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Study of the effectiveness of masks of all types. What are the best masks?

Study of the effectiveness of masks of all types. Which masks are better?

During the pandemic, the requirement to wear masks has become mandatory for everyone. But if in medical institutions personal protective equipment is recommended for employees, in everyday life we ​​get by with face masks. Only not all masks belong to personal protective equipment: the mask does not protect the person who wears it from others, but vice versa. In addition, while protecting all masks in different ways.

What are the best medical masks? What non-medical masks can you buy? Together with the Federal Medical and Biological Agency of Russia (FMBA), we analyzed the market for medical masks and personal protective equipment.

Our study included masks of all types: medical (FaceSafe, CSVT), personal protective equipment (KN95, Top Striker) and face masks (disposable and reusable) masks (MD STM, Odintsovskaya sewing factory, Organic bug, Save Tex, Hydrop, Fastfation LLC, Invita, Duet LLC, Petty Star Mask, SmartMi). All masks were purchased from pharmacies, online stores, supermarkets. A study was conducted of medical masks and personal protective equipment of 14 brands (TM) of four main types: medical disposable, fabric reusable, non-fabric reusable and FFP2 respirators. Nine masks were produced in Russia, five in China.

Before testing medical masks, we collected consumer concerns and myths about masks to answer the following questions:

Immediately, we note that all masks comply with TR CU 017/2011 “On the safety of light industry products” in terms of “toxicity index” and do not contain formaldehyde, acetaldehyde, acetone, isopropanol and methanol. Masks of all TM showed satisfactory results in the following indicators: microbial purity, irritant and sensitizing effect on the skin. This means the products are safe. When wearing a mask, you will not inhale toxic elements.

Four products had labeling irregularities: Top Striker, Hydrop, Organic bug and KN95. The masks of these TM do not have information about the address (location), company name (name) of the manufacturer (performer, seller), authorized organization or authorized individual entrepreneur, importer in the labeling.

Read more about all types of masks HERE .

– For more than 40 years, a medical mask has been my companion, an obligatory attribute of work in the operating room. During the operation, a lot of tension is required, and the mask does not interfere with this. Therefore, when people say that it is uncomfortable for them to wear a mask, it is hard to breathe, I consider these excuses frivolous..

Why is it recommended to wear masks for everyone – both healthy and sick people? Patients should wear masks to protect those around them. When exhaling, coughing or sneezing, disease-causing particles can spread up to two or more meters from the patient. When a healthy person wears a mask, the number of viruses and bacteria that can enter the body is reduced. When the mask is on both a sick and a healthy person, a double barrier is already obtained and a greater protection effect is achieved.

How to choose a mask according to the degree of effectiveness.

When choosing a mask, the most important criterion is its ability to effectively trap bacteria and viruses. The more types of microorganisms it traps, the higher its effectiveness. During the examination of medical masks, we determined the level of filtration (dry and wet), and also tested medical masks for strength, air permeability, hygroscopicity, developed by Roskachestvo in cooperation with testing laboratories. The mask must be not only effective, but also comfortable and safe to wear..

1. Filtration level (microbial and viral permeability)

Do masks really protect against bacteria and viruses? To determine the level of filtration efficiency of masks in the laboratory, a research experiment was carried out, which took place in three stages..

In the first two experiments, conditions were recreated that were close to GOST R 58396-2019 National Standard of the Russian Federation “Medical masks. Requirements and Test Methods “, which is used to standardize medical masks. The third stage – viral permeability – was first developed for this study..

Each stage of testing simulated a particular life situation in order to bring the experiments with masks as close as possible to everyday conditions. The first experiment simulated inhalation through a mask in an environment contaminated with bacteria. The second is protection against aerosol spray of bacteria in the air. The third is the direct bandwidth of the mask when a virus enters it, which is comparable in size to the COVID-19 virus. Accordingly, combined, all three experiments provided a balanced picture of which masks would show the most effective protection against bacteria, fungi and viruses. If the mask is not able to protect against bacteria, then it will be ineffective against viruses..

In total, the studies were carried out with seven microorganisms: Escherichia coli 1257, Staphylococcus aureus 906, Enterococcus faecalis 29215 ATCC, Klebsiella pneumoniae 700603 137474 ATCC, Salmonella enteritidis 5765, Pseudomonas aeruginosa 10145 ATCC. All masks have passed these tests twice: wet and dry, and after washing. Some bacteria, in particular Staphylococcus aureus 906, resemble those aerosol droplets through which COVID-19 spreads in their shape and mode of action..

Microbial permeability test.

