• Particle and aerosol research
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• v.13 no.1
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• pp.11-16
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• 2017

Indoor air quality is of increasing concern because it is closely related human health. An air handling unit (AHU) can be used to control the indoor air quality related to particulate matters and $CO_2$ as well as air conditioning such as temperature and humidity of indoor air. An electrostatic precipitator has a high collection efficiency and low pressure drop, however, ozone can possibly generate from its chargers, which is one of drawbacks to apply it for indoor air control. Here we compared four charging electrodes such as a $50{\mu}m$ tungsten wire, a $100{\mu}m$ tungsten wire, a $16{\mu}m$-thickness Al foil and a carbon fabric comprised of $5-10{\mu}m$ fibers. The carbon fabric electrode showed a superior particle collection efficiency and a lower ozone generation at a given power consumption compared to tungsten wires of 50, $100{\mu}m$ and an Al foil electrode. This low ozone generating, micro-sized electrode can be applied to the electrostatic precipitator in AHU for indoor air control.

• Journal of Korean Society for Atmospheric Environment
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• v.17 no.1
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• pp.39-50
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• 2001

The spatial distribution characteristics of airborbe mercury(Hg) were investigated used its concentration data from six measurement sites selected to represent:(1) three terminal sites with heavy traffic loads in urban area, (2) one urban residential site and (3) two mountainous sites in Korea. The measurement data obtained during September 1997 through May 1998 indicated that the mean concentration of Hg from different study sites were comparably high with the mean values spanning from 5-9ng./㎥. The concentration from all those sites were systmatically high compared to those of most background sites around world or to other Korean sites investigaed previously. When results of correlation analysis between Hg and relevant parameters were compared among different study sites. temperature was most frequently found out to be in strong correlation with Hg concentrations. Results of factor analysis also indicated that Hg concentrations could be affected simultaneously by th factors affecting such parameters as ozone, temperature, ozone, carbon monoxide, and PM. The findings of enhanced Hg levels from Ji-Ri Mountain relative to terminal site suggest that is distributions may be rather homogeneous not enough to clearly distinguish areal differences and the associated source signatures between urban and rural area. The existence of systmatically high concentrations from all investigated sites also indicate that the impact of its source processes should be quite ubiquitous, while highly variable in relatively long term scale.

• Korean Chemical Engineering Research
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• v.49 no.6
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• pp.835-839
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• 2011

The characteristics of torch-type atmospheric pressure plasma and its sterilization effects have been analyzed. The length of plasma flame was varied with the level of applied voltage and the mixture gases composed of argon and oxygen. The effect of plasma flame on the temperature increase of surface treated was limited to $43^{\circ}C$ as a maximum temperature under exposing time of 10 min. The sterilization for E. coli was strongly affected by the applied voltage, the oxygen ratio in the mixture gas and the treatment time. At a high concentration of ozone, the increase of treatment time under the direct contact with plasma flame yields to maximize the effect of the sterilization on E. coli.

• Journal of Korean Society for Atmospheric Environment
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• v.28 no.1
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• pp.77-85
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• 2012

In this study, emission rates (ER) of biogenic volatile organic compounds (BVOCs) were measured by varying levels of photosynthetically active radiation (PAR). An appropriate plan for ozone reduction according to increasing ecology area ratio in future metropolitan areas was suggested. Several trees were selected as representative tree species in urban areas. Emission rates and composition ratios of monoterpene and isoprene emitted from these trees were estimated and compared. As a result, it was found that emission rates of BVOCs were considerably different depending on tree species. Especially, BVOCs emitted from Platanus orientalis and Quercus mongolica could significantly affect ozone increase in the metropolitan area, because the emission rates were several thousands to ten thousand times higher than those emitted from Zelkova serrata and Prunus serrulata. Furthermore, it was observed that emission rates of BVOCs by species increased maximum up to 10 times when PAR, which has close relations with temperature, rose. It was concluded that tree species such as Zelkova serrata et al., was appropriate for metropolitan areas since the species has low ozone potential and good landscape. Suppose this type of trees are planted on purpose in the urban areas, better ambient air quality will be promised in the future.

• Asian Journal of Atmospheric Environment
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• v.5 no.1
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• pp.29-40
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• 2011

In this study, the effects of an urban thermal environment on air quality were investigated using hourly surface weather observation data and air quality data over six summers from 2000 to 2005 in two cities on the Korean Peninsula. One, the city of Daegu, is representative of basin topography and the other, the city of Busan, represents a coastal area. It is known that the characteristics of an urban thermal environment are represented as an "urban heat island". Here, we focus on the nighttime urban thermal environment, which is called a "tropical night", during the summer. On tropical nights in Busan, the temperature and cloud cover levels were higher than on non-tropical nights. Wind speed did not appear to make a difference even on a tropical night. However, the frequency of southwestern winds from the sea was higher during tropical nights. The prevailing southwest winds in all areas meant an inflow of air from the sea. So at most of the air quality stations, the ozone concentration during tropical nights was lower than during non-tropical nights. In Daegu, the tropical nights had higher temperatures and cloud covers. Despite these higher temperatures, the ozone concentration during the tropical nights was lower than that on non-tropical nights at most of the air quality stations. This feature was caused by low irradiance, which in turn caused an increased cloud cover. Wind speed was stronger during the tropical nights and dispersed the air pollutants. These meteorological characteristics of the tropical nights reduced ozone concentrations in the Daegu Basin.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.6
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• pp.773-787
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• 2003

