2019, Vol.28, No.2

Journal of Environmental Impact Assessment 2023 KCI Impact Factor : 0.51

pISSN : 1225-7184
https://journal.kci.go.kr/kseia

This study, we conducted a non-parametric trend test (Seasonal Kendall tests, LOWESS) and Cross Correlation.We aimed to identify water quality trends using the weekly data for 9 variables (Water Temperature, EC, DO, BOD, COD, T-N, T-P, TOC and Chl-a) collected from 4 sites in the Paldang Lake from 2004.01 to 2016.12. According to the Seasonal Kendall test, Water temperature increased but EC, T-N and T-P decreased trend. LOWESS showed that BOD was gradually decreased from 2013 to 2016. but COD gradually increased between 2012 and 2016. As a result, it was confirmed that the period between 2012 and 2013 was a turning point in the increase of COD along with the decrease of BOD at all sites in Paldang Lake. Results of Cross Correlation showed that there was no time difference between all of Water variables and Sites. In this study, it is necessary to analyze the cause of the transition period and to monitoring the water quality more precisely for better water quality management in Paldang Lake.

Over the last few years, air pollution (PM10, PM2.5) in the Seoul metropolitan area (SMA) has emerged as one ofthe most concerned and threatening environmental issues among the residents. It brings about various harmful effects on human health, as well as ecosystem and industrial activities. Governments and individuals pay various costs to mitigate the level of air pollutants. This study aims to empirically find the willingness to pays (WTP) among the parents from different socio-cultural groups - international and domestic groups to mitigate air pollution (PM10, PM2.5) in their residential area. Contingent Valuation Methods (CVM) is used with employing single-bounded dichotomous choice technique to elicit the respondent’s WTP. Using tobit (censored regression) and probit models, the monthly mean WTP of the pooled sample for green electricity which contributes to improve air quality in the region was estimated as 3,993 KRW (3.58 USD). However, the mean WTP between the international group and domestic group through a sub-sample analysis shows broad distinction as 3,325KRW (2.98 USD) and 4,449 KRW (3.98 USD) respectively. This is because that socio-cultural characteristics of each group such as socio-economic status, personal experience, trust in institutions and worldview are differently associated with theWTP. Based on the results,the society needs to raise awareness of lay people to find a strong linkage between the current PM issue and green electricity. Also, it needs to improve trust in the government’s pollution abatement policy to mobilize more assertive participation of the people from different socio-cultural background.

The concentration and coating thickness of black carbon (BC) were measured along with fine dust in the fall of 2018, at the Seoul Metropolitan Area Intensive Monitoring Station (SIMS). In fall, the concentration of PM10 and PM2.5 was 23 ± 12.6 μg/m3 and 12 ± 5.8 μg/m3, respectively, lower than that in other seasons. The BC level, measured using an Aethalometer, was 0.73 ± 0.43 μg/m3, while the levels of elemental carbon (EC) and refractory-BC (rBC), measured by semi-continuouscarbon analyzer (SOCEC) and single particle soot photometer (SP2), were 0.34 ± 0.18 μg/m3 and 0.32 ± 0.18 μg/m3, respectively. As such,the concentration level differed according to the measurement method, but its time-series distribution and diurnal variation showed the same trends. The BC concentration at SIMS was primarily affected by automobiles with higherlevels of BC during morning and evening commuting times due to increased traffic congestion. rBC, measured by SP2, had a peak concentration and coating thickness of 84 nm and 43 nm,respectively. Notably,the coating thickness had an inverse relationship with particle size.