjusted for day of the week, holiday, temperature, relative humidity, and long-term trend. We also conducted stratification analyses to examine the potential effect modification by age group, seasonality, and COVID-19. RESULTS: We found that there was a negative association between daily ambient air pollution and the PBS usage level at a single lag day 1 (i.e., air quality a day before the event) across all four pollutants. Our results suggest that days with high levels of air pollutants (at 95th percentile) are associated with a 0.91% (0.86% to 0.96%) for PM2.5, 0.89% (0.85% to 0.94%) for PM10, 0.87% (0.82% to 0.91%) for O3, and 0.92% (0.87% to 0.98%) for NO2, reduction in cycling behavior in the next day compared to days with low levels of pollutants (at 25th percentile). No evidence of effect modification was found by seasonality, age nor the COVID-19 pandemic for any of the four pollutants. CONCLUSIONS: Our findings suggest that high concentrations of ambient air pollution are associated with decreased rates of PBS usage on the subsequent day regardless of the type of air pollutant measured.

Effect of COVID-19 response work experience on turnover intention among employees of dedicated COVID-19 hospitals in Seoul.

BACKGROUND: According to previous studies, stress and job burnout among medical personnel increased during the COVID-19 pandemic. This study analyzed the effect of the experience of COVID-19 response work on the intention of municipal hospital staffs to leave their workplaces during the pandemic. METHODS: The 3556 employees who had worked for more than 1 year at one of the eight Seoul Municipal Hospitals that either provided inpatient treatment for quarantined COVID-19 patients or operated as screening clinics were taken as the study population. In total, 1227 employees completed a web or mobile survey between October 21 and November 18, 2020. A chi-squared test was performed to confirm the difference in the distribution of turnover intention depending on whether the employees performed COVID-19 response tasks. Multiple logistic regression analyses were performed to determine the factors that affected the intention to leave. RESULTS: Of the 1227 respondents, 761 (62.0%) were frontline workers who were the first line of response to COVID-19. Experience with COVID-19 response tasks (OR = 1.59, p = 0.003) was significantly associated with the intention to leave. Additionally, the probability of turnover intention was significantly higher among workers aged 20-29 years (OR = 2.11, p = 0.038) and 40-49 years (OR = 1.57, p = 0.048), unmarried individuals (OR = 1.66, p = 0.005), doctors (OR = 2.41, p = 0.010), nurses (OR = 1.59, p = 0.036), and technical staff members (OR = 2.22, p = 0.009). High turnover intention was found among those who experienced high levels of burnout (OR = 2.03, p < 0.001) and those working in non-directly managed municipal hospitals (OR = 1.87, p = 0.018). CONCLUSION: Employees directly involved in COVID-19 response work displayed higher turnover intention. Various personal, job, and organizational factors significantly influenced employees' intentions to leave their positions in dedicated COVID-19 hospitals. These findings suggest the necessity of introducing management programs to aid workers who have experienced sudden changes in their duties and loss of autonomy while performing COVID-19 response tasks.

Characteristics of undertriaged older patients in the emergency department: Retrospective study.

BACKGROUND: Older patients are more likely to be undertriaged as they often suffer from multiple diseases and complain of non-specific symptoms. Therefore, it is necessary to identify the characteristics of undertriaged older patients in emergency departments. METHODS: This descriptive study retrospectively reviewed and analyzed the electronic medical records of older patients who visited the emergency department of a general hospital in Seoul between January and December 2019. RESULTS: Approximately 29 % (n = 4,823) of older patients who visited the emergency department during the study period were classified as Korean Triage and Acuity Scale (KTAS) level 4 or 5, and approximately 8 % (n = 397) were undertriaged. Approximately 73 % (n = 288) of patients were hospitalized after visiting the emergency department. The undertriaged older patients exhibited nervous system symptoms such as dizziness and headache (28.8 %), cardiopulmonary symptoms such as chest discomfort, palpitations, and abdominal pain (28.4 %), head trauma (12.8 %), and respiratory symptoms such as cough and dyspnea (12.5 %). CONCLUSION: Triage nurses in emergency departments should carefully triage older patients as their chief complaints can be non-specific. In particular, when older patients visit the emergency department and exhibit symptoms such as dizziness, abnormal pain, chest discomfort, palpitations, and head trauma, they are more likely to be admitted to the intensive care unit. Therefore, meticulous care for older patients showing these symptoms is essential.

Patterns and sources of spatial inequity in freight crashes: An application of decomposition analysis.

