• 한국대기환경학회지
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• 제9권3호
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• pp.247-254
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• 1993

A simple and direct method is developed for the determination of light Elements in atmospheric particulates by X-ray fluorescence spectrometry. Calibration standards for the light elements such as Al, Mg, K, Ca, etc are prepared by filtering real atmospheric particulates over variable time and subsequently standardizing them by Inductively Coupled Plasma-Mass Spectrometry(ICP-MS) or Atomic Absorption Spectrophotometry(AAS) analysis. The validity of this calibration method is tested by analyzing more than 100 aerosol samples, collected at urban(Seoul) and rural(Padori) sites over a two year period with this method and then comparing them with those by other accuracy proven methods such as AAS or ICP-MS: for all metals tested the results showed reasonably good agreements (R $\geq$ 0.95).

• 한국대기환경학회지
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• 제17권5호
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• pp.385-393
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• 2001

We have developed a Differential Absortion LIDAR (DIAL) method for the measurement of lower tropospheric ozone concentration. We used two laser beams from quadrupled Nd:YAG (266 nm) for the resonance wavelength and dye lasers (299.5 nm) for non -resonance wavelength. Aerosol extinction coefficients in the lower troposphere was computed by both Klett and Slope methods. To correct the SIN (Signal -Induced Noise) effect caused by photo detector, we subtracted a new-fitted baseline on the background part of a LIDAR signal, after the subtraction of the DC level. This is because SIN can be treated as an exponentially decaying tail. Using theme results, ozone profiles were obtained approximately 2km at daytime and 3km at nighttime. We compared the results derided by the Slope method with those measured by UV spectrometer. The computed results are in mostly good agreement with experimental results. In the measurement of the vertical layer, we observed the variation of the ozone profiles around the top mixed layer.

• 한국대기환경학회지
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• 제12권4호
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• pp.377-387
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• 1996

This study was carried out to monitor the visibility including measurement and analysis of the various parameters such as particle size distribution, chemical composition, and meteorotical conditions to understand the characteristics and causes of this phenomenon. According to the analysis of intensive sampling, $SO_4^{2-}, NO-3^-, Cl^-, NH_4^+$ ion concentration increased together with the mass concentration around 1 $\mu$m in the case of low visibility. $(NH_4)_2SO_4, NH_4NO_3$, and $NH_4Cl$ were thought to be the major components of fine particles. The statistical analysis showed that the scattering effect of particle was 81.2%, the absorption effect was 14.9%. Therefore, these effects were the major factors to reduce the visibility. In conclusion, the visibility was reduced by the fine particle of sulfate (18.6%), nitrate (14.2%), organic carbon (10.8%), element carbon (25.8%), and residual (24.8%) during this study.

• 한국대기환경학회지
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• 제26권2호
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• pp.190-201
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• 2010

Fine particulate matter < $1.8{\mu}m$ was collected as a slurry using the Semicontinuous Elements in Aerosol Sampler with time resolution of 30-min between May 23 and 27, 2002 at the Sydney Supersite, Florida, USA. Concentrations of 11 elements, i.e., Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Se, and Zn, in the collected slurry samples were determined off-line by simultaneous multi-element graphite furnace atomic absorption spectrometry. Temporal profiles of $SO_2$ and elemental concentrations combined with meteorological parameters such as wind direction and wind speed indicate that some transient events in their concentrations are highly correlated with the periods when the plume from an animal feed supplement processing facility influenced the Sydney sampling site. The peaking concentrations of the elemental species during the transient events varied clearly as the plume intensity varied, but the relative concentrations for As, Cr, Pb, and Zn with respect to Cd showed almost consistent values. During the transient events, metal concentrations increased by factors of >10~100 due to the influence of consistent plumes from an individual stationary source. Also the multi-variate air dispersion receptor model, which was previously developed by Park et al. (2005), was applied to ambient $SO_2$ and 8 elements (Al, As, Cd, Cr, Cu, Fe, Pb, and Zn) measurements between 20:00 May 23 and 09:30 May 24 when winds blew from between 70 and $85^{\circ}$, in which animal feed processing plant is situated, to determine emission and ambient source contributions rates of $SO_2$ and elements from one animal feed processing plant. Agreement between observed and predicted $SO_2$ concentrations was excellent (R of 0.99; and their ratio, $1.09{\pm}0.35$) when one emission source was used in the model. Average ratios of observed and predicted concentrations for As, Cd, Cr, Pb, and Zn varied from $0.83{\pm}0.26$ for Pb to $1.12{\pm}0.53$ for Cd.

