• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1678-1683
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• 2003

DBD(Dielectric Barrier Discharge) plasma in air is well established for the production of large quantities of ozone and is more recently being applied to aftertreatment processes for HAPs(Hazardous Air Pollutants). Although DBD high electron density and energy, its potential use as nano and sub-micron sized particle charging are not well known. Aim of this work is to determine design and operating parameters of a two-stage ESP with DBD. DBD and ESP are used as particle charger and precipitator, respectively. We measured particle precipitation efficiency of two-stage ESP and estimated ozone decomposition of both pelletized $MnO_2$ catalyst and pelletized activated carbon. To examine the particle precipitation efficiency, nano and sub-micron sized particles were generated by a tube furnace and an atomizer. AC voltage of $7{\sim}10$ kV(rms) and 60 Hz is used as DBD plasma source. DC -8 kV is applied to the ESP for particle precipitation. The overall particle collection efficiency for the two-stage ESP with DBD is over 85 % under 0.64 m/s face velocity. Ozone decomposition efficiency with pelletized $MnO_2$ catalyst or pelletized activated carbon packed bed is over 90 % when the face velocity is under 0.4 m/s in dry air.

• Applied Chemistry for Engineering
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• v.28 no.2
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• pp.193-197
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• 2017

In this study, we report on the catalyst process installed in conjunction with a wet plasma electrostatic precipitator to remove the oil mist and fine dust emitted from large-size grill restaurants. The multi-stage catalyst module reduced odor through catalytic reaction of acetaldehyde on catalysts even at an ambient temperature with ozone as an oxidant readily produced in a wet plasma electrostatic precipitator. Two types of manganese-based catalysts, $Mn_2O_3$ and $CuMnO_x$ were fabricated by extrusion molding for structured catalysts in practical applications, and the optimum conditions for high removal efficiencies of acetaldehyde and ozone were determined. When two optimized catalysts were applied in a two-stage catalyst module, the removal efficiency of acetaldehyde and ozone were ${\geq}85%$ and 100% respectively at the space velocity of $10,000h^{-1}$ and the reaction temperature of $100^{\circ}C$.

• Journal of Environmental Impact Assessment
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• v.22 no.6
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• pp.609-626
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• 2013

Air quality models have been widely used to study and simulate many air quality issues. In the simulation, it is important to raise the accuracy of meteorological predicted data because the results of air quality modeling is deeply connected with meteorological fields. Therefore in this study, we analyzed the effects of meteorological fields on the air quality simulation. This study was designed to evaluate MM5 predictions by using different initial condition data and different observations utilized in the data assimilation. Among meteorological scenarios according to these input data, the results of meteorological simulation using National Centers for Environmental Prediction (Final) Operational Global Analysis data were in closer agreement with the observations and resulted in better prediction on ozone concentration. And in Seoul, observations from Regional Meteorological Office for data assimilations of MM5 were suitable to predict ozone concentration. In other areas, data assimilation using both observations from Regional Meteorological Office and Automatical Weather System provided valid method to simulate the trends of meteorological fields and ozone concentrations. However, it is necessary to vertify the accuracy of AWS data in advance because slightly overestimated wind speed used in the data assimilation with AWS data could result in underestimation of high ozone concentrations.

• Korean Chemical Engineering Research
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• v.50 no.3
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• pp.421-426
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• 2012

The effect of synthesis conditions such as various organic material and composition of organic-inorganic material in ozone resistance and surface characteristic of ultraviolet cured organic-inorganic hybrid coating film has been investigated. Organic-inorganic hybrid coating solution was prepared using tetraethoxysilane (TEOS), silane coupling agent methacryloyloxypropyltrimethoxysilane (MPTMS), 2,2,2-trifluoroethylmethacrylate, and various organic materials with acrylate group, bar-coated on substrates using applicator and densified by UV-curing. It was found that ozone resistance and surface hardness of the coating film was increased with contents of TEOS. It was also found that ozone resistance of coating film was increased with contents of 2,2,2-trifluoroethylmethacrylate. On the other hand, surface hardness was decreased with increase of 2,2,2-trifluoroethylmethacrylate. In addition, Surface hardness of coating film was increased with the addition of aliphatic urethane acrylate. It was also found that the transmittance of coating films was not influenced by content of TEOS and 2,2,2-trifluoroethylmethacrylate. In addition, the coating film exhibited high transmittance of above 90%.

