• Atmosphere
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• v.25 no.1
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• pp.185-191
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• 2015

Ambient measurements of aerosol light absorption (${\sigma}_a$) and scattering coefficients (${\sigma}_s$) were done at Gosan climate observatory during summer 2008 using a 3-wavelength photoacoustic soot spectrometer (PASS). PASS was deployed photoacoustic method for light absorption and integrated nephelometry for light scattering measurements. The ${\sigma}_a$ and ${\sigma}_s$ from PASS were compared with those from co-located aethalometer and nephelometer measurements. The aethalometer measurements of ${\sigma}_a$ correlated reasonably well with photoacoustic measurements, but the slope of the linear fitting line indicated the PASS measurement values of ${\sigma}_a$ were larger by a factor of 1.53. The nephelometer measurement values of ${\sigma}_s$ correlated very well with PASS measurements of ${\sigma}_s$, with a slope of 1.12 and a small offset. Comparing to the aethalometer measurements, the photoacoustic measurements of ${\sigma}_a$ didn't exhibit a significant (i.e., the ratio between aethalometer and PASS increased) change with increasing relative humidity (RH). The ratio of ${\sigma}_s$ between nephelometer and PASS increased with increasing RH, especially when the RH increased beyond 80%. This apparent increase in ${\sigma}_s$ with RH may be due to the contribution of hygroscopic growth of aerosols.

• Atmosphere
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• v.18 no.4
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• pp.459-474
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• 2008

Aerosol scattering coefficients for three different wavelengths ($\lambda$=450,550,700 nm) are measured almost continuously by a nephelometer in Seoul for a period of 13 months (February 2007-February 2008), which includes two weeks break in August 2007 for measurements at Daegwallyeong and YoungJongdo. The mean of the daily average scattering coefficients at $\lambda$=550 nm is $194.1{\pm}144.2Mm^{-1}$ and the minimum and maximum are $14.3Mm^{-1}$ and $998.1Mm^{-1}$, respectively. The scattering coefficient shows a general increasing trend with atmospheric relative humidity (RH). When the data are classified according to weather conditions, the days with no major weather events show the smallest scattering coefficient and also the lowest RH. Surprisingly haze/fog days show the largest scattering coefficient and Asian dust days comes in second. Although the variation is large within a season, winter shows the largest and autumn shows the smallest scattering coefficient. The average ${\AA}ngstr{\ddot{o}}m$ exponent is $1.40{\pm}0.32$ for the entire Seoul measurement. As expected, Asian dust days show the smallest ${\AA}ngstr{\ddot{o}}m$ exponent and haze/fog days are the next, suggesting more efficient hygroscopic growth of aerosols for this weather condition. Aerosol scattering coefficient seems to show better correspondence with CCN concentration rather than total aerosol concentration, which may indicate that CCN active aerosols are also good scattering aerosols.

• Particle and aerosol research
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• v.11 no.1
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• pp.1-8
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• 2015

In this study, indoor $PM_{10}$ concentration was measured by different type of real-time instruments in public transport vehicles. Light-scattering method is widely used in measuring the size of particulate matters and there is two types of light-scattering methods; one is the nephelometer type which measures the light-scattering degree by aerosol cloud, the other is the spectrometer type which measures light-scattering degree by individual particle. We observed the variation of $PM_{10}$ in KTX, subway and express bus carriages by 1-minute resolution and found that there is similar tendency in pattern among 4 light-scattering devices but difference in absolute concentrations. By comparing gravimetric result in a subway cabin, the spectrometer type device, C, was chosen as a reference device. The conversion factors of nephelometer device A-1, A-2, and B were 1.666, 1.463 and 2.125 respectively.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.11a
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• pp.57-58
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• 2000

대기 중에 분포되어 있는 다양한 크기와 종류의 에어로졸은 산업의 발전과 급속한 인구의 증가로 인해 가중되고 있으며, 특히 이로 인해 도심지역의 시정감쇄에 큰 영향을 미치고 있다. 특히 도시지역의 대기 중 미세 입자(PM2.5)의 시정감쇄에 대한 영향은 거대입자에 비하여 지배적인 것으로 나타난다. 그 과정에서 대기중 입자의 광학적인 성질 뿐 만 아니라 기상적인 변동 특히 온도와 습도에 의한 시정의 변화는 큰 영향을 받고 있다. (중략)

