Authors. As for protection ratio. It is nothing but value inverse to air inflow ratio. And the protection ratio can be calculated only for anti-aerosol PSERA in accordance with GOST 12.4.119-82. Methods of calculation protection ratio for gases and fumes are not mentioned anywhere. Thus it is incorrect to use this term in the context of protection from gases and fumes. Further, it is hard to understand what the requirements for aerosols is based on. It is not connected with requirements of the new, harmonized with European, standards. To be exact, filtering half-masks FFP1 (for example, respirator "Lepestok-40") and anti-aerosol filters P1 are not obliged to certification in this case. But these items have to be certified in Europe.

MWG. Thereupon we would like to draw authors' attention to the fact that the protection ratio for fumes and gases is in common use in the "Sorbent" enterprise represented by the authors. You can take the product description of this enterprise and see that protective properties of PSERA produced by them are expressed, for example, as 310 MPC (maximum permissible concentration) for carbon monoxide. Figure 310 is protection ratio. It means the "Sorbent" has experts who know how to calculate this parameter!? And the calculation method is a secret only for the authors of the article. To explain the figure we have just to look and interpret correctly regulations of GOST 12.4.041-2001 "Filtering personal safety equipment of respiratory apparatus". Why did they (on ignorance or purposely) misinformed readers about specific technical matter? We should say that there are unanswered, in particular, methodical questions upon this problem. We believe they should be considered by the qualified experts of the area at an appropriate scientific and technical level, instead doing this in public!

Bringing the protection ratio in was the result of common practice of evaluation of personal safety equipment of respiratory apparatus of filtering type (PSERA) by its components - filtering-absorbing element (FAE) separately, front part - separately, etc., that actually leads to a deceit of the consumer even having the obligatory certificate for the product! So, for instance, having declared in advertisements and passport of the self-rescuer its high protective properties they actually mean only properties of FAE and do not tell a single word about low protective properties of the front part (meaning the whole product) and confuse the consumers. Similar PSERA made in accordance with such documents and having disproportionate protective properties of the components have filled the market although even non-experts perfectly know that consumer does not use PSERA in parts! If the authors of remarks have other way to solve this problem, apart from bringing protection ratio also for PSERA of filtering type in, the working group is ready to discuss it.