Thank you to ACOI member, Charlene Lepane, DO, FACOI for sending this very helpful information to share with our membership! Dr. Peter Tsai, inventor of the filtration fabric in the N95 mask recommends the following methods for reusing the N95 respirator:
MASK REUSE METHOD #1
When reusing N95 masks, leave a used respirator in dry, atmosphere air for 3-4 days to dry it out. Polypropylene in N95 masks is hydrophobic, and contains zero moisture. COVID-19 needs a host to survive--it can survive on a metal surface for up to 48 hours, on plastic for 72 hours, and on cardboard for 24 hours. When the respirator is dry in 3-4 days, the virus will not have survived.
Take four N95 masks, and number them (#1-4).
On day 1, use mask #1, then let it dry it out for 3-4 days.
On day 2, use mask #2, then let it dry out for 3-4 days.
Same for day 3, and day 4…
MASK REUSE METHOD #2
You can also sterilize the N95 mask by hanging it in the oven (without contacting metal) at 70C (158F) for 30 minutes—it is reported that COVID-19 cannot survive at 65C (149F) for 30 minutes.
Use a wood clip to hang the respirator in the kitchen oven to do the sterilization.
When sterilizing N95 masks, be wary of using UV light--keep N95 masks away from UV light / sunlight. N95 masks are degraded by UV light because it damages the electrostatic charges in the polypropylene material. It is unclear how long the masks can be exposed to UV light before they are ineffective.
TIPS FOR REUSE METHOD #1 AND METHOD #2
- DO NOT place the respirator on a metal surface, or too close to metal--the temperature on the metal surface is higher than the air temperature.
- Keep N95 masks away from UV light / sunlight.
- When removing the mask, hold the edge of the straps attached to take off the N95 mask. Your hands may get contaminated touching mask, grab from ear strings.