• 한국산업보건학회지
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• 제24권4호
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• pp.462-470
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• 2014

Objectives: The purpose of this study was to evaluate quartz concentrations in airborne respirable dust and particle size-related quartz concentrations. Methods: Respirable dust samples were collected using a 10 mm Dorr-Oliver nylon cyclone equipped with a 37 mm, $5{\mu}m$ pore size PVC filter. Dust samples were collected with a Marple's personal cascade impactor from stone grinding operations in five stone-related business located in the Gyeongsangbuk-do area. Results: The geometric mean of quartz concentration in the respirable dust was $0.170mg/m^3$, and the rate of exceeding the Korean Occupational Exposure Limit(KOEL) was 93.3%. The quartz concentration by particle size shows that it was the highest($0.115mg/m^3$) in stage 5($3.50-6.00{\mu}m$), which corresponds with the size of respirable particle. The smaller the particle sizes were, the higher quartz the content became. The mass fractions of inhalable, thoracic, and respirable dust were 72.1%, 36.0%, and 14.4%. Conclusions: The rate of the quartz concentration in respirable dust from stone grinding operations exceeding the American Conference of Governmental Industrial Hygienists Threshold Limit Values was 100%, which means proper work environmental management is required through regular working environmental measurements. Given that the stone grinding operations had a higher small size dust concentrations, there is a need to reduce respirable dust, such as through wet operation and local exhaust ventilation.

• 한국산업보건학회지
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• 제25권2호
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• pp.166-173
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• 2015

Objectives: The purpose of this study was to evaluate cobalt concentrations in airborne inhalable, total and respirable dust from manufacturing industries using cobalt. Methods: To compare cobalt concentrations, three types of dust samplers(a 37mm closed cassette sampler, Institute of Occupational Medicine(IOM) sampler, and Aluminum cyclone sampler) were used. The analysis of cobalt concentrations was conducted using AAs based on the NIOSH 7300 method. Results: The geometric mean of cobalt concentration in total dust was $1.47{\mu}g/m^3$, and the rate of excess of the Korean Occupational Exposure Limit(KOEL) was 10.0%. The geometric mean concentrations of cobalt in super alloy manufacturing industries were higher than those in plating industries, and molding operations showed higher exposure levels to cobalt than did other operations. Conclusions: The rate of cobalt concentration in inhalable dust from super alloy manufacturing industries exceeding the Workplace Exposure Limit(WEL) as recommended by the Health & Safety Executive(HSE) was 7.1%, which means proper work environmental management is required through wet work environments. Given that molding operations had higher cobalt concentrations, it is necessary to apply measures such as local exhaust for reducing airborne dust in cobalt manufacture industries.

• 천문학회보
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• 제44권1호
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• pp.44.3-44.3
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• 2019

Massive stars, supernovae, and kilonovae are among the most luminous radiation sources in the universe. Observations usually show near- to mid-infrared (NIR-MIR, 1-5~micron) emission excess from H II regions around young massive star clusters (YMSCs) and anomalous dust extinction and polarization towards Type Ia supernova (SNe Ia). The popular explanation for such NIR-MIR excess and unusual dust properties is the predominance of small grains (size a<0.05micron) relative to large grains (a>0.1micron) in the local environment of these strong radiation sources. The question of why small grains are predominant in these environments remains a mystery. Here we report a new mechanism of dust destruction based on centrifugal stress within extremely fast rotating grains spun-up by radiative torques, namely the RAdiative Torque Disruption (RATD) mechanism, which can resolve this question. We find that RATD can destroy large grains located within a distance of ~ 1 pc from a massive star of luminosity L~ 10^4L_sun and a supernova. This increases the abundance of small grains relative to large grains and successfully reproduces the observed NIR-MIR excess and anomalous dust extinction/polarization. We show that small grains produced by RATD can also explain the steep far-UV rise in extinction curves toward starburst and high redshift galaxies, as well as the decrease of the escape fraction of Ly-alpha photons observed from HII regions surrounding YMSCs.

