... effect of preventing dust, no particles ultrasonic sealing edge;UsageUsed in medical, food hygiene, electronics, dust-free clean rooms, public health ... nose clip3. Tiny Respiration resistance l, sanitary wearing. The aerosol of harmless gas , including dust, fume, droplet, gas and ... less than 5 microns respirable dust in the process of passing through such a filter was attracted by electrostatic and ...