Vacuum filtration. For the first method, a special device was used – a cascade impactor, which creates a pressure drop. An aerosol with bacteria was placed in one part of the device; under pressure, the microorganisms passed to a fragment of the mask, which served as a filter. The air containing the bacteria was drawn in and the bacteria lingered on the mask. And then they calculated what percentage of bacteria the mask does not let through. Accordingly, a 100% result meant that the mask traps 100% of bacteria..

Class III biological safety box used as an aerosol chamber.

Spray can. For the second method, a suspension containing a suspension of microorganisms was sprayed into an aerosol chamber. Aerosol droplets with microbes were formed in the chamber: it is through such aerosols in the air that COVID-19 spreads. Then a sample was taken from the chamber with a special portable device for collecting air samples. A fragment of a mask served as a filter in the device: it was on it that bacteria settled. The air stream, containing a suspension of microorganisms, passed through the mask, fell on the Petri dish with the nutrient medium. Those bacteria that were able to “pass” through all the layers of the mask ended up in the nutrient medium. After incubation, it was counted how many microorganisms passed through the mask. Again, a 100% result meant that the mask trapped 100% of bacteria..

Portable instrument used for sampling for microbiological air testing.

So, the best medical masks and non-woven masks in terms of the level of bacterial protection:

Reusable protective mask “Invita”

Disposable three-layer mask “Fast fashion”

Medical three-layer disposable mask made of nonwoven materials CSVT.

Hygienic face mask (reusable) MD STM.

All other masks allow one or more types of microorganisms to pass through.

Viral Penetration Test.

In addition to the first two experiments, a unique experiment was carried out for the first time to answer the question of concern to everyone: does the mask protect against viruses, which are on average 50 times smaller than bacteria??

Pressure filtration device used to determine the permeability of viral particles to mask tissues.

The laboratory used a solution of Sabin 1 poliovirus (poliomyelitis, identical in size to coronavirus). It was applied to a flap from a mask and passed through the layers under pressure. And then the liquid was examined for the number of viral particles that penetrated the mask..

Important! For a sufficient level of viral permeability, an indicator of 70% was taken, corresponding to the indicators of a medical mask (according to the results of the experiment).

Unfortunately, no mask can guarantee 100% protection against viruses. The best results were shown by the hygienic face mask (reusable) MD STM, it lets through up to 56.2% .

And the worst are the KN95 FFP2 face shield with a valve. Its throughput is 97.11%. This respirator mask will trap less than 3% of viruses.

Bottom line: we found that in terms of effectiveness against bacteria and viruses, some reusable non-fabric masks are really not inferior to disposable masks (medical and non-medical). When choosing, it is important to focus on the overall effectiveness and functionality of the mask, not the type, material or reusability.

2. Material of manufacture.

For the manufacture of medical masks, meltblown is most often used – a fine-grained mesh of polypropylene threads. The thickness of the polypropylene fibers ranges from 0.01 to 0.2 dtex. Another material that is used is spunbond. It is a nonwoven type microporous polypropylene vapor barrier material. It is resistant to acids and alkalis and reacts well to sterilization. Spunbond is a very durable material, so it is used to form the skeleton of the mask. SMS is a composite material made of several layers of spunbond and meltblown. Together with spunbond, it is also used as a frame for masks. Neoprene, polyurethane, and other synthetic blends can be used in non-fabric masks. Cotton or coarse calico is used in fabric masks. However, most manufacturers do not indicate the material from which their product is made..

Tip: focusing on the material of manufacture is not the best option when choosing. The effectiveness of the mask will depend primarily on the assembly and arrangement of the layers and the density of the fabric, not just the material. For example, if you compare medical masks, two polyurethane masks – SmartMi and Petty Star Mask – have a big difference in filtering efficiency for both bacteria and viruses. SmartMi is not recommended for use, while Petty Star Mask has one of the best viral penetration results..

Important! Cloth masks generally have lower filtration efficiencies, and none of the masks tested are recommended unconditionally for use..

3. Air permeability.

Another indicator that is important for determining the breathability of a mask is differential pressure. This is the breathability of a mask, measured by measuring the difference in air pressure between the inside and outside of the mask at specific airflow, temperature and humidity conditions. Indicators below the norm (according to GOST R 58396-2019) were in 2 TM: Top Striker, Hydrop. TM Save Tex has indicators below the norm after washing.

Conclusion: As we can see, some masks do have a breathability problem. However, the opinion that they all restrict breathing to a state of hypoxia is a myth. How to test a medical mask for breathability? Choose a mask that is easy to breathe, so you do not have to periodically remove it, putting yourself and others at risk..

