[BitWielder1]

Depends on how long the virus lasts outside the human body.
It could be that after X minutes, the virus trapped in the mask can no longer infect. But I don't have any numbers,

[Mom MD]

The virus survives for days on hard surfaces

[ProtectOurFreedom]

I’ve read that the experts think the virus can “live” 2 - 3 hours in the open environment. It’s an RNA virus and isn’t “alive” in the classical sense. It needs a host cell where it can inject itself, then take over the cell’s replication machinery to make copies of itself. It is truly incredible how these things work.

[LesbianThespianGymnasticMidget]

Contaminated surface viability: Flu and cold Coronavirus.. about 1 day. MERS and SARS Coronavirus, up to 2 weeks. I am going to guess this is going to be more like MERS and SARS.

All of it is temp and humidity dependent so those are just guidelines.

[bgill]

I’d be more worried about who the last person was who used the copy machine at work. Or who hand made your restaurant meal. Or who last squeezed the Charmin or smelled the grapefruit at the grocery store. Or who sat in that bus seat. Or sneezed in the elevator. Or who bumped you on the sidewalk. Or which snotty nosed kid is sharing scissors with your kid at school than how long a mask works because it doesn’t.