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As it is predicted that the amount of urban on-road CO2 emissions will continue to increase, it is essential to manage urban on-road CO2 concentration for effective urban CO2 mitigation. However, limited observation of on-road CO2 concentration prevents the full understanding of the variation of urban on-road CO2 concentration. Therefore, in this study, a machine learning based model that predicts on-road CO2 concentration (CO2traffic) was developed for Seoul, South Korea. This model predicts hourly CO2traffic with high precision (R2 = 0.8 and RMSE = 22.9 ppm) by utilizing CO2 observation, traffic volume, traffic speed, and wind speed data as main factors. Analyzing the CO2traffic data predicted by the model, the high spatiotemporal inhomogeneity of CO2traffic over Seoul with 14.3 ppm by time and 345.1 ppm by road was found. The large spatiotemporal variability of CO2traffic is related to different road types (major arterial road, minor arterial road, and urban highway) and land-use types (residential, commercial, bare ground, and urban vegetation) where the road belongs. The cause of the increase in CO2traffic was different by its road type, and the diurnal variation of CO2traffic was different by its land-use type. Our results demonstrate that high spatiotemporal on-road CO2 monitoring is needed to manage the urban on-road CO2 concentration showing high inhomogeneity. In addition, it suggests that a model using machine learning techniques can be an alternative for monitoring CO2 concentrations on all roads without conducting the observation.This work was supported by Korea Environment Industry &Technology Institute(KEITI) through "Climate Change R&D Project for New ClimateRegime.", funded by Korea Ministry of Environment(MOE) (2022003560006).

For the first time, mobile campaign and building monitoring experiments were conducted in downtown Seoul, Korea during the 2018/2019 winter period to assess the possibility of the co-benefit of CO2 emission reduction and air quality improvement. Given that CO2 and air pollutants in cities both originate from fossil fuel combustion, monitoring urban CO2 concentrations using a mobile vehicle and from the top of tall buildings can be a potentially effective approach for diagnosing the air quality. The local enhancement values (△species) related to urban emission sources were estimated by eliminating baseline concentrations. The results obtained showed high correlation coefficients between △CO2 and △air pollutants (i.e., 0.753, 0.505, and 0.525 for △CO, △NOX, and △NO2), confirming the applicability of CO2 as an indicator of air pollutant sources in downtown Seoul. The evaluation of the air quality in the study area using air pollutant ratios, including the ratios of CO and NOX/NO2, relative to CO2 showed that the ratios of △CO, △NOX, and △NO2 relative to △CO2 were 5.76, 1.89, and 0.21 ppb ppm−1. The estimated △NO2/△NOX ratio (11%) and a comparison of the △NOX/△CO2 ratios obtained with those reported for other cities in different countries suggested the possibility of a relationship between the current air quality in downtown Seoul and the use of diesel vehicles. Results suggest that the development of municipal policies aimed at mitigating climate change should consider the co-benefit of air quality improvement so as to ensure the effective reduction of CO2 and air pollutant emissions.

With the increasing importance of monitoring and verifying urban CO2 concentrations to mitigate carbon emissions from cities, a high-resolution ground networks of low-cost CO2 sensors are emerging that have a price advantage over existing high-cost sensors. This study develops a low-cost CO2 instrument called the Seoul National University CO2 Measurement (SNUCO2M) to monitor and analyze intra-city CO2 concentrations over Seoul, Korea. The first step of establishing this low-cost CO2 sensor network involved installing the SNUCO2M at the Yongsan Building (YSB; 113 m MASL) and Namsan Seoul Tower-High (NSTH; 385 m MASL) on October 18, 2018 and July 8, 2019, respectively. For comparison with the SNUCO2M, we utilized CO2 concentrations measured by the Picarro instrument (high-cost CO2 sensor) at Gwanak Mountain (GWA) background measurement site and the lower part of the NST (NSTL). The initial CO2 measurements from the SNUCO2M, show that 1) the SNUCO2M has a 0.71% maximum error range and is sufficient to measure urban atmospheric CO2 concentrations; and 2) the SNUCO2M captures 26.92 and 20.30 ppm of Seoul’s summer and winter time CO2 enhancement compared to the GWA background site. Our results suggest that the low-cost sensors such as SNUCO2M successfully detect urban CO2 characteristics over the megacity and has great potential to replace high-cost sensors with cost and management limitations.

