This study investigated odor generation and external leakage characteristics in a combined sewer system through field monitoring of manholes, catch basins, and box culverts. Odor samples were analyzed for malodor intensity in terms of the dilutionto- threshold (D/T) ratio using the air dilution sensory (ADS) test. In addition to the ADS tests, 22 offensive odorants as defined in the Korean Malodor Prevention Act were quantified. Among the odorants monitored, hydrogen sulfide showed not only the highest concentrations but was also the most frequently detected, indicating representative odor compounds. The mean hydrogen sulfide concentration reached 1,132 ppbv, with a maximum of 13,709 ppbv, corresponding to complex odor concentrations of up to 1,442 dilution-to-threshold units. On average, approximately 13% of the internal sewer odors escaped through manhole openings, which could easily cause odor nuisance exceeding the legal threshold at boundary lines. A comparison with national odor management standards indicated that the current regulations, based solely on in-pipe hydrogen sulfide concentration, do not adequately represent human sensory perception. The findings highlight the need to establish practical odor-control criteria that consider external leakage and perceptual intensity for effective sewer odor management in urban environments.

본 연구의 목적은 2023년 4월 충청남도 홍성군 대형산불피해지를 대상으로 산불로 인한 온실가스 배출량을 산정하여 국가 온실가스 인벤토리 고도화에 기여하고자 한다. 산불로 인한 온실가스 배출량은 2006년 IPCC 가이드라인에 따라 산정하였으며, 산정 인자인 연소면적은 Sentinel-2A 위성영상 기반의 differenced Normalized Burn Ratio (dNBR)을 활용하여 제작한 산불피해등급도를 이용하였고 지표층 및 수관층의 연료량 및 연소효율은 현장자료를 바탕으로 추정하였다. dNBR을 활용하여 제작한 산불피해등급도를 기반으로 산정한 온실가스 배출량은 약 19,336.9톤으로, 국립산림과학원 자료를 이용한 결과보다 약 4.0% 증가한 것으로 나타났다. 본 연구는 현장자료를 반영하여 산불로 인한 온실가스 배출량을 보다 정밀하게 산정한 데 의의가 있다. 향후에는 국내 생태계 특성을 반영한 각 요소별 고유 지표의 도입이 요구된다.

Accurate estimation of vehicle exhaust emissions at urban intersections is essential to assess environmental impacts and support sustainable traffic management. Traditional emission models often rely on aggregated traffic volumes or measures of average speed that fail to capture the dynamic behaviors of vehicles such as acceleration, deceleration, and idling. This study presents a methodology that leverages video data from smart intersections to estimate vehicle emissions at microscale and in real time. Using a CenterNet-based object detection and tracking framework, vehicle trajectories, speeds, and classifications were extracted with high precision. A structured preprocessing pipeline was applied to correct noise, missing frames, and classification inconsistencies to ensure reliable time-series inputs. Subsequently, a lightweight emission model integrating vehicle-specific coefficients was employed to estimate major pollutants including CO and NOx at a framelevel resolution. The proposed algorithm was validated using real-world video data from a smart intersection in Hwaseong, Korea, and the results indicated significant improvements in accuracy compared to conventional approaches based on average speed. In particular, the model reflected variations in emissions effectively under congested conditions and thus captured the elevated impact of frequent stopand- go patterns. Beyond technical performance, these results demonstrate that traffic video data, which have traditionally been limited to flow monitoring and safety analysis, can be extended to practical environmental evaluation. The proposed algorithm offers a scalable and cost-effective tool for urban air quality management, which enables policymakers and practitioners to link traffic operations with emission outcomes in a quantifiable manner.

This study sought to improve the accuracy of estimating national emissions of volatile organic compounds (VOCs) from consumer solvent products (CSPs) by updating emission factors and category-specific activity data. The classification of the CSPs, which was originally proposed by the U.S. Environmental Protection Agency, was reorganized to reflect domestic consumption patterns in Korea. VOC contents, product sales, and atmospheric evaporation rates of the CSPs were analyzed for subcategories including personal care products, household products, and automotive aftermarket products to update their emission factors. Additionally, the category-specific activity data, previously based on only population statistics, were newly applied to count the characteristics of each classification, such as the number of households and the number of registered automobiles. The updated emission factors were calculated to be 1.90 kg/capita·yr for personal care products, 4.37 kg/household·yr for household products, and 2.36 kg/car·yr for automotive products. An evaluation of uncertainties revealed the limitation in the product classification, the shortage of sales data, and the lack of information on VOC contents depending on the product forms (liquid, solid, and aerosol). This study highlighted the necessity of developing detailed classification systems and standardized VOC content measurement methods, ultimately contributing to more accurate and practical assessments of VOC emissions from the CSPs.

