This study attempted to find an alternative method for fine dust control in the pre-exiting facilities of metro-subway stations. A new double-layer design was proposed for the MVAC (mechanical ventilation and air control) system. Several filter lay-outs were combined a pre-filter with electret filter (EF), electret bundle filter (EBF), or electret pleated filter (EPF), and were then examined focusing on the collection efficiency of particulate matters and pressure drop across the filter layers. The experimental results from the lab and field tests showed the best collection efficiency with EPF, which achieved 85% for $PM_{10}$ and 55% for $PM_{2.5}$. It was also found from the long term field test that the new filter lay-out could provide quite consistent dust level particularly in underground platform regardless of external condition.