Exact assessment of urban atmospheric CO2 enhancement, which is higher than background CO2 concentrations, is critical to mitigate carbon emissions in the city. However, ground-based atmospheric CO2 measurements covering the diverse landscape across the city are still limited. This study utilizes the column integrated CO2 concentration (XCO2) data obtained from the NASA Orbiting Carbon Observatory-2 (OCO-2) to evaluate urban CO2 enhancements over Seoul Capital Area (SCA) of South Korea for the period 2014–2018. In this study, Jirisan National Park (JNP), which is the cleanest area on the same orbit track with SCA, is defined as the background area considering its strong vegetation activity and low anthropogenic carbon emissions. By comparing XCO2 between SCA and JNP based on wind speed, we find an apparent increase in XCO2 by 1.71 to 2.21 ppm over SCA only on the days with wind speed less than 4 m s−1. Strong wind speed (e.g., over 4 m s−1) disrupts the identification of XCO2 enhancements over SCA due to atmospheric mixing between SCA and JNP. In addition, we compare estimated XCO2 differences between SCA and JNP from OCO-2 with other low-resolution data. This increase in XCO2 over SCA is only observed in OCO-2. Overall, our results suggest that high-resolution satellite remote sensing of XCO2 constrained by wind speed has strong potential to open up the possibility of identifying atmospheric CO2 enhancements in the city where ground-based observations are limited.

Out-of-hospital cardiac arrest (OHCA) is a notable public health issue with negative outcomes, such as high mortality and aftereffects. Additionally, the adverse effects of extreme temperatures on health have become more important under climate change; however, few studies have investigated the relationship between temperature and OHCA. In this study, we examined the association between temperature and OHCA and its underlying risk factors. We conducted a two-stage time-series analysis using a Poisson regression model with a distributed lag non-linear model (DLNM) and meta-analysis, based on a nationwide dataset from South Korea (2008-2018). We found that 17.4% of excess OHCA was attributed to cold, while 0.9% was attributed to heat. Based on central estimates, excess OHCA attributed to cold were more prominent in the population with hypertension comorbidity (31.0%) than the populations with diabetes (24.3%) and heart disease (17.4%). Excess OHCA attributed to heat were larger in the populations with diabetes (2.7%) and heart disease comorbidity (2.7%) than the population with hypertension (1.2%) based on central estimates. Furthermore, the time-varying excess OHCA attributed to cold have decreased over time, and although those of heat did not show a certain pattern during the study period, there was a weak increasing tendency since 2011. In conclusion, we found that OHCAs were associated with temperature, and cold temperatures showed a greater impact than that of hot temperatures. The effects of cold and hot temperatures on OHCA were more evident in the populations with hypertension, diabetes, and heart diseases, compared to the general population. In addition, the impacts of heat on OHCA increased in recent years, while those of cold temperatures decreased. Our results provide scientific evidence for policymakers to mitigate the OHCA burden attributed to temperature.

Aims It has been well known that air pollution and sleep deprivation individually have impacts on human health; however, the association between the two has not been well researched. The aim of this study was to investigate this relationship at a community level. Methods We collected sleep outcomes from the Korean Community Health Survey between years of 2008 and 2016. The data contained 1 130 080 selected adults aged ⩾ 19 years, from 141 communities. As sleep outcomes, annual chronic sleep deprivation (% of people who sleep ⩽ 5 h per day on average) and average values of daily mean sleep duration were used. Community-specific annual averages of particulate matter with a diameter ⩽ 10 μm (PM10), nitrogen dioxide (NO2) and carbon monoxide (CO) were collected and then applied to a linear mixed effects model to estimate the association between air pollution over the past 4 years and sleep outcomes. Population density, green space, health behaviour, and gross regional domestic product per capita variables were considered as confounders in all mixed effect models. Results From the linear mixed effect models, we found that the chronic sleep deprivation % was positively associated with PM10 (0.33% increase with 95% CI 0.05–0.60; per 10 μg/m3) and NO2 (0.68% with 95% CI 0.44–0.92; per 10 ppm). Higher PM10 and NO2 were also associated with shorter sleep duration, with a reduction of 0.37 min (95% CI −0.33 to 1.07 min; per 10 μg/m3) and 2.09 min (95% CI 1.50–2.68 min; per 10 ppm), respectively. The associations between PM10 and sleep outcomes were higher in females than males and in the older age groups (⩾ 60-years) than in younger age groups (19–39 and 40–59 years). However, the association between NO2 and sleep outcomes were more higher in males than in females and in the younger age groups (19–39 years) than other age groups. Conclusions Our findings provide epidemiological evidence that long-term interventions to reduce air pollutions are anticipated to provide improvements in sleep deficiency.

