• Journal of Korean Society for Atmospheric Environment
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• v.28 no.1
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• pp.68-76
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• 2012

SULEV (Super Ultra Low Emission Vehicle) which is one of the emission standards in Fleet Average System introduced to Korea from 2009 is known as the most severe standard to achieve with internal combustion engine. Considering low sales volume of hybrid vehicles in Korea, vehicle manufacturers are required to develop SULEV technologies for conventional gasoline and LPG vehicles to meet the future Fleet Average standard. In this study, the comparison of emissions has been made between SULEV developed and ULEV LPG vehicles mainly produced in this time. To estimate the emission reduction of SULEV vehicles, CVS-75 and NIER test modes have been used. CVS-75 has been used for emission certification of gasoline and LPG vehicles. NIER modes cover various average vehicle speed and reflect Korean real driving patterns better than CVS-75. The test results show that SULEV LPG vehicles have very high potential to reduce $NO_x$ in regulated emissions, $N_2O$ in green house gases and toluene in VOCs. However, SULEV LPG vehicles don't affect much on the reduction of CO and total green house gases.

• Journal of Korean Society for Atmospheric Environment
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• v.33 no.2
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• pp.77-86
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• 2017

Globally, use of affordable fuels such as briquettes, woods and wood pellets has increased. Organic pollutants emitted from non-point sources using solid fuels may have contributed to air pollution in urban environment. In this study, we utilized simulated incinerator proposed by U.S. EPA and investigated concentrations of PM, $PM_{10}$, $PM_{2.5}$, OC/EC, CO, $SO_x$, $NO_x$, VOCs and PAHs emitted while cooking meat and fish using briquettes, woods and wood pellets, and developed emission factors. As a result, wood combustion produced more air pollutants than the others. Particulate matter emission factors for woods and wood pellets were 13.54 g/kg and 9.15 g/kg, respectively. Total VOCs emission factors for briquettes, woods and wood pellets were 36.12mg/kg, 46.13mg/kg and 18.26mg/kg, respectively. Additionally, total PAHs emission factors for briquette, woods and wood pellets were 0.44 mg/kg, 18.84mg/kg and 101.62mg/kg, respectively.

• Journal of ILASS-Korea
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• v.23 no.4
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• pp.175-184
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• 2018

Emission characteristics of regulated (NOx, PM, CO, NMHC) and unregulated (VOCs, aldehydes, PAHs) air pollutants were investigated for diesel heavy duty buses equipped with different after-treatment systems (DPF+EGR and SCR) under urban driving cycle. The combustion temperature and the working temperature of SCR catalysts were important to make impact on NOx emissions, whereas PM emissions were low. The alkane groups dominated NMVOCs emissions, making 42.6~59.4% of sum of the NMVOCs emissions. Especially, alkane emissions of DPF+EGR-equipped vehicle included DOC had 14.9~15.5% higher than those of SCR-equipped vehicle due to low efficiency of oxidation catalyst. In the case of individual NMVOCs, n-nonane and propylene emissions highly occupied for DPF+EGR and SCR, respectively. Formaldehyde emissions among aldehydes were the highest and PAHs emissions were hardly detected except naphthalene and phenanthrene. The NMHC speciation has been shown to be the highest of the formaldehyde ranged 20.8~21.5%. The results of this study will be contributed to establish Korean HAPs emission inventory for automobile source.

• The Plant Pathology Journal
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• v.38 no.2
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• pp.115-130
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• 2022

Though information exists regarding the pathogenesis of the shot-hole disease (SH) in flowering cherry (FC), there has been a lack of research focusing on SH management. Therefore, here, we investigated the inhibitory activities of antagonistic bacteria against SH pathogens both in vitro and in vivo as well as their biochemical characteristics and bioactive compounds. Two biosurfactant-producing bacterial antagonists, identified as Bacillus velezensis strains JCK-1618 and JCK-1696, exhibited the best effects against the growth of both bacterial and fungal SH pathogens in vitro through their cell-free culture filtrates (CFCFs). These two strains also strongly inhibited the growth of the pathogens via the action of their antimicrobial diffusible compounds and antimicrobial volatile organic compounds (VOCs). Crude enzymes, solvent extracts, and biosurfactants of the two strains exhibited antimicrobial activities. Liquid chromatography/electrospray ionization time-of-flight mass spectrometric analysis of the partially purified active fractions revealed that the two antagonists produced three cyclic lipopeptides, including iturin A, fengycin A, and surfactin, and a polyketide, oxydifficidin. In a detached leaf assay, pre-treatment and co-treatment of FC leaves with the CFCFs led to a large reduction in the severity of the leaf spots caused by Epicoccum tobaicum and Bukholderia contaminans, respectively. In addition, the two antagonists produced indole-3-acetic acid, siderophore, and a series of hydrolytic enzymes, along with the formation of a substantial biofilm. To our knowledge, this is the first report of the antimicrobial activities of the diffusible compounds and VOCs of B. velezensis against the SH pathogens and their efficiency in the biocontrol of SH.