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.4
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• pp.319-329
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• 2015

The characteristics of aerosol light extinction were investigated by comparing measured and calculated extinction coefficient to understand the contribution of air pollutants on visibility impairment for data during 4 months (Jan~ April), 2014. The integrated nephelometer and aethalometer system were installed to measure the scattering and absorption coefficients of aerosol as well as BAM 1020, MARGA, semi-continuous OCEC analyzer, and online-XRF to calculate the extinction coefficient. The IMPROVE_2005 equation was used to determine the contributions of different chemical components on visibility impairment in $PM_{2.5}$ and $PM_{10}$ due to highest correlation with measured data. Sulfate, nitrate, and organic mass by carbon (OMC) of fine aerosol were the major contributors affecting on visibility impairment. Total contributions to light extinction were calculated as $631.0Mm^{-1}$ for the worst-case and $64.4Mm^{-1}$ for the best-case. The concentrations of aerosol component for the worst-case were 38.4 times and 45.5 times larger than those of the best-case for $(NH_4)_2SO_4$ and $NH_4NO_3$, respectively. At lower visibility condition, in which extinction coefficient was higher than $400Mm^{-1}$, extinction coefficient varied according to the relative humidity variation regardless of $PM_{2.5}$.

• Tuberculosis and Respiratory Diseases
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• v.50 no.5
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• pp.615-623
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• 2001

Background : Pneumoconiosis is a parenchymal lung disease that results from the accumulation of coal dust in the lungs and the consequent tissue reaction. To evaluate the role of various personal factors in pneumoconiosis and the significance of some serologic markers for assessing the disease activity related to pneumoconiosis, the Rheumatoid Factor(RF), ${\alpha}_1$-AT, C-Reactive Protein(CRP), ceruloplasmin and fibrinogen levels were measured. Method : All the patients were males, 45-76 years old, and the mean duration of coal dust exposure was 23.2 years. 51 patients were classified as having Simple Pneumoconiosis (SP), 59 had Progressive Massive Fibrosis (PMF). Fifty eight men with ages ranging from 26-70 years were used as normal controls. The serum RF and CRP were titrated using an Autochemistry analyzer (HITACHI 7150 : Japan) and the ${\alpha}_1$-AT and ceruloplasmin levels were measured using a Nephelometer (Behring Nephelometer : Germany) and the fibrinogen levels were estimated by using an Autoanalyzer for hematologic coagulation. Result : There was a higher RF level in the SP, and PMF groups than in the control groups but there was no statistical difference. The CRP, ${\alpha}_1$-AT, and ceruloplasmin levels were also higher in the SP, and PMF groups. However, the fibrinogen concentration was within the normal ranges in both the SP and PMF groups. Conclusion : The CWP (Ed note : Define CWP) patients had significantly higher CRP, ${\alpha}_1$-AT, and ceruloplasmin levels compared to the control group. It is believed that these serologic changes could be used as a marker of the disease activity.

• Tuberculosis and Respiratory Diseases
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• v.46 no.2
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• pp.165-174
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• 1999

Background: Coal-worker's pneumoconiosis(CWP) is radiologically divided into two major groups: simple pneumoconiosis (SP), in which small, rounded or irregular opacities smaller than 1cm are observed, and progressive massive fibrosis(PMF), which is characterized by opacities larger than 1cm. SP has a life expectancy equivalent to miners with no radiographic evidence of CWP, but PMF is associated with more obvious impairments of ventilatory capacity and premature death. But only minority of workers develop PMF when exposed to dust concentrations similar to those experienced by workers who develop only SP. In this study, immune status in patients with CWP were evaluated by measurement of the serum immunoglobulin levels between control, SP and PMF groups. Method: Coal workers selected for this study were emplyees of the Tae-Baek and Dong-Hae Hospital. All the patients were men of 45-76 years old and the mean duration of exposure to coal dust were 23.2 years. By X-ray examination, 51 patients were classified in SP, 59 in PMF category. The normal controls examined were 58 men of 26-70 years old. Serum Ig levels were estimated by using Nephelometer(Behring Nephelometer : Germany) and serum were collected 51 in SP, 49 in PMF and 57 cases in control group. Results: The levels of IgG were increased but the levels of IgM were decreased with increasing age in control groups. There were no statistical difference of immunoglobulin levels between smokers and nonsmokers in control groups. There were no statistical difference of immunoglobulin levels between Control, SP and PMF groups. Multiple regression analysis were undertaken to determine the statistical significance of the apparent trends and estimate the effects associated with age, smoking habit and radiological category of CWP. According to this analysis, the levels of IgG were decreased significantly in SP group and had decreasing tendancy, but not statistically significant in PMF group. Conclusion : From the observations described, CWP patients had decreased IgG concentration compared to control gorup. Therefore, there was some relation between CWP and immunoglobulin concentration.

