• Journal of Preventive Medicine and Public Health
• /
• 제39권1호
• /
• pp.81-86
• /
• 2006

Background: A number of studies have reported associations between the ambient air pollution concentrations and various health outcomes. Especially, ozone is well known for primary risk factor of asthma attacks. The results of a recent study indicate that the size of the effect on health outcomes due to air pollution varied according to several conditions, including age, gender, race and the socioeconomic status. Therefore, this study was conducted to examine the associations of ozone with the childhood asthma hospitalizations as stratified by the socioeconomic status (SES) at the community level in Seoul, Korea, 2002. Methods: SES at aggregated levels was measured on the basis of average regional health-insurance rate per citizen in the area. We applied the generalized additive model to analyze the effect of ozone on asthma after controlling for the potential confounding variables that were capable of influencing the results. Results: Our analysis showed that the number of children who were hospitalized for asthma increased as the SES of the residence area decreased. The estimated relative risks of hospitalization for asthma, as stratified by the SES of the community level, were 1.12 (95% confidence interval 1.00-1.25) in districts with the highest SES levels, 1.24 (95% CI=1.08-1.43) within the moderate SES levels, and 1.32 (95% CI=1.11-1.58) in the districts with the lowest SES levels. Conclusions: Our analysis showed that exposure to air pollution did not equally affect the health status of individuals. This suggests that not only the biological-sensitivity markers, but also the SES of the subjects should be considered as potentially confounding factors.

• 한국물환경학회지
• /
• 제20권2호
• /
• pp.145-150
• /
• 2004

This study investigated the effect of chlorine dose and chlorine reaction time for the formation of haloacetic acids (HAAs). According to the results, HAA formation was highly affected by chlorine dose and chlorine reaction time. HAA formation reached a plateau value at 30 mg/L of chlorine dose and 24 hr of chlorine reaction time. For the speciation of formed HAAs in the test water, the concentration of brominated-HAAs was significantly lower than that of chlorinated-HAAs because of low level of bromide ion concentration in the test water. It also investigated the removal efficiency of HAA precursors by several unit processes, such as ozone alone, UV alone, and combined ozone/UV system. Of them, ozone/UV system was proved as the best process to control the HAAs formation. The increase of the brominated-HAAs was observed during ozonation with and without UV irradiation showing the slight increase of total HAA concentrations.

• 무역상무연구
• /
• 제14권
• /
• pp.349-370
• /
• 2000

The environmental problems such as global climate change, global waming, ozone depletion, environmental pollution have been caused by the rapid economic growth, increasing in use of fossil fuels for industrialization and scientific technology development. Especially human activities are significantly altering the atomosphere's composition and its radiative properties. To Stabilize greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system, the international community adopted the UN Framework Convention on Climate Change in 1992 and Kyoto protocol in 1997. Also to protect ozone layer the international community adopted the Vienna Convention for the Protection of the Ozone Layer in 1985, and the Montreal Protocol on Substances that Deplete the Ozone Layer in 1987. To achieve global environmental objectives, some multilateral environmental agreements includes trade regulation. For example, Montreal Protocol includes the provisions to regulate the world trade of the sudstances which might destroy ozone layer. However Kyoto Protocol has no provisions to regulate trade and is not in force yet. Although there is no trade regulation article in Kyoto Protocol, the international world trade will be influenced by limitation and reduction of CO2 and strengthening the CO2 emission standard for import good. For example Korean car industy agreed with EU to reduce CO2 emission from new passenger car and Korean Semiconductor industry agreed with WSC(World Semiconductor Council) to reduce PFCs in 1999.

