Air quality monitoring data and meteorology data which had collected from 1995. 1. to 1999. 2. in six areas of Daegu, Manchondong, Bokhyundong, Deamyungdong, Samdukdong, Leehyundong and Nowondong, were investigated to determine the distribution and characteristic of ozone. A equation of multiple regression was suggested after time series analysis of contribution factor and meteorology factor were investigated during the day which had high concentration of ozone. The results show the following; First, 63.6% of high ozone concentration days, more than 60 ppb of ozone concentration, were in May, June and September. The percentage of each area showed that; Manchondong 14.4%, Bokhyundong 15.4%, Deamyungdong 15.6%, Samdukdong 15.6%, Leehyundong 17.3% and Nowondong 21.6%. Second, correlation coefficients of ozone, SO2, TSP, NO2 and CO showed negative relationship; the results were respectively -0.229, -0.074, -0.387, -0.190(p<0.01), and humidity were -0.677. but temperature, amount of radiation and wind speed had positive relationship; the results were respectively 0.515, 0.509, 0.400(p<0.01). Third, R2 of equation of multiple regression at each area showed that; Nowondong 45.4%, Lee hyundong 77.9%, Samdukdong 69.9%, Daemyungdong 78.8%, Manchondong 88.6%, Bokhyundong 77.6%. Including 1 hour prior ozone concentration, R2 of each area was significantly increased; Nowondong 75.2%, Leehyundong 89.3%, Samdukdong 86.4%, Daemyungdong 88.6%, Manchondong 88.6%, Bokhyundong 88.0%. Using equation of multiple regression, There were some different R2 between predicted value and observed value; Nowondong 48%, Leehyundong 77.5%, Samdukdong 58%, Daemyungdong 73.4%, Manchondong 77.7%, Bokhyundong 75.1%. R2 of model including 1 hour prior ozone concentration was higher than equation of current day; Nowondong 82.5%, Leehyundong 88.3%, Samdukdong 80.7%, Daemyungdong 82.4%, Manchondong 87.6%, Bokhyundong 88.5%.

The aerodynamic resistance(Ra) to vertical transfer in the surface boundary layer can be formulated in terms of the friction velocity, height of observation, vertical heat flux and surface roughness. Unlike previous studies which focused on the role of Rc, present study perform additional tests using a variety of Ra formulae. Several Ra formulations available in the literature, suitable for unstable conditions, were tested for their influence on the dry deposition velocity. The canopy resistance(Rc) determines the shape of the diurnal pattern, while a small amplitude diurnal cycle in Vd was attributed to the aerodynamic resistance. The aerodynamic resistance is the major contributor to the formation of spikes in nighttime and Ra is relatively important at night because the canopy resistance is smaller. All formulations show similar diurnal cycle and yield good agreement with the observations. Although present Vd formulations are suitable for numerical air quality models, the research must continue for further improvements in resistance parametrizations.

Photochemical-Trajectory model was used to understand the production of ozone in the atmospheric boundary layer. This model was composed of the trajectory and the photochemical models. To calculate trajectories of air parcels, winds were obtained from the three-dimensional nonhydrostatic mesoscale model (PSU/NCAR MM5V2), and the results were interpolated into constant height surfaces. Numerical integration in the trajectory model was performed by the Runge-Kutta method. The photochemical model consisted of chemical reactions and photodissociation processes. Chemical equations were integrated by the semi-implicit Bulirsch-Stoer method. We performed our experiments from 21 July to 23 July 1994 during the summer time for Seoul area. During the time of maximum ozone concentration in Seoul, four trajectories of air parcels which traveled from Inchon to Seoul were selected. Ozone concentrations estimated by two models are compared with observed one in Seoul area and the photochemical-trajectory model is better fitted than pure photochemical model. During the selected period, high ozone concentrations in Seoul area were more influenced by transferred pollutants from Inchon than emitted pollutants in Seoul.

