Although the rate of wearing masks has increased to 97.9%, there is a possibility that a gap between mask and face may occur because it does not completely fit to face, or that the virus may spread due to the poor performance of the mask. Accordingly, many studies are being conducted to evaluate performance of masks, or to measure the flow rate of coughing with PIV (Particle Image Velocimetry). However, most of these studied the performance inside or on the surface of a mask, and research on particle emitting after wearing masks is insufficient. Therefore, in this study, the particle concentration leaked after wearing masks in the negative pressure isolation room experimental chamber was measured, using particle counters and low-cost sensors. A manikin was installed on a bed to release aerosols, and the tendency of particles to decrease after one cough was analyzed. As a result, most of the particles were removed within 10 minutes. The low-cost sensors and particle counters installed in the centre and right wall exhaust diffuser show that with N95 mask on, particles were removed the fastest, and with surgical mask on, particles leaked the most immediately after coughing and were removed the slowest.