• Korean Journal of Remote Sensing
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• v.31 no.6
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• pp.599-608
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• 2015

In this present study, we quantified the $SO_2$ effect on $O_3$ retrieval from the Ozone Monitoring Instrument (OMI) measurement. The difference between OMI-Total Ozone Mapping Spectrometer (TOMS) and OMI-Differential Optical Absorption Spectrometer (DOAS) total $O_3$ is calculated in high $SO_2$ volcanic plume on several volcanic eruptions (Anatahan, La Cumbre, Sierra Negra, and Piton) from 2005 through 2008. There is a certain correlation ($R{\geq}0.5$) between the difference and $OMI-SO_2$ in volcanic plumes and the significant difference close to 100 DU. The high $SO_2$ condition found to affect TOMS $O_3$ retrieval significantly due to a strong $SO_2$ absorption at the TOMS $O_3$ retrieval wavelengths. Besides, we calculated the difference against various $SO_2$ levels. There is the considerable difference (average = 32.9 DU; standard deviation = 13.5 DU) in the high $OMI-SO_2$ condition ($OMI-SO_2{\geq}7.0DU$). We also found that the rate of change in the difference per 1.0 DU change in middle troposphere (TRM) and upper troposphere and stratosphere (STL) $SO_2$ columns are 3.9 DU and 4.9 DU, respectively.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.3
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• pp.297-310
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• 2007

Recent evidence has demonstrated that the pollutant recirculation can play an important role in leading to high ozone $(O_3)$ concentrations. In this study, the MM5-CAMx air quality modeling system was applied to simulate the pollutant recirculation and identify the transport of pollution during the high $O_3$ event (the maximum $O_3$ of 195 ppb) observed in the Greater Seoul Area (GSA) on $1{\sim}4$ June in 2004. The results showed a weak northeasterly synoptic wind during the night and early morning moved the air parcels containing the locally emitted urban pollution to the coast, which contributed to enhance $O_3$ formation in the southwest part of the GSA. As the sea breeze developed and started to penetrate inland in the late afternoon, the rapid build-up of $O_3$ concentration was found in the southwest coastal area due to the recirculation of the polluted air loaded with high level $O_3$. The simulated backward trajectories and observations at coastal sites confirmed the recirculation of pollutant with the late sea breeze is the dominant factor affecting the occurrence of high $O_3$ concentrations in the southwestern GSA.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.261-265
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• 2001

In this paper, a current-source type parallel indudor compensated load resonant high-frequency soft switching inverter using IGBTs for driving the newly-produced silent discharge type ozone generating tube and excimer lamp for UV generation which incorporate a single switched capacitor resonant snubber between the port in DC busline side is presented, together with its pulse modulated unique output power regulation characteristics.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.3
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• pp.136-142
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• 2002

HFC-134a is currently used as the refrigerant in automobile air-conditioner, replacing the ozone depleting refrigerant CFC-12. Although HFC-l34a has no ozone depletion potential, it has a relatively high global warming potential, approximately 1300 tins that of CO$_2$ over a 100 year time horizon. Therefore, HFC- l34a does not seem to be a perfect alternative refrigerant due to high GWP. For this reason, non-azeotrope refrigerant mixture have been proposed as a long-term and drop-in alternative to HFC-l34a in the automobile air-conditioning system which has variable operating conditions with changes in RPM and pressure ratio. In this study,OS-l2a of which thermodynamic properties are similar to those of HFC-l34a is selected among the mixed refrigerant. HFC-l34a and OS-l2a are examined experimently by the performance test in the same automobile air-conditioning system.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.563-565
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• 1993

This paper describes ozone concentration and discharge characteristics in flowing $O_2$ with variation of Re at high voltage nozzle(HVN). HVN type ozonizer is equipped with ten nozzle. The important conclusions obtained from this paper are as follows. For constant pulse width(Pw) and pulse frequency(Pf) the more Re increases, the higher corona onset voltage(Vc) rise. Vc is inversely proportional to Pw and Pf. Ozone concentration($O_{3con}$) increases with less Re for constant Pw and Pf. $O_{3con}$ increases with less Pw. $O_{3con}$ is proportional to Pf.

• Journal of Environmental Health Sciences
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• v.31 no.3
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• pp.215-220
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• 2005

The atmospheric transportation and dispersion processes of air pollutants are important issues in dealing with air pollution problems. Air pollutants originated from biological and anthropogenic activities are not only limited to the local emission sources, but could also be transported and dispersed to other regions by synoptic weather systems. Besides, the complexity of topography of central Taiwan helps accumulating air pollutants to promote high-concentration episodes. The techniques of tethersonding were applied to monitor the vertical profiles of winds, air temperatures and humidity, as well as to collect air samples, to be analyzed for pollutants $(O_3,\;NO_2,\;NO\;and\; NMHC)$ from the ground up to 1000m. A time period of about one week, 19-26 October 2002, was chosen as the sampling period due to the high frequency of episode occurrence in autumn based on the past records. Associating with the analysis of weather patterns, the atmospheric characteristics over high-concentration areas can be resolved in more detail. The result of the tethersonding studies showed that weak northerly sea breeze (with thickness about 300m) with low wind speed (about 1 to 2 m/sec) could help develop high ozone concentrations in the down-wind areas. It is also important to have a built-up aloft of precursors and ozone to develop high concentration on the previous day.