How many times can a patient use an N95 mask? It seems like quite a few times for say short trips to the grocery store or to a doctors appointment. I ask because I have a small supply and I want to give some of them to a friend who is a nurse in Boston. His wife just posted on Facebook that he is in desperate need of masks. They have four small children with the oldest being my son's age of 12 and the youngest being an infant. I know I need to give this small supply to him but I'm wonder how many I can get by with reasonably. Maybe five? Any input would be appreciated.