The N95 mask is one of 9 types of particulate protective masks certified by NIOSH (National Institute for Occupational Safety and Health). The N95 mask can filter particles with an aerodynamic diameter of 0.24 ± 0.6μm (physical diameter of 0.075µm ± 0.020µm) to reach more than 95%. The aerodynamic diameter of airborne bacteria and fungal spores mainly varies between 0.7-10µm, which is also within the protection range of N95 masks. N95 masks can effectively filter and purify the inhaled abnormal odors (except toxic gases), helping to reduce the exposure level of certain respirable microbial particles. The US Department of Labor has recommended that medical personnel use N95 masks to prevent microbial airborne diseases such as influenza and tuberculosis.