• 한국환경과학회지
• /
• 제27권7호
• /
• pp.543-554
• /
• 2018

From November 2013 to December 2016, ambient fine particulate matter ($PM_{2.5}$) was sampled in the downtown area of Jeju City, South Korea, which has seen rapid urbanization. The atmospheric concentrations of elements were measured in the $PM_{2.5}$ samples. This study focused on Cd, Cr, Cu, Mn, Ni, Pb, As, Sb, Sn, V, and Zn. The concentrations of Al, Na, K, Fe, Ca, Mg, Sr, and La were also obtained for reference. The objectives of this study were to examine the contributions of these elements to $PM_{2.5}$ concentrations in downtown Jeju City, and to investigate the inter-element relationships and the elemental sources by using enrichment factors and principal components analysis (PCA). A composition analysis showed that the 19 elements constituted 6.65 % of the $PM_{2.5}$ mass, and Na, K, Al, Fe, Ca, Mg, and Zn constituted 98 % of the total ion mass. Seasonal trend analysis for the sampling period indicated that the concentrations of the elements increased from November to April. However, no substantial seasonal variations were found in the concentrations of the elements. The composition ratios of some elements (Cu/Zn, Cu/Cd, Cu/Pb, V/Ni, and V/La) were found to be out of range when compared to the literature from other urban areas. The ratios between the elements and the PCA results showed that local contaminant sources in Jeju City rarely influence the composition of $PM_{2.5}$. This suggests that the major sources of $PM_{2.5}$ in Jeju City may include long-range transport of fine particulate matter produced in other areas.

• 한국환경과학회지
• /
• 제31권7호
• /
• pp.637-652
• /
• 2022

In this study, the contributions of emissions (foreign and domestic) and atmospheric physical and chemical processes to PM_2.5 concentrations were evaluated during a high PM_2.5 episode (March 24-26, 2018) observed on the Jeju Island in the spring of 2018. These analyses were performed using the community multi-scale air quality (CMAQ) modeling system using the brute-force method and integrated process rate (IPR) analysis, respectively. The contributions of domestic emissions from South Korea (41-45%) to PM_2.5 on the Jeju Island were lower than those (81-89%) of long-range transport (LRT) from China. The substantial contribution of LRT was also confirmed in conjunction with the air mass trajectory analysis, indicating that the frequency of airflow from China (58-62% of all trajectories) was higher than from other regions (28-32%) (e.g., South Korea). These results imply that compared to domestic emissions, emissions from China have a stronger impact than domestic emissions on the high PM_2.5 concentrations in the study area. From the IPR analysis, horizontal transport contributed substantially to PM_2.5 concentrations were dominant in most of the areas of the Jeju Island during the high PM_2.5 episode, while the aerosol process and vertical transport in the southern areas largely contributed to higher PM_2.5 concentrations.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제17권6호
• /
• pp.1-8
• /
• 2012

This study is to suggest a few efficient ways of rainwater utilization, through monitoring and analyzing 143 rainwater storage systems and 110 artificial recharge systems, which are installed in the recommended facilities by law, among the rainwater harvesting systems in Jeju Island. In the case that catchment facilities are damaged, rainwater could be contaminated by leaves and debris so that the rates of rainwater usages come to be lower. It is possible that contaminated rainwater could contaminate artificial recharge wells or rainwater discharging out of the rainwater harvesting system could result in flood and damage for the downgradient area. For maintaining high quality of rainwater and increasing rainwater utilization rate, it is necessary to install screening facilities and purification plant functioning precipitation and filtration. Also, in order to efficiently preclude the overflowing rainwater exceeding storage capacity, it is recommended to associate rainwater storage tanks with artificial recharge well or infiltration trench facilities.

• 한국환경과학회지
• /
• 제24권12호
• /
• pp.1649-1656
• /
• 2015

Jeju Island is the highest rain-prone area in Korea that possesses affluent water resources, but future climate changes are predicted to further increase vulnerabilities as resultant of increasing of extreme events and creating spatial-temporal imbalance in water resources. Therefore, this study aimed to provide basic information to establish a proper water resources management plan by evaluating the effects of climate change on water resources using climate change scenario. Direct runoff ratio for 15 years (2000~2014) was analyzed to be 11~32% (average of 23%), and average direct runoff ratio for the next 86 years (2015~2100) was found as 28%, showing an increase of about 22% compared to the present average direct runoff ratio (23%). To assess the effects of climate change on long-term runoff, monthly runoff variation of future Gangjeong watershed was analyzed by dividing three time periods as follows: Present (2000~2030), Future 1 (2031~2070) and Future 2 (2071~2100). The estimated results showed that average monthly runoff increases in the future and the highest runoff is shown by Future 2. Extreme values has been expected to occur more frequently in the future as compared to the present.

• 수산해양기술연구
• /
• 제56권1호
• /
• pp.11-17
• /
• 2020

The occurrence of eggs of hairtail, Trichiurus japonicus was examined in the coastal waters of Jeju Island, Korea in spring from May to June in 2014, April to May in 2015, and April to in 2016. As a whole, hairtail eggs occurred abundantly in May, 2014. Especially, high densities over 300 ind./1,000 ㎥ of eggs abundances in May and June, 2014 occurred in the north-western area of Jeju Island where is upwelling phenomenon occurred throughout the year. In the relationship between T-S and the hairtail eggs abundances, high densities over 100 ind./1,000 ㎥ of eggs abundances occurred in temperature of 18.1-18.7℃ and salinity of 33.92-34.87‰ in May when hairtail eggs occurred abundantly.

