• Title, Summary, Keyword: Surface ozone

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Characteristics of Surface High Ozone Concentration on Pusan Coastal area, Korea (부산 해안지역의 고농도 오존 발생 특성에 관한 연구)

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    • Journal of Environmental Science International
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    • v.9 no.4
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    • pp.295-302
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    • 2000
  • This study was conducted to investigate the characteristics of surface ozone concentration and occurrence of high ozone concentration using hourly ozone, nitrogen dioxide and meteorological data for 1997~1998 in Pusan coastal area. Monthly mean ozone concentration was the highest at Dongsamdong in Spring(35.4ppb), at Kwangbokdong in Fall(25.1ppb) and the lowest Dongsamdong(22.2ppb) and Kwangbokdong(16.0ppb) in Winter. Relative standard deviation indicating clearness of observation site was 0.42 at Dongsamdong and 0.49 at Kwangbokdong that is similar to urban area. The diurnal variation of ozone concentration of Dongsamdong and Kwangbokdong showed maximum at 1500~1600LST and minimum 0700~0800LST that typical pattern of ozone concentration. In ozone episode period(Sept. 10~15, 1998), diurnal change of ozone concentration was very high, and ozone concentration was related to meteorological parameters such as temperature, relative humidity, wind speed, cloud amount and radiation on a horizontal surface. During the episode days peak ozone concentrations are much higher than the normal values, wind speeds are always lower, and solar radiation is high with the exception of the September episode.

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Synoptic Weather Patterns and Variation of Ozone Concentrations Association with High Ozone Days at Five Major Cities in Korea (고농도 오존이 발생하는 날의 종관 기상 패턴과 주요 5대 도시별 오존 농도 변화)

  • 김유라;윤일희;김희종
    • Journal of Environmental Science International
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    • v.10 no.6
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    • pp.437-444
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    • 2001
  • The characteristic features of surface ozone concentration and the forecasting procedure of high ozone days have been studied. The ozone concentration was continuously measured during 3 years (1997~1999) at air quality monitoring stations in five major cities in Korea. The diurnal variation of surface ozone concentration on high ozone days is characterized by low ozone concentration at night. The ozone concentration Increases continuously after sunrise, In reach a peak at 1500~1600 LST. Thereafter it decreases steadily to a low concentration at sunset. The diurnal and annual maximum of the surface ozone concentration at Seoul were observed in May and June, respectively. The favorable synoptic condition for the high ozone day is divided into 4 different synoptic weather patterns: a high-pressure system from the Sea of Okhotsk, the Pacific subtropical high extending westward, a moving high-pressure system covering the Korean peninsula. and a synoptic system In front of a typhoon. Most of high ozone days occur under the high pressure system in Korea.

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Meteorologically Adjusted Ozone Trends in the Seoul and Susan Metropolitan Areas (서울과 부산지역 기상의 영향을 제거한 오존농도 추세)

  • 김유근;오인보;황미경
    • Journal of Korean Society for Atmospheric Environment
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    • v.19 no.5
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    • pp.561-568
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    • 2003
  • Surface ozone concentrations are highly sensitive to meteorological variability. Therefore, in order to reveal the long-term changes in ozone due to the changes in precursor emissions, we need to remove the effects of meteorological fluctuations on the annual distribution of surface ozone. In this paper, the meteorologically adjusted trends of daily maximum surface ozone concentrations in two major Korean cities (Seoul and Busan) are investigated based on ozone data from 11 (Seoul) and 6 (Busan) sites over the period 1992 ∼ 2000. The original time series consisting of the logarithm of daily maximum ozone concentrations are splitted into long-term, seasonal and short-term component using Kolmogorov-Zurbenko (KZ) filter. Meteorological effects are removed from filtered ozone series using multiple linear regression based on meteorologcial variables. The long-term evolution of ozone forming capability due to changes in precursor emission can be obtained applying the KZ filter to the residuals of the regression. The results indicated that meteorologically adjusted long-term daily maximum ozone concentrations had a significant upward trend (Seoul: + 3.02% yr$^{-1}$ , Busan: + 3.45% yr$^{-1}$ ). These changes of meteorologically adjusted ozone concentrations represent the effects of changing background ozone concentrations as well as the more localized changes in emissions.

