Improvement of the procedure of new filter masks development Serhii Cheberyachko, Yurii Cheberyachko, Dmytro Radchuk, Oleg Deryugin and Olha Nesterova MATEC Web Conf., 305 (2020) 00038 Published online: 17 January 2020 DOI: 10.1051/matecconf/202030500038