Protective mask

from Wikipedia, the free encyclopedia

Protective masks are used to protect the face or parts of it ( eyes , nose , etc.) and the respiratory organs . They protect mechanically against injuries or as filter masks or fresh air masks against gases, vapors, liquid mist, coarse and fine dust (dust mask) and / or annoying odors.

Areas of application

Protective masks or visors are used at work, e.g. B. used in welding , grinding , sandblasting , painting and cleaning work, but also in sports ( ice hockey mask, fencing mask), fire protection , military and medicine ( gas mask , respirator , mouth and nose protection ). Diving masks are part of diving equipment .

Product defects

Information on defective products can be found on the website of the Federal Institute for Occupational Safety and Health (BAuA). In its “Dangerous Products” database, it publishes product recalls, product warnings, prohibition orders and other information on individual dangerous products that may be used in Germany. a. are regulated by the Product Safety Act (ProdSG).

The Rapid Exchange of Information System (RAPEX) is in place across Europe to provide information and a. using dangerous or non-standard protective masks. The German contact point for the RAPEX system is the Federal Institute for Occupational Safety and Health (BAuA).

Infection protection masks

In the context of the COVID-19 pandemic , various protective masks and their respective effectiveness with regard to internal and external protection became very important and were the subject of various public debates. The mask requirement in many countries (since April 2020 also in the whole of Germany) relates to masks that should be worn by everyone to protect the environment. Everyday masks in particular are not officially regarded as protective masks, but rather as makeshift "mouth and nose covers" or "makeshift mouth and nose masks" because they offer the wearer of the mask little self-protection.

Recommendations of the Federal Institute for Occupational Safety and Health (BAuA)

Classification of protective masks in connection with SARS-CoV-2 according to the recommendations of the BAuA
Mask type image Protection of the wearer Protection of the environment for health workers Reprocessing
Everyday mask (makeshift fabric mask, community mask) * Homemade plaid mask from British Columbia.jpg low , but limited reduction in the risk of contact transmission through touching the mouth and nose (see effectiveness of everyday masks ) yes (reduction in the release of droplets , thereby lower virus concentration in the ambient air of a separator) No possible through disinfecting laundry; at least at 60 degrees (see here )
medical mouth and nose protection (MNS) ( EN 14683) A surgical mask (2017) .jpg limited (filtration of the droplets by 95 or 98%, but lateral penetration likely; see also effectiveness of mouth and nose masks ) possible when working on patients without suspicion of COVID-19; when working on patients suspected of COVID-19, only if the patient is also wearing an MNS Not intended for single-use products, exceptions possible in the case of acute pandemic-related bottlenecks
FFP2 mask without exhalation valve (EN 149), N95 mask N95mask.jpg yes (at least 95% filtration of droplets when inhaled) when working on COVID-19 suspect patients; only if there is a low risk of infection from aerosols Not intended for single-use products, exceptions possible in the case of acute pandemic-related bottlenecks
FFP3 mask without exhalation valve (EN149) yes (at least 99% filtration of droplets when inhaled) when working on COVID-19 suspect patients; even if there is a high risk of infection from aerosols
FFP3 mask with exhalation valve (EN 149) Breathing air filter disposable mask.jpg No
Fan assisted hoods or helmets (EN 12941 and EN12942) yes (filtration of droplets when inhaling depending on the particle filter class ) Breathing connection (including mask body); Filter change
*According to the German Society for Pneumology and Respiratory Medicine, masks made from fabrics probably have a protective effect, but this has not yet been proven in clinical studies. The filter performance of different substances varies considerably.

Protection of the wearer in comparison

In connection with the COVID-19 pandemic , in particular , the question of the extent to which the various protective masks protect the wearer from a virus infection arose. The state of research on this issue was relatively weak until the beginning of the pandemic.

The assessment of everyday masks is difficult and difficult to generalize, among other things, because the production and the requirements are not subject to any standardization and the properties of various everyday masks therefore differ considerably from one another. In contrast, medical mouth and nose masks, N95 masks and FFP masks are each standardized (see table above), which allows better comparability.

