Carbo-Tech's (Essen, Germany) D43/1 (macro and micropores, 0.534 and 0.432 cm(3)/g) and D55/2 (macro and micropores, 0 and 0.309 cm(3)/g) active carbons, BET sp. surfaces 1073.3 and 616.0 m(2)/g, Dubinin-Radushkevich's micropore surfaces 722.2 and 749.9 m(2)/g, resp., were comminuted, sieved each to collect fractions (a) 0.5-0.71 and (b) 0.71-1 mm in particle size, and predried 4-6 h at 110-120degreesC. They were studied at 20degreesC as 5.187 cm(2) x 1.5 cm layers in dynamic adsorption of tert-butylbenzene (TBB, substitute for sarin) that was passed as a TBB(1 +/- 0.1 mg/L)-air mixture at flow rate 1 L/(min.cm(2)). Exit concentration vs. time curves (termed the isoplanes) were measured and the Jonas-Wheeler equation was used to interpret the data. The D43/1, fraction a, showed the longest breakthrough time, 79 min, and the max. (specific) dynamic sorption capacity, 400 mg (124 mg/g). These carbons were found to differ essentially in transport (macro + meso)pore volumes, > 0.5 and similar to0 cm(3)/g, resp. At low breakthrough concentrations, this volume controls the accessibility of adsorption (micro + meso)pores and affects the degree of utilization of the dynamic adsorption capacity.