• Journal of Korean Society for Atmospheric Environment
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• v.27 no.6
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• pp.663-671
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• 2011

Although a scooter is a convenient transportation means for a short distance traveling with a light package in the congested urban center, it might be one of the significant sources of air pollutants to which many people can easily be exposed during its passing-by. In this paper, we measured concentrations of gases and particles emitted from a scooter at roadside with no other traffic. To understand the characteristics of scooter emissions with respect to driving speed (idling, 30 km/h) at the roadside, total particle number concentration, particle size distribution, average surface area of particles deposited in the alveolar region, and concentrations of black carbon, CO, and $NO_x$ were measured. The concentrations of the particle number, surface area of deposited particles, CO, and $NO_x$ were highly fluctuated in the scooter's idling condition. The trends of particle number concentration, CO, and $NO_x$ generation were similar to one another. When the scooter started to move, all of $NO_x$, CO and particle number concentrations increased and after it passed by at the speed of 30 km/h, the concentration peaks of the particles and gases appeared at the same time. Unimodal size distribution with ~70 and ~93 nm mode diameters was observed for the idling and cruising condition, respectively. From this work, we found that emission from a passing vehicle could be characterized using a roadside monitoring technique.

• Journal of the Korean Society of Combustion
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• v.15 no.1
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• pp.43-49
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• 2010

Co-combustion of syngas in an existing boiler can be one of the options for replacing conventional fossil fuel with alternative fuels such as waste and biomass. This study is aimed to investigate effects of syngas cocombustion on combustion characteristics and boiler efficiency. An experimental study was performed for a pilot-scale furnace with 4 oil burners. Tests were conducted with mixture-gas as a co-combustion fuel and heavy oil as a main fuel. The mixture-gas was composed of 15% CO, 7% $H_2$, 3% $CH_4$ and 75% $N_2$ for simulating syngas from air-blown gasification. And LHV of the mixture-gas was 890 kcal/$Nm^3$. Temperature distribution in the furnace and flue gas composition were measured for various heat replacement ratio by the mixture gas. Heat loss through the wall was also carried out through heat & mass balance calculation, in order to obtain informations related to boiler efficiency. Experimental results show that similar temperature distribution and flue gas composition can be obtained for the range of 0~20% heat replacement by syngas. NOx concentration is slightly decreased for higher heat replacement by the syngas because fuel NOx is decreased in the case. Meanwhile, heat loss is a bit decreased for higher heat replacement by the syngas, which implies that boiler efficiency can be a bit decreased when syngas co-combustion is applied to a boiler.

• KSBB Journal
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• v.13 no.2
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• pp.187-194
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• 1998

For mass production of polyhydroxyalkanoates (PHA), high cell density cultures of Alcaligenes eutrophus by fed-batch culture under phosphate-limitation condition has been investigated. PHA accumulation by the regulation by the regulation of initial phosphate concentration could be automatically induced, and high density cell culture above 200 g/L also could be successfully produced. The production of Poly-$\beta$-hydroxybutyrate (PHB) and dry cell weight increased with increasing the initial phosphate concentration. When the initial concentrations of phosphate were in the ranges of 1.5~4.5 g-PO$_4$/L, PHB and dry cell weight obtained were 83~266 g/L and 61~216 g/L, respectively, and PHB productivity was in the ranges of 1.35~3.10 g/L.h. When a mixture of glucose and propionic acid is used as carbon sources, poly(3-hydroxybutyrate-co-poly-3-hydroxyvalerate), P(3HB-co-3HV), could be also successfully produced under phosphate limitation condition. When the mole ratio of propionic acid to glucose in the feeding solution is 0.22, a final dry cell weight of 150 g/L and a P(3-HB-co-3HV) of 90 g/L were produced. Morphological changes and size distribution of PHB granules synthesized in A. eutrophus under phosphate-limitation condition are determined by TEM during the course of fed-batch. Mean granule diameters of PHB produced are in the range of 0.36~0.39 $\mu$m, and mean cell size was elongated from 0.54~0.59 $\mu$m$\times$ 1.3~1.5 $\mu$m to 0.83~0.89 $\mu$m $\times$2.0~2.3 $\mu$m. Phosphate concentration in media did not affect size distribution of PHB granule and cell.

