Regional classification of high PM10 concentrations in the Seoul metropolitan and Chungcheongnam-do areas, Republic of Korea.

Since the Seoul metropolitan area is a highly developed megacity, many people are often exposed to high concentrations of particulate matter (PM), with mean aerodynamic diameters equal to or less than 10 µm (PM10), in cold seasons. PM10 concentrations can be influenced by a combination of various factors, including meteorological conditions, anthropogenic emissions, atmospheric chemical reactions, transboundary transport, and geographic characteristics. However, the establishment of an efficient air quality management plan remains challenging due to the limited understanding of the regional PM concentration characteristics. Here, the Seoul metropolitan (Seoul, Gyeonggi-do, and Incheon) and Chungcheongnam-do (Chungcheongnam-do, Daejeon, and Sejong) areas were regionally classified to identify the spatiotemporal air quality in areas where megacities and emission sources are mixed. The four representative regions were determined using the K-means clustering method based on the temporal variations in the observed PM10 concentrations. The first cluster consisted of small cities in the southern and eastern parts of Gyeonggi-do and Chungcheongnam-do, respectively, while the second cluster consisted of Incheon, West Gyeonggi-do, and Seoul. In addition, the third and fourth clusters included West Chungcheongnam-do and East Gyeonggi-do, which are adjacent to the Yellow Sea and downstream area of the westerly wind, respectively. The characteristics of each cluster during the high PM10 concentration events are explainable by wind patterns and the local air pollutant emissions, including nitrogen oxides and sulfur oxides. The obtained regional classification was different from the provincial-level administrative division of South Korea. Therefore, the present study is expected to be a scientific basis for overcoming the limitations of air quality management in administrative districts.

Inhibition of Human Neutrophil Elastase by Sesquiterpene Lactone Dimers from the Flowers of Inula britannica.

A new sesquiterpene lactone dimer [1], together with five known compounds (2-6), was isolated from the flowers of Inula britannica. The structures of these compounds were established by extensive spectroscopic studies and chemical evidence. The inhibitory activities of these isolated compounds (1-6) against human neutrophil elastase (HNE) were also evaluated in vitro; compounds 1 and 6 exhibited significant inhibitory effects against HNE activity, with IC50 values of 8.2 and 10.4 µM, respectively, comparable to that of epigallocatechin gallate (EGCG; IC50 = 10.9 µM). In addition, compounds 3 and 5 exhibited moderate HNE inhibitory effects, with IC50 values of 21.9 and 42.5 µM, respectively. In contrast, compounds 2 and 4 exhibited no such activity (IC50 ＞ 100 µM). The mechanism by which 1 and 3 inhibited HNE was noncompetitive inhibition, with inhibition constant (Ki) values of 8.0 and 22.8 µM, respectively.

ROS Scavenging and Anti-Wrinkle Effects of Clitocybin A Isolated from the Mycelium of the Mushroom Clitocybe aurantiaca.

Clitocybin A, an isoindolinone from Clitocybe aurantiaca, was investigated to assess its anti-wrinkle properties, through reactive oxygen species (ROS)-scavenging and elastase inhibitory activities, procollagen synthesis, and matrix metalloproteinase-1 (MMP-1) expression, in human primary dermal fibroblast-neonatal (HDF-N) cells. Clitocybin A exhibited no significant cytotoxicity up to 10 ppm in HDF-N cells, with cell viability and cell proliferation activity greater than 94.6% and 91.9%, respectively. Strong and concentration-dependent ROS radical scavenging activities of clitocybin A were observed following irradiation with UVB at 30 mJ/cm2. Furthermore, clitocybin A treatment of cells at 0.1, 1, and 10 ppm exhibited decreased elastase activity, in a concentration-dependent manner, by 1.97%, 6.6%, and 8.31%, respectively, versus the control group. The effects of clitocybin A on procollagen synthesis and MMP-1 expression were investigated. Clitocybin A treatment of cells at 1, 5, and 10 ppm increased procollagen synthesis, by 67.9%, 74.4%, and 112.9%, respectively, versus the control group. At these concentrations, MMP-1 expression decreased significantly following UV irradiation. Together, these findings suggest that clitocybin A may be an effective ingredient for use in anti-wrinkle cosmetic products.

Estimation of surface-level PM concentration from satellite observation taking into account the aerosol vertical profiles and hygroscopicity.

Surface-level PM10 distribution was estimated from the satellite aerosol optical depth (AOD) products, taking the account of vertical profiles and hygroscopicity of aerosols over Jeju, Korea during March 2008 and October 2009. In this study, MODIS AOD data from the Terra and Aqua satellites were corrected with aerosol extinction profiles and relative humidity data. PBLH (Planetary Boundary Layer Height) was determined from MPLNET lidar-derived aerosol extinction coefficient profiles. Through statistical analysis, better agreement in correlation (R = 0.82) between the hourly PM10 concentration and hourly average Sunphotometer AOD was the obtained when vertical fraction method (VFM) considering Haze Layer Height (HLH) and hygroscopic growth factor f(RH) was used. The validity of the derived relationship between satellite AOD and surface PM10 concentration clearly demonstrates that satellite AOD data can be utilized for remote sensing of spatial distribution of regional PM10 concentration.

Sesquiterpenes from the fruiting bodies of Ramaria formosa and their human neutrophil elastase inhibitory activity.

Two new sesquiterpene derivatives (1 and 2), ramarin A (1) and ramarin B (2), together with three known compounds (3-5) were isolated from the fruiting bodies of Ramaria formosa. The structures of the two sesquiterpenes were established by extensive spectroscopic studies and chemical evidence. The inhibitory activity of the isolated compounds (1-5) against human neutrophil elastase (HNE) was evaluated in vitro. All compounds tested inhibited HNE by 35-30% at the highest concentration used (100 µM), whereas the positive control, epigallocatechin gallate (EGCG), exhibited 60% inhibition at 100 µM.

Inhibition of human neutrophil elastase by labdane diterpenes from the fruiting bodies of Ramaria formosa.

Two new labdane diterpenes (1 and 2) were isolated from the fruiting bodies of Ramaria formosa. The structures of these compounds were established by extensive spectroscopic studies and chemical evidence. The inhibitory activity of compounds 1 and 2 against human neutrophil elastase (HNE) was evaluated in vitro. Compounds 1 and 2 inhibited HNE activity moderately. The IC50 values for compounds 1 and 2 were 36.4 ± 1.2 and 40.8 ± 1.5 µM, respectively; the IC50 value for the positive control, EGCG, was 12.5 ± 0.8 µM. In addition, the mechanism by which 2 inhibited HNE was a mixed-type noncompetitive inhibition, with a Ki of 41.5 ± 1.8 µM.