• 천문학회보
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• 제46권1호
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• pp.54.1-54.1
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• 2021

Observing sub-mm continuum emission from cold dust can play an important role in measuring star formation rates of galaxies, especially in the case of AGN host ones, since AGNs contaminate FIR fluxes by dust heating. To measure star formation rates, we observed total 49 local AGN host galaxies(z<0.2) by SCUBA-2 camera at James Clerk Maxwell Telescope(JCMT) at 450㎛ and 850㎛. We performed several tests with the observed images to determine whether each source is detected, and adopted 3s as the flux upper limit in non-detection cases. Using these measurements and FIR archival data, we modeled spectral energy distributions of the galaxies to estimate star formation rates. The effect of AGN activity on host galaxy star formation will be discussed.

• 천문학회보
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• 제29권2호
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• pp.33.2-33.2
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• 2004

• 한국안전학회지
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• 제23권2호
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• pp.1-6
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• 2008

The present study investigates on improvement of inhalation efficiency of hood in ventilation system for elimination of industrial dust. The hood, one of local exhaust ventilation system, has an important function to inhale a pollution source such as harmful dust and industrial waste. In this study, in order to improve the inhalation efficiency of the industrial hood, a new device named "gas-guide-device" was attached to inside of hood. The thermal fluid commercial code "Phoenics ver 3.1" was used to analyze the flow velocity distribution at the hood inlet and around the hood after gas-guide-device was installed. And the flow velocity on each position inside and around the hood was actually measured using the hot wire type anemometer under the same condition as that of numerical analysis. Also, in order to identify the optimum shape of gas-guide-device, numerical analysis and experiments are performed under various conditions and their results are presented. The results of this study revealed that the hood attached with gas-guide-device was higher the inhalation efficiency than that for without one and can be possible to improve the capture velocity of the industrial dust. And the optimum shape of gas-guide-device was identified that the ratio of two sizes of gas-guide-device, X to Y, has 4 to 6 on the basis of the hood size in use and the width (b) of gas-guide-device.

• 대한원격탐사학회지
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• 제37권5_3호
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• pp.1461-1473
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• 2021

본 연구는 토지피복 자료의 공간 해상도가 미세먼지의 국지적 분포 및 확산 양상에 어떠한 영향을 미치는지 확인하는 데에 목적을 둔다. 이때 시공간적 지표상태 및 기상상태의 변화를 고려하는 CALPUFF 모델을 사용하여, 경기도 안양시의 평촌 신도시 지역에 대해, 미세먼지 모의를 진행하였다. 모델링의 입력 데이터로 20 m, 50 m, 100 m의 세 가지 해상도 토지피복도를 사용하여 비교하였다. 20 m 해상도의 토지피복 자료를 사용했을 경우 모의 영역의 풍속은 가장 크게 모의 되었으며 PM10 농도는 가장 낮게 모의 되었다. 본 연구를 통해 미세먼지의 국지적 분포 및 확산 양상에 토지피복 자료의 공간 해상도가 영향을 미칠 수 있으며 이는 CALPUFF 모의에 영향을 줄 수 있음을 확인하였다. 따라서 향후 CALPUFF를 사용하여 미세먼지를 모의할 때, 토지피복의 형태에 따른 공간 해상도에 대한 영향을 사전에 확인하고 모의를 진행하는 것이 더 정확한 결과를 확보할 수 있음을 제시해볼 수 있다.

• 대기
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• 제32권2호
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• pp.119-133
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• 2022

