• Journal of Environmental Health Sciences
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• v.45 no.2
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• pp.113-125
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• 2019

Objectives: Although the risk assessments for nitrogen dioxide ($NO_2$) and ozone ($O_3$) have been extensively studied, most of the existing risk assessments were limited mainly to indoor environments such as workplaces, schools, and multi-use facilities. Therefore, integrated risk assessment is needed to consider exposure in all microenvironments, including outdoors. The purpose of this study was to assess the differences in risk among sub-population groups according to time-activity patterns and reported concentrations, as well as the lifetime risk of Koreans. Methods: In this study, we estimated time-weighted average exposure concentrations of $NO_2$ and $O_3$ for preschool children, students, housewives, workers, and seniors using residential time and indoor concentrations (house, school or workplace, other), outdoors, and transport by meta-analysis method. The risk for $NO_2$ and $O_3$ were assessed by hazard quotient using reference concentrations 30 and 60 ppb, respectively. The risk assessments were conducted through 1,000,000 Monte-Carlo simulations for probabilistic analysis. Results: Preschool children, students, housewives, workers, and seniors spent 91.9, 86.0, 79.8, 82.2, and 77.3% of their day in a house, school, or workplace, respectively. The risk assessment for the lifetime of a housewife and a worker showed that 33.8 and 28.4% of hazard quotients of $NO_2$ exceed 1, respectively, and more than 99% of hazard quotient of $O_3$ were less than 1. Conclusions: The risk of $NO_2$ and $O_3$ by sub-population group and for the lifetime of housewives and workers were assessed. The risk for $NO_2$ was higher than for $O_3$ and showed a different risk by sub-population group. Both $NO_2$ and $O_3$ showed a higher risk for housewives than for workers. This study can be used as a basis for lifetime exposure and risk assessment for $NO_2$ and $O_3$.

• 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.

• Korean Journal of Environmental Agriculture
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• v.18 no.3
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• pp.259-264
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• 1999

This experiment was carried out to investigate the changes of antioxidant enzymes activities in soybean leaves, exposed to 0.2ppm of ozone. We have investigated whether Eunhakong and Samnamkong may scavenge ozone induced activated oxygen species by invoking antioxidant enzymes such as ascorbate peroxidase(APOX), glutathione reductase(GR), monodehydroascorbate reductase(MDHAR), dehydroascorbate reductase(DHAR). Ozone exposure preferentially increased APOX, GR and MDHAR activities, whereas that of DHAR only decreased slowly. When soybean plans were fumigated with 0.2ppm of ozone, the levels of ascorbate and reduced glutathione decreased within a few hours. In eunhakong, which has, slightly a strong tolerance to ozone, was found to have higher antioxidants levels than samnamkong. However, there was no remarkable difference two cultivars in the activities of enzymes which protect plant against active oxygen species.

• Environmental Analysis Health and Toxicology
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• v.14 no.1_2
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• pp.21-33
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• 1999

A large number of studies have indicated associations between the impairment of respiratory health and exposure to ambient air pollutants such as ozone (O$_3$) , nitrogen dioxide (NO$_2$) , sulfur dioxide(SO$_2$) , particulate matters (PM$\_$10/). To evaluate this associations, we used the pulmonary function tests (peak expiratory flow rate : PEFR) by mini-wright peak flow meter and counting neutrophils in the nasal lavage (NL) as biomarker. From 15 June to 16 July 1998, for the workers in the highway tollgates, PEFR and NL were measured three times daily and twice per week. and association between the level of air pollutants and PEFR and NL were analyzed using the multiple regression model and the poisson regression model respectively. The results indicated that the effects of all measured air pollutants (SO$_2$, NO$_2$, O$_3$, PM$\_$10/) were not significantly associated with the value of PEFR. On the other side, SO$_2$, NO$_2$, PM$\_$10/ were significantly associated with the number of neutrophils in NL. The increase in SO$_2$, NO$_2$of 10ppb and in PM$\_$10/ of 10$\mu\textrm{g}$/m$^3$was associated with 24%, 21%, 35% increases in neutrophil counts. But the ozone exposure was not associated with NL.

