Researchers at the University of Hong Kong tested how long viruses retain their ability to infect people on different types of surfaces. They sprayed H1N1 flu virus on six common household materials and tested viability up to 24 hours.
There’s little data on how long the Covid19 coronavirus remains viable. The CDC says that the coronavirus may remain viable for hours to even days. A recent study (that has not been formally published yet) tested the viability of the new coronavirus (HCoV-19) and the “old” coronavirus, SARS (SARS-CoV-1). They sprayed the two viruses on plastic, stainless steel, copper, and cardboard.
Based on these two studies, leaving a mask to dry for 48 hours should be enough to kill coronavirus, SARS, and influenza A viruses. Leaving masks for 72 hours would be even more conservative.
Click here to read more on these two studies and how we get to the conclusion: https://smartairfilters.com/en/blog/disinfect-clean-n95-mask-virus-coronavirus/