Due to the coronavirus pandemic, interest in face masks has increased markedly. Many already know that only a special virus filter can stop the pathogen. But is it possible to do it yourself, and if so, how?
What are mask filters?
Fabric masks by themselves do not protect against viruses, or even dust. Viruses have sizes from 0.01 to 0.5 microns, and dust - 1-100 microns. For comparison, 1 micron is 0.001 millimeters. To delay such small particles and prevent penetration to the mucous membranes, special non-woven materials or cartridges with filter filling (for example, with activated carbon) are used.
Carbon filter
The most popular carbon filter for use in everyday life, in factories and factories. It contains a sorbent that absorbs harmful substances. The degree of protection depends on the manufacturer. The filter can only retain large solid particles, and can have the highest protection class, saving from viruses (this effect, unfortunately, cannot be reproduced at home).
Types of carbon filters:
- Inserts. The basis is a filtering non-woven material. Most often, the filter has several layers and is inserted into the pocket of the fabric mask.
- Cartridges. Used for respirators, half masks and full face masks. Activated carbon is located inside the filter.
Types of filters
Filters for masks are distinguished by purpose: for respirators, fabric masks. They also differ in protection class:
- FFP1. This class has disposable respirators with filters that capture from 75 to 80% of the contaminants coming in with the air. Coarse dust is retained: cement, coal, wood and metal chips. Suitable for cleaning in the apartment and house, for carpentry, carpentry and repair work.
- FFP2. Block from 89 to 94% of all pollution. Products do not allow fine dust, liquid aerosols, dolomite dust. Used in various industries.
- FFP3. The highest class of protection. Respirators with this label block up to 99% of all substances, including bacteria, viruses, fungi spores.
About filters and gas masks that protect against viruses, described in more detail here.
According to the US Centers for Disease Control and Disease, a 95 series respirator protects against coronavirus. Products with a protection class of FFP2 are considered to be analogues in Russia.
As filter materials use sorbents, nonwoven webs, HEPA filters. The effectiveness of the protective mask (respirator) is determined as a whole. It is important that it fits snugly on the face and does not impede breathing.
How to make a filter with your own hands?
Various workshops on manufacturing not only masks, but also filters for them filled the Internet. What just do not offer to use as a filter layer:
- toilet paper;
- cotton wool;
- napkins and disposable towels;
- sanitary towels for women;
- dust bags for a vacuum cleaner;
- spandbond;
- various technical filter cloths.
The selected material is folded into several layers and cut to the size of the mask. Often it is placed between tissue layers. To make the mask reusable, it is better to make a special pocket for the filter.
It cannot be reliably said whether a makeshift filter protects against viruses by at least 30-40%. Tests in this regard have not been conducted. Of course, a homemade device cannot guarantee complete protection - to obtain such a result, industrial technologies have been improved for several decades.
WHO recommends that the good old cotton-gauze dressings of 3–7 layers of bandage (gauze) and 1 layer of cotton for self-manufacture.
Terms of use
Most filters are recyclable. Washing or ironing leads to deterioration of the material and loss of filtering properties. Some manufacturers allow antiseptic treatment or UV irradiation to extend their life.
The duration of use of the filter can vary from 2-6 hours (for cotton wool) to 10 days (for respirator cartridges). Inserts usually last 8–72 hours.
The basis of the mask must be processed daily. Textile products are washed and ironed on both sides. Reusable respirators in the bulk are disinfected with UV lamps.
The thicker the filter in the mask, the better?
Not. The degree of protection depends on the characteristics of the material and multilayer. In a protective mask with a thick filter layer, breathing is extremely difficult. The product quickly gets wet and loses its effectiveness. And stuffy masks can provoke an attack in people with chronic diseases of the cardiovascular or respiratory system.
Will face mask protect against viruses?
To some extent. First of all, disposable and reusable fabric masks are worn to protect others from their own biological fluids (saliva, mucus). Such products are not able to retain a microscopic particle of the virus. But they stop large aerosols and dust. Due to this, the number of viruses entering the body is reduced. The fewer of them, the more likely that the immune system will cope with the infection.
The presence of a filter in the mask increases its effectiveness. For guaranteed protection, it is better to use replaceable inserts from the manufacturer that have passed the tests. If this is not possible, you can make it yourself from improvised means. The greatest number of positive reviews won spandbond and cotton.