peter tsai helped invent N95 masks and thinks there's a way to clean and reuse them

peter tsai helped invent N95 masks and thinks there's a way to clean and reuse them

material scientist peter tsai, who invented the technology that makes material used in N95 masks, says there could be away to make them safe to reuse. he is researching whether blasting N95 masks at intense temperatures for short periods will kill the virus without degrading the mask.


in an interview with vice news he said that he hopes to publish the results of his research within days. he is one of several researchers at companies or institutions looking at heat as a potential low-tech solution for the shortage of masks impacting frontline workers and members of the public around the world due to the coronavirus pandemic.

peter tsai helped invent N95 masks and thinks there's a way to clean and reuse them

image courtesy of 3M



‘we are going to use heat, [158 degrees fahrenheit (70 degrees celsius)], for 30 minutes, to see if we can kill covid-19,’ he told vice news. ‘we should get the results in one or two days.’


the shortage of masks has gotten so bad that nurses and doctors are using alcohol and clorox wipes to try to decontaminate their masks, vice news reports. this could cause more harm than good, putting those who work on the frontline in potentially more danger than they are already.


tsai is using data collected from virologists in china, where the pandemic first broke out, who conducted similar experiments. according to him, a portion of those virologists similarly found that ’65 degrees celsius [149 degrees fahrenheit] for 30 minutes’ would kill covid-19.


the difficulty is finding a temperature that kills covid-19 without destroying the mask. that includes both burning the mask and rendering its functions ineffective. the masks are also electrostatically charged, which allows them to suck in and trap airborne particles that might contain viruses. according to tsai, this could be undone if the mask is exposed to extreme temperatures.


whilst european certification requires a mask to be able to withstand 158 degrees fahrenheit (70 degree celsius) for up to 24 hours, to kill any virus it could require over 200 degrees, a temperature that has the potential to kill any virus. vice news also spoke to scott mechler, a mechanical engineer at the massachusetts-based consolidated sterilizer systems, who cautioned that, even if this was successful, the masks would likely only be reusable three to five times if they’re sterilized in this way.

  • Peter, I have been using activated oxygen ( O3) to disinfect my N95. Good or not?

    Mike Courteau
  • Could anyone please give me any contact information for Peter Tsai, please – phone or email or…? Many thanks.

    Bennett Little
  • Can you advise if there’s been attempts to reprocess n95s using the STERRAD® 100NX SYSTEM? And if so is there a report I can reference for research?

    Thank you in advance for a response

    Lisa Rizzo
  • Perry, N95 masks are constructed in four layers. The virus filtration layer exists in the middle. Outer layers are permeable to allow materials to pass, and only the middle layers trap particles as small as the coronavirus. Since UV light can’t penetrate the outer layers, ultraviolet as a method of sterilization won’t work.

    James L
  • What about freezing them? Does the virus die at extreme cold temp?

  • I am making cotton masks for the general public, but had a request to make a cotton mask the would fit over an N95 mask to keep it clean at least on the outside. What is your take on that?

    Ruthanne Huber
  • It depends on the materials that are used in this mask ,if it is any kind of polysynthetic materials it will attract and contain viruses for days . It needs to be cotton,linen with antibacterial copper intervowen mesh plant based fabrics that will be easy to clean and they will not contain viruses as plastic based fabrics would.

  • Why not try ultraviolet light? This could destroy the virus in a relatively short time and would not involve heating the fabric. Or would it undermine the integrity of the fabric?

    Perry Travis

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