With regard to the pure separation efficiency, medical mouth and nose masks (type I), N95 masks and FFP-2 masks are essentially identical: All masks have a bacterial filter efficiency (BFE) of at least 95%; Depending on the standard, a particle separation of 95% with a particle size of 0.1 µm (corresponds to 100 nanometers ) must also be achieved. Purely based on the separation performance, type II surgical masks with a BFE of 98% (see classification of mouth-nose masks ) are even more efficient than FFP-2 masks and N95 masks, but less efficient than FFP-3 masks with a BFE of 99%.

The main difference between FFP and N95 masks and mouth-nose masks is the sealing of the mouth-nose area from the outside air, which is not guaranteed with mouth-nose masks. As a result, the effectiveness of mouth-nose masks is considerably reduced by the air flowing past. This has been confirmed by various studies: In 2008, for example, an experimental study commissioned by the Dutch Ministry of Health came to the conclusion that the effectiveness of filtering aerosols mainly depends on the type of protective mask. Analyzes were FFP2 masks , medical mouth-nose mask (MNS, surgical mask) and homemade Behelfsmasken from the material of tea bags . The effectiveness of these masks was examined with particle sizes from 0.02 to 1 µm. FFP2 masks, which ensure a tight fit around the wearer's mouth and nose, were found to be around 25 times more effective than medical mouth and nose protection (despite the identical filter efficiency compared to the FFP-2 masks examined) and 50 times more effective as makeshift masks.

In April 2020, the Max Planck Institute for Chemistry tested the separation efficiency of a wide variety of materials, such as those used in commercial and self-made masks. Different mechanisms of action with regard to particle size and pressure difference were examined. Particles in the size range from 100 to 500 nm in diameter were generally stopped with the lowest efficiency ( Most Penetrating Particle Size ). This can be explained by the different mechanisms of action ( interception , impaction , diffusion separation , electrostatic separation ) of a filter, which in combination have the least efficient effect in this size range. The study showed that in the range of the size of SARS-CoV-2 viruses, the separation efficiency of the materials used for everyday masks is significantly lower than that of surgical masks ; However, since the viruses are transported on droplets of very different sizes, this finding is of limited practical relevance. In particular, particles with a diameter of 5 μm and larger were separated very efficiently from all of the materials examined in the study. Droplets that arise when coughing and sneezing are mainly found in this size range, while virus-carrying aerosol particles that are emitted when speaking and singing can also be significantly smaller.

The specified protective effect can generally be reduced by improper use. In particular, it must be ensured that the mask fits snugly on the face, completely covers the mouth and nose, is not touched if possible, and is not moistened.

See also

Web links

Commons : protective mask  - collection of images, videos and audio files

Individual evidence

  1. Search in the product safety database on baua.de
  2. ^ What Countries Require Masks in Public or Recommend Masks? masks4all.co, accessed May 26, 2020.
  3. ^ Mouth and nose coverings infektionsschutz.de
  4. a b BfArM - Recommendations of the BfArM - Information from the BfArM on the use of self-made masks (so-called "community masks"), medical mouth and nose protection (MNS) and filtering half masks (FFP2 and FFP3) in connection with the coronavirus (SARS-CoV-2 / Covid-19). Retrieved April 27, 2020 .
  5. Recommendations of the BAuA on the use of protective masks in connection with SARS-CoV-2 . Status: April 27, 2020; accessed on April 30, 2020
  6. ^ Nancy HL Leung et al. a .: Respiratory virus shedding in exhaled breath and efficacy of face masks . In: Nature Medicine . tape 26 , no. 5 , 2020, ISSN  1546-170X , p. 676-680 , doi : 10.1038 / s41591-020-0843-2 ( nature.com ).
  7. Statement of the DGP on the effect of nose-mouth masks on self-protection and external protection in the case of airborne infections in the population. German Society for Pneumology and Respiratory Medicine, May 8, 2020; accessed on May 21, 2020
  8. EN14683 Harmonizes Bacterial Filtration Efficiency and Differential Pressure with ASTM F2100. Nelson Labs , 2014, accessed June 13, 2020 .
  9. ^ Marianne van der Sande, Peter Teunis, Rob Sabel: Professional and Home-Made Face Masks Reduce Exposure to Respiratory Infections among the General Population. PLOS ONE, July 9, 2008, doi: 10.1371 / journal.pone.0002618 ; accessed on March 23, 2020.
  10. Frank Drewnick: Separation efficiency of mouth-nose protection masks, self-sewn face masks and potential mask materials . (PDF) In: MPI Mainz. April 10, 2020, accessed April 18, 2020 .