Abstract: A porous sheet article including a self-supporting nonwoven web of less than 20 weight percent polymeric fibers exhibiting no more than about 1 weight percent dimethyl methyl phosphonate uptake and at least 80 weight percent sorbent particles enmeshed in the web, the sorbent particles being sufficiently evenly distributed in the web and the fiber polymer(s) being such that the web has an Adsorption Factor A of at least 1.6×104/mm water. The articles have low pressure drop and can provide filter elements and other individual or collective protection devices having long service lives and an Adsorption Factor approaching and in some instances exceeding that of a packed carbon bed.