벼의 오존 처리에 따른 피해 경감 효과를 조사하기 위해 자포니카품종인 화명벼와 통일형 품종인 남천벼에 오존처리와 함께 식물생장조절제인 ABA를 농도별로 30일 동안 엽면 처리한 후 분얼기 및 수잉기에 생육, 수량 및 항산화 효소 활성의 변화를 조사한 결과를 요약하면 다음과 같다. 1. 오존처리에 의해 화명벼 수잉기의 ABA무처리에서 가장 낮은 초장억제를 보였고 ABA 104 M 처리에서 초장이 커지는 것을 볼 수 있다. 분얼기의 오존처리에 의한 분얼수의 감소는 크지 않았으나 분얼수 확보를 위해서는 104 M 처리가 바람직한 것으로 나타났다. 화명벼 분얼기 오존처리의 경우는 ABA 104 M, 화명벼 수잉기 오존처리의 경우는 103M, 남천벼 분얼기 오존처리의 경우는 ABA 104 M,그리고 남천벼 수잉기 오존처리의 경우는 ABA 104 M처리가 엽록소 함량 감소를 적게 하는 것으로 나타났다. 2. ABA 105M처리를 할 때 오존 피해에 의한 수량 감소를 최소화하는데 유리한 것으로 판단된다. 3. 남천벼 분얼기 오존처리의 경우 모든 ABA 처리에서 SOD 활성이 증가한 것으로 나타났으며, APX는 분얼기와 수잉기 화명벼의 오존 15일간 처리에서 활성이 약간 낮아지는 것으로 나타났고, 분얼기 벼의 GPX활성이 다른 처리구들에 비해 낮게 나타났다.

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, to 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.

The vertical structure of atmosphere was observed to investigate the variation of surface ozone concentration by vertical downward mixing of residual ozone in the atmospheric boundary layer at the Busan coastal area. Airsonde and pilot balloon measurements were made at Gamcheondong and the Kimhae airport for April 26∼27, 1996. The vertical profile of potential temperature showed a residual layer between 510m and 1800m from 2100LST April 26 to 0900LST April 27. The downward mixing of ozone in the residual layer of the atmospheric boundary layer was confirmed from vertical profile of mixing ratio near 600m in the morning. The thickness of the sea breeze layer was 900m at 1500LST April 26. Thereafter, it become to be lowered with time. A low level jet was measured near 900m at 0300LST on April 27 from a pibal measurement. Early morning sharp increase of surface ozone concentration at the Busan coastal area was caused by vertical downward mixing of ozone concentration rather than by photochemical reaction in the atmospheric boundary layer.

This study was carried out to evaluate the pollutant removal efficiencies of the advanced drinking water treatment using ozonation. For raw water, Nakdong River was used. By conducting batch ozonation test, the following results were obtained. When ozone dosage of 5㎎/ℓ was used, preozonation of raw water reduced turbidity, KMnO4 consumption, DOC(dissolved organic carbon), UV254 absorbance, THMFP(trihalomethane formation potential) as much as 3.9 NTU, 5.5㎎/ℓ, 1.15㎎/ℓ, 0.112 and 0.065㎎/ℓ, respectively. In case of postozonation of sand filtered water, water quality was also improved with decrease in turbidity, KMnO4 consumption, DOC, UV254 absorbance and THMFP at the amount of 0.08NTU, 2.6㎎/ℓ, 0.88㎎/ℓ, 0.042 and 0.018㎎/ℓ, respectively. On the other hand, contents of dissolved oxygen increased at the level of 1.3㎎/ℓ after preozonation process' and 1.0㎎/ℓ after postozonation process. The effect of ozone dosage was higher than that of its contact time for the removal of the pollutants.

오존수 처리콩나물의 저장 중 품질변화를 조사하였다. 콩나물 재배 중 오존수 처리는 콩의 수침시와 주수시에 물을 사용한 것(W/W), 수침 시만 오존수를 처리한 것 (O/M), 주수 시에만 오존수를 처리한 것 (W/O), 수침시와 주수시에 각각 처리한 것(O/O)으로 나누어 각각 5일간 재배하였다. 저장은 콩나물을 0.01 mm polyethylene film 에 포장하여 1와 2에서 저장하였다. 저장수명은 오존수 처리와 무처리간의 뚜렷한 차이를

Two rice cultivars of the japonica type, ozone-resistant Ilpumbyeo (IL) and ozone-susceptible Keu-mobyeo#l (KM) were exposed to ozone (O3 ) at 0.15 ppm for 30 days. The available nutrient regimes were varied by doubling the supply of nitrogen (N), phosphorus (P) and potassium (K) within a basic fertilizer status (N, P, K; 15, 12, 12 kg l0a-1 ). There was little difference on plant height between ozone-treated and nontreated plants. The most significant ozone stress on tiller number was shown on the 30th day of ozone exposure. Slight recovery from ozone stress was noted on the 60th day. On the 30th day, tiller number was greatly decreased by 40.8% in IL and 64.6% in KM, whereas at a high nitrogen supply regime (2N), it was decreased by 21.4% in IL and 42.7% in KM as compared to the control not treated with ozone at basic fertilizer status. The inhibition of tiller production caused by ozone exposure was alleviated on the 60th day. In both cultivars, number of spikelets per plant and weight of 100 grains were affected little by the ozone treatment irrespective of nutrient regime. However, the number of panicles per plant and yield were reduced significantly. In both cultivars, yield of ozone-treated plants with 2N status was 12.4-16.1 % higher than that of the ozone-treated plants with basic nutrient status. A significant yield decrease of 47.8% and 33.4% was observed for IL and KM, respectively, in ozone-treated plants with higher potassium (2K) status.