This study aimed to assess the current global efforts to reduce greenhouse gas emissions and understand the domestic scenario, particularly focusing on pavement-marking works during road-construction projects. Using internationally commercialized programs, this study aimed to calculate carbon emissions from these projects, identify areas that require further action or improvement, and propose strategies to address them. This study assessed the current global efforts to reduce greenhouse gas emissions and understand the domestic scenario, particularly focusing on pavement-marking works during road-construction projects. Using internationally commercialized programs, this study aimed to calculate carbon emissions from these projects, identify areas that require further action or improvement, and propose strategies to address them. Carbon dioxide emissions from pavement-marking projects were estimated. For a 5,746 m2 construction project, a total of 96.637 was emitted; for a 5,032 m2 project with four types of markings, 89.840 was emitted. A project involving five types of markings, traffic controls, and safety measures resulted in 6.662 emissions. On average, 16.8 was emitted per 1 m2, with 17.8 for the four types and 9.3 for the five types of markings. This study is significant because it calculated the carbon dioxide emissions from domestic pavement-marking works. The use of unit price data is convenient, and for more accurate calculations, expanding environmental product declaration (EPD) certified items and accelerating the establishment of a domestic life-cycle inventory (LCI) are recommended.

PURPOSES : The study aims to establish a comprehensive life cycle assessment model for bridges in South Korea considering domestic carbon emission factors. The main aims are to evaluate the carbon emission of bridge construction, focusing on the Seong-ri Bridge as a case study, and to improve national environmental policies and management strategies. METHODS : We utilized the life cycle assessment (LCA) methodology, adhering to standards set by ISO, to categorize each phase of the bridge's life cycle. The process involved selecting the bridge type based on the compilation of a detailed analysis range. The analysis covered various stages from raw material supply (A1-A3) to construction (A4-A5) and maintenance (B2-B5), excluding certain stages due to data unavailability. Carbon emission factors were then applied to quantify emissions at each stage. RESULTS : The findings indicate that the raw material production phase (A1-A3) contributes to approximately 96% of the total carbon emissions, highlighting its significant impact. We report detailed calculations of emissions using domestically developed emission factors for materials such as steel and concrete and establish a carbon emission per unit length measure for comparative analysis with other infrastructure. CONCLUSIONS : We leveraged LCA ISO standards to analyze each stage of the Seong-ri bridge, calculating its carbon emissions based on domestic factors for CO2, CH4, and N2O. By tailoring the study to Korea-specific emission factors, we develop a greenhouse gas model closely aligned with the nation’s environmental conditions. The results contribute to improving environmental impact assessments and strategically aiding national policy and management decisions.

This study aimed to estimate the odor emission rate from swine nursery facilities (naturally and mechanically ventilated) using probability distribution. Odor occurrence trends in the study facilities were very different; odor concentration and gas flow had a lognormal distribution. Monte Carlo simulation was used to carry out the uncertainty analysis. Odor emission rate was found to range from 18.05 OU/sec (10th percentile) to 621.88 OU/ sec (90th percentile), and odor emission rate per head ranged from 0.02 OU/sec · head (10th percentile) to 0.64 OU/ sec · head (90th percentile).

PURPOSES : This study proposes a methodology to collect data necessary for microlevel emission estimation, such as second-by-second speeds and road grades, and to accordingly estimate emissions. METHODS: To ease data collection for microlevel emission estimation, a vehicle equipped with speed- and location-recording instruments as well as equipment for measuring road geometry was used. As a case study, this vehicle and the proposed methodology were used on a 10- km-long highway in Yongin City, Korea. Emissions from the vehicle during driving were estimated in various microscale driving conditions. RESULTS : Differences in the estimated emission under different microscale driving conditions cannot be ignored. Compared with the estimations obtained when second-by-second data were not considered, CO and NOx emissions were more than threefold higher when considering second-by-second speed; similarly, CO and NOx emission estimations were higher by approximately 10% and 3%, respectively, when considering second-by-second road grade. CONCLUSIONS : The proposed method can estimate vehicle emissions under real-world driving conditions in such applications as road design and traffic policy assessments.

In this study, leachate treatment facility (outlet, facility inside) and landfill sections (vent systems, landfill surface)of nine landfills is being buried in korea were studied emission characteristics of odor compounds. Air dilutionvalue in ventpipes of landfill section was generally highest and was more 3 times higher than emission standard(air dilution value of facilities outlet : 500) in Daejeon, Tongyeong, and Busan landfill. Outlet of leachate treatmentfacilities in Tongyeong and Daegu landfill, in case, was higher respectively 20 times, 6 times than other landfills,commonly show that a large contribution to the odor of hydrogen sulfide. In case of ordor emission rate, ammoniaand hydrogen sulfide were surveyed to comprise a high rate for odor emission rate. Odor emissions based onlandfill scale, large landfill (Sudokwon) and small landfills (Yeosu, Chuncheon, Chungju) is low in odor emissionsper unit area, whereas medium landfill (Busan, Daejeon, Daegu) was estimated to be high odor emissions. In caseof large landfill, leachate treatment facilities is management in good condition and discharged odor emission oflandfill sections was low into ambient air. In case of small landfill, decay gases and leachate is few. Thereforeodor emissions is fewer than estimated medium landfill. In case of medium landfill, management condition ofleachate treatment facility was in poor and landfill sections was under not stabilization stage. Thus, mediumlandfills was identified that needs to be intensive care.

