Particulate matter (PM) pollution is serious human health issue. Various filter technologies have been developed to improve the air filtration efficiency. In this study, we demonstrate a high efficiency PM2.5 capture air-filter by electrospun polyacrylonitrile nanofibers (EPNFs). The surface of the EPNFs was modified by oxygen plasma treatment for generating functional groups such as eCONH2, eCOOH and eCOOR. The EPNFs were utilized as air filter in hand-made PM removal system which is consisted of DC power supply, PM source, PM sensor and PM removal test chamber. The test result showed high air flow and effective air filtration (PM2.5 removal efficiency: 94.02%, pressure drop: 18 Pa, Time to reach the PM level recommended by the World Health Organization (TWHO PM2.5): 15 min, quality factor: 0.1564 Pa−1 ) compared to commercial filters.