• Journal of Korean Society for Atmospheric Environment
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• v.30 no.3
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• pp.251-260
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• 2014

Biomass burning is one of the significant emission source of PM and CO, but a few studies are reported in Korea. Air pollutants emission from biomass burning such as wood stove and boiler, and wood-pellet stove and boiler were estimated in this study. Activity levels related to biomass burning such as fuel types, amount of fuel loading, and location and temporal variation were investigated by field survey over Korea. Fuel loadings were 14.9 kg/day for wood stove, 31.3 kg/day for wood boiler, 12.8 kg/day for wood-pellet stove, 32.5 kg/day for wood-pellet boiler during the season of active use. These were mostly burned in winter season from october to april of next year. Estimated annual emissions from wood stove & boiler were CO 76,677, $NO_x$ 710, $SO_x$ 70, VOC 20,941, TSP 6,605, PM10 2,921, PM2.5 1,851, and NH3 7 ton/yr, respectively. Emissions from wood-pellet stove and boiler were CO 32,798, $NO_x$ 1,830, $SO_x$ 25, VOCs 5,673, TSP 629, PM10 457, PM2.5 344, and $NH_3$ 2 ton/yr, respectively. When the emission estimates are compared with total emissions of the national emission inventory (CAPSS: Clean Air Policy Support System), Those occupy 12.5%, 2.8% of total national emission for CO and PM10, respectively. These results show wood and wood-pellet burning appliances were one of the major source of air pollution in Korea. In future, these types of heaters need to be regulated to reduce air pollution, especially in suburb area.

• Journal of Microbiology and Biotechnology
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• v.28 no.2
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• pp.199-209
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• 2018

Volatile organic compounds (VOCs) are increasingly been recognized as the chemical mediators of mold interactions, shaping their community dynamics, growth, and metabolism. Herein, we selectively examined the time-correlated (0 D-11 D, where D = incubation days) effects of intraspecies VOC-mediated interactions (VMI) on Aspergillus oryzae KCCM 60345 (S1), following co-cultivation with partner strain A. oryzae KACC 44967 (S2), in a specially designed twin plate assembly. The comparative evaluation of $S1_{VMI}$ (S1 subjected to VMI with S2) and its control ($S1_{Con}$) showed a notable disparity in their radial growth ($S1_{VMI}$ < $S1_{Con}$) at 5 D, protease activity ($S1_{VMI}$ > $S1_{Con}$) at 3-5 D, amylase activity ($S1_{VMI}$ < $S1_{Con}$) at 3-5 D, and antioxidant levels ($S1_{VMI}$ > $S1_{Con}$) at 3 D. Furthermore, we observed a distinct clustering pattern for gas chromatography-time of flight-mass spectrometry datasets from 5 D extracts of $S1_{VMI}$ and $S1_{Con}$ in principle component analysis (PC1: 30.85%; PC2: 10.31%) and partial least squares discriminant analysis (PLS-DA) (PLS1: 30.77; PLS2: 10.15%). Overall, 43 significantly discriminant metabolites were determined for engendering the metabolic variance based on the PLS-DA model (VIP > 0.7, p < 0.05). In general, a marked disparity in the relative abundance of amino acids ($S1_{VMI}$ > $S1_{Con}$) at 5 D, organic acids ($S1_{VMI}$ > $S1_{Con}$) at 5 D, and kojic acid ($S1_{VMI}$ < $S1_{Con}$) at 5-7 D were observed. Examining the headspace VOCs shared between S1 and S2 in the twin plate for 5 D incubated samples, we observed the relatively higher abundance of C-8 VOCs (1-octen-3-ol, (5Z)-octa-1,5-dien-3-ol, 3-octanone, 1-octen-3-ol acetate) having known semiochemical functions. The present study potentially illuminates the effects of VMI on commercially important A. oryzae's growth and biochemical phenotypes with subtle details of altered metabolomes.