Cities are a major source of atmospheric COAnnual COOur results demonstrated that most urban areas acted as CO

With the spread of the COVID-19 virus globally, cities worldwide have implemented unprecedented social distancing policies to mitigate infection rates. Many studies have demonstrated that improved air quality and reduced carbon emissions have resulted from the COVID-19 pandemic. Yet, questions remain regarding changes in atmospheric CO2 concentrations because of the complex cycles involving the interaction of CO2 with the natural environment. In this study, we compared the changes in urban CO2 enhancement (△CO2) reflecting the contribution of local CO2 emissions to the atmospheric CO2 in urban areas, according to the intensity of social distancing policies implemented during the COVID-19 pandemic in Seoul, South Korea. We used data from three CO2 ground observation sites in the central area of Seoul and outside the urban area of Seoul. By comparing the urban CO2 concentration in Seoul with that of the background area using two different methods, considering both vertical and horizontal differences in CO2 concentration, we quantified the △CO2 of the pre-COVID-19 period and two COVID-19 periods, during which intensive social distancing policies with different intensities were implemented (Level 1, Level 2.5). During the pre-COVID-19 period, the average △CO2 calculated using the two methods was 24.82 ppm, and it decreased significantly to 16.42 and 14.36 ppm during the Level 1 and Level 2.5 periods, respectively. In addition, the urban contribution of Seoul to atmospheric CO2 concentration decreased from 5.27% during the pre-COVID-19 period to 3.54% and 3.19% during the Level 1 and Level 2.5 periods, respectively. The results indicate that the social distancing policies implemented in Seoul resulted in reduced local CO2 emissions, leading to a reduction in atmospheric CO2 concentration. Interestingly, it also shows that the extent of atmospheric CO2 concentration reduction can be greatly affected by the intensity of policies. Our study suggests that changes in human activity could reduce the urban direct contribution to the background CO2 concentration helping to further mitigate climate change.

With the spread of the COVID-19 virus globally, cities worldwide have implemented unprecedented social distancing policies to mitigate infection rates. Many studies have demonstrated that improved air quality and reduced carbon emissions have resulted from the COVID-19 pandemic. Yet, questions remain regarding changes in atmospheric CO2 concentrations because of the complex cycles involving the interaction of CO2 with the natural environment. In this study, we compared the changes in urban CO2 enhancement (△CO2) reflecting the contribution of local CO2 emissions to the atmospheric CO2 in urban areas, according to the intensity of social distancing policies implemented during the COVID-19 pandemic in Seoul, South Korea. We used data from three CO2 ground observation sites in the central area of Seoul and outside the urban area of Seoul. By comparing the urban CO2 concentration in Seoul with that of the background area using two different methods, considering both vertical and horizontal differences in CO2 concentration, we quantified the △CO2 of the pre-COVID-19 period and two COVID-19 periods, during which intensive social distancing policies with different intensities were implemented (Level 1, Level 2.5). During the pre-COVID-19 period, the average △CO2 calculated using the two methods was 24.82 ppm, and it decreased significantly to 16.42 and 14.36 ppm during the Level 1 and Level 2.5 periods, respectively. In addition, the urban contribution of Seoul to atmospheric CO2 concentration decreased from 5.27% during the pre-COVID-19 period to 3.54% and 3.19% during the Level 1 and Level 2.5 periods, respectively. The results indicate that the social distancing policies implemented in Seoul resulted in reduced local CO2 emissions, leading to a reduction in atmospheric CO2 concentration. Interestingly, it also shows that the extent of atmospheric CO2 concentration reduction can be greatly affected by the intensity of policies. Our study suggests that changes in human activity could reduce the urban direct contribution to the background CO2 concentration helping to further mitigate climate change.

