N95 is one of the filter standards (42CFR84) for respirator type masks
prescribed by the US National Institute for Occupational Safety and
Health (NIOSH) in 1995. It is recommended for serious communicable
diseases such as tuberculosis, SARS, and influenza. The “N” stands for
“Not resistant to oil,” and the evaluation requirements for N95 masks
stricter than for surgical masks and they also have high filtration efficiency.