Ozone (O3 )-induced changes in chlorophyll content and specific activities of antioxidant enzymes, such as superoxide dismutase (SOD), ascorbate peroxidase (APX), guaiacol peroxidase (GPX), dehydroascorbate reductase (DHAR) and glutathione reductase (GR) were investigated in two rice cultivars (Oryza sativa L.) grown under variable nutrient treatments. For this study, two rice cultivars of Ilpumbyeo (IL) and Keumobyeo#l (KM), which were known as resistant and susceptible to O3 , respectively, were exposed to O3 at 0.15ppm for 30 days and investigated with 10 days interval. The available nutrient regimes were varied by doubling the supply of nitrogen (N), phosphorus (P) and potassium (K) Within a basic fertilizer status (N, P, K; 15, 12, 12kg/l0a-1 ). In both cultivars and at all nutrient status, chlorophyll content in O3 -treated plants decreased with prolonged treatment period, although higher N, P and K supply with O3 treatment alleviated the decrease in chlorophyll content. The activities of almost all enzymes investigated for this study were decreased during initial stages of O3 - exposure except GPX which maintained higher activity throughout the exposure period than the non-treated plant. However, the antioxidant enzymes in O3 -treated plants showed almost the same or higher activities on 30 days after O3 - exposure. The most significant changes in activities were observed in GR of the O3 -treated leaves. With the prolonged treatment period, the activity of GR at 30 days was increased by 3-8 times compared to those in 10 days. Most of the investigated enzymes showed very similar tendency to O3 treatment in all fertilizer status. There was no observed evidence for enhanced detoxification of O3 -derived activated oxygen species in plants grown under higher fertilizer status compared with that in plants grown under basic fertilizer status. The increase in the activities of SOD, APX and GR in rice leaves by relatively long-term treatment with O3 at low concentration is considered to indicate that the plant became adapted to the O3 stress and the protection system increased its capacity to scavenge toxic oxygen species. Our results in two rice cultivars indicated that there was little difference in the activities of antioxidant enzymes between IL and KM, which were known as resistant and susceptible cultivar to O3

This study examined blends of styrene butadiene rubber(SBR) and chloroprene rubber(CR) prepared from an open 2-roll mill following the conventional polymer blend method for a wide range of the blend composition. Rubber vulcanizates were manufactured by hot press and then mechanical properties, heat and ozone resistance of the specimens were examined. Due to the post cure during the aging test, hardness of vulcanizates was increased. It was found that the undesirable characteristics of heat and ozone resistance of pure SBR was significantly improved through the blending of SBR with CR.

The purpose of this experiment is to prepare ethylene propylene diene terpolymer(EPDM)/acrylonitrile butadiene rubber(NBR) blend which represents good environmental resistant properties including favorable oil and ozone resistance. With incorporation of EPDM, NBR and other ingredients, the rubber and chemical additives were mixed by mechanical method such as Banbury mixer and open 2-roll mill. Then rubber vulcanizates were manufactured by hot press and mechanical properties, oil and ozone resistance of the test specimens were measured. The oil resistance and ozone resistance of EPDM and NBR, respectively, is remarkably improved by blending EPDM with NBR. The optimum results of oil and ozone resistant characteristics were obtained at EPDM/NBR(=25/75 wt%) composition ratio.

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.lppb) 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.

This study was performed to investigate the characteristics of nocturnal maximum ozone occurrence and the meteorological relevance using to hourly ozone data and meteorological data for 1995∼1996 in Pusan coastal area. Kwangbokdong showed the highest occurrence of nocturnal maximum ozone as 36.9%, and Deokcheondong showed the lowest occurrence(9.2%) for research period in Pusan. The occurrence rates of nocturnal maximum ozone concentration were decreased toward land area. The low maximum temperature, high minimum temperature, low diurnal range, high relative humidity, high wind speed, high cloud amount, low sunshine and low radiation were closely related to the main meteorological characteristics occurring the nocturnal maximum concentration of ozone. It was shown that normal daily variation of ozone concentration by strong photochemical reaction at the before day of nocturnal maximum ozone. The concentration of nocturnal maximum ozone were occured by entrainment of ozone from the upper layer of developed mixing layer. There are no ozone sources near the ground at night, so that the nighttime ozone should be entrained from the upper layer by forced convection.