고형페기물 매립지에서 온실가스 배출량 산정은 기후변화에 대응 측면에서 매우 중요한 사항이다. 국내에서 메탄가스 배출량 산정은 주로 IPCC(Intergovernmental Panel on Climate Change)가이드라인에 근거하여 매립지 표면에서 직접적으로 flux chamber를 이용하여 배출량을 측정하거나, 또는 FOD(First Order Decay)방법에 의존하여 왔다. 그러나 FOD방법은 매립특성을 반영한 매립가스발생속도상수(k)를 정확히 산정하는데 어려움이 존재하고, 또한 표면 발산량을 측정하는 방법은 매립지 표면에서 배출량이 다양하고 측정이 한정된 기간에만 국한된다는 문제점을 내재하고 있다. 대안으로 본 연구에서는 plume measurement의 한 방법으로 대기확산모델을 활용한 역모델링기법을 적용하는 것을 검토하였다. 역모델링에 의해서 매립지 메탄가스 배출량을 직접 계산하기 위한 방법론을 정리하고, 실제 대전매립지에서 측정한 메탄농도를 이용하여 역모델링기법을 적용한 매립지 메탄 배출량 산정하는 방법에 대하여 제시하였다. 역모델링 과정을 검증하기 위해서 임의의 배출량으로 모델링을 수행하여 모델 예측농도와 확산변수 를 계산하였으며, 역으로 예측농도와 확산변수 를 이용하여 배출량을 재산정 하였다. 재산정한 배출량이 임의의 배출량과 동일함을 확인함으로써 본 연구에서 제시하고 있는 역모델링 절차가 적절함을 검증하였다. 또한, 본 연구에서는 역모델링 기법을 적용하여 실제 대전매립지를 대상으로 메탄 배출량 산정하였다. 대전매립지를 대상으로 메탄배출량을 산정한 결과 29.65~36.68 g/㎡-day로 산정되었으며, 주요 메탄 배출지점은 매립지 내의 유사한 지점에서 일관되게 나타났다. 본 연구방법은 기존의 방법과 비교하면, 메탄농도의 측정방법이 간단하고 비용이 적게 소요되므로 지속적인 모니터링이 가능한 장점이 있으며, 불균일한 매립지 표면의 배출량을 비교적 간편하게 산출이 가능한 것으로 파악되었다. 한편, 본 연구는 제한된 실험에 의한 결과이므로 향후 실제 매립지 배출량을 직접 측정하거나, 또는 추적자 실험을 통해서 그 방법론을 추가로 검증할 필요가 있는 것으로 판단된다.

Organic light emitting diode(OLED) has been developed fast from 1963 when electric light emitting phenomenon was discovered. PMOLED(passive matrix OLED) is producted earlier than AMOLED(active matrix OLED). PMOLED is mainly mounted at sub display, but AMOLED is mounted at main display. Nowadays AMOLED is expanded to PMP(portable multimedia players), navigation and TV market. Even thought OLED's market is opening to many applications, OLED's life is worried until now. If we know about OLED's real life, we need time to test so much time over 20,000hrs. Realistically, there is difficult to test such as long time with products from the information-technology sector having a short life cycle. In this paper, we study about OLED's accelerated test to reduce life test by current. We can design OLED's accelerated life model by the result of test. The model consists of design variables like ratio of light emitting, organic material structure, condition of aging, etc. In conclusion, this model can be applied to study about organic material, machine and manufacturing process etc, and also it's possible to develop a method of manufacturing process & materials, so we need to study on the subject of this paper continuously.

This study is deal with the high frequency induction hardening (HF at 850℃, 120kHz & 50kW condition) SM45C steel. (1) The HF specimen which was tempered at 150℃, did not appear any tempering effect. A brittle fracture occurred at rounded area of the tensile specimen. AE amplitude distribution showed between 45~60dB. (2) The HF specimen which was tempered at 300℃, slip and fracture occurred at the hole area of the tensile specimen. As it passes the yield point, the AE energy increased intermittently and AE amplitude distribution showed between 70~85dB. In addition, after the maximum tensile load, it showed high amplitude and energy distribution. The AE amplitude showed between 45~70dB. (3) The HF specimen which was tempered at 450℃, a brittle fracture occurred as if it is torn in the direction of 45℃ on parallel area over the both sides of the tensile specimen, which led to several peak to be appeared in AE energy. It was found that the AE amplitude was relatively low and the AE energy was high.

We are often faced with the task of having to estimate the amplitude of a source signal in the presence of a background. In the simplest case, the background can be taken as being flat, and of unknown magnitude B, and the source signal of interest assumed to be the amplitude A of a peak of known shape and position. We present a robust method to find the most probable values of A and B by applying the one-dimensional Newton-Raphson method. In the derivation of the formula, we adopted the Bayesian statistics and assmumed Poisson distribution so that the results could be applied to the analysis of very weak signals, as observed in FIMS (Far-ultraviolet IMaging Spectrogaph).