• 한국환경과학회지
• /
• 제17권12호
• /
• pp.1413-1419
• /
• 2008

The Kyoto Protocol, that had been in force from February 16, 2005, requires significant reduction in $CO_2$ emissions for all anthropogenic sources containing transportation, industrial, commercial, and residential fields, etc, and automotive emission standards for air pollutants such as particulate matter (PM) and nitrogen oxides $(NO_x)$ become more and more tight for improving ambient air quality. This paper has briefly reviewed homogeneous charge compression ignition (HCCI) combustion technology offering dramatic reduction in $CO_2,\;NO_x$ and PM emissions, compared to conventional gasoline and diesel engine vehicles, in an effort of automotive industries and their related academic activities to comply with future fuel economy legislation, e.g., $CO_2$ emission standards and corporate average fuel economy (CAFE) in the respective European Union (EU) and United States of America (USA), and to meet very stringent future automotive emission standards, e.g., Tier 2 program in USA and EURO V in EU. In addition, major challenges to the widespread use of HCCI engines in road applications are discussed in aspects of new catalytic emissions controls to remove high CO and unburned hydrocarbons from such engine-equipped vehicles.

• 대한기계학회논문집B
• /
• 제28권11호
• /
• pp.1376-1383
• /
• 2004

In the present work, a series of experiments have been performed on electro-hydrodynamic atomization of non-conducting liquid using a charge injection type nozzle. Effects of liquid flow rate, input voltage, and distance between the needle and the ground electrode (nozzle-embedded metal plate) have been examined. For fixed electrode distances, total and spray currents increase with the increase of liquid flow rate and input voltage. When the distance between the needle tip and the ground electrode becomes closer, the total, leakage and spray currents increase, while the onset voltage for the dielectric breakdown decreases. When the electric field strength of the liquid jet exceeds that for the air breakdown, a portion of the electric charges in the liquid jet is dissipated into the ambient air, and the charge density shows a limiting value. Atomization quality can be improved by increasing the liquid flow rate due to the higher charge density and the enhanced aerodynamic effect.

• 한국환경보건학회지
• /
• 제15권2호
• /
• pp.1-9
• /
• 1989

A pilot study was conducted in order to measure indoor and outdoor formaldehyde levels during August 3 - 22, 1988 in several underground spaces in Seoul. Formaldehyde concentrations were monitored during 1 week in selected sampling areas (subway station, underground shopping center, underpass, tunnel, underground parking lot) using passive formaldehyde monitors. In order to investigate a relationship between respiratory prevalence and levels of formaldehyde, each subject was asked to answer respiratory questions. The mean formaldehyde concentrations were 60.1 ppb in subway station, 122.2 ppb in underground shopping stores, 72.1 ppb in underpasses, 39.7 ppb in tunnel, and 75.9 ppb in underground parking lots, respectively. The mean indoor formaldehyde concentrations in underground environments varied from 28.6 ppb to 118.7 ppb. Generally, the mean formaldehyde concentrations in ticketing office in subway stations appeared higher than those level measured in platform. The mean formaldehyde concentrations of underground shopping center in Gangnam Terminal were higher than any other areas and it exceeded 100 ppb of the American Ambient Air Quality Standards of formaldehyde. Prevalence rates of respiratory symptoms of dwellers seemed to be related to higher indoor formaldehyde levels.

• Asian Journal of Atmospheric Environment
• /
• 제3권1호
• /
• pp.1-8
• /
• 2009

Enhancement of aerosol optical thickness (AOT) and surface aerosol mass concentration in Korea for an active forest fire episode in Northeast Asia were estimated by Community Multi-scale Air Quality (CMAQ) model. MODIS/TERRA remote detects of fires in Northeast Asia for May 2003 gave a constraint for estimation of wildfire emissions with an NDVI distribution for recent five years. The simulated wildfire plumes and enhancement of AOT were evaluated and well resolved by comparing multiple satellite observations such as MODIS, TOMS, and others. Scatter plots of observed daily mean aerosol extinction coefficient versus $PM_{10}$ concentration in ground level in Korea showed distinctively different trends based on the ambient relative humidity.

• 한국전기전자재료학회논문지
• /
• 제18권7호
• /
• pp.600-604
• /
• 2005

We studied that structural and optical properties of ZnO films depend on oxygen contents. ZnO films were deposited on Si (111) substrates at room temperature by rf sputtering system and the thickness of films was 100 nm. The ZnO films were annealed in thermal furnace for 2 h at 800 and $900^{\circ}C$ in $H_2O,\;N_2$, and air ambient gases to control oxygen contents. We used AES, PL, XRD, AFM. As our result, crystal quality and luminescence improved until O/Zn is 1. However, when O/Zn ratio Is larger than 1, the structural and optical properties were getting worse.