Despite considerable increases in road freight traffic and associated crashes over the past decade, our understanding of their spatial distribution remains limited. This is concerning because freight vehicle crashes often lead to fatal and severe injuries. This study focuses on Seoul, South Korea and contributes to the literature by investigating the patterns and sources of spatial inequity in freight crashes. Specifically, it examines whether socioeconomically disadvantaged neighborhoods experience a higher concentration of freight crashes. Using the Gelbach's decomposition technique, this study also aims to identify the factors contributing to differences in freight crashes between disadvantaged and less-disadvantaged neighborhoods and quantify their relative contributions. The regression results show that severe freight crashes are more prevalent in disadvantaged neighborhoods before adjusting for other factors-a pattern not observed in non-severe crashes. The decomposition analysis reveals that the observed disparities in severe freight crashes between disadvantaged and less-disadvantaged neighborhoods are fully explained by differences in several neighborhood characteristics, including local road density, truck traffic volume density, proximity to logistics terminals, and off-road bicycle lane density, between neighborhood types. Interestingly, differences in built environment characteristics between neighborhood types not only fail to explain but instead counteract the disparities in severe freight crashes. The findings of this study suggest detailed policy implications for mitigating freight crash occurrences and addressing related spatial inequities.

Characteristics of Using Oriental Medicine Clinics during the Japanese Occupation: An Analysis of the 1931 Seoul Bochun Clinic Account Book.

This article analyzes the "account book" of Kim Young-hoon (1882-1974), which summarizes information about patients at his Bochun Clinic in Seoul (then Gyeongseong) in 1931. Kim Young-hoon was a pivotal figure in the medical scene throughout the Korean Empire, the Japanese occupation, and the early years of the Republic of Korea. He left behind a large amount of documentation during his 60 years of practice at the Bochun Clinic, which he opened in the spring of 1909. In particular, the 1931 "account book" offers an insight into the daily life histories of his patients. Among the patient-visitors recorded in the account book, there were many influential people of the time, ranging from privileged individuals to anti-Japanese independence activists, from those in political and economic fields to those in academic and entertainment fields. At the same time, a significant number of lower-class people also visited the Clinic. Geographically, patients were centered in the city center of the capital, Gyeongseong, but were also widely distributed throughout the country. There are indications that those from the rural areas stayed in the homes of their acquaintances in Seoul. As such, the account book provides a tangible, concrete picture of the clinic's management for the year 1931, including visitor demographics, visiting diagnoses, telephone consultations, and the total cost of medicinal prescriptions. Because the account book is a one-year statistic, it has its limitations; however, it is the smallest unit that can be analyzed statistically. It provides insights into how many people came in over the course of a year and how much they spent. The expenditures are kept per individual family. The patient's name, prescribed medication, and the price of the medicine are mandatorily included, and in many cases, the place of residence and family relationships are also noted. The account book shows several layers of householders, servants, and employees in the extended family; it also shows people in various occupations. A few privileged families accounted for nearly half of the total expenditures, and the powerful visited frequently, utilizing Oriental medicine for many of their daily needs. For some, the Bochun Clinic is reminiscent of the royal temples of the dynasties. Patients come from the center and suburbs of Seoul, as well as from all over the country. In one year, more than one thousand types of prescriptions are issued and the total cost of medicines is about 33 seom (≒180 liters of rice). Although there is a concentration of high-frequency prescriptions, more than a thousand prescriptions are prescribed only once, which shows that the practice is specialized for each individual. Patient visits, consultations, and telephone use are observed, and the use of new drugs, quinine, and special ginseng as one-herb medication (danbang) are also noticeable. The statistical analysis of the 1931 Bochun Clinic "account book" can serve as a milestone for comparative analysis of the patterns of herbal medicine use before and after that year. Meanwhile, the Bochun Clinic "account book" shows the continuation of traditional practices of herbal medicine by both the powerful and the masses. On the one hand, Koreans responded to the coercive tide of modernity symbolized by the Imperial Governorate of Japan, but on the other hand, they were unwilling to let go of tradition and their own authority. While actively embracing the tide of civilization, Koreans also internalized their own rationality and sought to open a new path forward, a sentiment discernible between the lines of the "account book."

The April Revolution and the Sense of Place in Medical Space: Focusing on Major Hospitals in Downtown Seoul.