• Journal of Korean Society for Atmospheric Environment
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• v.11 no.3
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• pp.291-298
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• 1995

An intensive field study was carried out during Aug. 1993 in Seoul to study the characteristics of summertime visibility and diurnal trend of ionic composition of ambient particles. A transmissometer, nephelometer with heated and unheated inlets, PM3 fine particle sampler, and cascade impactor were used to measure optical and particle properties of ambient air. During this study period, a weak smog episode has occurred. Light scattering by particles is the most dominant factor on total light extinction. The effect of light absorption by particles in Seoul is much higher than other major cities in U.S.A. throughout the summer and fall with relatively constant values. The effect of water on $b_{sp}$ was small during the period. The particle size distribution shows a typical bimodal one. Sulfate, ammonium, chloride, and nitrate are the major chemical species in fine fraction aerosols, about 30% of toral mass concentration. Concentraion of sulfate is higher during the daytime while those of nitrate and chloride are higher during the nighttime. Ammonium concentration is constant through the daytime.

• Journal of Korean Society for Atmospheric Environment
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• v.10 no.2
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• pp.137-145
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• 1994

A visibility analysis model based on the Mie theory is applied to the measurements during the fall, 1993 in Seoul. Model estimations of the total extinction coefficient $b_{ext}$, and the particle scattering coefficient, $b_{sp}$ are in good agreement with the measured values by a transmissometer and a nephelometer, respectively. These values show strong dependency on the mass loading of fine particles( $D_{p}$ ＜3.0${\mu}{\textrm}{m}$) but show no apparent relation with that of coarse particles(3.0${\mu}{\textrm}{m}$＜ $D^{p}$ ＜10${\mu}{\textrm}{m}$). Relative humidity plays an important role in determining the size of particles which in turn, affects the optical efficiency of aerosol. Based on the composition analysis with cut size nitrate concentration is higher than the sulfate concentration in PM3-10 but they are comparable to each other in PM3. Considering in 1985, it demonstrates a drastic increase of nitrate concentration between 1985 and 1993. It is found that measured and estimated light extinction budget were in good agreement within 10% and that scattering by particles is responsible for about 50-55% and 70-80 % of total extinction during clear and smoggy periods respectively.y.

• Particle and aerosol research
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• v.6 no.2
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• pp.91-103
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• 2010

Size-segregated number concentration and scattering coefficient of urban aerosols were measured using an SMPS (scanning mobility particle sizer) and a nephelometer, respectively in Seoul, Korea, during the winter season of 2003. The average number concentrations of ultrafine particles (20~100 nm) and accumulation mode particles (100~600 nm) were $2,170\;particles\;cm^{-3}$ and $1,521\;particles\;cm^{-3}$, respectively. The scattering coefficient at the wavelength of 550 nm ranged from $62.6Mm^{-1}$ to $330.1Mm^{-1}$ and average value was $163.4Mm^{-1}$. The peak concentrations of ultrafine particles and accumulation mode particles were simultaneously recorded between 6:00 and 9:00 A.M., indicating the effect of vehicle emissions which are major air pollution sources in the urban atmosphere. On average, the number concentration of ultrafine particles was 1.4 times higher than that of accumulation mode particles, although it was a little higher during the morning peak time. The variation of aerosol scattering coefficient was in good agreement with that of accumulation mode particle number concentration rather than that of ultrafine particle number concentration.g coefficient was in good agreement with that of accumulation mode particle number concentration rather than that of ultrafine particle number concentration.