Purpose of mask-
MASKS are just like seive.
The less the size of pores in the seive, More is the filtering capacity of mask.
What determines the efficacy of a mask is the pore size in between its threads and the manner of using the mask.
while buying or making a cloth mask, make sure you look for following points-
- The density of thread used in the cloth play an important role in their efficacy of filteration.
- Combination of atleast 3 DIFFERENT cloth materials together in mask increases the filtration efficacy of a mask.
Researchers at University of Chicago found the fabrics used in household clothings offer atleast 40% blocking of droplets when used as single layer. On combining 2 layers this efficacy rises to 98%. Substituting the chiffon with natural silk or flannel—or using a cotton quilt with cotton-polyester batting—produced similar results.
Materials for Cloth Mask
For the sake of comfort while wearing a cloth mask, WHO recommends using the following materials for various layers of cloth mask-
INNER LAYER – absorbent material – COTTON
This will help absorb the sweat and oils from your skin. Making it more comfortable during use
MIDDLE LAYER – non-woven non-absorbent material – POLYPROPYLENE
OUTER LAYER – non-absorbent material – POLYESTER or POLYESTER BLEND
These layers will help repel the water from your mask and help it stay usefull longer.
CDC has given various ways on how to make your own cloth mask.
Also check out – PREVENTIVE MEASURES FOR DERMATOLOGISTS IN COVID-19
CLOTH MASK WITH VALVES
You might have come across masks containing small valves/respirators on masks. These are sold by shopkeepers boosting that these are more breathable than the masks not conatining these valves.
According to recent reports, the valves on these masks, push the virus excreted by an infected individual out through the valve; thereby making other people around at risk. Hence they fail in the purpose of mask of protecting one and all.
Recently the Government of India issued notice against use of masks containing VALVES/RESPIRATORS.
Even CDC (Centre for disease control) does not recommend use of masks or cloth masks for source control if they have an exhalation valve or vent.
HOW TO WASH A CLOTH MASK?
For machine wash-
For washing by hand-
- Prepare a bleach solution by mixing:
- 5 tablespoons (1/3rd cup) household bleach per gallon of room temperature water
- OR 4 teaspoons household bleach per quart of room temperature water
- Check the label to see if your bleach is intended for disinfection. Some bleach products, such as those designed for safe use on colored clothing, may not be suitable for disinfection.
- Ensure the bleach product is not past its expiration date.
- Never mix household bleach with ammonia or any other cleanser.
- Soak the mask in the bleach solution for 5 minutes.
- Rinse thoroughly with cool or room temperature water.
For more information about Masks and all related myths check out-https://www.medicalmythbuster.info/search/label/Masks
CLOTH MASKS with atleast 3 different layers of cloth, without valves can provide enough protection to protect against corona virus.
That’s all for this topic !!
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- CDC – https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/how-to-make-cloth-face-covering.html
- CDC – https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/how-to-wash-cloth-face-coverings.html
- Efficacy and Use of Cloth Masks: A Scoping REVIEW by Mehr Jain et al. Cureus. 2020.
- Effectiveness of Cloth Masks for Protection Against Severe Acute Respiratory Syndrome Coronavirus by Abrar A Chughtai et al. Emerg Infect Dis. 2020 Oct.
- Cloth face masks to prevent Covid-19 and other respiratory infections [Article in Spanish, Portuguese, En] by Magda Milleyde de Sousa Lima et al. Rev Lat Am Enfermagem. 2020.
- Ability of fabric face mask materials to filter ultrafine particles at coughing velocity by Eugenia O’Kelly et al. BMJ Open. 2020.
- Viral Filtration Efficiency of Fabric Masks Compared with Surgical and N95 Masks by Harriet Whiley et al. Pathogens. 2020.