| CPC A62B 23/02 (2013.01) [A62B 7/10 (2013.01); A62B 18/04 (2013.01); A62B 18/10 (2013.01); A62B 19/00 (2013.01); B01D 46/30 (2013.01); B01D 46/0036 (2013.01); B01D 46/10 (2013.01); B01D 46/64 (2022.01); B01D 46/645 (2022.01)] | 20 Claims |

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1. A protective mask, comprising:
a lens configured to allow a user of the mask to see therethrough;
a sealing portion configured to at least partially seal an inner volume of the mask from an ambient atmosphere; and
a filter interface configured to removably attach a filter to the mask, such that an outside gas can travel through the filter and the filter interface into the inner volume of the mask,
wherein, the filter includes a container, a first mechanical filter screen disposed between an interior of the container and the outside gas, a second mechanical filter screen disposed between the interior of the container and the inner volume of the mask, and a filtering medium disposed in the container, said filtering medium comprising active particles that are loose, substantially uniform in size, and derived from a polymeric precursor, and
wherein, the active particles comprise metallic additives and organic additives,
a ratio of standard deviation of the active particles' dimensions compared to an average particle dimension is less than 0.35, and
the polymeric precursor comprises at least one of polyvinylidene chloride (PVDC), polyvinylidene fluoride (PVDF), a PVDC copolymer, or a PVDF copolymer.
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