This article focuses on the medical activities conducted by major hospitals in downtown Seoul during the April Revolution in 1960, examining their experiential context and significance. The influx of guns and bullets into Korean society following the liberation in 1945 intertwined with the political and social conflicts of the period, resulting in numerous assassinations, crimes, and terrorism. Gunshot wounds were traumas that became a part of the everyday life of Koreans, as well as scars which reflected their historical contexts. At the same time, the frequent occurrence of gunshot wounds led to the development of medical capacities to treat them. The Korean surgical academia expanded its technical foundation with experiences during and after the Korean War. This progress was particularly noticeable in areas closely related to gunshot wounds, such as craniotomy, thoracotomy, vascular anastomosis, debridement, anesthesia, and blood transfusion. Major hospitals in downtown Seoul served as medical spaces where these experimental and technical foundations were concentrated, allowing them to minimize the death toll despite the massive gunfire by the National Police in April 1960. Thus, the aftermath of the epidemic of gunshots resulted in a rather paradoxical outcome. This development became a resource for doctors and nurses, who added their revolutionary implications in reconstructing the experience of April 1960 in their various memoirs and reports. While memoirs reorganized general medical activities, portraying injured patients as participants in the revolution, reports provided forensic descriptions and interpretations of the deaths, giving authority to the main narrative of the revolution. As the interpretations and significance based on historical contexts gained prominence, major hospitals in downtown Seoul also developed a sense of place closely associated with the revolution.

Microbiome of lovebug (Plecia longiforceps) in Seoul, South Korea.

Lovebugs appeared in large numbers across a wide area in Seoul, South Korea, in June 2023. The sudden appearance of exotic insects not only discomforts people but also fosters anxiety, as their potential for pathogen transmission would be unknown. In this study, targeted next-generation sequencing (NGS) of the 16S rRNA gene V4 region was performed using iSeq 100 to screen for bacteria in lovebugs. Forty-one lovebugs (20 females and 21 males) collected in Seoul, Korea, were identified as Plecia longiforceps based on mitochondrial cytochrome oxidase subunit 1 sequencing data using PCR. We analyzed the microbiome of the lovebugs and detected 453 species of bacteria. Among all bacteria screened based on NGS, Rickettsia was detected in all samples with an average relative abundance of 80.40%, followed by Pandoraea and Ewingella. Diversity (alpha and beta) between females and males did not differ; however, only Tumebacillus showed a higher relative abundance in females. Sequencing analysis of Rickettsia using a gltA gene-specific primer by PCR showed that it had higher sequence similarity to the Rickettsia symbiont of arthropods than to the spotted fever group rickettsiae. Eleven samples in which Pandoraea was detected by iSeq 100 were confirmed by PCR and exhibited 100% sequence identity to Pandoraea oxalativorans strain DSM 23570. Consequently, the likelihood of pathogen transmission to humans is low. The applied method may play a crucial role in swiftly identifying bacterial species in the event of future outbreaks of exotic insects that may be harmful to humans.IMPORTANCELovebugs have recently emerged in large numbers in Seoul, causing major concern regarding potential health risks. By performing the next-generation sequencing of the 16S rRNA gene V4 region, we comprehensively examined the microbiome of these insects. We identified the presence of numerous bacteria, including Rickettsia and Pandoraea. Reassuringly, subsequent tests confirmed that these detected bacteria were not pathogenic. The present study addresses health concerns related to lovebugs and shows the accuracy and efficiency of our detection technique. Such methods prove invaluable for rapidly identifying bacterial species during potential outbreaks of unfamiliar insects, thereby ensuring public safety.

Impact of terephthalic acid emissions from intensive nocturnal biomass incineration on oxidative potential in Seoul, South Korea.

This study investigated the impact of large-scale incineration facilities on PM2.5 levels in Seoul during winter. Due to the challenge of obtaining accurate combustion data from external sources, heat supply records were used as a proxy for combustion activity. To assess health risks, dithiothreitol-oxidative potential (DTT-OP) was analyzed to identify potential hazards to human health. By comparing DTT-OP with PM2.5 sources related to combustion, the study aimed to understand the impact of local pollution sources on human health in Seoul. The diurnal analysis showed that oxidative potential (0.19 µM/m3) and the biomass burning factor (5.53 µg/m3) peaked between 4:00 and 8:00 AM, with lower levels observed from 12:00 to 20:00. A significant correlation was found between combustion sources and oxidative potential, with a high correlation coefficient (r2 = 0.92). The presence of terephthalic acid (TPA) in the Cellulose combustion source profile, which is produced by the pyrolysis of plastics like polyester fiber and polyethylene terephthalate (PET), further supported the link to emissions from incineration facilities. These findings suggest that the biomass burning source is strongly correlated with DTT-OP, indicating a significant association with health risks among various local sources of PM2.5 in Seoul.

Effects of chemical composition of ambient PM2.5 measured in Seoul on potential health risks and generation of reactive oxygen species.