A Study on the Characteristics of Surface Ozone Concentration at Dongsamdong, Pusan (부산 동삼동 지역의 지표오존농도 특성 연구)

  • Jeon, Byung Il
    • Journal of Environmental Impact Assessment
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    • v.8 no.2
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    • pp.21-29
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    • 1999
  • This study was conducted to investigate the characteristics of surface ozone concentration and occurrence of high ozone concentration using hourly ozone and meteorological data of 1997~1998 in Pusan coastal area. Monthly mean ozone concentration was highest in Spring(35.4ppb) and lowest in Winter(22.2ppb). Relative standard deviation indicating clearness of observation site was 0.42 that is similar to urban area. The diurnal variation of ozone concentration of Dongsamdong showed maximum at 15~16LST and minimum 07~08LST that typical pattern of ozone concentration. In ozone episode period(May 18~23, 1998), diurnal change of ozone concentration was very high, and ozone concentration was related to meteorological parameters such as temperature, relative humidity, wind speed, cloud amount and radiation on a horizontal surface.

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Characteristics of near-surface ozone distribution

  • Kim, Yoo-Keun;Lee, Hwa-Woon;Kim, Jae-Hwan;Moon, Yun-Seob;Song, Sang-Keun
    • Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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    • v.4 no.3
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    • pp.127-137
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    • 2000
  • This study presents an analysis of the characteristics of vertical ozone distribution near the surface using ozonesonde data(l995 to 1998), plus surface ozone and meteorological data from the Pohang region. These features were examined in detail using three case studies. The first related to episodes of high surface ozone concentrations during the Spring season when the frontogenesis between the high and low pressure associated with the upper-level jet stream was found to be located near the surface. The second was a 5-day winter period(l3 -17 December, 1997) in the Pohang province when the hourly concentrations exceeded 90 ppb on several occasions owing to low-level jets(LLJs) induced by a nocturnal stable layer. Accordingly, this explains why the high surface ozone concentrations occurred at night as the ozone was transported across the zone by a strong wind speed( over 12.5 ms .1). The third case study was ozone enhancement due to photochemical reactions. In this case, the maximum concentration of ozone exceeded 60 ppb in the summer(23 -28 August, 1997). When an ozone peak appeared within the boundary layer, the occurrence frequency of a low-level jet due to the nocturnal stable layer was about 77%, similarly the occurrence frequency of a near-surface ozone peak relative to the appearance of an LLJ was about 76%. Accordingly, there is clearly a close correlation between the occurrence of LLJs and near-surface ozone peaks.

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Time Dependant Ozone Generation due to Oxidation of the Surface of Corona Discharge Wires (코로나방전선 표면 산화에 따른 오존발생량의 경시특성)

  • Jung, Sung-Jin;Park, Seung-Lok;Moon, Jae-Duk
    • Proceedings of the KIEE Conference
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    • pp.22-25
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    • 2000
  • Time dependent ozone generation characteristics of some oxide layers grown by ozone on the surface of corona discharge wires have been investigated experimentally in air ambience. Four wires of stainless steel, iron, silver and copper were used for the corona discharge wire of an ozone generator. And the effect of the metal oxide layers on ozone generation was studied and the contamination morphology of each layers was characterized. With the SEM images and the EDS spectra, it was found that all the surface of the corona wire were oxidized by the generated ozone and contaminated by airborne particles through the gradient force. As a result, the morphology and the electrical property of metal oxide layer grown on corona wire surface influenced on ozone generation characteristics i.e. discharge mechanisms.