• 한국연소학회:학술대회논문집
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• 1998.10a
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• pp.23-30
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• 1998

The stabilization characteristics of diffusion flame formed in the wake of a cylindrical flame holder were investigated. Distribution of turbulence intensity, concentration distribution of combustion gas, and ion currents were measured. The turbulence intensity in the wake of cylindrical- game holder is increased with increase of diameter or blockage ratio of grid. If the auxiliary fuel is injected into recirculation zone, the concentration of $C_3H_8$ is high, but the concentration of $CO_2$ is low at the boundary of recirculation zone. The region with highest average value of ion currents in the middle of flame is moved to the upstream side by the turbulent components of main stream. The flame mass with partially active reaction is moved fast for uniform flow and turbulence generator G3, but the flame mass with relatively slow reaction is moved slowly for turbulence generator G1.

• Journal of the Korean earth science society
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• v.23 no.3
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• pp.270-279
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• 2002

The concentrations of major greenhouse pollutants which include $CO_2$ and $CH_4$ were determined from the outlet of 42 ventpipes in Nan-Ji-Do area of Seoul during September/October of 2000. Using these data, the concentration distribution of major greenhouse gases was checked and compared. The mean concentrations of $CO_2$ and $CH_4$, computed using the data sets collected from 42 ventpipes, were 27.8 and 50.9%, respectively. Because the concentration levels were different not only between plain and slope areas of each sector but also between chemicals, evaluation of the data sets was made after dividing them separately into four data groups. The results of our analysis clearly indicate that their distribution is rather homogeneous than those of minor constituents of landfill ventilated gases (e.g., Hg).

• Journal of Environmental Science International
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• v.17 no.5
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• pp.501-507
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• 2008

The concentrations of HCHO(formaldehyde), $PM_{10}$(particulate matter), $CO_2$(carbon dioxide) and TBC(total bacteria counter) distribution in schools(Chung-Nam Area) were examined, and the results were compared with the recommended criterion of the administration law of indoor air. The subjects were an elementary school, a middle school and a high school in Chung-Nam area, and the concentration of TBC was examined by Single Stage Air Cascade Sampler, which applied the inertia collision catching method of 28.29L/min(flux) during 5 months from March, 2007 to July, 2007. The instrument(LD-3B, SIBATA Company)was used to examine $PM_{10}$, by a light scattering method and a light transmission method. The instrument(Airboxx(KD Engineering) was used to examine $CO_2$. The instrument(Z300XP(Environmental sensor)was used to examine HCHO. The result indicated that the $PM_{10}$ average concentrations of the surveyed classrooms were $49{\mu}g/m^3$ in Spring and $59{\mu}g/m^3$ in Summer. The $CO_2$ average concentration of the surveyed schools were 576 ppm in the classroom and 527 ppm in the stateroom. The average concentration of TBC were $729CFU/m^3$ in an elementary school, $401CFU/m^3$ in a middle school, $381CFU/m^3$ in a high school. The HCHO average concentration of the surveyed schools were 0.03 ppm in the classroom, 0.02 ppm in the stateroom.

• 보존과학연구
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• s.28
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• pp.91-104
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• 2007

The goal of this study was to provide basic data for arrangement of management in museum environment. We investigated characteristics of distribution on indoor air pollutants at exhibition halls and storages in museums between July and August, 2007. The monitoring carried out at three cultural sites, Pusan, Daejeon and Kyungjoo which is possessed their own exhibition hall and storage in Museums. We adopt the several pollutants for this survey such as $PM_{10}$, $PM_{2.5}$ $CO_2$, Formaldehyde, TBC, CO, $NO_2$, Rn, VOCs, $O_3$ and followed the standard method of Ministry of Environment, Korea for sampling and analysis, respectively. The results of this survey revealed that average concentration of $PM_{10}$ and $PM_{2.5}$ in storages were $117.3{\mu}g/m^3$ and $92.6{\mu}g/m^3$, respectively. The average concentration in storages of gases pollutants and microorganism such as $CO_2$, Formaldehyde, $NO_2$, Rn, TVOC, $O_3$, and TBC showed as: 788.8ppm, $30.7{\mu}g/m^3$, 0.4ppm, 6.4ppb, $1.3pCi/{\ell}$, $1,374.9{\mu}g/m^3$, 2.4ppb, and $119.4cfu/m^3$, respectively. In addition, average concentration of $PM_{10}$ and $PM_{2.5}$ in exhibition halls were $49.5{\mu}g/m^3$ and $56.1{\mu}g/m^3$, respectively. The average concentration in exhibition halls of gases pollutants and microorganism such as $CO_2$, Formaldehyde, $NO_2$, Rn, TVOC, $O_3$, and TBC showed as: 475.2ppm, $94.1{\mu}g/m^3$, 0.3ppm, 12.4ppb, $0.3pCi/{\ell}$, $1,179.1{\mu}g/m^3$, 5.2ppb, 2.4ppb, and $24.8cfu/m^3$, respectively.

