• Title, Summary, Keyword: Number concentration

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The Characteristics of the Aerosol Number Concentration in Jeju Area During Asian Dust Events (황사 시 제주지역 에어로졸의 수농도 특성)

  • Kang, Chang-Hee;Hu, Chul-Goo
    • Journal of Environmental Science International
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    • v.22 no.3
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    • pp.347-358
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    • 2013
  • The aerosol number concentration have measured with an aerodynamic particle sizer spectrometer(APS) at Gosan in Jeju Island, which is known as background area in Korea, from March 2010 to February 2011. The obtained results of asian dust events and non-asian dust period have been compared. The results show that the entire averaged aerosol number concentration from APS measurement during asian dust events and non-asian dust period are about 341 particles/$cm^3$ and 240 particles/$cm^3$, respectively. During asian dust events, the number concentration in small size ranges(${\leq}0.4{\mu}m$) are similar to non-asian dust period, however, those in large size ranges(${\geq}0.7{\mu}m$) are very higher than non-asian dust period. The contributions of the size resolved number concentration(23 channel in $0.25{\sim}10.0{\mu}m$) to total number concentration in that range are dramatically decreased with increased particle size. The contributions of smaller size ranges(${\leq}0.4{\mu}m$) during asian dust events are very low compared with non-asian dust period, on the other hand, those of larger size ranges(${\geq}0.4{\mu}m$) are higher than non-asian dust period. The number concentration in each size range are strongly correlated with the concentration in adjacent size range. And the total aerosol number concentration are depended on the number concentration in range of smaller than $0.58{\mu}m$ during non-asian dust period and asian dust events. On the other hand, $PM_{10}$ mass concentration has mainly affected with the number concentration in range of smaller than $1.0{\mu}m$ during non-asian dust period, however, during asian dust events, the mass concentration has mainly affected with the number concentration in range of $0.65{\sim}3.0{\mu}m$.

Investigation of Aerosol Number Concentration at Gosan Site in Jeju, Korea

  • Kang, Chang-Hee;Hu, Chul-Goo
    • Journal of Environmental Science International
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    • v.21 no.1
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    • pp.23-30
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    • 2012
  • The aerosol number concentration have measured with an aerodynamic particle sizer spectrometer(APS) at Gosan site in Jeju, Korea, from March 2010 to March 2011. And then the atmospheric aerosol number concentration, the temporal variation and the size distribution of aerosol number concentration have been investigated. The aerosol number concentration varies significantly from 748 particles/$cm^3$ to zero particles/$cm^3$. The average number concentration in small size ranges are very higher than those in large size ranges. The number concentrations in the size range 0.25~0.28 ${\mu}m$, 0.40~0.45 ${\mu}m$ and 2.0~2.5 ${\mu}m$ are about 84 particles/$cm^3$, 2 particles/$cm^3$ and 0.4 particles/$cm^3$, respectively. The number concentrations in range of larger than 7.5 ${\mu}m$ are below 0.001 particles/$cm^3$. The seasonal variations in the number concentration for smaller particle(<1.0 ${\mu}m$) are not much, but the variations for larger particle are very evident. And strong amplitudes of diurnal variations of entire averaged aerosol number concentration are not observed. Size-fractioned aerosol number concentrations are dramatically decreased with increased particle size. The size-fractioned aerosol number concentrations in size range 0.8~4.0 ${\mu}m$ during nighttime are evidently higher than during daytime, but similar levels are appeared in other size range. The seasonal differences in the size-fractioned number concentrations for smaller size range(<0.7 ${\mu}m$) are not observed, however, the remarkable seasonal differences are observed for larger size than 0.7 ${\mu}m$.

Continuous Measurements of Size Separated Atmospheric Aerosol Number Concentration in Background Area (대기배경지역 에어로졸의 입경별 수농도 연속 측정)

  • Kang, Chang-Hee;Hu, Chul-Goo
    • Journal of Environmental Science International
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    • v.21 no.4
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    • pp.535-543
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    • 2012
  • The aerosol number concentration have measured with an aerodynamic particle sizer spectrometer(APS) at Gosan site, which is known as background area in Korea, from January to September 2011. The temporal variation and the size distribution of aerosol number concentration have been investigated. The entire averaged aerosol number concentration in the size range 0.25~32.0 ${\mu}m$ is about 252 particles/$cm^3$. The number concentration in small size ranges(${\leq}0.5{\mu}m$) are very higher than those in large size ranges, such as, the number concentration in range of larger than 6.5 ${\mu}m$ are almost zero particles/$cm^3$. The contributions of the number concentration to PM10 and/or PM2.5 are about 34%, 20.1% and 20.4% in the size range 0.25~0.28 ${\mu}m$, 0.28~0.30 ${\mu}m$ and 0.30~0.35 ${\mu}m$, respectively, however, the contributions are below 1% in range of larger than 0.58 ${\mu}m$. The monthly variations in the number concentration in smaller size range(<1.0 ${\mu}m$) are evidently different from the variations in range of larger than 1.0 ${\mu}m$, but the variations are appeared similar patterns in smaller size range(<1.0 ${\mu}m$), also the variations in range of larger than 1.0 ${\mu}m$ are similar too. The diurnal variations in the number concentration for smaller particle(<1.0 ${\mu}m$) are not much, but the variations for larger particle are very evident. Size-fractioned aerosol number concentrations are dramatically decreased with increased particle size. The monthly differences in the size-fractioned number concentrations for smaller size range(<0.7 ${\mu}m$) are not observed, however, the remarkable monthly differences are observed for larger size than 0.7 ${\mu}m$.