This study assesses the health effects associated with the chemical species of ambient particulate matter (PM) with an aerodynamic diameter ≤2.5 µm (PM2.5) in Seoul, focusing on identifying key chemical constituents and their sources. We employed two approaches to estimate health risks: (1) evaluating carcinogenic and noncarcinogenic risks using IRIS (Integrated Risk Information System) data from the US EPA (Environmental Protection Agency), and (2) quantifying the generation of hydroxyl radicals (·OH) following exposure to PM2.5 in surrogate lung fluid (SLF). Our results show a significant impact on human health from certain elements (Cr, Ni, As, and Cd) and polycyclic aromatic hydrocarbons (PAHs) (DaeP, DahA, and BaP for carcinogenic risks; BaP and BeP for noncarcinogenic risks). Notably, Cr and BaP, which are influential in both risk assessment and ·OH generation, highlight their significant roles in human health impacts. However, other components (e.g., CPP, BaP, BghiP, BaA, CHR, PYR, FLT, Ca, Mg, and Cu), though contributors to ·OH generation, were not included in the EPA's health risk assessment, suggesting a need for a broader PM2.5 compositional analysis to more accurately determine exposure concentrations and assess inhalation risks. These components predominantly originate from anthropogenic sources, such as combustion, vehicles, and industrial activities, underscoring the significant health implications of the pollutants emitted from these sources. The study concluded that focusing solely on the mass reduction of PM2.5 may not suffice; a dual approach that reduces both mass concentration and chemical-specific health risks is imperative for effective public health protection.

Residential mobility according to health status in South Korea's largest metropolitan city during the COVID-19 pandemic using generalized estimating equations for longitudinal data.

This study examines whether residential mobility differed according to health status in Seoul, the largest metropolitan city in South Korea, during the COVID-19 pandemic. Before the COVID-19 pandemic, people who moved had better health status in the baseline year than those who did not. However, during the pandemic, the residential mobility of people with poor health status increased, particularly in 2019-2020. This pattern appeared to be driven by the 55-74 age group. The effect of health status on residential mobility was not attenuated, even after adjusting for covariates at multiple levels.

A case study of surface ozone source contributions in the Seoul metropolitan area using the adjoint of CMAQ.

To quantitatively investigate the transboundary behaviors and source attributions of ozone (O3) and its precursor species over East Asia, we utilize the adjoint technique in the CMAQ modeling system (the CMAQ adjoint). Our focus is on the Seoul Metropolitan Area (SMA) in South Korea, which is the receptor region of this study. We examine the contributions of both local and transported emissions to an O3 exceedance episode observed on June 3, 2019, estimating up to four days in advance. By using the CMAQ adjoint, we can determine the sensitivity of O3 remaining in the SMA to changes in O3 precursor emissions (emissions-based sensitivity) and concentrations (concentrations-based sensitivity) along the long-range transport pathways and emission source regions overseas. These include Beijing-Tianjin-Hebei (BTH), Shandong, Yangtze River Delta (YRD), and Central China. CMAQ adjoint-derived source attributions suggest that overseas precursor emissions and O3 contributed significantly to the O3 exceedance event in SMA. The emissions-based sensitivities revealed that precursor emissions originating from Shandong, YRD, Central China, and BTH contributed 11.42 ppb, 4.28 ppb, 1.24 ppb, 0.9 ppb, respectively, to the O3 exceedance episode observed in the SMA. Meanwhile, Korean emissions contributed 31.1 ppb. Concentrations-based sensitivities indicated that 19.3 ppb of contributions originated in regions beyond eastern China and directly affected the O3 level in the SMA in the form of background O3. In addition to capturing the transboundary movements of air parcels between the source and receptor regions, we performed HYSPLIT backward trajectory analyses. The results align with the trajectories of O3 and its precursors that we obtained from the adjoint method. This study represents a unique effort in employing the adjoint technique to examine the impacts of regional O3 on South Korea, utilizing a combination of emissions-based and concentrations-based sensitivities.Implications: This research brings to light the critical role of both local and regional precursor emissions in contributing to an ozone (O3) exceedance event in the Seoul Metropolitan Area (SMA), South Korea. Utilizing the CMAQ adjoint technique, a novel approach in the context of South Korea's O3 investigations, we were able to delineate the quantitative contributions of different regions, both within South Korea and from overseas areas such as Beijing, Shandong, Shanghai, and Central China. Importantly, the results underscore the substantial influence of transboundary pollutant transport, emphasizing the need for international collaboration in addressing air quality issues. As metropolitan areas around the globe grapple with similar challenges, the methodology and insights from this study offer a potent tool and framework for regions seeking to understand and mitigate the impacts of O3 on human health and the environment. By integrating different sensitivity types, coupled with HYSPLIT backward trajectory analyses, this research equips policymakers with comprehensive data to design targeted interventions, emphasizing the significance of collaborative efforts in tackling regional air pollution challenges. However, it's important to note the limitation of this study, which is a case study conducted over a short time period. This constraint may impact the generalizability of the findings and suggests a need for further research to validate and expand upon these results.

