Jihyun Han

Photochemical Air Pollution of Seoul in the Last Three Decades

In Korea, photochemical air pollution has drawn public attention as one of the major environmental issues since 1990s. To abate ozone and air pollution, new legislation was enacted and regulation was reinforced in conjunction with basic researches. As a result, the air quality has been much improved in terms of primary pollutant such as CO and the occurrence of extremely high ozone concentration. In Seoul, on the other hand, concentrations of ozone and exeedance hours of its national standard have increased since 2005, which is intimately coupled with variations. It indicates the need for further research at long-term bases to improve our understanding on complex processes determining ozone concentrations. In this paper, the characteristics of ozone variation was analyzed with 13-year measurement data obtained in Seoul. In addition, the previous studies and their main results were summarized that have been performed in association with photochemical air pollution in Korea over the last three decades.

Semi-continuous Measurements of PM 2.5 OC and EC at Gosan: Seasonal Variations and Characteristics of High-concentration Episodes

At Gosan ABC superstation in Jeju Island, we measured organic carbon (OC) and elemental carbon (EC) in from October 2009 to June 2010 using a Sunset Laboratory Model-4 Semi-Continuous OC/EC Field Analyzer. It employs TOT (Thermal-Optical-Transmittance) method with NIOSH 5040 protocol and enables to continuously monitor OC and EC concentrations with 1-hour time resolution. The mean values of OC and EC for the entire period of measurements were and , respectively. The OC/EC ratio was 3 and EC accounted of total carbon (TC, TC

Ionic Compositions and Carbonaceous Matter of PM 2.5 at Ieodo Ocean Research Station

The purpose of this study is to determine concentrations and compositions of PM2.5 and their characteristic variations at Ieodo Ocean Research Station in the East China Sea and to examine the influence of air pollutants transported from Asia continents. O3 and meteorological parameters were measured since June 2003 and PM2.5 filter samples were collected from June 2004 to June 2008. In total, 244 samples were analyzed for water soluble ions and carbonaceous compounds. The mean mass concentration of PM2.5 and O3 were 21.8±14.9 μg/m and 51.6 ±16.1 ppb, respectively. The average concentrations (mass fractions) of sulfate and ammonium were 6.26 μg/m (28.74%) and 1.59 μg/m (7.31%), respectively. Nitrate was considered to be lost through evaporation due to long stay at the station. The mean concentrations of EC and OC were 1.01 μg/m and 2.34 μg/m, respectively, from June 2006 to June 2008. The average OC/EC ratio was 2.31. The organic matter converted from OC by multiplying 2.1 and elemental carbon constituted 22.60% and 4.66% of PM2.5 mass, respectively.