Comparison of Dustiness of Eleven Nanomaterials using Voltex Shaker Method (볼텍스쉐이커를 이용한 11개 나노물질의 분진날림 비교)

  • Lee, Naroo;Park, Jinwoo
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.28 no.3
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    • pp.273-282
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    • 2018
  • Objectives: Dustiness of nanomaterials is considered as exposure index of essential material. Research on dustiness of nanomaterial is needed to control exposure in workplaces. Method: Dustiness measurement using vortex shaker were installed in the laboratory. Nanomaterials, 1 g, was put in the glass test tube and shaked using vortex shaker. Aerosol dispersed was measured using scanning mobility particle sizer(SMPS) and optical particle counter(OPC). Mass concentration using PVC filter and cassette was measured and TEM grid sampling was conducted. Total particle concentration and size distribution were calculated. Image and chemical composition of particles in the air were observed using transmission electron microscopy and energy dispersive X-ray spectrometer. Eleven different test nanomaterials were used in the study. Results: Rank of mass concentration and particle number concentration were coincided in most cases. Rank of nanomateirals with low concentration were not coincided. Two types of fumed silica had the highest mass concentration and particle number concentration. Indium tin oxide, a mixture of indium oxide and tin oxide, had high mass concentration and particle number concentration. Indium oxide had very low mass concentration and particle number concentration. Agglomeration of nanoparticles in the air were observed in TEM analysis and size distribution. In this study, mass concentration and particle number concentration were coincided and two index can be used together. The range of dustiness in particle number concentration were too wide to measure in one method. Conclusion: Particle number concentration ranged from low concentration to high concentration depend on type of nanomaterial, and varied by preparation and amount of nanomaterial used. Further study is needed to measure dustiness of all nanomaterial as one reference method.

Uninary Nicotine and Cotinine Levels in Smokers and Nonsmokers Related to Smoking Habit in Korea

  • Hwang, Keon-Joong;Rhee, Moon-Soo;Ra, Do-Young
    • Journal of the Korean Society of Tobacco Science
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    • v.23 no.1
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    • pp.71-76
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    • 2001
  • This study was conducted to determine the urinary nicotine and cotinine concentration in 126 smokers and 143 nonsmokers. While urine samples were being collected, personal characteristics related to smoking habit such as sex, age, number of years since a person has been a smoker, average number of cigarettes consumed per day, and number of smokers in the family were surveyed. Urinary nicotine and cotinine concentration were analyzed by GC/NPD. The smokers smoked an average 17.0 cigarettes per day and the average concentration of nicotine and cotinine was 3.88 $\mu\textrm{g}$/ml and 3.64 $\mu\textrm{g}$/ml, respectively. The average number of smokers in the family was 0.72 persons and the average concentration of nicotine and cotinine were 0.11 $\mu\textrm{g}$/ml and 0.02 $\mu\textrm{g}$/ml in the urine of non-smokers, respectively. The concentration of nicotine and cotnine in smoker\`s urine was dependent on the number of cigarettes smoked per day(p<0.01). The number of years since a person had been a smoker, and the number of smokers in the family were not associated with the concentration of nicotine and cotinine. Also there was no significant effects of passive smoking on the family of smokers by the level of nicotine and cotinine concentration. We describe the relationship between smoking habit as assessed by urinary nicotine and cotinine excretion. This study provides an evidence for the assessment of active and passive exposure to tobacco smoke.

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Comparison of particle size distribution and particle number concentration measured by APS 3321 and Dust Monitor 1.108 (APS 3321과 Dust Monitor 1.108을 이용한 입자 크기분포 및 수농도 측정결과 비교)

  • Lim, Kyoung-Soo;Park, Hyun-Seol
    • Particle and aerosol research
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    • v.5 no.2
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    • pp.63-70
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    • 2009
  • The size distribution and number concentration of atmospheric aerosol were measured and compared using APS 3321 and Dust Monitor 1.108. The particle size distribution and number concentration measured by two devices were also compared at a particle generation system of standard PSL and fly ash. The number concentration of atmospheric aerosol measured by APS was higher than that by Dust Monitor in particle size range of less than $3.0{\mu}m$, but there was good accordance between them in particle size range of over $3.0{\mu}m$. In the particle generation system of PSL and fly ash, different measurement results were shown because the particle concentration was higher than that of atmospheric aerosol. The number concentration measured by Dust Monitor was higher than that by APS in most particle size ranges. However, the peak concentration of PSL particles measured by Dust Monitor was lower than that by APS. The difference of the collection efficiency in a scrubber by APS and Dust Monitor measurement was less than 10%, but in the particle size of $1.5{\mu}m$, it was over 20%.

