Regarding the naysayers about Nanomasks, I would like to comment that for most of us price is an issue in practical preps for any disaster. The company openly acknowledges that after 48 hours due to the moisture buildup you should change the filter. But two masks and 25 filters cost less than 50 bucks, so that is a fifty bucks for fifty days. Filters are cheap.
The N95s with exhalation valves cost over four bucks at WalMart for two, and over five at Home Depot for two, so you need to wear each one also for two to three days to pay a dollar a day to filter air.
Would anybody want to wear an N95 longer than one day? The virus lives on soft material for at least another day and you can't clean it. The Nanomask in contrast is hard plastic and you can wipe down the edges that touch your face, or dip the whole thing in weak bleach before you put in a new filter. An N95 walking through the store is one thing, but if you had direct contact with a very sick family member, why not pay the same price for two days with a nanomask that you'd pay for two days with an exhalation N95?
The airtight seal and the maker's claimed filtering capacity is such a major difference, for such a potentially fatal disease, that I can't see any reason not to try and get an airtight nanomask. - Lyn