Using adsorption (yes, with a "d"), activated charcoal in these military items attracts harmful chemical vapors
These self-contained adsorption systems are used for vapor phase
... [DOC] [TLE] Guide for the Selection of Personal Protective Equipment - National ... [PAR] particular, the development of chemical and biological defense equipment 
guides for ...... of Justice (NIJ), the Technical Support Working Group (TSWG), the 
U.S. Army Soldier and ... factors that should be considered when purchasing and 
using PPE, .... NFPA Standard 1991Vapor-protective suits that provide gas-
tight... [DOC] [TLE] How to Make a Water Filter - Scribd [PAR] On top of the sand, place a layer of activated charcoal.