Nutrient loads in inland rivers can propagate downstream to estuaries and near-coastal waters, where water-quality conditions may affect fisheries and aquaculture. This study examines the effect of a nutrient load control program on total phosphorus in South Korea. Using a difference-in-differences approach with fixed effect models, the study constructs monitoring stations in the Nakdong, Geum, and Yeongsan rivers as the treatment group and monitoring stations in the Han River as the control group. The study leverages total phosphorus (TP) control as the policy intervention. Using monitor-by-time data from the national Total Maximum Daily Load network from 2007 to 2012, the study found that TP levels decreased by approximately 3.6% after the policy intervention. The study further examines flexible and honest DIDs and finds limited but suggestive evidence of this improvement. The findings provide suggestive evidence of load-based regulation in reducing TP and provide policy-relevant evidence on upstream nutrient control that may inform broader downstream water-quality management in connected river-estuary systems.

This study examines the relationship between short-run variation in vessel activity and coastal air quality in a major coastal city. Hourly monitor-level air-quality readings in Busan, South Korea are linked to a port-exposure index that aggregates hourly vessel tonnage at piers using inverse-distance weights. Panel regressions with fixed effects suggest a positive relationship between port exposure and PM10 and PM2.5. A back-of-the-envelope calculation implies that a 1,000-unit increase in the exposure index corresponds to about 0.18% higher PM10 and 0.33% higher PM2.5. The estimates provide an exposure-concentration mapping that may serve as a basis for further study into port-related environmental impacts in coastal cities.

PIM-1 (polymer intrinsic microporosity-1)은 뒤틀린 구조에 기인한 높은 기체 투과 특성을 가지고 있기 때문에 기 체 분리막 소재 중 하나로 활발히 연구되어졌다. 높은 기체 투과 특성의 장점에도 불구하고 높지 않은 기체 선택성의 한계점 이 존재함에 따라 본 연구에서는 PIM-1 분리막에 PEG/PPG-CN을 첨가함으로써 CO2의 용해도 증가에 따른 기체 선택도를 높이고 열처리를 진행하여 PIM-1과 PEG/PPG-CN의 사이아노기가 트라이아진으로 전환되는 재배열을 유도하였다. 그 결과 2 wt%의 PEG/PPG-CN이 첨가되고 열처리된 PIM-1 분리막의 성능은 열처리만 된 PIM-1 분리막과 비교하였을 때 단일 및 혼 합 기체 조건에서 더 높은 이산화탄소의 투과도와 선택도를 가지는 것으로 측정되었다. 혼합 기체 조건에서는 단일 기체 조 건에서 보다 높은 이산화탄소 투과도와 선택도를 보이며 실제 기체 분리 공정의 적용 가능성이 높다는 것을 확인하였으며 트 라이아진의 가교에 의하여 기체 분리막이 가소화 저항성(anti-plasticization)을 가지는 것으로 확인되었다.

This study proposes the use of a cobalt-based Prussian blue analogue (Co-PBA; potassium cobalt hexacyanoferrate), as an adsorbent for the cost-effective recovery of aqueous ammonium ions. The characterization of Co-PBA involved various techniques, including Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, nitrogen adsorption-desorption analysis, and zeta potential. The prepared Co-PBA reached an adsorption equilibrium for ammonium ions within approximately 480 min, which involved both surface adsorption and subsequent diffusion into the interior. The isotherm experiment revealed a maximum adsorption capacity of 37.29 mg/g, with the Langmuir model indicating a predominance of chemical monolayer adsorption. Furthermore, the material consistently demonstrated adsorption efficiency across a range of pH conditions. Notably, adsorption was observed even when competing cations were present. Co-PBA emerges as a readily synthesized adsorbent, underscoring its efficacy in ammonium removal and selectivity toward ammonium.