How you can reuse N95 masks. It’s a very technical paper but the takeaways I got from it are:
- The N95 mask gets most of its filtration capability from semi-permanently electrically charged particles in the mask material.
- Attempting to clean the masks with alcohol or even alcohol vaper will SERIOUSLY degrade the filtration ability of the mask. Don’t do that!
- “…it is reported (if it is true) that COVID-19 cannot survive at 65C for 30 minutes. Therefore, it is safe to treat the masks in hot air at 70C for 30 minutes and this process can be repeated multiple times to reuse the masks without a noticeable loss of efficiency. But be sure to suspend the masks in the hot air in the oven without contacting or putting the masks too close to a metal surface. The respirator can be hung in the oven using a wood or a plastic clip on its edge of non-breathing zone or put on a wood grill at least 6” away from a metal surface.”
- “…our investigation showed that the charge loss on the electret is unnoticeable by sterilization using 125oC steam for three minutes.”
- “…our investigation showed that the charge loss on the media is unnoticeable in boiling water for three minutes but stirring on the mask is not recommended to avoid its physical damage.”
- If you plan to use water to sterilize the mask “…be sure that the inner or the outer veil of the mask is not made of paper-like tissues – paper pulp or nonwovens bond by water soluble binder, which will either dissolve in water resulting in loose fibers in the veil or the loss of its strength after exposing to water.”
To save you a minute or so of your time, 70C is 158F and 125C is 257F.