• Journal of Korean Society for Atmospheric Environment
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• v.22 no.E1
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• pp.35-43
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• 2006

Ambient particle size distributions of PCBs and their dry deposition fluxes were measured at a site in Seoul to quantify dry deposition fluxes of PCBs and size characteristics of PCBs in the air, and to estimate ambient concentrations of gaseous PCBs and dry deposition fluxes. The dry deposition plate was used to measure dry deposition fluxes of particulate mass and PCBs and a cascade impactor and rotary impactor were used to measure ambient particle size distributions for small ($D_p<9{\mu}m$) and large ($D_p>9{\mu}m$) particles, respectively. Six sample sets were collected from April to July 1999. The fluxes of particulate total PCBs (the sum of 43 congeners) ranged from 160 to $607ng\;m^{-2}day^{-1}$. The size distribution of total PCBs was bimodal with two peaks in small particle size ($D_p{\sim}0.6\;and\;6{\mu}m$, respectively) and, thus, mass concentration being dominant in small particles. The mean particulate PCBs concentration was $6.9{\mu}g$ PCBs/g. The concentrations of PCB homologues in the gas phase were estimated based on the particle/gas partition coefficient ($K_p$) with the measured values of particulate PCBs in this study and they were comparable to those observed in other previous studies. Dry deposition fluxes were estimated by calculating dry deposition velocities.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.4
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• pp.453-461
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• 2014

Objective: Based on the fact that fine particles are more likely to produce negative influences on the health of occupants as well as the quality of indoor air compared to coarse particles, it is critical to determine concentrations of aerosol particles with different sizes. Thus, this study focused on the size distribution and concentrations of aerosol particles in university buildings. Method: Aerosol particles in indoor air were collected from four areas: corridors in buildings(In-CO), lecture rooms(In-RO), laboratories(In-LR), and a cafeteria(In-RE). Samples were also collected from outside for comparison between the concentrations of indoor and outdoor particles. For the collection of the samples, an eight stage non-viable cascade impactor was used. Result: The average concentration of $PM_{10}$ in the samples collected from indoor areas was $34.65-91.08{\mu}g/m^3$,and the average for $PM_{2.5}$ was $22.65-60.40{\mu}g/m^3$. The concentrations of the aerosol particles in the corridors, lecture rooms, and laboratories were relatively higher than the concentrations collected from other areas. Furthermore, in terms of mass median aerodynamic diameter(MMAD), the corridors and lecture rooms had higher numbers due to their characteristics, showing $2.36{\mu}m$ and $2.11{\mu}m$, respectively. Laboratories running an electrolysis experiment showed $1.58{\mu}m$, and the cafeteria with regular maintenance and ventilation had $1.96{\mu}m$. Conclusion: The results showed that the $PM_{10}$ concentrations of all samples did not exceed indoor air quality standards. However, the $PM_{2.5}$ concentration was over the standard and, in particular, the concentration of fine particles collected from the laboratories was relatively higher, which could be an issue for the occupants. Therefore, it is important to improve the quality of the indoor air in university buildings.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.3
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• pp.575-585
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• 2000

Mass and elemental dry deposition fluxes and ambient particle size distributions were measured using dry deposition plates, a cascade impactor. and a CPS(Coarse Particle Sampler), from July to November 1998 in Seoul. Korea. Primarily anthropogenic elemental fluxes (Cu, Mn, Ni, Pb, Zn) were on average one to two orders of magnitude lower than primarily crustal elements (Al, Ca). Complete total and elemental particle size distributions showed trimodal size distributions due to the peak in particles larger than $10{\mu}m$ in diameter. A multi-step model and the Sehmel-Hodgson model were used to calculate total and cumulative deposition fluxes. The result indicated that dry deposition fluxes were extremely sensitive to the mass of particles larger than $10{\mu}m$ in diameter due to their high dry deposition velocities. The result showed that particles larger than $10{\mu}m$ in diameter dominated atmospheric dry deposition. The modeled fluxes calculated using the measured atmospheric particle size distributions and modeled deposition velocities were compared to measured ones. In general, the measured mass and elemental fluxes agreed well with the modeled ones.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.1
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• pp.1-10
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• 2006