• Journal of Korean Society for Atmospheric Environment
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• v.7 no.2
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• pp.119-126
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• 1991

Air pollution is directly and indirectly associated with the toxicology through the increase of mortality, the decrease of oviposition rate, and the decline of insect population, as well as the disruption of equilibria with higher or lower trophic levels. To investigate intrinsic decrease rates, oviposition period, and emerging rates of pupae of house fly under air pollution stresses, healthy individuals of Musca domestica L. were collected in the field, cultured in the laboratory for 2 $\sim$ 3 generations, and artificially exposed to $O_3 (4 ppm) in automatically controlled air pollutant fumigation chambers. Results from this study are summarized as follows: 1. Survivorship curves of both control group and exposed groups of healthy house fly to 4 ppm $O_3$ have linearly or stair-like decreasing trends of revers S-shape. 2. For cohorts exposed to 4 ppm of $O_3$, intrinsic decrease rate of cohort exposed for 2 hours significantly increases compared to that of control group, slight increases were observed for those exposed for 4 hours and 8 hours, which shows no distinct relationships between exposure period and intrinsic decrease rate. 3. While the numbers of pupae of exposed cohorts increase with the increase of exposure period, emerging rate shows a distinct decrease. 4. The relationships between emerging rate (E) of pupae and the exposure period (T) for cohorts exposed to 4 ppm of $O_3$ are expressed with the equation, E (%)=21.027 - 7.942 ln (T).

• Korean Journal of Environmental Agriculture
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• v.11 no.1
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• pp.50-58
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• 1992

Studies were conducted to determine the combined effect of uniconazole [(E) -1-(4-chlorophenyl)-4, 4-demethyl 2-(1,2,4 triazol-1-yl)-1-penten-3-ol] and silver thiosulfate $[Ag {(S_2O_3)}^3\;_2-]$ (STS) on reduction of ozone injury in tomato plants(Lycopersicon esculentum Mill. 'Pink Glory'). Plants were given a 50ml soil drench of uniconazole at concentrations of 0, 0.001, 0.01 and 0.1 mg/pot at the stage of emerging 4th leaf. Two days prior to ozone fumigation, STS solution contained 0.05% Tween-20 was also sprayed at concentrations of 0, 0.3 and 0.6 mM. Uniconazole at 0.01 mg/pot and STS at 0.6 mM were effective in providing protection against ozone exposure(20h at 0.2ppm) without severe retardation of plant height and chemical phytotoxicity, respectively. Combined treatment with uniconazole, STS significantly reduced ozone injury at the lower concentration than a single treatment with uniconazole or STS. Uniconazole treatment reduced plant height, stem elongation and transpiration rate on a whole plant level and increased chlorophyll concentration. STS did not give any effect on plant growth and chlorophyll content but increased transpiration rate in non-ozone-fumigated plants. Ethylene production in the leaves of ozone-fumigated plants was decreased by uniconazole and STS pretreatment, but there was no protective effect on epinasty of leaves in uniconazole-treated plants. STS increased ethylene production in non-ozone-fumigated plants, but it significantly reduced the degree of epinasty and defoliation of cotyledons when plants were exposed to ozone. Uniconazole slightly increased superoxide dismutase and peroxidase activities. But STS showed little or no effects on such free radical scavengers. Day of flowering after seeding was shortened and percentages of fruit set were increased by uniconazole treatment. STS was highly effective on protecting reduction of fruit set resulting from ozone fumigation. These results suggest that combined use of uniconazole and STS should provide miximum protection against ozone injury without growth retardation resulting in yield loss.

