During these unprecedented times, masks have become an inevitable accessory in our lives. The term “N95” indicates that the respirator blocks minimum 95 percent of test particles of 300 nm. Studies conducted in labs depict that the most penetrating particle size (MPPS) of N95 respirators is 0.03-0.1 μm, and of surgical masks, it is approximately up to 0.3 μm. Simple surgical masks fail to provide substantial protection from aerosols of at least up to 0.5 μm. Thereby, its postulated that for nano-sized airborne viral agents, N95 respirators blocking ability shall be less than 95%, which was significantly lower for surgical masks. COVID-19 spreads through aerosol pathogen transmission which are small (>5 μm) droplet nuclei that can lingers in the air and is expelled over 6 feet.
Recent literature in JAMA Internal Medicine, Sickbert-Bennett and colleagues published a study regarding the efficiency of N95 masks. Results of the study demonstrated that N95 masks which are reprocessed using ethylene oxide sterilization, as well as masks that are markedly 11 years past expiration, verily maintain high filtration efficiency. N95 masks, evidently with suboptimal fit still have comparable filtration efficiency of more than 90%.
Use of N95 is significantly instrumental in combating the COVID pandemic.