• 한국대기환경학회지
• /
• 제7권1호
• /
• pp.67-71
• /
• 1991

최근 미국, 영국, 일본 등 선진국들의 정상이 모이는 G7 회담 등에서 논의되고 있는 것들 중 정치적인 문제를 제외하고는 환경문제를 가장 많이 다룬다는 외신보도를 우리는 여러번 접한 바 있다. 산업혁명 후 산업의 끊임없는 발달은 인류에게 생활수준의 향상과 편리성을 도모해 준 반면 환경오염으로 인한 지구파멸이란 위기감을 또한 우리에게 주었다. 1900년 이후 급격한 산업발달에 따른 석탄, 석유등 화석연료의 급증은 대기와 수질오염 등을 야기시켜 마침내는 고농도로 인한 인체피해가 수차례 대두되게 되었으며 이에 따라 1960년 이후 각국에서는 국민 건강 보호를 위하여 나라별로 일정한 기준을 설정하여 대기수질 등 오염물질을 규제하기 시작하였다. 따라서 본 고에서는 여러가지 기준중 대기환경기준 설정에 관한 정확한 의미와 내용을 분석하고 아울러 환경기준 제정시 기초가 된 내용을 상세히 풀이하여 환경기준을 이해하고 이를 지켜 나가는데 도움이 되고자 하였다.

• 한국대기환경학회:학술대회논문집
• /
• 한국대기환경학회 2003년도 추계학술대회 논문집
• /
• pp.209-210
• /
• 2003

국제 표준화 연구와 관련하여, 측정 및 분석과 관련된 국제기관들이 참여하여 1993년에 발행된 측정 불확도의 표현지침인 GUM은 데이터의 품질 관리 및 보증의 수단으로서 활발히 연구되고 있다. 특히, 국제적으로도 CCQM, CITAC, Eurachem, NIST 등의 기관을 중심으로 GUM 규격의 적용이 활발히 연구되고 있으나, 미국보다는 유럽에서 데이터 품질의 계량화 기술로서 연구되고 있다. 한편, 유해 대기오염물질인 중금속측정 자료가 국내에 축적되고 있음에도 불구하고 이러한 물질에 대한 측정 불확도가 거의 평가된 적이 없어 분석 값에 대한 보증을 위해 행하는 일련의 과정에 대한 표준 절차서가 시급한 현실이다.(중략)

• 한국대기환경학회지
• /
• 제8권4호
• /
• pp.262-268
• /
• 1992

The trend of international concerns on environmental conservation and domestic demand of ambient air quality improvement, specially on sulfur dioxide level has resulted in the establishment of mid-term strategy of environmental improvement and stepwise strengthening of emission regulations in this decade in Korea. Development of flue gas desulfurization(FGD) process is becoming an essential task to be accomplished especially for the power plants and large industrial facilities. This study is an initial stage researc focusing on the mass transfer principles in wet type FGD process and the effects of operating variables of a jet bubbling scrubber utilizing limestone slurry on sulfur dioxide removal efficiency. Experimental results showed this type of scrubbing system has some advantages in terms of mass transfer mechanism and removal efficiency. More rigorous research is needed for the reaction system and the comparison with existing FGD processess for the possible development of a process which is compatative in view of installation cost and treatment of by-products.

• 한국환경보건학회지
• /
• 제19권1호
• /
• pp.1-12
• /
• 1993

I. 서론 : 공해방지법이 1963년 11월 15일에 최초로 제장 공포된 이후 14년이 지난 1977년 환경보전법으로 개정되어 다음해 7월부터 본법을 시행하게 되었는바 이때 환경기준에 관한 규정이 최초로 설정되었다. 환경기준의 설정목적은 쾌적한 환경을 보전하고 환경오염으로부터 사람의 건강을 보호하기 위한 것으로서, 최초설정 당시에는 아황산가스, 일산화가스, 질소산화물, 부유분진, 옥시단트 등 5개 항목이었으나, 시행령에서 구체적 기준을 규정한 것은 아황산가스의 1개 항목으로서 장기기준(0.05ppm이하), 단기기준(0.15ppm이하)의 2가지로 구분설정하였다. 동시에 보사부장관과 시.도지사는 전국 혹은 관할 행정구역내에 측정망을 설치하여 환경오염도를 상시 측정토록 규정하고 있다. (생략)

• 한국대기환경학회지
• /
• 제22권5호
• /
• pp.590-603
• /
• 2006

Size-and time-resolved aerosol samples were collected using an eight-stage Davis rotating unit for monitoring (DRUM) sampler from 23 March to 29 April 2001 at Gosan, Jeju Island, Korea, which is one of the super sites of Asia-Pacific Regional Aerosol Characterization Experiment(ACE-Asia). These samples were analyzed using synchrotron X-ray fluorescence for 3-hr average concentrations of 19 elements including Al, Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb, and Pb. The size-resolved data sets were then analyzed using the positive matrix factorization(PMF) technique to identify possible sources and estimate their contributions to particulate matter mass. PMF analysis uses the uncertainty of the measured data to provide an optimal weighting. Twelve sources were resolved in eight size ranges($0.09{\sim}12{\mu}m$) and included continental soil, local soil, sea salt, biomass/biofuel burning, coal combustion, oil combustion, municipal incineration, nonferrous metal source, ferrous metal source, gasoline vehicle, diesel vehicle, and volcanic emission. The PMF result of size-resolved source contributions showed that natural sources represented by local soil, sea salt, continental soil, and volcanic emission contributed about 79% to the predicted primary particulate matter(PM) mass in the coarse size range ($1.15{\sim}12{\mu}m$) while anthropogenic sources such as coal combustion and biomass/biofuel burning contributed about 58% in the fine size range($0.56{\sim}2.5{\mu}m$). The diesel vehicle source contributed mostly in ultra-fine size range($0.09{\sim}0.56{\mu}m$) and was responsible for about 56% of the primary PM mass.