Concentration and identification of airborne bacteria in the regulated public facilities were examined with the six-stage cascade impactor. Geometric mean total and respirable concentrations of airborne bacteria were $404cfu/m^3$ and $194cfu/m^3$ in hospital, $931cfu/m^3$ and $358cfu/m^3$ in kindergarten, $294cfu/m^3$ and $134cfu/m^3$ in day-care center, and $586cfu/m^3$ and $254cfu/m^3$ in postpartum nurse center, respectively. As a result, culturable total and respirable concentrations of airborne bacteria were significantly highest in kindergarten and lowest in day-care center (p<0.05). The ratio of respirable to total concentration of airborne bacteria in the investigated public facilities was ranged from 30% to 40% but there was no significant difference among them (p>0.05). The mean I/O ratio of culturable total and respirable concentrations were 0.58 and 0.66 in hospital, 0.71 and 0.83 in kindergarten, 0.28 and 0.41 in day-care center, and 0.63 and 0.78 in postpartum nurse center, respectively. Day-care center showed the lowest I/O ratio of culturable total and respirable concentration of airborne bacteria (p<0.05) but a significant difference was not found among other facilities. Indoor concentration of airborne bacteria did not correlated significantly with indoor temperature and relative humidity (p>0.05) but had a significant positive correlation with $CO_2$ and surrounding condition (p<0.05). Staphylococcus spp., Micrococcus spp., Corynebacterium spp., and Bacillus spp. were dominant genera and amounted to over 95% of total airborne bacteria identified in the investigated public facilities. Size distributions of four dominant genera did not observed inconsistently regardless of type of public facility.

• Korean Journal of Environmental Biology
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• v.21 no.3
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• pp.240-244
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• 2003

Conidia of molds within the Asian dust were captured in the ambient air of mid-west Korea, in springtime of 2000~2002. An eight-stage Cascade impactor and 0.22 $\mu\textrm{m}$ pore size membrane filters were used for the dust samples. Several kinds of molds grown from the samples were identified to the genus level. Those are Aspergillus, Basipetospora, Epicoccum, Fusarium, Monotospora and Penicillium. Relatively diversified mycelia of hyphomycetes were grown on the fine dust sample (1.1~2.1 $\mu\textrm{m}$) in the first year Asian dust episode (23~24 March, 2000). On the other hand, some fluffy molds and dark molds aggregations were grown on even the backup particle sample less than 0.43 $\mu\textrm{m}$ during the second year episode (24~26 April, 2001). The result of the last year episode (21~22 March, 2002) showed various mycelia grown on the sample contained from 1.1 to 2.1 $\mu\textrm{m}$ sized particles, just like the result of the first year episode (23~24 March, 2000). These variations between the episodes might be caused by the difference of the dust origins.

• Asian Journal of Atmospheric Environment
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• v.4 no.2
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• pp.72-79
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• 2010

In this study, the ionic composition of volcanogenically derived particles and their temporal and spatial distributions have been investigated to evaluate the impact of the volcanic eruption on the local ecosystem and residents. To this end, an intensive field study was conducted to measure the size-segregated particulate matters at the east part of Sakurajima in Japan. Fractionated sampling of particles into > $PM_{10}$, $PM_{10-2.5}$, and $PM_{2.5}$ was made by a multi nozzle cascade impactor (MCI). The concentration of various ions present in the size-resolved particles was determined by Ion chromatography. The time dependent 3-dimensional Volcanic Ash Forecast Transport And Dispersion (VAFTAD) model developed by the NOAA Air Resources Laboratory (ARL) indicated that the sampling site of this work was affected by the volcanic aerosol particles plume. The temporal distributions of sulfate and $PM_{2.5}$ during the field campaign were significantly variable with important contributions to particle mass concentration. The chlorine loss, suspected to be caused by acidic components of volcanic gases, occurred predominantly in fine particles smaller than $10\;{\mu}m$.