• 한국펄프종이공학회:학술대회논문집
• /
• 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.2
• /
• pp.325-329
• /
• 2006

Nippon Paper Industries, Co., Ltd. declared conversion of all the bleaching process to ECF, and most of the production had converted by now. To reduce ECF bleaching cost, we found that depending on electricity supply condition of the mill, utilization of ozone bleaching could be very effective. In addition, hot acid treatment of unbleached pulp also seemed to be effective for hardwood. In this study, several conditions for each technology were examined with the pulps from our own mills to reduce bleaching cost and to keep fiber quality acceptable level. In hot acid treatment study, with mild conditions (temperature lower than $90^{\circ}C$), sufficient reduction in Kappa number and hexenuronic acids content of the pulp were observed, while pulp viscosity was maintained. Moreover, to maintain strength of bleached pulp that subjected both to ozone bleaching and hot acid treatment, recommended Kappa number after ozone bleaching was more than 3. Based on these findings, two of our mills had installed medium-consistency ozone bleaching facilities and three mills installed hot acid treatment. Especially in Yatsushiro mill, both were installed in one bleaching line (A-ZD-E/P-D sequence), and running successfully.

• 한국안전학회지
• /
• 제15권3호
• /
• pp.66-70
• /
• 2000

In order to cope with environmental problems caused by harmful gases emitted from various industrial sources, a new technology which employs discharge plasma formed in ordinary atmospheric pressure has been intensively investigated in many industrialized nations. Although a plenty of useful outcomes and suggestions have been made public by scientists in this field, few commercial products which effectively decompose pollutant gases have appeared as yet. This is partly because that the energy efficiency of a most effective plasma reactor has not reached a satisfactory level in comparison with those of devices using conventional technologies. In an attempt to solve the problem mentioned above, we noticed to combine heterogeneous electrical discharges. This concepts is based on that each plasma reactor has its specific spatial region in which chemical reaction are active and by electrically affected with another reactor of different type, the activated region would increase - which may lead to cutting down the energy consumption. To prove this concept experimentally, two different discharge equipments, a plane ceramic-based surface discharge electrode and a corona electrode with tungsten needle may, are selected and combined to fabricate a hybrid plasma reactor. The results are summarized as follows; (1) Ozone concentration generated in the plasma region drastically increases when the positive corona discharge is added to the surface discharge. The rate of increase of ozone depends on the frequency of the surface discharge. The negative corona, however, does not contribute to the improvement of the ozone generation. (2) NO(nitrogen monoxide) decomposition rate also improves by simultaneously applying the surface and the positive corona discharges. The effect of the corona superposition is more evident when the level of the surface discharge is moderate. (3) By adjusting the corona level, the net energy efficiency during NO decomposition improves in comparison with the simple surface discharge reactor.

• 한국대기환경학회지
• /
• 제27권1호
• /
• pp.30-40
• /
• 2011

Numerical simulations were carried out to investigate the impact of SST spatial distribution on the result of air quality modeling. Eulerian photochemical dispersion model CAMx (Comprehensive Air quality Model with eXtensions, version 4.50) was applied in this study and meteorological fields were prepared by RAMS (Regional Atmospheric Modeling System). Three different meteorological fields, due to different SST spatial distributions were used for air quality modeling to assess the sensitivity of CAMx modeling to the different meteorological input data. The horizontal distributions of surface ozone concentrations were analyzed and compared. In each case, the simulated ozone concentrations were different due to the discrepancies of horizontal SST distributions. The discrepancies of land-sea breeze velocity caused the difference of daytime and nighttime ozone concentrations. The result of statistic analysis also showed differences for each case. Case NG, which used meteorological fields with high resolution SST data was most successfully estimated correlation coefficient, root mean squared error and index of agreement value for ground level ozone concentration. The prediction accuracy was also improved clearly for case NG. In conclusion, the results suggest that SST spatial distribution plays an important role in the results of air quality modeling on high ozone episode at coastal region.

• 한국대기환경학회:학술대회논문집
• /
• 한국대기환경학회 2000년도 춘계학술대회 논문집
• /
• pp.55-56
• /
• 2000

급격한 도시화는 도시의 기후변조와 함께 오존오염 문제를 야기 시켰다. 즉 지표오존(ground-level ozone)의 고농도 현상이 도시대기환경의 주된 관심사가 되었고, 이를 해결하기 위해 여러 연구가 국내·외에서 지역특성에 맞게 활발히 이루어지고 있는 실정이다. 일반적으로 지표오존은 전구물질의 배출량 및 도시의 지형학적 위치와 기상학적 특성에 따라 생성·소멸·이류 메카니즘이 다르게 나타난다. 따라서 이러한 국지적 특성의 고려는 지표오존의 고농도분석에 있어 반드시 수반되어야 하며, 이를 바탕으로 최종적으로 농도예측이 이루어 져야 할 것이다. (중략)

