There has been lot’s of discussion regarding face masks during the COVID event, particularly the question, “Can I wear my COVID Cloth Mask to remove particulates while indoors or outdoors?” The National Library of Medicine conducted research in August, 2016, evaluating the efficacy of cloth face masks in reducing particulate matter exposure. They determined that cloth masks are only marginally beneficial in protecting individuals from particles less than 2.5 microns. So, a cloth face mask can help reduce the amount of particulates; however, there are no standards for cloth masks. Cloth masks come in all sorts, sizes, thread counts, commercially and home made. Since there are no standards, you will not know your level of protection, the actual size of particles the cloth mask is capable of filtering. Also, any mask worn must be tight fitting with a good seal.
Small particles can easily pass through cloth face masks. For example a virus ranges in size from 0.005 microns to 0.30 microns. A cloth mask will do little to prevent a virus from passing through the cloth fibers and/or any leakage from the the perimeter of the mask. N95 masks can add alittle more protection, however, under the best conditions the N95 can filter out particles that are at least 0.30 microns, anything smaller are likely to pass through the N95. The N95 is capable of reducing or eliminating the exposure to solid and liquid aerosols that do not contain oil. They are not to be used for the removal or reduction of gases, vapors, oil aerosols, the chemical MDA and abrasive blasting. It’s important that the N95 is clean and in good working order. It needs to be fitted tightly to a clean shaven face and ensure there is no leakage at the seal. If worn properly the N95 can filter at least 95% of airborne particles at a size greater than 0.3 microns. It’s expected that an N95 has 5% leakage.
For better protection, you can use a half face respirator with a P 100 hepa filter, high efficiency particulate air filter. If worn per the manufacturer, the respirator can filter particulates as small as 0.3 microns at 99.9%. These are good for dust, pollen, mold, smoke and bacteria.
However, a virus can still pass through the hepa filter. Therefore, do not get too confident and expose yourself to a hazardous condition.