Researchers conclude that homemade and medical masks can tolerate simple disinfection without significantly reducing their efficiency.
A new study has found that disinfecting homemade masks with a mask disinfector may not significantly decrease their effectiveness. Some medical masks can go through this process and still be effective.
Disinfecting and cleaning the mask
In light of the evidence found, the researchers behind the present study set out to examine ways of disinfecting masks safely while killing any SARS-CoV-2 without decreasing the effectiveness of the masks over time. They studied means of disinfecting homemade masks and for healthcare workers using CPAP cleaning machine or virtuclean CPAP and mask cleaner since reusing masks may help ease pressure on dwindling stocks.
To investigate how effective masks are after disinfection by heat exposure, the researchers applied different masks to the heads of mannequins considered to simulate the drawing of breath. Since it had already been established that heating to 158oF could kill SARS-CoV-2, the researchers did not require to work with the virus. As an alternative, they used soot from a kerosene lamp, the particles of which are roughly the same size as SARS-CoV-2 particles. They also suggested that cleaning of a mask can be done using any CPAP mask cleaner machine.
Heating does not reduce effectiveness
The researchers concluded that one N-95 respirator and the surgical mask could be disinfected and cleaned by heat exposure ten times without losing their effectiveness if fitted tightly on a plastic mannequin. The N-95 mask attained a filtration efficiency of 95%, while the surgical mask achieved 70%. The other N-95 respirator became faulty after being frequently applied to the mannequin. Nevertheless, when the researchers used the masks on the softer, silicone, mannequin with a fit that a person would typically use, they found that filtration levels were significantly lower. It came to about 40% for both the surgical mask and the N-95 respirator.
Using a mannequin to enhance filtration
When the team used homemade cotton masks on the softer mannequin, they learned that the filtration effectiveness was 55%. That was better than either the surgical mask or the N-95 respirator when used with a regular fit. Heating the homemade masks also had no impact on their filtration capacity. However, one can use the best CPAP cleaner for cleaning and sanitizing a mask.
The researchers also explored the efficiency of homemade nose clips applied to the mask. They noticed that the nose clips significantly increased filtration efficiency to 98% for the N-95 mask and up to 88% for the surgical masks when applied to disposable masks with a regular fit.