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Direct Numerical Simulation of Mass Transfer in Turbulent new Around a Rotating Circular Cylinder ( I ) - At Sc=1670 - (회전하는 원형단면 실린더 주위의 난류유동 물질전달에 대한 직접수치모사 ( I ) - 높은 Schmidt 수에 대하여 -)

  • Hwang Jong-Yeon;Yang Kyung-Soo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.29 no.7
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    • pp.837-845
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    • 2005
  • In this paper, an investigation on high-Schmidt number (Sc=1670) mass transfer in turbulent flow around a rotating circular cylinder is carried out by Direct Numerical Simulation. The concentration field is computed for three different values of low Reynolds number, namely 161, 348 and 623 based on the cylinder radius and friction velocity. Statistical study reveals that the thickness of Nernst diffusive layer is very small compared with that of viscous sub-layer in the case of high Sc mass transfer. Strong correlation of concentration field with streamwise and vertical velocity components is observed. However, that is not the case with the spanwise velocity component. Instantaneous concentration visualization reveals that the length scale of concentration fluctuation typically decreases as Reynolds number increases. Statistical correlation between Sherwood number and Reynolds number is consistent with other experiments currently available.

Characteristics of Incheon Aerosol during Asian Dust Period in 2004 using Optical Particle Counter (OPC) (광학적 입자계수기를 이용한 2004년 황사기간 인천지역 에어로졸 특성)

  • Jung Chang-Hoon;Cho Yong-Sung;Lee Jong-Tae
    • Journal of Environmental Science International
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    • v.14 no.6
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    • pp.565-575
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    • 2005
  • The characteristics for the aerosol number distribution was studied during spring, 2004 in Incheon. Optical Particle Counter (OPC, HIAC/ROYCO 5230) was used in order to measure the number concentration of aerosol in the range of $0.3\~25{\mu}m.$. The obtained results were compared with $PM_{2.5}\;and\;PM_{10}$ data during Asian dust events. The results show that the size resolved aerosol number concentration from OPC measurement has a similar tendency with $PM_{10}\;and\;PM_{2.5}$ mass concentration. During Asian dust periods, the number concentrations in large particle $(CH5\~CH8)$ increase more than small particles which diameter is less than $2.23{\mu}m(CH5)$ and the same results were shown when $PM_{10}$ was compared with $PM_{2.5}$ data compared with non-dust days, Consequently, this study shows that size resolved aerosol number concentration from OPC measurement can be used as a useful tool in comparison of mass concentration data.

Urban Aerosol Number Concentration and Scattering Coefficient in Seoul, Korea, during Winter (서울지역 겨울철 대기 에어로졸의 수 농도 및 산란계수 분석)

  • Lee, Hyun-Hye;Kim, Jin Young;Lee, Seung-Bok;Bae, Gwi-Nam;Yum, Seong Soo
    • 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.

The Concentration of TSP and Heavy Metals in the Indoor Air of Local PC Rooms (지방 일개도시 PC방에서의 실내공기중 TSP농도와 TSP내 중금속 농도)

  • Cha Hyun Su
    • Journal of Korean Public Health Nursing
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    • v.16 no.1
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    • pp.190-200
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    • 2002
  • This study was carried out to investigate and analyze TSP of the PC rooms. The concentration of the total suspended particulate and heavy metals contained in the total suspended particulate of the 15 PC rooms located in one local city were measured. The statistical correlation coefficients between the total suspended particulate and factors of the indoor condition (number of fan or size of pc room, illumination), between the heavy metals and factors of the indoor condition were studied. The results are as follows: 1. The factors of the indoor condition of the 15 PC rooms are as follows. Average illumination was 24 luxes. Average number of computers installed were 37. Average number of the fans was 7. and the size of investigated PC rooms was $139.94m^2$. 2. The mean age of the subjects was 21.8 years old. they $(51.5\%)$ used the 15 pc rooms for fewer than 2 hours per one day. 3. The mean concentration of total suspended particulate (TSP) is lower in the evening ${139.085\;(2.462)\;{\mu}g/m^3}$ than the night ${166.216(2.609){\mu}g/m^3}$. 4. The mean concentration of total suspended particulate was industrial work area) residential area) commercial area. 5. The distribution of heavy metals were indicated as Zn>Cr>Pb>Cd in the indoor air at PC rooms. and the concentration rate of Zn was the highest among heavy metals. but this increase didn't show any relationship with many factors of indoor condition (number of fan or size of pc room, lighting) 6. The concentration of TSP & heavy metals didn't have any relationship between the factors of indoor environment (number of fans, size of pc room, lighting).

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