• Journal of Preventive Medicine and Public Health
• /
• v.26 no.2 s.42
• /
• pp.268-281
• /
• 1993

The aquatic quality of the Naktong river after two or three months in June, 1991 with phenol spillage from a electrical factory in Kumi was investigated. The samples were collected at six sites of the Naktong river basin and Kachang and Kongsan lakes. Phenol was not detected from all water samples. Turbidity was very much increased to the down stream in the Naktong river. The BOD and COD values exceeded the 2nd grade(3mg/l) of the Korean standard quality of Environmenal Water Act at the all sampling sites of the Naktong river. Especially, the value of COD at Kaejin (12.5mg/l) was poorly classified as to the 5th grade of water class for the environmental quality standards. Organophosphorous pesticides such as parathion, malathion, fenitrothion and diazinon were investigated but not detected. Diazinon was only detected at the Ilsan bridge(1.42ppb), Okkye stream(6.95ppb), Waekwan bridge(0.32ppb), Gangjung reservior(0.13ppb), Kaejin (0.05ppb). Of the carbamates such as carbanyl, isoprocarb and cabofuran, the carbofuran was detected all sites except tap water, and Kachang and Kongsan lakes. The content of heavy metals such as Cd, Pb, Zn, Fe, Mn, Hg were not exceeding for drinking water standards at the all sampling region, but only mecury was detected from Okkye stream(0.018ppb) and Kaejin (0.09ppb). In the regions of Kachang and Kongsan lakes, the content of heavy meatals were lower than that of reservior of Naktong river.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.25 no.1
• /
• pp.48-59
• /
• 2023

Ground-level ozone affects human health and plant growth. Ozone is produced by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOCs) from anthropogenic and biogenic sources. In this study, two different land cover and emission factor datasets were input to the MEGAN v2.1 emission model to examine how these parameters contribute to the biogenic emissions and ozone production. Four input sensitivity scenarios (A, B, C and D) were generated from land cover and vegetation emission factors combination. The effects of BVOCs emissions by scenario were also investigated. From air quality modeling result using CAMx, maximum 1 hour ozone concentrations were estimated 62 ppb, 60 ppb, 68 ppb, 65 ppb, 55 ppb for scenarios A, B, C, D and E, respectively. For maximum 8 hour ozone concentration, 57 ppb, 56 ppb, 63 ppb, 60 ppb, and 53 ppb were estimated by scenario. The minimum difference by land cover was up to 25 ppb and by emission factor that was up to 35 ppb. From the modeling performance evaluation using ground ozone measurement over the six regions (East Seoul, West Seoul, Incheon, Namyangju, Wonju, and Daegu), the model performed well in terms of the correlation coefficient (0.6 to 0.82). For the 4 urban regions (East Seoul, West Seoul, Incheon, and Namyangju), ozone simulations were not quite sensitive to the change of BVOC emissions. For rural regions (Wonju and Daegu) , however, BVOC emission affected ozone concentration much more than previously mentioned regions, especially in case of scenario C. This implies the importance of biogenic emissions on ozone production over the sub-urban to rural regions.

• Asian Journal of Atmospheric Environment
• /
• v.11 no.2
• /
• pp.114-121
• /
• 2017

Real-time monitoring of hourly concentrations of atmospheric Radon-222 ($^{222}Rn$, radon) and some gaseous pollutants ($SO_2$, CO, $O_3$) was performed throughout 2013-2014 at Gosan station of Jeju Island, one of the cleanest regions in Korea, in order to characterize their background levels and temporal variation trend. The hourly mean concentrations of radon and three gaseous pollutants ($SO_2$, CO, $O_3$) over the study period were $2216{\pm}1100mBq/m^3$, $0.6{\pm}0.7ppb$, $211.6{\pm}102.0ppb$, and $43.0{\pm}17.0ppb$, respectively. The seasonal order of radon concentrations was as fall ($2644mBq/m^3$)$${\sim_\sim}$$winter ($2612mBq/m^3$)>spring ($2022mBq/m^3$)>summer ($1666mBq/m^3$). The concentrations of $SO_2$ and CO showed similar patterns with those of radon as high in winter and low in summer, whereas the $O_3$ concentrations had a bit different trend. Based on cluster analyses of air mass back trajectories, the air mass frequencies originating from Chinese continent, North Pacific Ocean, and the Korean Peninsula routes were 30, 18, and 52%, respectively. When the air masses were moved from Chinese continent to Jeju Island, the concentrations of radon and gaseous pollutants ($SO_2$, CO, $O_3$) were relatively high: $2584mBq/m^3$, 0.76 ppb, 225.8 ppb, and 46.4 ppb. On the other hand, when the air masses were moved from North Pacific Ocean, their concentrations were much low as $1282mBq/m^3$, 0.24 ppb, 166.1 ppb, and 32.5 ppb, respectively.