From 2015 to 2021, high-concentration fine dust episodes with a daily average PM_2.5 concentration of 50 ㎍ m^-3 or higher were selected and classified into 3 types [long range transport (LRT), mixed (MIX) and Local emission and stagnant (LES)] using synoptic chart and backward trajectory analysis. And relationships between the fine particle data (PM_2.5 and PM₁₀ concentration and PM_2.5/PM₁₀ ratio) and meteorological data (PBLH, Ta, WS, U-wind, and Rainfall) were analyzed using hourly observation for the classification episodes on the Korean Peninsula and the Seoul metropolitan area (SMA). In LRT, relatively large particles such as dust are usually included, and in LES, fine particle is abundant. In the Korean peninsula, the rainfall was relatively increased centered on the middle and western coasts in MIX and LES. In the SMA, wind speed was rather strong in LRT and weak in LES. In LRT, rainfall was centered in Seoul, and in MIX and LES, rainfall appeared around Seoul. However, when the dust cases were excluded, the difference between the LRT and other types of air quality was decreased, but the meteorological variables (Ta, RH, Pa, PBLH, etc.) were further strengthened. In the case of the Korean Peninsula, it is difficult to find a clear relationship because regional influences (topographical elevation, cities and coasts, etc.) are complexly included in a rather wide area. In the SMA, it is analyzed that the effects of urbanization such as the urban heat island centered on Seoul coincide with the sea and land winds, resulting in a combination of high concentrations and meteorological phenomena.

• 서비스연구
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• 제10권1호
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• pp.55-67
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• 2020

미세먼지 문제는 최근 우리나라 국민의 최대 관심사로 부상되었고 정부 및 지방자치단체에서도 상당한 노력을 기울이고 있다. 그간 미세먼지와 관련하여 다수의 학술적 연구가 진행되어왔지만 경제 분야의 연구는 상대적으로 미흡하였다. 본 연구에서는 미세먼지가 개별 주식에 어떠한 영향을 끼치는지에 대하여 빅데이터 분석을 통해 알아보고자 한다. 2013년부터 2017년까지 총 5개년을 대상으로 PM10농도 미세먼지 데이터와 미세먼지 테마주 데이터와의 관계를 분석하였다. 연구방법으로는 일반화최소제곱법을 사용한 선형회귀모형을 사용하여 회귀분석을 실시하였다. 연구 결과 미세먼지 농도가 전일에 비해서 증가했을 때 미세먼지 테마주의 주가가 상승하는 것으로 나타났다. 그리고, 2013년부터 2017년까지 주가변동 분석결과 회귀계수 값이 큰 기업은 매년 달라졌다. 5개년 동안 제일 큰 반응을 보인 기업은 오공, 웰크론, 동성제약, 삼일제약, 모나리자 순이었다. 그 중 연도별로 반복적으로 등장하는 기업으로는 모나리자가 2014년, 2015년, 2017년에, 삼일제약은 2015년, 2016년, 2017년에, 웰크론은 2016년, 2017년에 반복적으로 회귀계수가 크게 나타났으며 해당 기업은 미세먼지 농도에 주가가 민감하게 반응하는 기업이라고 사료된다. 향후 PM2.5 측정 데이터가 충분히 쌓이게 된다면 PM2.5의 농도를 독립변수로 한 연구와 비교·분석하는 것도 의미가 있을 것이다. 본 연구에서는 미세먼지 농도만을 독립변수로 하였는데 설명력을 높일 수 있는 변수를 추가한다면 좀 더 의미있는 연구결과를 기대할 수 있을 것이다.

• 한국컴퓨터정보학회논문지
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• 제26권8호
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• pp.181-185
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• 2021

도로 미세먼지는 단순히 대기오염의 문제가 아닌 보도를 이용하는 보행자 등 국민의 건강과 생명을 위협하고 있다. 이에 도로 미세먼지 저감과 관련하여 다양한 정책안이 있으나 실질적인 효과에 대해서는 장담할 수 없는 상황이다. 따라서 국민의 안전하고 쾌적한 통행을 보장하기 위해 도로 미세먼지 관리형 보도포장(인도포장)을 장소, 용도, 기능 등을 고려하여 적합한 포장 재료 및 공법을 선정하여 설계하거나 보도 시설 등을 마련하여야 할 것이다. 이에 본 연구에서는 보도포장의 개념 및 법적근거를 살펴보고 대기오염을 정화하는 보도포장 관련 기술 현황 등을 검토하여 미세먼지 저감용 보도포장 지침 개정안, 「녹색제품구매촉진에 관한 법률」상 보도포장재 활용방안, 지방자치단체 보도포장 관리 규칙 개정안 등을 제시하여 인도포장 기술을 조기에 적용할 수 있는 법적 기반을 구축하고자 한다.