Jang-Yeul Sohn

Assessment of the Emission Characteristics of VOCs from Interior Furniture Materials during the Construction Process

In this study, the indoor concentrations of pollutants from different materials that are used in kitchens and living rooms are measured during the construction process. The measurements are carried out in three households: the first is built using only conventional materials, the second household uses some environmentally sound materials and the last uses nothing but environmentally sound materials. The construction stage that had the greatest effect on indoor pollutant concentration is evaluated after installing all of the materials and measuring the indoor concentrations throughout the construction process. The pollutant concentration is measured 10 times at different stages of construction and in the days following the completion of construction. Results show that the living room and kitchen furniture made of particle board and MDF emits the largest amounts of pollutants. In addition, of all the pollutants measured, including benzene, toluene, ethylbenzene, styrene, 1,4-dichloro-benzene and formaldehyde, only toluene did not satisfy the Indoor Air Quality Management Act of Korea. The toluene concentration increase rapidly after the introduction of kitchen and living room indoor furniture. This is due to the material of which the furniture is composed and these results are validated using a small chamber method.

Development of Analytical Tool for Indoor VOC Concentration Using Enthalpy Changes in New Apartments in Korea

This study evaluated the indoor air quality in 36 new apartment houses in six big cities in Korea from July 2005 to January 2006. Most of the indoor finishing materials in the new houses were environment-friendly and designated by the Korea Air Cleaning & Researching Association. In the new apartments, which were all built with the same finishing materials, air levels of toluene averaged 1475 μg · m-3 in summer, when there were relatively high temperatures and humidity, and averaged 2711 μg· m-3 in winter. In addition, benzene, ethylbenzene, styrene, xylene, and formaldehyde measured 9.99, 628, 232, 2392 and 951μg·m-3 in summer and 9.99, 628, 232, 2392, and 951μg·m-3 in winter, respectively. Concentrations of volatile organic compounds (VOCs) and formaldehyde were increased as indoor temperature and humidity increased. This study evaluated concentrations of VOCs compounds in a room according to season using enthalpy, which considers two indexes, temperature and humidity. Concentrations of benzene, ethylbenzene, styrene, xylene, and formaldehyde increased with increased enthalpy.

Evaluation of the Dynamic Stiffness and Heavy-weight Floor Impact Sound Reduction by Composition of Resilient Materials

Resilient materials are generally used for the floating floors to reduce the floor impact sound. Dynamic stiffness of resilient material, which has the most to do with the floor impact sound reduction. The resilient materials available in Korea include EPS(styrofoam), recycled urethane types, EVA(ethylene vinylacetate) foam rubber, foam PE(polyethylene). glass fiber & rock wool, recycled tire, foam polypropylene. compressed polyester, and other synthetic materials. In this study, we tested dynamic stiffness of resilient material and floor impact sound reduction characteristic to a lot of kinds of resilient materials. It was found that dynamic stiffness of multi-layered damping material could be estimated if know value of each layer that compose whole structure. And the test showed that the amount of the heavy-weight impact sound reduction appeared by being influenced from this dynamic stiffness of resilient material. The dynamic stiffness looked like between other resilient materials, a similar to the amount of the heavy-weight impact sound reduction was shown.

Sound absorption characteristics of PTFE membrane Material and their application to a multi-purpose stadium:

Due to an increase in sport events such as world-cup soccer and other large-scale outdoor performances, a large number of multipurpose stadiums and gymnasiums were constructed throughout the world. Some research have been conducted on plans to utilise all-whether stadiums with fine figures, where large-scale spaces are available for various utilisations. All over the world, dome-type stadiums have been built, and are utilised not only for sports events but also for a variety of other large-scale events. PTFE (Polytetrafluoroethylene) is a membrane material mainly used for the outer ceiling surface of membrane structures. However, sufficient research has not been performed on the acoustical properties of the PTFE membrane material, which is widely used in the multipurpose stadiums. In this study, the air permeability values and sound absorption coefficient of PTFE membrane materials were measured and evaluated in a gymnasium. Practical application: This research will provide guidance to solving acoustical problems in dome type stadiums by explaining absorption properties of membrane materials. Solving the acoustical problems will greatly extend the functionality of dome type stadiums, such as hosting live concerts or recitals. The extended functionality will ultimately result in increased revenues for existing stadiums.

A Study on the Seasonal Effects of Plant Quantity on the Reduction of VOCs and Formaldehyde

Abstract This study aims at examining the reduction of indoor air contaminants by plants placed in an indoor space. The effect of reducing the concentration of air contaminants by three species of plants was studied in a full-scale mock-up model. Field measurements were performed using Aglaonema brevispathum, Pachira aquatica and Ficus benjamiana which were verified as air-purifying plants by NASA. Their positions and amount were controlled. Two conditions for the amount of plants (10%, 5%) and positions (sun-shine, scatter) were used in two separate rooms whose dimensions are identical. The concentration of Volatile Organic Compounds (VOCs) was monitored three hours, and three days after the plants were put in place. The variations of concentration of Benzene, Toluene, Ethylbenzene, Xylene, Stylene, TVOC and Formaldehyde, which are all known as the major elements of Volatile Organic Compounds were monitored. The more plants were used, the more a reduction of indoor air contaminants occurred. The effect of reducing the concentration of air contaminants increased when the amount of plants increased.

A Literature Survey of Research Trends of Volatile Organic Compounds and Field Indoor Air Quality in Korea

室内空気質関連の研究の内，揮発性有機化合物（以下VOCs）に関する研究の動向を把握するために大韓建築学会，大韓設備工学会，韓国生態環境建築学会及び韓国生活環境学会の論文集における関連論文を調べた。調査対象期間は2001年1月から2006年12月までであり，4学会で発表されたVOCsに関する論文を三つの分野に分けて研究動向を把握した。三つの分野は，1）室内で汚染物質を放散させる建築資材におけるチャンバー実験と室内汚染物質濃度の実態調査，2）汚染物質の挙動及び室内空気質の改善方法，3）空気質が在室者に及ぼす影響である。調査の結果，VOCsに関する研究は2005年以降，特に1）と2）の分野で活発に行われていること，また3）の分野は最近になって研究が始まったため研究の幅が他の分野ほど広くはないことが把握できた。