• Proceedings of the KIEE Conference
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• 2008.04a
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• pp.182-183
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• 2008

환기시설이 열악한 도시 지하철역 내의 대기환경은 지상보다 열악할 수밖에 없다. 현재 지하철역을 주로 사용하는 시민들의 안전을 보호 하고 지하철의 대기환경을 개선하기 위해 스크린 도어, 자동 제어 환기시설, 종합 영상 감지시스템 등 다양한 노력을 기울이고 있다. 하지만 일부 지하철역에 설치되어 있는 공기질 모니터링 시스템은 수입품에 의존하고 고가의 장비이므로 초기설치 비용뿐만 아니라 유지보수의 어려움을 겪고 있다. 본 논문에서는 이러한 문제점을 해결하기 위해 무선 센서 네트워크 기술을 적용하여 저가형 대기환경 모니터링 시스템을 개발했다. 이 시스템의 구성은 센서노드(ZED : ZigBee End Deice), 네트워크 코디네이터(ZCM : ZigBee Coordinator Modem), 수신서버로 구성된다. 지하철역 내부의 미세먼지, CO2, CO, 온습도, VOCs 데이터를 센싱할 수 있는 확장 센서보드를 설계한 후, 지하공간에서의 열악한 통신환경에서 QoS를 보장할 수 있도록 ZigBee 라우팅 기술을 이용한 센서노드(ZED)를 인터페이스하여 하나의 통합된 대기환경 센서 노드(ZED)를 개발했다. 또한 수신서버에 USB방식으로 연결되어 각각의 ZED로부터 데이터를 수신하는 센서노드(ZCM)과 전송된 데이터를 저장 및 처리하여 언제 어디서나 누구든지 인터넷을 통해 확인 가능하도록 지하철 대기환경 모니터링을 위한 수신서버를 개발했다.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.4
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• pp.493-501
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• 2004

The principle of vortex tube and cyclone was introduced to enhance the treatment efficiency of waste air streams containing particulate matters, toluene, and others developed by Hangreen Tech, Ltd. and Hoseo Chemical and Industrial Technology R＆D Center. Adsorption, condensation, and/or coagulation could be induced at low temperature zone formed by vortex tube and Joule-Thomson expansion. The pressurized air was introduced at the tangential direction into the cyclone system applied with the coaxial funnel tube. Easily condensible vapors such as toluene. carbon dioxide, and water vapor were adsorbed enforcedly on coagulated or condensed materials which were formed as cores for coagulation or condensation by themselves. These types of coagulation or condensation rates were rapidly promoted as the diameter being growing up. The maximum removal efficiency for carbon dioxide and toluene was achieved to about 87 and 90 percent, respectively. The Joule-Thomson coefficients were increased with the pressure of air injected in the range of the relative humidities between 10% and 30%. An optimum value was observed within the range of the tested temperatures at a fixed pressure. In conclusion. it could be identified that the treatment efficiency would be depended on the pressure of the process air introduced and physical and chemical characteristics of waste air streams containing target materials for a designed system. The final design parameters should be decided depending upon the given system and target materials.

• KIEAE Journal
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• v.10 no.3
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• pp.37-42
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• 2010

Together with the concern about the indoor air quality as sick house syndrome, the Ministry of Environment announced "Indoor Air Quality Control Law for the Multi Purpose Facility," which made the interests to be focused in the urgent understanding of current condition and preparation of measures about the indoor air pollution. The law was revised to obligatorily notify the amount of Formaldehyde and Volatile Organic Compounds in the case of newly constructed apartments with more than 100 houses. School also have its own indoor air quality guideline. Indoor air quality in school is very important because, children who very weak to indoor pollutants reside long time in there. The purpose of this paper is to to survey indoor air quality in school by field measurement. Field measurements were performed in 11 schools which were selected from 3 major cities(Incheon, Dae-jeon, chuncheon) in korea, Totally concentration of indoor pollutants were determined in 32 classroom. Target air pollutants were TVOC, formaldehyde, dust, CO, CO2. For the result of this investigation, Indoor air quality in classroom was very poor and it was found that some pollutants(TVOC, float bacteria) exceed the guideline.

• Journal of Environmental Science International
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• v.16 no.4
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• pp.433-440
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• 2007

The photodegradation and by-products of the gaseous toluene with $TiO_2$ (P25) and short-wavelength UV ($UV_{254+185nm}$) radiation were studied. The toluene was decomposed and mineralized efficiently owed to the synergistic effect of photochemical oxidation in the gas phase and photocatalytic oxidation on the $TiO_2$ surface. The toluene by the $UV_{254+185nm}$ photoirradiated $TiO_2$ were mainly mineralized $CO_2$ and CO, but some water-soluble organic intermediates were also formed under severe reaction conditions. The ozone and secondary organic aerosol were produced as undesirable by-products. It was found that wet scrubber was useful as post-treatment to remove water-soluble organic intermediates. Excess ozone could be easily removed by means of a $MnO_2$ ozone-decomposition catalyst. It was also observed that the $MnO_2$ catalyst could decompose organic compounds by using oxygen reactive species formed in process of ozone decomposition.