The United States has the highest numbers of confirmed cases and deaths during the novel coronavirus disease 2019 (COVID-19) pandemic. Previous studies reported that urban residents are more vulnerable to the spread and mortality of COVID-19 than rural residents. However, the pathways through which urban environments affect COVID-19 spread and mortality are unclear. We collected daily data on the number of confirmed cases and deaths of COVID-19 from Mar. 01 to Nov. 16, 2020 for all 91 counties in New York, New Jersey, and Connecticut in the United States. We calculated the COVID-19 incidence %, daily reproduction number, and mortality %, then estimated the associations with urban environment indicators using regression models. COVID-19 outcomes were generally highest in areas with high population density, and this pattern was evident in the early period of epidemic. Among the area-level demographic variables, the percentage of Black or Hispanic residents showed the strongest positive association with COVID-19 outcomes. Higher risk of COVID-19 outcomes was also associated with higher percentage of overcrowded households, uninsured people, and income inequality. The percent elderly, sex ratio (the ratio of males to females), and greenness were negatively associated with risk of COVID-19 outcomes. The results of this study could indicate where resources are most needed., Graphical abstract Unlabelled Image

Social restriction in cities to curb infection rates of COVID-19 has become an opportunity to investigate the relationship between humans and the urban atmosphere We evaluate the impact of the decline in human activities as a result of social distancing on the urban CO2 concentrations and air quality in Seoul during February and March of 2020 compared to 2019 Due to the reduction in human activity in 2020, local measurements of CO and NO2 show a decrease in background concentration (up to –11 9% and –41 7%, respectively) and urban enhancement (up to –16 7% and –38 1%, respectively) compared to the previous year In contrast, the background concentration of CO2 increases by 3 9% in 2020 Ratios of CO:CO2 and NO2:CO2 also show a decrease in 2020 compared to the previous year, signaling an improvement in the urban air quality of Seoul Moreover, the insignificant change in wind speed and wind direction during the months of February and March 2020 compared to 2019 implies that CO2, CO, and NO2 concentrations have not been influenced by meteorological conditions, but mainly by changes in emissions from decreased human activity Despite the rise in background CO2 concentration, urban contributions of CO2 show a decline of –12 6%, indicating that cities with high emissions have the potential to reduce urban CO2 enhancements and air pollutant concentrations, and ultimately impact the global atmosphere © The Author(s)

PURPOSE To compare the efficacy between 23-gauge sutureless pars planar vitrectomy (PPV) and anterior vitrectomy in the management of vitreous loss associated with posterior capsular rupture during cataract surgery. METHODS Medical records of 139 eyes which sustained posterior capsular rupture and vitreal prolapse to anterior chamber during cataract surgery were retrospectively reviewed. Thirty-two eyes which underwent 23-gauge sutureless PPV (group PPV) and 107 eyes which underwent anterior vitrectomy (group AntV) were compared in postoperative visual and anatomical outcomes, operation time, and complications. RESULTS No significant differences were found between the groups in final best-corrected visual acuity of 20/40 or better (AntV vs. PPV = 80.4 vs. 90.6%, P = 0.139). However, the visual recovery rates (20/40 or better) 1 day, 1 week, 1 month postoperatively were significantly higher in group PPV (AntV vs PPV = 22.4 vs. 44%, 32.2 vs 58.6, 51.9 vs. 78.1%). Postoperative intraocular pressure-related complications requiring medication were less evident in group PPV (AntV vs. PPV = 52.3 vs. 6.3%, P < 0.001). Twelve cases (11.2%) of group AntV and 0 cases of group PPV underwent secondary operation during follow-up. Although no postoperative complications occurred in group PPV, complications such as endophthalmitis, retinal detachment, cystoid macular edema, intraocular lens instability were observed in the AntV group (none vs. 14%, P = 0.022). CONCLUSION Twenty-three-gauge sutureless PPV is a safe and reliable solution for managing vitreous loss during cataract surgery. Therefore, it is expected to be considered primarily in institutes with vitreoretinal surgeons.