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Effect of Ozone Treatment on Dyeability of Polyethylene Film (오존 처리가 폴리에틸렌 필름의 염색성에 미치는 영향)

  • 박수진;신준식;김학용;이덕래
    • Polymer Korea
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    • v.27 no.2
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    • pp.98-105
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    • 2003
  • The surface energy and the effect of functional groups on the surface of the ozone-treated low-density polyethylene (LDPE) film were studied. Treatment conditions were treatment time, total amount of transferred ozone, and ozone concentration. The introduction of polar groups on the surface of LDPE film after ozone treatment was confirmed by FTIR-ATR and XPS analyses. Surface fee energy of the LDPE film was examined by a contact angle method. The ozone treated-LDPE film showed a decreased water contact angles about 15$^{\circ}$ mainly due to the increased concentration of oxygen-containing functional groups, which was attributed to the increased surface free energy or $O_{IS}/C_{IS}$Also, the concentrations of the oxygen-containing functional groups on the surface of LDPE film increased with ozone treatment time and concentration, whereas no significant effects were found for the total amount of transferred ozone. From the dyeability test using Kubelka-Munk equation, it was found that the ozone treatment plays an important role in the growth of oxygen-containing functional groups of LDPE film, resulting in the improvement of dyeability for basic dyeing agent.

Surface Composition Change of UV/Ozone Modified Polypropylene (UV/오존에 의해 개질된 폴리프로필렌의 표면 조성 변화)

  • Kim, J.I.;Ryu, S.H.
    • Elastomers and Composites
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    • v.37 no.1
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    • pp.49-56
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    • 2002
  • Polypropylene is oxidized with UV/ozone as a function of UV treatment time and ozone flow rate and its surface characteristics are investigated using contart angle measurements and XPS. The aging behavior of oxidized surface is investigated under air, water and ethylene glycol as the aging media. Adhesion strength is also investigated using a lap shear test. Polar surface energy increases with increasing UV/ozone treatment time as well as ozone flow rate. No polar surface energy change is observed under water aging, while under air aging it decreases significantly within 2-3 days and reaches the close value as that of the untreated PP. Adhesion strength increases with increasing UV/ozone treatment time as well as ozone flow rate.

Post Sliced Cleaning of Silicon Wafers using Ozone and Ultrasound (오존과 초음파를 이용한 실리콘 웨이퍼의 Post Sliced Cleaning)

  • Choi, Eun-Suck;Bae, So-Ik
    • Korean Journal of Materials Research
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    • v.16 no.2
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    • pp.75-79
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    • 2006
  • The effect of ozone and/or ultrasound treatments on the efficiency of slurry removal in post sliced cleaning (PSC) of silicon ingot was studied. Efficiency of slurry removal was evaluated as functions of time, temperature and surfactant with DOE (Design of Experiment) method. Residual slurries were observed on the wafer surface in case of cleaning by ozone or ultrasound separately. However, a clean wafer surface was appeared when cleaned with ozone and ultrasound simultaneously. It has found that cleaning time was the main effect among temperature, time and surfactant. Elevated temperature, addition of surfactant and high ozone concentration helped to accelerate efficient removal of slurry. The improvement of removal efficiency seems to be related to the formation of more active OH radicals. The highly cleaned surface was achieved at 10 wt% ozone, 1 min and 10 vol% surfactant with ultrasound. Application of ozone and ultrasound might be a useful method for PSC process in wafer cleaning.

Effects of Corona Electrode Shape and Discharge Gap Spacing on Ozone Concentration (방전공격과 방전극 형상이 오존발생농도에 미치는 영향)

  • Park, Seung-Lok;Lee, Jae-Chan;Jung, Sung-Jin;Moon, Jae-Duk
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.50 no.4
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    • pp.169-175
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    • 2001
  • Ozone has been widely applied to many industrial fields because of its strong oxidation power, Therefore, the studies have been carried out for the methods on an effective and high concentration ozone generation. The silent or surface discharge type ozone generators have been mainly used for high concentration ozone generation in many fields of applications. But these two types of ozone generators have shortcomings to be improved. In this study, the ozone generator which improved the shortcomings of above ozone generators was proposed and fabricated for the high concentration ozone generation. And the proposed ozone generator could generate the surface and barrier discharge simultaneously. For this purpose, a mesh type discharge electrode was proposed and studied as a function of the widths output maximum ozone concentration of 2.96[vol%] was obtained at 5.6[kV], 830[mA], for 0.3[mm] width and 0.8[mm] vacancy of the mesh electrode and gap spacing of 0.65[mm] respectively.

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