4. Hygroscopicity.

The hygroscopicity of the material is one of the hygienic properties of textiles, which affects the comfort to wear. Quality medical masks should not absorb moisture, but release it into the environment. This will provide comfort to wear and allow you to breathe freely. The normative indicators of hygroscopicity were taken from TR CU 017, where the norm is at least 6%. Indicators below the norm are determined for 9 TM masks: Fastfation LLC, Top Striker, Hydrop, Petty Star Mask, CSVT, Duet LLC, MD STM, SmartMi, KN95.

Conclusion: low hygroscopicity is a problem with nonwoven masks. Moisture collects on their surface, causing difficulty in breathing. Carry several masks with you so that you can replace the moisturized mask with a dry one. This will allow you to breathe easily and will increase the filtration efficiency..

5. Durability.

There is no strength standard for masks, therefore, when testing the fastening strength of component parts, the experts were guided by GOST 3813-72 “Textile materials. Fabrics and piece goods. Methods for determination of tensile breaking characteristics ”. Indicators below the norm were found in 5 TM masks: Fastfation LLC, Petty Star Mask, CSVT, Duet LLC, Save Tex.

Nevertheless, there are only a third of such fragile masks. Among them are masks of different types.

Conclusion: the strength of the mask does not depend on the type and material and can vary from manufacturer to manufacturer. In case the mask is damaged, carry a few spare.

Does the wet mask decrease in effectiveness??

When worn for a long time, the mask becomes moist from exhaled air and saliva. Since the masks were tested in dry and wet conditions, it was possible to compare whether their effectiveness decreases if the mask is wet.

It is impossible to answer unequivocally that the effectiveness is falling: the study included masks of several TM, whose effectiveness remained unchanged. The two TM masks even increased their effectiveness when wet. But the wet masks of 4 TM showed a decrease in their effectiveness against bacteria: these are Odintsovskaya Garment Factory, Save Tex, Feisseif and SmartMi. If in a dry state their efficiency was higher than 95%, then in a wet state the filtration efficiency of this or that type of bacteria dropped below 95%. .

Tip: to protect yourself and others, change wet ones after wearing masks to dry ones.

What are the most effective masks?

It is important to remember that not only registered medical masks can be sold in pharmacies, but other types of masks as well. Therefore, it is necessary to focus not on the place of sale, but on the marking (indication of the registration certificate on it). When choosing a mask, you need to remember that it is primarily created in order to filter what comes from the patient. An effective mask redistributes the air flow of a coughing or sneezing person. Drops when wearing a mask go sideways and downward, which reduces the risk to other people.

Important: in each category of masks, except for cloth masks, those were found that showed a fairly high level of both bacterial and viral filtration. Among medical – CSVT, among FFP2 respirators (without valve) – Top Striker, among reusable non-fabric – MD STM, Petty Star Mask. They (except Top Striker) have no air permeability issues.

However, all of them do not provide 100% protection, are not suitable for use in the “red zones” of hospitals and can be used in everyday life in compliance with all other preventive measures..

Recommendations for use.

For the mask to be effective, you must follow some rules for its use. It should be remembered that even the correct wearing of a mask with a high filtration efficiency does not give a 100% guarantee. In real life, many factors can affect the effectiveness of a mask, from proper wearing to mask moisture after extended use. It is necessary to observe all precautions, keep a social distance, combine wearing a mask with preventive measures such as washing hands, disinfecting objects, avoiding crowded places.

– It is important to wear the mask correctly, covering the nose and mouth, so that it fits as tightly as possible to the face. The mask should be changed every two hours or as it gets wet. When coughing and sneezing, the mask becomes moist and is a good environment for the rapid growth of viruses and bacteria. Unfortunately, we often see how a person’s mask dangles somewhere on the chin or only covers the mouth. It is clear that it cannot perform protective functions in this way..

If you are using a reusable mask, wash it daily with soap or powder. WHO recommends washing masks at a water temperature of at least 60 degrees. Reuse only a completely dry mask. If the mask gets wet or dirty, remove it and change it to another. Put the used mask in a plastic bag. If the mask is dry but you want to remove it, do not put it in your pocket or bag with other belongings. Always place the mask in a clean bag that can be closed so that the mask is isolated from other objects and surfaces. Change the mask every two to three hours of continuous use. Carry multiple masks with you in case of replacement.

Do not reuse non-woven disposable medical masks. The used disposable medical mask must be placed in a separate bag, hermetically closed and only then thrown into the trash can, trash can or waste container.

If you take off the mask for a while, put it in a bag too. Wear the mask with clean hands. Don’t touch your eyes, nose and mouth.

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