• Journal of Korean Society for Atmospheric Environment
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• v.13 no.4
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• pp.285-296
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• 1997

The suspended particulate matters had been collected on quartz fiber fiters by a cascade impactor having 9 size stages for 4 years (Sep. 1991 to Dec. 1995) in Kyung Hee University-Suwon Campus. Membrane filters were used to collected the particulate matters on each stage. The weight concentration on each stage was obtained by a microbalance and further chemical element levels were determined by an x-ray fluorescence system. Based on these chemical information, our study focused on applying the target transformation factor analysis (TTFA), a receptor model, to identify aerosol sources and to apportion quantitatively their mass contribution. There are total of 63 ambient data sets. Each data set consists of the 8 size-ranged subdata sets characterized by 16 elemental variables. By the results, four to five sources were extracted from each size range and some sources reappeared in other size ranges. Then total of 8 source profiles were statistically generated from all the ranges, such as oil burning source, soil source, field burning source, gasoline related source, coal burning source, marine source, glass related source, and unknown sources. Apportioning aerosol mass to each source was intensively examined by investigating emission inventories near the study area. The results showed that soil particle source was the most significant contributor. However, coal and oil burning sources were the major anthropogenic ones. The study finally proposed some air quality control strategies to achieve the clean air quality in Suwon area.

• Proceedings of the Korean Environmental Health Society Conference
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• 2003.06a
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• pp.76-85
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• 2003

Mass and elemental dry deposition fluxes and ambient particle size distributions were measured using dry deposition plates and a cascade impactor, from March to November 1998 in Seoul, Korea. During the spring sampling period several yellow sand events characterized by long range transport from China and Mongolia impacted the area. During these events the mass fluxes were statistically the same as during springtime non-yellow-sand events. However, most elemental fluxes were higher. In general, the flux ratios of both crustal (Al, Ca, Mn) and anthropogenic elements (Ni, Pb) to total mass measured during the daytime yellow-sand events were substantially higher than those measured in spring daytime during non-yellow-sand time periods. During all seasons the average measured daytime fluxes were about two times higher than at nighttime. The flux of primarily anthropogenic metals (Cu, Ni, Pb, Zn) and Mn was on average one to two orders of magnitude lower than the flux of the crustal metals Al and Ca. As is typically found two modes, fine (0.1∼l.0 $\mu\textrm{m}$) and coarse (1.0∼10.0 $\mu\textrm{m}$) were present in the measured size distributions (<10 $\mu\textrm{m}$). The particles in the coarse mode constitute a major portion of the measured mass size distribution during the yellow-sand events possibly due to the long-range transport of those particles from China.

• Journal of Environmental Health Sciences
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• v.34 no.2
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• pp.131-136
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• 2008

The variation of the particle size distribution and density as well as the chemical composition of aerosols is important to evaluate the particles. This study measured and analyzed airborne particles using a scanning mobility particle sizer (SMPS) system and an aerodynamic particle sizer (APS) at the University of Seoul during every season. The highest particle number concentration of airborne particles less than $0.9\;{\mu}m$, occurred in winter, while the highest particle number concentration of airborne particles more than $0.9\;{\mu}m$, occurred in spring. Mass concentration appeared highest at spring. Also, when we compared $\beta$-ray's mass concentration with calculated mass concentration by using the SMPS-APS system during each season, density of the winter is $1.92\;g/cm^3$, spring density is $1.64\;g/cm^3$, fall density is $1.57\;g/cm^3$. We found out that PM10 density was differ every season. However, while the calculated density is whole density for PM10 the density of each diameter was different. In this study the density estimation equation of the QCM cascade impactor measured mass concentration of each diameter.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.E1
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• pp.45-48
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• 2006

Mass size distributions of atmospheric particles in Cheonan were determined using a high volume air sampler equipped with a 5-stage cascade impactor. Bimodal distributions that are typical for urban atmospheric particles were obtained. A MMD of the fine particle mode was $0.47{\pm}0.05{\mu}m$ with a GSD of $2.72{\pm}0.21$, and those of the coarse particles were $5.15{\pm}0.18{\mu}m\;and\;2.09{\pm}0.09$, respectively. The annual average concentrations of TSP, PM10, PM2.5, and PM1 were 74.1, 67.5, 54.2, and $42.3{\mu}g/m^3$, respectively. Although the daily PM10 concentrations were under the current National Standard, the daily PM2.5 concentrations frequently exceeded the US Standard even in non asian dust periods. The fractions of PM 10, PM2.5, and PM1 in TSP were $0.905{\pm}0.013,\;0.723{\pm}0.022,\;and\;0.572{\pm}0.029$, respectively, and fine mode particles occupied $57{\sim}72%$ of the total particle mass. The results indicate that fine particles were at the concerning level, and should be the target pollutant for the regional air quality strategy in Cheonan.