Interactions between physical activity and psychological factors in the association with the risk of lean type 2 diabetes mellitus.

Background: The extent to which physical activity and psychological factors may affect the risk of diabetes mellitus among lean individuals remains unclear.Purpose: This study aimed to investigate the associations of total physical activity (TPA) and psychological factors with lean type 2 diabetes mellitus (T2DM) risk.Research Design: A prospective cohort study.Study Sample: The study population included 1,945 Korean adults who maintained a body mass index <23 kg/m2.Data Collection and Analysis: Baseline data on TPA and psychological factors were collected and T2DM incidence was assessed for 10 years. For analysis, a multivariable Cox proportional hazards regression model was used.Results: TPA was inversely associated with T2DM risk and this association was more pronounced in participants who were depressed or distressed; the top TPA quartile exhibited significant reductions in T2DM risk of 66% (95% confidence interval [CI]: 0.15, 0.78) and 65% (95% CI: 0.14, 0.88) among participants who reported depressed mood and those who perceived high distress, respectively, compared with the bottom TPA quartile.Conclusions: The current study demonstrated the preventive effects of physical activity on T2DM in lean adults through its interaction with psychological factors.

Temporal dynamics of public transportation ridership in Seoul before, during, and after COVID-19 from urban resilience perspective.

We delve into the temporal dynamics of public transportation (PT) ridership in Seoul, South Korea, navigating the periods before, during, and after the COVID-19 pandemic through a spatial difference-in-difference model (SDID). Rooted in urban resilience theory, the study employs micro-level public transportation card data spanning January 2019 to December 2023. Major findings indicate a substantial ridership decline during the severe COVID impact phase, followed by a period in the stable and post-COVID phases. Specifically, compared to the pre-COVID phase, PT ridership experienced a 32.1% decrease in Severe, followed by a reduced magnitude of 21.8% in Stable and 13.5% in post-COVID phase. Interestingly, the observed decrease implies a certain level of adaptability, preventing a complete collapse. Also, contrasting with findings in previous literature, our study reveals a less severe impact, with reductions ranging from 27.0 to 34.9%. Moreover, while the ridership in the post-COVID phase exhibits recovery, the ratio (Post/Pre) staying below 1.0 suggests that the system has not fully returned to its pre-pandemic state. This study contributes to the urban resilience discourse, illustrating how PT system adjusts to COVID, offering insights for transportation planning.

The associations between maternal and fetal exposure to endocrine-disrupting chemicals and asymmetric fetal growth restriction: a prospective cohort study.

Recent evidence has revealed associations between endocrine-disrupting chemicals (EDCs) and placental insufficiency due to altered placental growth, syncytialization, and trophoblast invasion. However, no epidemiologic study has reported associations between exposure to EDCs and asymmetric fetal growth restriction (FGR) caused by placenta insufficiency. The aim of this study was to evaluate the association between EDC exposure and asymmetric FGR. This was a prospective cohort study including women admitted for delivery to the Maternal Fetal Center at Seoul St. Mary's Hospital between October 2021 and October 2022. Maternal urine and cord blood samples were collected, and the levels of bisphenol-A (BPA), monoethyl phthalates, and perfluorooctanoic acid in each specimen were analyzed. We investigated linear and non-linear associations between the levels of EDCs and fetal growth parameters, including the head circumference (HC)/abdominal circumference (AC) ratio as an asymmetric parameter. The levels of EDCs were compared between fetuses with and without asymmetric FGR. Of the EDCs, only the fetal levels of BPA showed a linear association with the HC/AC ratio after adjusting for confounding variables (ß = 0.003, p < 0.05). When comparing the normal growth and asymmetric FGR groups, the asymmetric FGR group showed significantly higher maternal and fetal BPA levels compared to the normal growth group (maternal urine BPA, 3.99 µg/g creatinine vs. 1.71 µg/g creatinine [p < 0.05]; cord blood BPA, 1.96 µg/L vs. -0.86 µg/L [p < 0.05]). In conclusion, fetal exposure levels of BPA show linear associations with asymmetric fetal growth patterns. High maternal and fetal exposure to BPA might be associated with asymmetric FGR.