Carbonaceous adsorbents from sawdust pellets from coniferous trees (pines) were obtained by CO2 activation and used as nitrogen dioxide adsorbents. Activation was performed at 800 degrees C for four different periods of time (30, 60, 90 and 120 min). The effect of NO2 adsorption in dry and wet conditions on the sorption ability of the activated samples obtained was tested. The results have shown that NO2 sorption properties of the activates increase with increasing time of activation and reach maximum for the samples activated for 90 min. On the basis of measurements in dry and wet conditions, the presence of water was found to increase the NO2 breakthrough capacity. The sorption capacity of the adsorbents obtained towards NO2 was proved to be determined by the surface chemistry and the reactions taking place on the surface rather than by the specific surface area development. (C) 2010 Elsevier Ltd. All rights reserved.