• Advances in materials Research
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• v.6 no.1
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• pp.1-12
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• 2017

The aim of the work was to evaluate the effect of ultraviolet-ozone ($UV-O_3$) irradiation with different times on the structure and thermal properties of hydroxypropyl methylcellulose (HPMC) in the form of a thin film to be used as bioequivalent materials according to their important broad practical and medical applications. HPMC thin films were exposed to $UV-O_3$ radiation in air at a wavelength of 184.9 nm.The beneficial effects of this treatment on the crystallinity and amorphousity regions were followed by X-ray diffraction technique and FTIR spectroscopy. Differential scanning calorimetry, thermogravimetric and differntial thermal analyses were used in order to study the thermal properties of HPMC samples following the process of photodegradation. The obtained results indicated that the rate of degradation process was increased with increasing the exposure time. Variations in shape and area of the thermal peaks were observed which may be attributed to the different degrees of crystallinity after exposing the treated HPMC samples. This meant a change in the amorphousity of the treated samples, the oxidation of its chemical linkages on its surface and its bulk, and the formation of free radical species as well as bond formation.

• Environmental and Resource Economics Review
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• v.30 no.2
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• pp.207-235
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• 2021

This paper examines the effects of ambient air pollution by ozone and particulate matter on traveling by mode of transport. We estimate the SUR model of travel time by different modes of transportation using individual level data of travel diaries. We find that, as air pollution levels rises, traveling by privately-owned vehicles increases but traveling by bus decreases. Our results also show that, when an air quality alert is issued, bus traveling increases in an effort to reduce pollution levels, but traveling by own car does not change and traveling by train declines. This suggests that alert programs may not be highly effective in reducing air pollution emissions from vehicles because voluntary switching to public transportation induced by air quality alerts is outweighed by individual effort of avoiding exposure to pollution.

• Korean Journal of Agricultural and Forest Meteorology
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• v.5 no.4
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• pp.226-232
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• 2003

To examine the effects of ozone (O$_3$), one of the major air pollutants in the city area, on genetic changes in Cornus controversa Hemsl., we compared genetic structures between sensitive (S) and tolerant (T) tree groups of C. controversa fumigated with ozone using isozyme markers. The genetic structures were measured in terms of allele and genotype frequencies determined at ave polymorphic enzyme loci. Marked genetic differences between the two groups were detected at three loci (Lap-2, Mdh-1 and Skdh-1). Genetic parameters, genetic multiplicity, genetic diversity and heterozygosity showed that the tolerant group retained greater genetic variation than did the sensitive group. Results of the study were congruent with the general expectation that the more heterozygous individuals and/or populations exhibit higher resistance to various stress factors.

• Asian Journal of Atmospheric Environment
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• v.12 no.1
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• pp.1-16
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• 2018

Ground-level ozone ($O_3$) can be a menace for vegetation, especially in Asia where $O_3$ levels have been dramatically increased over the past decades. To ensure food security and maintain forest ecosystem services, such as nutrient cycling, carbon sequestration and functional diversity of soil biota, in the over-populated Asia, environmental standards are needed. To set proper standards, dose-response relationships should be established from which critical levels are derived. The predictor of the response in the dose-response relationship is an $O_3$ metric that indicates the dose level to which the plant has been exposed. This study aimed to review the relevant scientific literature and summarize the $O_3$ metrics used worldwide to provide insights for Asia. A variety of $O_3$ metrics have been used, for which we discuss their strengths and weaknesses. The most widely used metrics are based only on $O_3$ levels. Such metrics have been adopted by several regulatory agencies in the global. However, they are biologically irrelevant because they ignore the plant physiological capacity. Adopting AOT40 ($O_3$ mixing ratios Accumulated Over the Threshold of $40nmol\;mol^{-1}$) as the default index for setting critical levels in Asia would be a poor policy with severe consequences at national and Pan-Asian level. Asian studies should focus on flux-based $O_3$ metrics to provide relevant bases for developing proper standards. However, given the technical requirements in calculating flux-based $O_3$ metrics, which can be an important limitation in developing countries, no-threshold cumulative exposure indices like AOT0 should always accompany flux-based indices.