• Journal of Korean Society of Environmental Engineers
• /
• v.31 no.12
• /
• pp.1161-1168
• /
• 2009

This research was conducted on characteristic of offensive odors in Shihwa industrial complex. Result of blocks distribution of TVOC indicates that mechanic block, site D, was the highest concentration (74 ppb). Chemistry block, site A, was the second highest concentration (50 ppb). Also, mixed blocks, metal blocks and park etc. were measured almost similar concentration about 30 ppb, but mixed block, site F, was the place where concentrations were the smallest. Average of TVOC was shown about 35 ppb concentration. Aldehydes including acetaldehyde, butyraldehyde and hydrogen sulfide concentrations were prevalent among offensive odors in Shihwa industrial complex. Comparing the offensive odor intensity mostly about acetaldehyde, butyraldehyde and hydrogen sulfide which contain high offensive odor intensity showed results that sites A, B (chemistry block) and site D, I (mechanic block) site H (metal block) have showed the intensity over 1. In the case of acetaldehyde, relatively the high odor intensities over '2' were able to obtain in many cases. The correlation coefficient (r) for hydrogen sulfide was 0.91, so that high positive correlation exists between offensive odor intensity and the hydrogen sulfide element. Butyraldehyde also showed high positive correlation coefficient, as 0.82. Correlation coefficient of acetaldehyde that had the highest value as offensive odor substance was 0.62, had somewhat correlation with offensive odor intensity.

• Asian Journal of Atmospheric Environment
• /
• v.11 no.4
• /
• pp.300-312
• /
• 2017

To improve the understanding of secondary organic aerosol (SOA) formation from the photo-oxidation of anthropogenic and biogenic precursors at the regional background station on Baengnyeong Island, Korea, gas phase and aerosol chemistries were investigated using the Proton Transfer Reaction Time of Flight Mass Spectrometer (PTR-ToF-MS) and the Aerodyne High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS), respectively. HR-ToF-AMS measured fine particles ($PM_1$; diameter of particle matter less than $1{\mu}m$) at a 6-minute time resolution from February to November 2012, while PTR-ToF-MS was deployed during an intensive period from September 21 to 29, 2012. The one-minute time-resolution and high mass resolution (up to $4000m{\Delta}m^{-1}$) data from the PTR-ToF-MS provided the basis for calculations of the concentrations of anthropogenic and biogenic volatile organic compounds (BVOCs) including oxygenated VOCs (OVOCs). The dominant BVOCs from the site are isoprene (0.23 ppb), dimethyl sulphide (DMS, 0.20 ppb), and monoterpenes (0.38 ppb). Toluene (0.45 ppb) and benzene (0.32 ppb) accounted for the majority of anthropogenic VOCs (AVOCs). OVOCs including acetone (3.98 ppb), acetaldehyde (2.67 ppb), acetic acid (1.68 ppb), and formic acid (2.24 ppb) were measured. The OVOCs comprise approximately 75% of total measured VOCs, suggesting the occurrence of strong oxidation processes and/or long-range transported at the site. A strong photochemical aging and oxidation of the atmospheric pollutants were also observed in aerosol measured by HR-ToF-AMS, whereby a high $f_{44}:f_{43}$ value is shown for organic aerosols (OAs); however, relatively low $f_{44}:f_{43}$ values were observed when high concentrations of BVOCs and AVOCs were available, providing evidence of the formation of SOA from VOC precursors at the site. Overall, the results of this study revealed several different SOA formation mechanisms, and new particle formation and particle growth events were identified using the powerful tools scanning mobility particle sizer (SMPS), PTR-ToF-MS, and HR-ToF-AMS.

• Journal of dental hygiene science
• /
• v.8 no.4
• /
• pp.387-393
• /
• 2008

This study was undertaken to determine the halitosis status of urban area in Dae-Gu city. The sample of this study consisted of 332 persons who lived at Dae-Gu city. The results were as follows. 1. The persons consisted of 44.6% male and 55.4% female. The 32.5 % persons were under 38 years and 82.2% of persons were married. 2. The 26.8% persons answered the last meal time was before 1-2 hours and 63.3% persons answered middle halitosis. The 26.3% persons answered the time of worst halitosis was after breakfast and 33.1% persons answered the smell type of halitosis was nasty smell. The 11.4% persons experienced dental treatment for halitosis, and 63.9% persons required dental treatment for halitosis. 3. The 100 ppb~149 ppb concentration of halitosis was 156 persons. Over 150 ppb concentration of halitosis was 54 persons. The average of halitosis concentration was 122.76 ppb and, the 63.3% persons required halitosis management and treatment. An aged persons of the halitosis concentration was significantly increased than younger persons (p < 0.05). Higher smell preception of halitosis was significantly increased in halitosis concentration test practically (p < 0.001). Subjects who treated dental treatment for halitosis was significantly increased (p < 0.01). This study results have informed that the knowledge and management of halitosis was demand and required public relation for halitosis. The halitosis management and education program will improve the oral health. Therefore halitosis management program which based on data collection and planning will be developed and activated in further study.