• Animal Systematics, Evolution and Diversity
• /
• nspc9호
• /
• pp.73-79
• /
• 2016

In the present study, to explore the current status of mammals that inhabit Jindo Island, Jeollanam-do, South Korea, a survey was conducted from July 6 to July 9, 2016. Using several survey methods, such as Sherman's live trap, footprint, caves, excretions, and road-kill investigations, the mammals observed on Jindo Island were found to be from 5 orders and 9 families, including 12 species in total. Among them, three species of small mammals were Mogera wogura, Crocidura shantungensis, and Apodemus agrarius. Additionally, two legally protected species were found through excretion observations. Lutra lutra and Prionailurus bengalensis, which were designated to endangered wild animal classes I and II, respectively. The survey results can be used as a valuable resource for identifying the distribution and habitat status of mammals in the Jindo-gun area, as well as for building a database for ecosystem preservation.

• 한국환경과학회지
• /
• 제21권9호
• /
• pp.1031-1041
• /
• 2012

This study was carried out to investigate the characteristics of disinfection by-products (DBPs-trihalomethanes (THMs), haloacetic acids (HAAs) and haloacetonitriles (HANs) formation in chlorination of principal raw waters used for drinking water on Jeju Island, Korea. The domestic water supply of other area and humic acid solution (HA) were used as a reference point. The effects of chlorine contact time, solution temperature and pH on DBPs formation potential (DBPFP) were investigated for raw waters. In addition, the effect of $Br^-$ was studied for HA. The DBPFP (THMFP, HAAFP and HANFP) were increased with increasing chlorine contact time. Comparing the individual DBPFPs for raw waters, they decreased in the order of HAAFP > THMFP ${\geq}$ HANFP. As the solution temperature was increased, the THMFP, HAAFP and HANFP increased. With increasing the solution pH, the THMFP was increased, but HAAFP and HANFP were decreased. With the addition of 0.3 mg/L $Br^-$ for HA, the DBPFP was increased and the major chemical species changed: from trichloromethane to dibromochloromethane and tribromomethane for THMs; from dichloroacetic acid and trichloroacetic acid to tribromoacetic acid for HAAs; and from dichloroacetonitrile to dibromoacetonitrile for HANs.

• 한국환경과학회지
• /
• 제26권5호
• /
• pp.591-600
• /
• 2017

This study was carried out to elucidate the chemical compositions of water-soluble inorganic ions in $PM_{10}$ and $PM_{2.5}$ aerosols collected during summer and winter in downtown Jejusi city. The ratios of $NO_3^-$ to the total mass of ionic species in $PM_{10}$ and $PM_{2.5}$ aerosols largely increase in winter compared to summer, while $SO_4^{2-}$ ratios in both aerosols appear to follow the opposite trend. Moreover, concentrations of $Na^+$, $Mg^{2+}$, $Ca^{2+}$ and $Cl^-$ in $PM_{10}$ and $PM_{2.5-10}$ aerosols are higher in winter than in summer. The nitrate concentrations in $PM_{10}$ and $PM_{2.5}$ aerosols increase with an identical increase in excess ammonium during winter, however, nitrate formation during summer is not important owing to ammonium-poor conditions.

• The Plant Pathology Journal
• /
• 제17권3호
• /
• pp.184-188
• /
• 2001

Phytophthora-induced diseases on citrus in Jeju island have been considered of minor importance because of the use as root stock of trifoliate orange, which is immune to Phytophthora. However, brown rot on fruit, which severely occurred in 1998 and 1999, has become a great threat to citrus production in the island. About one-half of the surveyed orchards were infected in 1998 and 4 out of 19 infected fields showed over 20% fruit infection rate. The disease was less severe in 1999, with an estimated infected area and total fruit reduction of 3,155 ha and 15,300 tons, respectively. Typical gummosis was also occasionally observed on cv. Shiranugi, which is mostly cultivated under plastic film houses. Two types of Phytophthora were consistently isolated from various plant parts, identified as P. citrophthora and P. nicotianae. The former was isolated from the aerial parts of the fruit, young leaf, and shoot in the fields. Meanwhile, the latter was only isolated from the basal stem showing gummosis in plastic film houses.

• 한국초전도ㆍ저온공학회논문지
• /
• 제16권4호
• /
• pp.62-65
• /
• 2014

To minimize most heat loss of current lead for high-temperature superconducting (HTS) rotating machine, the choice of conductor properties and lead geometry - such as length, cross section, and cooling surface area - are one of the various significant factors must be selected. Therefore, an optimal lead for large scale of HTS rotating machine has presented before. Not let up with these trends, this paper continues to improve of diminishing heat loss for HTS part according to different model. It also determines the simplification conditions for an evaluation of the main flux flow loss and eddy current loss transient characteristics during charging and discharging period.