N95 mask is one of 9 anti-particulate masks certified by NIOSH (National Institute of Occupational Safety and Health). "N" means particles that are not suitable for oiliness (oil fumes from fried dishes are oily particles, and the droplets generated by people talking or coughing are not oily); "95" refers to the test conditions specified in the NIOSH The filtration efficiency reaches 95%. N95 is not a specific product name. As long as it conforms to the N95 standard and has passed the NIOSH review, the product can be called "N95 mask".
A variety of masks such as N95 can effectively prevent the new coronavirus. If you are a medical worker or a person who often enters a high-risk area, you need to wear a medical mask.
The filtering efficiency of the N95 mask for particles with an aerodynamic diameter of ≥0.3µm is above 95%. The aerodynamic diameter of air bacteria and fungal spores mainly varies between 0.7-10µm, which is also within the protection range of N95 masks.
Therefore, the N95 mask can be used for respiratory protection of certain particles, such as grinding, cleaning and processing of dust generated by minerals, flour and certain other materials. Particulate matter that produces harmful volatile gases.
The principle of masks to prevent diseases is actually very simple, is to block the droplets of bacteria in the air.
The requirements for materials and filterability are not so high. Although disposable medical masks are very cheap, the barrier effect is actually not much different from expensive N95 masks. If you are not in close contact with the patient, just use a disposable mask. Leave the N95 mask more to the frontline medical staff.