• Communications for Statistical Applications and Methods
• /
• 제3권2호
• /
• pp.249-273
• /
• 1996

This paper reviews and develops several statistical models for extreme values, based on threshold methodology. Extreme values of a time series are modeled in terms of tails which are defined as truncated forms of original variables, and Markov property is imposed on the tails. Tails of the generalized extreme value distribution and a multivariate extreme value distributively, of the tails of the series. These models are then applied to real ozone data series collected in the Chicago area. A major concern is given to detecting any possible trend in the extreme values.

• 한국대기환경학회지
• /
• 제28권1호
• /
• pp.22-38
• /
• 2012

Adaptation of climate change is necessary to avoid unexpected impacts of climate change caused by human activities. Vulnerability refers to the degree to which system cannot cope with impacts of climate change, encompassing physical, social and economic aspects. Therefore the quantification of climate change impacts and its vulnerability is needed to identify vulnerable regions and to setup the proper strategies for adaptation. In this study, climate change vulnerability is defined as a function of climate exposure, sensitivity, and adaptive capacity. Also, we identified regions vulnerable to ozone due to climate change in Korea using developed proxy variables of vulnerability of regional level. 18 proxy variables are selected through delphi survey to assess vulnerability over human health sector for ozone concentration change due to climate change. Also, we estimate the weighting score of proxy variables from delphi survey. The results showed that the local regions with higher vulnerability index in the sector of human health are Seoul and Daegu, whereas regions with lower one are Jeollanam-do, Gyeonggi-do, Gwangju, Busan, Daejeon, and Gangwon-do. The regions of high level vulnerability are mainly caused by their high ozone exposure. We also assessed future vulnerability according to the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A2, A1FI, A1T, A1B, B2, and B1 scenarios in 2020s, 2050s and 2100s. The results showed that vulnerability increased in all scenarios due to increased ozone concentrations. Especially vulnerability index is increased by approximately 2 times in A1FI scenarios in the 2020s. This study could support regionally adjusted adaptation polices and the quantitative background of policy priority as providing the information on the regional vulnerability of ozone due to climate change in Korea.

• Journal of Periodontal and Implant Science
• /
• 제48권3호
• /
• pp.136-151
• /
• 2018

Purpose: The decontamination procedure is a challenging aspect of surgical regenerative therapy (SRT) of peri-implantitis that affects its success. The purpose of the present study was to determine the impact of additional topical gaseous ozone therapy on the decontamination of implant surfaces in SRT of peri-implantitis. Methods: A total of 41 patients (22 males, 19 females; mean age, $53.55{\pm}8.98years$) with moderate or advanced peri-implantitis were randomly allocated to the test group (ozone group) with the use of sterile saline with additional ozone therapy or the control group with sterile saline alone for decontamination of the implant surfaces in SRT of peri-implantitis. Clinical and radiographic outcomes were evaluated over a period of 12 months. Results: At the 12-month follow-up, the plaque and gingival index values were significantly better in the ozone group (P<0.05). Probing depth decreased from $6.27{\pm}1.42mm$ and $5.73{\pm}1.11mm$ at baseline to $2.75{\pm}0.7mm$ and $3.34{\pm}0.85mm$ at the end of the 12-month observation period in the ozone and control groups, respectively. Similarly, the clinical attachment level values changed from $6.39{\pm}1.23mm$ and $5.89{\pm}1.23mm$ at baseline to $3.23{\pm}1.24mm$ and $3.91{\pm}1.36mm$ at the 12-month follow-up in the ozone and control groups, respectively. According to the radiographic evidence, the defect fill between baseline and 12 months postoperatively was $2.32{\pm}1.28mm$ in the ozone group and $1.17{\pm}0.77mm$ in the control group, which was a statistically significant between-group difference (P<0.05). Conclusions: Implant surface decontamination with the additional use of ozone therapy in SRT of peri-implantitis showed clinically and radiographically significant. Trial registry at ClinicalTrials.gov, NCT03018795.