• 한국대기환경학회지
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• 제34권1호
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• pp.16-37
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• 2018

In this study, difference in chemical composition of $PM_{2.5}$ observed between the year 2013 and 2015 at six air quality intensive monitoring stations (Bangryenogdo (BR), Seoul (SL), Daejeon (DJ), Gwangju (GJ), Ulsan (US), and Jeju (JJ)) was investigated and the possible factors causing their difference were also discussed. $PM_{2.5}$, organic and elemental carbon (OC and EC), and water-soluble ionic species concentrations were observed on a hourly basis in the six stations. The difference in chemical composition by regions was examined based on emissions of gaseous criteria pollutants (CO, $SO_2$, and $NO_2$), meteorological parameters (wind speed, temperature, and relative humidity), and origins and transport pathways of air masses. For the years 2013 and 2014, annual average $PM_{2.5}$ was in the order of SL ($${\sim_=}DJ$$)>GJ>BR>US>JJ, but the highest concentration in 2015 was found at DJ, following by GJ ($${\sim_=}SJ$$)>BR>US>JJ. Similar patterns were found in $SO{_4}^{2-}$, $NO_3{^-}$, and $NH_4{^+}$. Lower $PM_{2.5}$ at SL than at DJ and GJ was resulted from low concentrations of secondary ionic species. Annual average concentrations of OC and EC by regions had no big difference among the years, but their patterns were distinct from the $PM_{2.5}$, $SO{_4}^{2-}$, $NO_3{^-}$, and $NH_4{^+}$ concentrations by regions. 4-day air mass backward trajectory calculations indicated that in the event of daily average $PM_{2.5}$ exceeding the monthly average values, >70% of the air masses reaching the all stations were coming from northeastern Chinese polluted regions, indicating the long-range transportation (LTP) was an important contributor to $PM_{2.5}$ and its chemical composition at the stations. Lower concentrations of secondary ionic species and $PM_{2.5}$ at SL in 2015 than those at DJ and GJ sites were due to the decrease in impact by LTP from polluted Chinese regions, rather than the difference in local emissions of criteria gas pollutants ($SO_2$, $NO_2$, and $NH_3$) among the SL, DJ, and GJ sites. The difference in annual average $SO{_4}^{2-}$ by regions was resulted from combination of the difference in local $SO_2$ emissions and chemical conversion of $SO_2$ to $SO{_4}^{2-}$, and LTP from China. However, the $SO{_4}^{2-}$ at the sites were more influenced by LTP than the formation by chemical transformation of locally emitted $SO_2$. The $NO_3{^-}$ increase was closely associated with the increase in local emissions of nitrogen oxides at four urban sites except for the BR and JJ, as well as the LTP with a small contribution. Among the meterological parameters (wind speed, temperature, and relative humidity), the ambient temperature was most important factor to control the variation of $PM_{2.5}$ and its major chemical components concentrations. In other words, as the average temperature increases, the $PM_{2.5}$, OC, EC, and $NO_3{^-}$ concentrations showed a decreasing tendency, especially with a prominent feature in $NO_3{^-}$. Results from a case study that examined the $PM_{2.5}$ and its major chemical data observed between February 19 and March 2, 2014 at the all stations suggest that ambient $SO{_4}^{2-}$ and $NO_3{^-}$ concentrations are not necessarily proportional to the concentrations of their precursor emissions because the rates at which they form and their gas/particle partitioning may be controlled by factors (e.g., long range transportation) other than the concentration of the precursor gases.

• 한국응용과학기술학회지
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• 제38권6호
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• pp.1687-1698
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• 2021

이 연구는 열역학적으로 불안정한 활성성분을 안정하게 봉입하기위해 초임계 상태에서 다중층의 리포좀을 생성하고 유효성분을 봉입하는 것에 관한 것이다. 초임계 상태에서 원활하게 리포좀을 형성시키기 위하여 식물성유래의 하이드로제네이티드 포스파티딜콜린과 그 유도체, 하이드로제네이티드 수크로오스다이스테아레이트를 포함하는 혼합 계면활성제를 고순도로 합성하였다. 이것을 반응조에 이산화탄소를 주입하여 초임계상태를 만들고 교반함으로써 거대 리포좀을 생성시키고, 여기에 제니스테인(genistein)과 쿼세틴(quercetin)을 첨가하여 봉입하는 제조방법에 대하여 기술하였다. 혼합지질계면활성제(SC-Lipid Complex)의 HLB는 12.50이었으며, 아주 낮은 농도에서도 다중층의 리포좀 소포체가 형성되었다. 이 계면활성제의 외관은 엷은 황색의 페이스트로 특이취가 있었으며, 비중은 0.972이었고, 산가는 0.12로 고순도로 합성이 되었음을 알 수 있었다. SC-Lipid Complex를 사용하여 20 wt%의 카플릭/카프릭 트리글리세라이드와 트리에칠헥사노인을 사용한 유화력 실험결과 96.2 %의 유화력을 가지고 있음을 알 수 있었다. 제니스테인을 봉입한 초임계 리포좀에 대하여 투과전자현미경(Cryo-TEM)을 통해 다중층의 리포좀 소포체가 형성되었다는 것을 확인하였다. 제니스테인이 봉입된 1차 리포좀화한 입자 크기는 253.9 nm이었고, 2차 캡슐의 크기는 18.2 ㎛ 이었다. 제니스테인을 표준물질로 하여 초임계 상태 리포좀의 봉입효율은 99.5 %이었고, 일반적인 리포좀은 93.6 %의 효율을 가지는 것으로 나타났다. 또한 쿼세틴을 봉입한 항산화력 실험은 DPPH법으로 확인한 결과 초임계리포좀에서 유의성 있게 우수한 항산화력을 유지하고 있음을 알 수 있었다. 이러한 결과를 바탕으로 효과는 우수하나 열역학적으로 불안정한 원료를 유기용매를 사용하지 않고 초임계 상태에서 리포좀에 봉입하고, 고기능성의 스킨케어 화장품, 메이크업 화장품, 두피보호용 화장품 등 다양한 제형에 응용이 가능할 것으로 기대한다.