• 공업화학
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• 제7권1호
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• pp.83-90
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• 1996

AO-AOT계내에서 S/D의 증가에 따라 흡수 및 형광 spectra의 변화 양상이 감소하다가 증가함을 알 수 있으며 회합 및 해리가 일어남을 알 수 있다. 그리고 온도 상승에 따라 순수한 AO계에서는 흡광도가 증가하나 premicellar영역(S/D=10, 20, 50 및 80)내에서는 흡광도가 오히려 점차 감소한다. 한편 AO-AOT계에 첨가한 염의 농도가 증가함에 따라 metachromasy 소멸도는 증가하나 $NaNO_3$의 경우는 이와 반대로 나타난다. 이러한 염의 양이온에 대한 metachromasy 소멸도의 증가 순서는 $Li^+$, $Na^+$ > $Mg^{2+}$ > $Ca^{2+}$이며, 염의 음이온에 대해서는 $Cl^-$ > $SO_4{^{2-}}$ > $NO_3{^-}$로 나타남을 알 수 있었다.

• 한국입자에어로졸학회지
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• 제8권2호
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• pp.89-95
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• 2012

Spherical mesoporous silica particles, of which main pore diameter was 3.8 nm, were successfully prepared by spray pyrolysis from aqueous silicic acid. The effect of precursor concentration, reaction temperature, and the addition of urea and PEG on the particle diameter and pore properties such as pore diameter, total pore volume, and specific surface area were investigated by using FE-SEM, particle size analyzer, and nitrogen absorption-desorption analysis. With an increase of the precursor concentration from 0.2 M to 0.7 M, the average particle diameter, total pore volume, and specific surface area of the porous silica particles increased from 0.56 to $0.96\;{\mu}m$, 0.434 to $0.486\;cm^3/g$, 467.8 to $610.4\;m^2/g$, respectively. Within the temperature range $(600\;^{\circ}C{\sim}800\;^{\circ}C)$, there was no significant difference in the pore diameter, total pore volume, and specific surface area. In addition, the addition of urea as an expansion aid led to slight increases in particle diameter, pore diameter, and specific surface area. However, when the polyethylene glycol (PEG) as an organic template was used, the total pore volume of porous particles increased dramatically.

• 한국입자에어로졸학회지
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• 제19권1호
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• pp.13-20
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• 2023

The Asian dust observation network operates β-ray attenuation samplers to measure PM₁₀ concentrations. In addition, equivalence evaluation and accuracy inspection(Precision Tests) are conducted every year for the reliability of data. β-ray attenuation samplers(16 units) were comparatively observed from May to June 2020 and from July to December 2021. During the observation period, the average daily temperature was the lowest at 6.4℃ in December and the highest at 27.3℃ in August. The average daily humidity ranged from 60% to 100%, but the average daily humidity was over 75% from July to September. The minimum value of the PM₁₀ Gravimetric method was 5.0 ㎍/m³, the maximum value was 53.4 ㎍/m³, and the average value was 17.8 ㎍/m³. The equivalence evaluation results of the PM₁₀ Gravimetric method and β-ray attenuation samplers satisfied the criteria (slope: 1±0.1, intercept: 0±0.5). A relative error analysis between the PM₁₀ Gravimetric method and β-ray attenuation samplers equipment showed that the relative error increased when the concentration was low and the temperature and humidity were high. In addition, in the β-ray attenuation samplers 5-minute interval observation data in May 2020, a relatively large Standard devication was shown as an average maximum ±23.4 ㎍/m³ and a minimum ±15.2 ㎍/m³. At standard deviations of 10% and 90%, equipment with high variability (deviation) was measured at 6 ㎍/m³and 61 ㎍/m³, and equipment with low variability was measured at 12 ㎍/m³ and 47 ㎍/m³. It was confirmed that concentration differences occurred due to differences in variability for each equipment.

• 한국대기환경학회지
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• 제17권6호
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• pp.475-485
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• 2001

