## 4 Conclusions  
The presented morphological tests studies of zeolite and silica materials showed that the most widely used modification with HDTMA adversely affected the textual parameters of those materials. While it did not change their phase structure, it did clog their mesopores and decreased specific surface area. In addition, this modification was conducive to agglomeration during the introduction of zeolite and silica materials in the structure of elementary polymeric fibers in the melt-blown process.  
The protection and functional tests of the studied nonwoven zeolite and silica composites in terms of breakthrough time revealed that the larger the BET specific surface area, the longer the reaction time with the vapors of volatile compounds (both organic and inorganic). The longest breakthrough time for ammonia vapors was observed for the composite containing the mesoporous silica material MCM-41, which was also characterized by high filtration performance against aerosols with both liquid and solid dispersed phases (NaCl and paraffin oil mist), ranging from 97% to 99%, as well as a satisfactory airflow resistance of approximately 330 Pa.  
The application of the SM molecular sieve (zeolite ZSM-5) in the PP nonwoven led to the longest breakthrough time against acetone and cyclohexane vapors at the maximum allowable concentrations (235 and 81 ppm, respectively), with reaction times of approximately 11 and 2 min, respectively. The presented basic studies of filtration performance showed the nonwoven composite with SM to be 97% effective against sodium chloride and paraffin oil mist aerosols at an airflow resistance of 283.5 Pa. The obtained results are in line with the results of research of other scientists [34; 35; 36], which showed that zeolites are good adsorbents for chemical compounds.  
As a result of the tests carried out and on the basis of the obtained results, it turned out that the material MCM-41 shows the highest PC values for ammonia. This indicates a high potential of interaction between the adsorbent surface and the gas being tested, which confirmed the results of the research presented in the articles [37; 38]. Similar observations were recorded for the zeolite SM material that showed the best efficacy against VOCs.  
Conceptualization, A.B.; Methodology, A.B.; Formal analysis, A.B., A.N., R.P. and W.F.; Investigation, A.B., A.N. and R.P.; Resources, A.B. and W.F.; Data curation, A.B., A.N., W.F. and R.P.; Writing--original draft preparation, A.B., A.N., W.F.; Writing--review and editing, A.B., A.N. and W.F. Supervision, A.B. and W.F.  
The publication is based on the results of Phase IV of the National Program \"Improvement of Safety and Working Conditions\" financed in the years 2017-2019 in the area of research and development by the Ministry of Science and Higher Education/National Centre for Research and Development. The Central Institute for Labour Protection--National Research Institute is theProgram's main coordinator.  
The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.