• Journal of the Korean Society of Tobacco Science
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• v.23 no.2
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• pp.179-184
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• 2001

This study was conducted to determine the smoke component distribution and the relationship between chemical components and physical characteristics of cigarettes. 16 different cigarette brands which were sold in the market were selected for this study. Five kinds of smoke components which have been tar, nicotine, water, carbon monoxide(CO) puff No., and six kinds of physical characteristics which were filter type, leaf weight, filter weight, UPD, EPD, dilution rate were analyzed. The average values in tar, nicotine, water, CO concentration were 6.5 mg/cig. 0.66 mg/cig, 1.12 mg/cig. and 6.32 mg/cig., respectively. The average ratios of nicotine/tar and CO/tar were 0.10, and 1.02 respectively. The distribution of smoke components collected in the cambridge filter and cigarette filter was different. The averages of tar and nicotine removal efficiency by a cigarette filter were 53%, and 48%, respectively. All smoking components were positively correlated with other smoking components. filter types, EPD, and dilution rate were showed high correlation to the changes of smoke components. Especially, dilution rate of cigarette strongly affected on the changes of all smoke components.

• Journal of Environmental Science International
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• v.16 no.2
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• pp.187-195
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• 2007

Long-term passive diffusive samplers(PDS) have been used to measure $NO_2\;and\;SO_2$ concentrations at 21 sampling sites in Daejeon, Korea during the period of January 2000 - December 2002. The spatial distributions of annual $NO_2\;and\;SO_2$ concentrations were mapped. Average annual $NO_2$ concentration over the sampling period was $28.5{\pm}12.5\;ppb$, ranging from 1.2 to 81.7 ppb. Average annual $SO_2$ concentration over the sampling period was $7.7{\pm}4.8\;ppb$, ranging from 0.6 to 26.8 ppb. On average, $NO_2$ concentration was approximately 5.8%(1.6 ppb) larger in 2002. $SO_2$ concentration was decreased by 13%(1.1 ppb) during the sampling period. The seasonal variation of $NO_2\;and\;SO_2$ concentration was observed with a tendency to be higher in fall and winter. $NO_2\;and\;SO_2$, concentrations measured at different site types(patterns of land use) show significant difference. The observed difference in concentration was associated with difference in emissions of $NO_2$ from motor vehicles and $SO_2$ by non-traffic fuel consumption for heating.

• Health Policy and Management
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• v.30 no.1
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• pp.50-61
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• 2020

Background: This study aims to analyze the effects of air pollutants, such as particular matter, to the number of outpatient visits for allergic rhinitis in eup, myeon, and dong administrative boundaries. Methods: Dependent variable was the number of outpatient visits for allergic rhinitis per 10,000 people by region. Independent variables were air pollutants such as PM₁₀, PM_2.5, SO₂, O₃, CO₂, NO₂, and temperature that estimated by using Kriging analysis in all eup, myeon, and dong boundaries. Panel analysis was applied for the analysis to prove the relation between outpatient visits and the concentration of air pollutants. Results: Analysis results showed that particular matter concentration varied by regions and season. Panel analysis showed that outpatient visits for allergic rhinitis had positive relationships with PM₁₀, PM_2.5, SO₂, O₃, and CO₂ in all panel models. Conclusion: Regional variation of particular matter concentration should be considered in establishing regional policies for allergic rhinitis.