The presence of airborne particles in the earth atmosphere expert important controls on the global climate because of their effects on the radiative balance. However, there are major uncertainties associated with the direct and indirect radiative effects of aerosols. In addition, their physicochemical properties cannot only the decline of air quality but also damage human health. Airborne particles were collected by two different commercial air samples, high volume sampler(for TSP) and low volume sampler(for P $M_{10}$ ) at the campus of Kunsan National University during February to September, 2000. In most cases, TSP and P $M_{10}$ were sampled once a week for the duration of 24 hours from 9:00 a.m. In addition samples were collected more intenisve, when the yellow dust was expected. Each sample was analyzed for pH and major ions concentration (C $l^{[-10]}$ , S $O_4$$^{2-}$, N $O_3$$^{[-10]}$ , N $a^{+}$, N $H_4$$^{+}$, $K^{+}$, $Mg^{2+}$, $Ca^{2+}$) by ion chromatography and atomic absorption spectrophotometry. Acidity (pH) of TSP and P $M_{10}$ ranged from 5.09 to 8.51 and from 6.22 to 7.54, respectively. The concentrations of airborne particles were found to satisfy both the short and long-term air quality standards during the sampling period. If the ratio of ionic concentrations originating from None sea salt(Nss) to sea salt(ss) in aerosol samples was concerned, it was found that the ionic concentrations from marine environment contributed dominantly in total mass concentration in the airborne particles. When seasonal trends were examined, the TSP concentrations in spring were higher than those of other seasons. It may result form frequent occurrences of yellow dust and during the spring season. The concentration ratio of P $M_{10}$ to TSP ranged from 0.78 to 1 during the sampling period. pH in the airborne particle was highest during spring, but the other seasons maintained almost same level. These results suggest that alkaline species in yellow dust can directly neutralize aerosol acidity. During spring season, yellow dust could be a positive factor that can defer the acidification of surface soil and water by neutralizing acidic aerosols in the atmosphere.osphere.

• 대한기계학회논문집
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• 제15권1호
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• pp.285-291
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• 1991

본 연구에서는 800 1pm인 대유량을 처리하고 공기중 1.8~4.5$\mu\textrm{m}$ 입자를 효율 적으로 선별하여 농축시키는 슬릿형 2단 가상충돌기를 설계 제작하고 그 성능이 평가 되었다. 즉, 첫째단과 둘째단에서 4.5$\mu\textrm{m}$과 1.8$\mu\textrm{m}$이 각각 50%의 효율로 분리되도록 설계되었다. 즉, 첫째단과 둘째단에서 4.5$\mu\textrm{m}$과 1.8$\mu\textrm{m}$이 각각 50%의 효율로 분리되도 록 설계한다. 설계인자(design parameter)들을 결정하기 위하여 먼저 슬릿형 노즐의 1단 가상충돌기의 분리효율(separation efficiency)에 대한 실험을 통하여 50% 커트오 프 Stokes수를 구하고, 이를 기초로 하여 2단 가상 충돌기의 주요치수와 작동조건을 결정하였다.

• 한국지구과학회지
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• 제39권1호
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• pp.53-66
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• 2018

지면반사도 정보는 열평형 및 환경/기후 모니터링에 중요하다. 본 연구에서는 정지궤도위성의 Geostationary Environment Monitoring Spectrometer (GEMS) 관측에서 300-500 nm 파장 영역의 지면반사도 산출 시에 오차 유발 요소에 대한 민감도를 조사하였다. 장차 GEMS 지면반사도 산출 시에 오차 분석을 위하여 극궤도 위성의 MODerate resolution Imaging Spectroradiometer (MODIS; 공간 해상도 $1km{\times}1km$) 자료 및 Ozone Mapping Instrument (OMI; $12km{\times}24km$) 자료 그리고 복사전달모델 수치실험도 분석에 사용하였다. 본 연구에서 오차 유발 요소는 구름, 레일리 산란, 에어로졸, 오존 그리고 지면 특성이다. GEMS 저해상도($8km{\times}7km$)에서의 구름 탐지율은 MODIS 대비 약 79%이었으나, GEMS 화소의 운량이 40% 이하에서는 상대적으로 낮았다. 이러한 경향은 구름 이외의 다른 효과(에어로졸, 지면 특성)로 인하여 주로 발생하였다. RGB 영상과 복사전달모델 계산을 기초로 조사된 레일리 산란 효과는 육지에 비하여 해양 지역에서 뚜렷하였다. 지면반사도가 0.2보다 작은 경우에 위성관측 대기상단 반사도는 에어로졸 양에 비례하였으나, 0.2보다 큰 경우에는 그 반대 경향을 보였다. 또한 에어로졸 양에 의한 지면반사도 산출 오차는 자외선 영역에서 파장에 따라 급격하게 증가하였으나, 가시광선에서는 일정하거나 다소 감소하였다. 오존 흡수는 자외선 영역(328-354 nm) 중 328 nm에서 가장 크게 나타났다. 지면반사도가 0.15인 육지 경우에 음의 오존전량 아노말리(-100 DU)로 인한 지면반사도 산출 오차는 +0.1이었다. 본 연구는 GEMS 위성관측을 이용한 지면반사도 원격탐사의 정확도를 높이는데 기여할 수 있다.