• Korean Journal of Food Science and Technology
• /
• v.35 no.4
• /
• pp.748-751
• /
• 2003

Acrylamide is considered as potential carcinogen and genotoxicant. Swedish National Food Administration reported that acrylamide was detected in heat treated starch rich food products. Acrylamide formation during food processing was confirmed by researchers of other countries including UK, Norway, Japan, Switzerland, and United States. It is noticed that the formation of acrylamide in potato products was greater than other food products. It may be due to high concentration of asparagine and glucose in potato products comparing to those of other food products. Interaction between asparagine and glucose during heat treatment resulted in acrylamide formation via Maillard reaction. Analytical method (LC-MS/MS) adopted by FDA was performed to monitor acrylamide concentrations in domestic food products. Acrylamide quantitation in several food categories, such as raw materials, boiled foods, fried foods, hardtacks, breads, breakfast cereals, potato chips, french fries, biscuits, and others, were carried out.

• Journal of fish pathology
• /
• v.12 no.1
• /
• pp.32-41
• /
• 1999

Ozonization for rearing seawater in land-based culture system has recently been utilized for disinfection of pathogenic microorganisms and improvement of water quality. This study was conducted to examine the effects of total residual oxidants (TRO) in ozone-treated seawater on survival, blood parameters, osmolality and oxygen consumption, and gill tissue of the flounder. Paralichthys olivaceus. Experiments were carried out with the starved flounder of 12~19 cm in total length at $20^{\circ}C$. The 48-hr and 96-hr $LC_{50}$ for the flounder amounts to 26.4 ppb and 22.3 ppb, respectively. With increase of TRO concentration from 24 to 39 ppb, the values of hematocrit, hemoglobin concentration, red blood cell count and osmolality of the flounder with respect to exposure time were significantly elevated, however, the oxygen consumption rates decreased. In the case of the fish exposed to 13 ppb for 96 hrs, blood glucose increased with an elapse of exposure time, while survival rate was 100%. Death apparently resulted by massive destruction of gill lamellar epithelium, severe osmotic imbalance and the lack of oxygen uptake. The results of this experiment indicated that to protect aquaculture organisms, the ozone-treated seawater should not contain any residual oxidants, and that relatively long-term exposure to TRO of low concentration can impact on survival and physiological conditions of the flounder.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.32 no.5
• /
• pp.593-600
• /
• 1999

The survival rates of Littorina brevicula exposed to experimental concentration regimes of TBTCl, HB and Cd on the large and the small size individuals during 80 days were $80\%$ at 0,9ppb TBTCl, 40 and $25\%$, respectively at 200ppb Hg, and 75 and $45\%$, respectively at 100ppb Cd. The growth rates of the experimental animals exposed to each concentration for 80 days was 0.023mm/day at control, 0.019mm/day at 0.1ppb and 0.014mm/day at 0.9ppb TBTCl, 0.022 mm/day at 5ppb, 0.008 mm/day at 200ppb Hg, and 0.017 mm/day at 5ppb, 0.008mm/day at 100ppb Cd. The respiration rates and excretion rates of the experimental animals exposed to chronic concentration of TBTCl, Hg and Cd were decreased until approximatively 40 days and increased after, Toxic effect of pollutants on L. brevicula was highest at TBTCl. The histological injury of L. brevicula exposed to TBTCl, Hg and Cd was shown at gill, digestive organ and muscle, respectively.

• Journal of Environmental Health Sciences
• /
• v.32 no.3
• /
• pp.207-214
• /
• 2006

This study was designed to assess the level of nitrogen dioxide from several microenvironments including inside the home, outdoors near the home, inside the school, outdoors near the school, and on the road for 42 primary schoolchildren during the month of December 2002 in Seoul, Korea. The average personal, indoor, outdoor $NO_2$ levels, and indoor/outdoor ratio were 45.08 ppb, 27.89 ppb, 30.96 ppb, and 0.89, respectively. The indoor $NO_2$ concentrations were significantly associated with the presence of a smoker with a gas stove. The estimated personal $NO_2$ exposure using time-weighted average equation of $34.64{\pm}5.29$ ppb was significantly lower than the measured personal exposure of $45.08{\pm}5.50$ ppb. Our results indicate that indoor $NO_2$ levels were associated with the presence of a smoker and a gas stove. Moreover, personal $NO_2$ exposure with a gas stove in the house was significantly higher than those without a gas stove.