@BusinessJing thank you for your question.
Those who are on duty in Corona related patient they need respiratory filtration type mask and also need surgical type of mask with face sheild. But mandatory mask is respiratory mask.
N95 Mask:
(The N95 mask has a full name of NIOSH-certified N95 respirator, which means these respirators are tested of 95% filtration and certified by the U.S. National Institute of Occupational Safety & Health (NIOSH)
KN95 mask:
(The KN95 respirator is a particulate-filtering mask tested using the China criteria)
FFP2 mask and KF94 mask:
FFP2 made as Europian standard and KF94 South korean standard.
(The FFP2 is a filtering facepiece score of 94% filter capacity approved by Europe and the KF94 is tested by Korea criteria. Actually, both the N95, KN95, FFP2 and KF94 respirators have almost the same filtration efficiency, it means that KN95, FFP2, and KF94 are as effective as the N95 respirator mask. The main difference between these respirators is that they are tested by different nations.
Comparative criteria:
N100 (99.97%) = FFP3 (99.95%) > N95 (95%) = KN95 (95%) = FFP2 (94%) = KF94 (94%) > KN90 (90%).
Hope you can understand now easily.
The normal and the safest way to avoid and suffering from corona is to stay at home.We are frontliner fighter working at battle field that u all are safe.Each and every life is important to the nation.
Plz keep maintain distance and wear mask in appropriate way.Stay safe.
Dr Mst Shabnam Shaila Sharmin.