A simultaneous control technology for nitrogen dioxide and toluene in indoor areas

摘要

Energy consumption has increased drastically as national industrialization has rapidly accelerated. These circumstances have led to greater air pollution problems with air pollution in Korea. In order to address this issue, the Department of the Environment has employed various kinds of policies to improve the ambient air quality of the Seoul metropolitan areas. However, these measures have not improved the ambient air quality in this region as much as had been expected (Sohn et al., 2008). Indoor air quality has significantly affected by the air quality outdoors. For example, the air quality within the Seoul Metro Subway is of great concern, since it is located near automobile roads, so subway air environment is of concern. This subway system is also approximately 25 years old, and contains a deteriorating infrastructure which may further contribute to the accumulation of indoor air pollutants (Kim et al., 2007). The most common compounds of concern associated with the subway system are PM-10, volatile organic compounds (VOCs), and NO_2. However, the concentration levels in the subway airshed are extremely low compared to those emitted from industrial plants. Subway air may be described as high flow and low concentration, and the ventilation area is usually not wide enough to install conventional control technologies such as Catalytic Oxidation or Catalytic Reduction. Although there are alternative control techniques (microwave, plasma, and electron beam) which may be employed, these methods tend to produce ozone as a by-product. In this study, only gaseous compounds (toluene and nitrogen dioxide) were considered as target indoor air pollutants. An adsorption technique using different types of activated carbon was chosen because the area of a typical subway ventilation system is small, thereby making this approach is more cost-effective. Simultaneous control methods for removing nitrogen dioxide and toluene are investigated and discussed.