Are N95 masks reusable?

 Mark Antony | 2min read

No, but there have been some studies done using different techniques, UV, low heat treating, and disinfecting chemicals to improve respirator availability during a pandemic by sterilizing and reusing. In case of high demand when the disease spreads widely, hundreds of thousands of masks will be needed by health workers, and tens of millions more will be used by panicked people trying to avoid the disease.

Please note that all healthcare workers have to go through a fitting to have that mask fitted appropriately. That's why these N95s are only approved for healthcare professionals, not the lay public.

Our research indicates that N95 respirators can be decontaminated and re-used in times of shortage for up to three times for UV and HPV, and up to two times for dry heat.

Techniques

Masks can be left out in the fresh air, dried out during the night, and reused. UVC, medium heat air, and boiling water vapor are effective. Hydrogen peroxide may be, but may reduce effectiveness. Microwave, heath above 194°F/90°C, and alcohol destroy masks.

Washing with alcohol seems to destroy the inner layers of spun polypropylene of the mask. High temperatures fuses those inner layers. 0.1% Hypochlorite bleach seems to work, but the remaining odor is a problem. Salt crystallization makes viruses inactive.

Table 1[1]

Despite there is no approved method for decontaminating masks, it does not object to using these sterilizers, disinfectants, devices, and air purifiers for effectively killing these viruses.

How long to wear a new N95 mask?

It depends on intense of the usage. If you use an N95 mask for 2 to 3 hours a day, you can use it for three to four days maximum.

Risks:

Although extended use and reuse of respirators have the potential benefit of conserving limited supplies of disposable N95 respirators, concerns about these practices have been raised. 

The most significant risk is of contact transmission from touching the surface of the contaminated respirator. 

Conclusion:

N95 mask can be reused after proper disinfection. To reduce the risk of contact transmission it is recommended using a cleanable face shield over an N95 respirator to avoid contamination and that respirator is discarded if they are obviously contaminated, or damaged, or are hard to breathe through.

Among all the masks N95 is the safest mask. The N95 mask can capture 95% of airborne particles when properly fitted and donned upon a face. It is made of special synthetic polymer whose inner layer structure prevents viruses, bacteria from going inside.

References:

[1] Data supplied courtesy of Professor Yi Cui| Materials Science and Engineering, Stanford University and Professor Steven Chu|Physics and Molecular & Cellular Physiology, Stanford University on behalf of 4C Air Incorporated.

[2] Recommended Guidance for Extended Use and Limited Reuse of N95 Filtering Facepiece Respirators in Healthcare Settings