Studies on the pattern of heatwave mortality using nationwide data that include rural areas are limited. This study aimed to assess the risk of heatwave-related mortality and evaluate the health risk-based definition of heatwave. We collected data on daily temperature and mortality from 229 districts in South Korea in 2011&ndash, 2017. District-specific heatwave-related mortality risks were calculated using a distributed lag model. The estimates were pooled in the total areas and for each urban and rural area using meta-regression. In the total areas, the threshold point of heatwave mortality risk was estimated at the 93rd percentile of temperature, and it was lower in urban areas than in rural areas (92nd percentile vs. 95th percentile). The maximum risk of heatwave-related mortality in the total area was 1.11 (95% CI: 1.01&ndash, 1.22), and it was slightly greater in rural areas than in the urban areas (RR: 1.23, 95% CI: 0.99&ndash, 1.53 vs. RR: 1.10, 95% CI: 1.01&ndash, 1.20). The results differ by age- and cause-specific deaths. In conclusion, the patterns of heatwave-related mortality risk vary by area and sub-population in Korea. Thus, more target-specific heatwave definitions and action plans should be established according to different areas and populations.

To examine the prognostic factors for visual outcome in Korean BD patients with uveitis.Seventy-seven Korean BD patients with uveitis were enrolled. HLA-B and HLA-A genotypes were determined by PCR-based method. Visual acuity was measured by Snellen chart. Vision loss was graded into visual impairment (VI) defined as VA20/40 for more than 6 months, loss of useful vision (LUV) as VA20/200, and near total blindness (NTB) as VA of light perception or worse.VI was associated with a longer duration of uveitis, posterior uveitis, and cataract, LUV with male gender, a longer duration of uveitis, posterior uveitis, and cataract, and NTB with a longer duration of uveitis, cataract, and glaucoma. HLA-B*51 and HLA-A*26:01 did not show any association with VI, LUV, or NTB. However, HLA-B*51 carriers had earlier onset of uveitis and HLA-A*26:01 was strongly associated with posterior uveitis. In patients with posterior uveitis, VI was associated with a longer duration of uveitis and cataract, LUV with a longer duration, and NTB with HLA-B*51.Longer duration of uveitis, posterior uveitis, male gender, cataract, and glaucoma were found to be associated with poor visual outcome in BD-related uveitis. HLA-B*51 was associated with NTB in patients with posterior uveitis. HLA-A*26:01 showed no association with VI, LUV, or NTB, however, was strongly associated with posterior uveitis.

Aim To evaluate the surgical outcome after the insertion of smooth surface tunnel porous polyethylene orbital implants (Medpor SST) in children with retinoblastoma. Methods 44 consecutive children with retinoblastoma who underwent primary enucleation and Medpor SST implantation at Seoul National University Hospital from November 2004 to August 2009, with at least 24 months of follow-up were included. A retrospective review of cases was performed. Results Mean age at the time of surgery was 24.7 months (range 1–65 months). The diameter of the spherical implant was 20 mm in 36 patients (81.8%) and 18 mm in 8 patients (18.2%). During a mean follow-up period of 60.1 months (range 26–93 months), there were no cases of implant exposure, extrusion or infection. Transient conjunctival thinning developed in three patients, but all resolved with conservative treatment. Anophthalmic socket complications such as lower lid malposition (retraction or entropion) (n=10, 22.7%), blepharoptosis (n=8, 18.2%) and enophthalmos (n=2, 4.5%) developed, but most showed acceptable cosmesis. Conclusions Medpor SST is relatively safe, allowing for a mean follow-up of 5 years in terms of implant exposure, and may be a good choice of orbital implant for children with retinoblastoma.

Purpose: To report a large-angle exotropia, limited adduction, epiblepharon, high myopia and no pupillary light reflex in a patient with hydranencephaly. Case summary: A ten-year-old girl with mental retardation presented with exotropia. The patient could fix only with the right eye and was unable to follow with either eye. The Krimsky test revealed 95 prism diopters of exotropia, and adduction was severely limited in both eyes. Pupillary light reflex was absent in both eyes. Cycloplegic refraction showed high myopia in both eyes. Slit lamp examination revealed lower lid epiblepharon and inferior corneal opacity in the right eye. No abnormal findings in the fundus examination were detected. A computed tomogram of the brain showed that the cerebral hemispheres were replaced by a cystic space filled with cerebrospinal fluid, compatible with hydranencephaly. Recession of the lateral rectus muscle and resection of the medial rectus muscle with epiblepharon repair of the lower lid were performed in both eyes. One week postoperatively, the epiblepharon was corrected, and the Krimsky test showed 16 prism diopters of left intermittent exotropia at near. Conclusions: When a combined manifestation of mental retardation, limited adduction, no pupillary light reflex and a large-angle exotropia is present, the possibility of a congenital developmental anomaly of the central nervous system including hydranencephaly should be suspected.