One year into this pandemic and COVID will stay for atleast a bit longer. With increasing demand, many people start to find out various ways to reuse mask! Autoclaving your mask is one such method which many people use to “Disinfect mask“. There is no derth of YouTube videos on YouTube telling you how you can autoclave your mask at home.
But lets find out what scientific studies have to say about – “AUTOCLAVE your MASK?” and “Does AUTOCLAVING affect your mask quality?”
is a process wherein an object is sterilised using steam and heat at high temperatures. This method uses both high temperature and steam to sterilize the object. There are specialised instruments available in market for autoclaving. These are mostly used in hospitals to sterilize linens.
But masks do not act like normal cloth materials when it comes to filteration capacity against viruses.
There are multiple factors which make a mask effective-
Scientists around the world have compared various methods to disinfect masks. These include AUTOCLAVING, UV STERILISATION, ALCOHOL, HEATING and others.
These methods were compared on following basis–
- disinfection capabilities
- effect on aerosol penetration
- effect onairflow resistance
- effect on breathability
- safe re-usability after disinfection
UV sterilising N95 and surgical mask was found to be effective in disinfecting the mask while keeping the mask quality intact!
But same is not the case when it comes to AUTOCLAVING your MASK. In various clinical studies it was found that AUTOCLAVING does affect mask quality.
Let’s see how-
Not just one but multiple studies were conducted to understand these effects (sources mentioned at the end of this post).
In some studies, COVID-19 virus was inoculated on the mask and difference in the filtration capacities was calculated before and after the process.
It was found that autoclaving your mask (N95 or surgical mask) cause physical degradation of the masks and this resulted in increased pore sizes.
These effects did vary from one mask type to other mask type.
Another effect that was seen is that processes like autoclaving and alcohol sprinkling affected the electrostatic charges in mask.
Electrostatic charges are the charges present on the centre layer of N95 and surgical masks. These play a role in repelling the certain charged virus away.
One study also stated that autoclaving decreased breathability of N95 masks after autoclaving it.
This means the mask becomes less breathable after autoclaving. Obviously these changes might not be felt to a person after one cycle of autoclaving, because these changes occur on a much smaller scale and can will be felt only after multiple cycles.
Hence autoclaving affected 3 most important factors of mask. These are-
- increased the pore sizes
- reduced the electrostatics charges of mask.
- breathing capacity of mask
That’s all for this topic !!
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- Microwave- and heat-based decontamination of N95 filtering facepiece respirators: a systematic review by S Gertsman et al. J Hosp Infect. 2020 Nov. doi: 10.1128/mBio.00997-20
- Proposed approach for reusing surgical masks in COVID-19 pandemic by Yuangang Liu, PhD, Sancy A. Leachman, MD, PhD, and Anna Bar, MD
- Autoclave sterilization and ethanol treatment of re-used surgical masks and N95 respirators during COVID-19: impact on their performance and integrity by S A Grinshpun et al. J Hosp Infect. 2020 A ug
- Filter quality of electret masks in filtering 14.6-594 nm aerosol particles: Effects of five decontamination methods by Tzu-Hsien Lin et al. PLoS One. 2017.
- Evaluation of five decontamination methods for filtering facepiece respirators by Dennis J Viscusi et al. Ann Occup Hyg. 2009 Nov.