There are variations in the temperature Held due to urban heat island and anthropogenic heating so that regional scale meteorological field is changed. Therefore we simulate and predict the regional climate change according to surface characteristics through regional meteorological model. This study investigates the regional meteorological field by urbanization that influences in local circulation system using CSU-RAMS and simulates dry deposition velocity (V$_{d}$) using PNU/DEM which includes surface characteristics (such as albedo, surface hydrology and rough-ness length etc.) with calculated meteorological field. During the summer, horizontal distributions of V$_{d}$ were simulated using CSU-RAMS and PNU/DEM at Busan metropolitan area. The estimated values of V$_{d}$ were larger in forest and agricultural areas than water areas since ozone with low water solubility is destroyed slowly at wet surface or water.water.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.2 no.4
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• pp.26-32
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• 1991

Korea Aerospace Research Institute(KARI) performs research on developing the scientific sounding rocket(KSR-420S) for measuring ozone profile and atmosphere layer over korean peninsula. Informations about performances of flighting scientific rocket, that is temperature, strain, acceleration, pressure, rocket attitude and ranging data, and measuring data of ozone, ionosphere and X-ray are transmitted ground system by rocket onboard transmitting system. In this paper, the telemetry ground system which is compatible with the KSR-420S is designed for tracking the trajectory and receiving the incoming signals.

• Journal of Power System Engineering
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• v.20 no.5
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• pp.92-97
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• 2016

In this study, the seawater Heat Pump System using seawater with temperature of annual domestic conditions ($0^{\circ}C$ to $25^{\circ}C$) is designed in order to compare its performance against the Heat Pump using unused heat of seawater. As a potential replacement for current refrigerants that exacerbate global warming and ozone delpetion, a Low GWP refrigerant's performance is analyzed. The basic water to water Heat Pump system is chosen and three commercial refrigerants - R134a, R410a, R32 - are used to compare against new Low GWP refrigerant R1234ze. When seawater with temperature of $25^{\circ}C$ is used, the performance change showed maximal increase in COP, 38.3%. low GWP refrigerant R1234ze, showed great performance characteristics reach to 5.242 and Existing commercial refrigerant, R134a showed only less than 0.03 performance difference against R1234ze. The study confirms notable performance of R1234ze refrigerant through simulation as environmentally friendly refrigerant for domestic seawater Heat Pump.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 1997.11a
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• pp.550-557
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• 1997

Production of so-called Halon fire extinguishing agents has been prohibited since January 1994 because of their ozone depletion potential, To replace them, several hydrofluorocarbons and fluorocarbons have been developed and utilized. A number of studies on flame extinguishing concentrations and flammability peak concentrations of them have been done. Although there was enough information for practical purpose, more knowledge on fire extinguishing characteristics of them should be attained for efficient use of them. In this study, peak concentrations of methane/air mixtures with gaseous halogenated hydrocarbons were measured at elevated temperature, because the former studies were done at room temperature and temperature of a fire room can be higher than usual. Measurement was done at $200^{\circ}C$, because measuring system could not endure higher temperature. This study revealed that peak concentrations of halogenated hydrocarbons differed little at elevated temperature. The halogenated hydrocarbons have almost the same fire extinguishing ability as Halon 1301.

• Journal of Preventive Medicine and Public Health
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• v.32 no.2
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• pp.191-199
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• 1999

Objectives: To examine the relationship between air pollution exposure and mortality in Seoul for the years of 1991-1995, Methods: Daily counts of death were analyzed by general additive Poisson model, with adjustment for effects of secular trend, seasonal factor, day of the week, heat wave, temperature, and humidity. Pollution variables were ozone, nitrogen dioxide, total suspended particles(TSP), and sulfur dioxide. Results: Daily death counts were associated with ozone(1 day before), nitrogen dioxide(1 day before), TSP(2 days before), sulfur dioxide(2 days before). The association with ozone was most statisfically significant and independent of other air pollutants. Increase of 100 ppb in ozone was associated with 0%(95% Cl= 2%-10%) increase in the daily number of death, This effect was greater in persons aged 65 and older. The relative risks of death from respiratory disease and cardiovascular disease were greater than for all-cause mortality in each pollutant. After ozone level exceeds 25 ppb, the dose-response relationship between mortality and ozone was almost linear. However, the effect of TSP, sulfur dioxide, and nitrogen dioxide on mortality might be confounded with each other. Conclusion: Daily variations in air pollution within the range currently occurring in Seoul might have an adverse effect on daily mortality.