Assessment of environmental benefit and cost of renovation of dust filtration unit in a subway ventilation chamber

Air quality of underground railway is of critical interests in Seoul, Korea. National government has emphasized the stringent management of IAQ of metro-subway. In order to satisfy the legislative standard and public needs, air purification must be much more enhanced with the addition of high quality control facilities. Thus, this work focused on the review of cost effectiveness for replacing fine dust filters. The inflow amount of PM10 and PM2.5 into the test ventilation chamber in which deals with the air, 900 CMM, was 19.4 kg/yr and 8.9 kg/yr respectively. It corresponds to US $ 5,857 for PM 10 and US $ 6,608 for PM2.5 based on the environmental cost evaluation. The current filtration system collects approximately 55% of the inlet PM10 and 35% of PM2.5. Even if it obeys the National IAQ regulation for platforms and ticket rooms, civic groups strongly insist better quality of air inside. Thus, additional facilities to improve the air filtration up to 80% of PM10 and 55% of PM2.5 would cost US$ 8,756 per year. In the future, however, the increase of environmental benefit on the atmospheric dust will in part compensate the cost.