Twenty-eight samples of peat, peaty lignites and lignites (of both matrix and xylite-rich lithotypes) and subbituminous coals have been physically activated by pyrolysis. The results show that the surface area of the activated coal samples increases substantially and the higher the carbon content of the samples the higher the surface area. The adsorption capacity of the activated coals for NO, SO2, C3H6 and a mixture of light hydrocarbons (CH4, C2H6, C3H8 and C4H10) at various temperatures was measured on selected samples. The result shows a positive correlation between the surface area and the gas adsorption. In contrasts the gas adsorption is inversely correlated with the temperature. The maximum recorded adsorption values are: NO=8.22x10(-5) mol/g at 35 degrees C; SO2=38.65 x 10(-5) mol/g at 60 degrees C; C3H6=38.9x 10(-5) mol/g at 35 degrees C; and light hydrocarbons= 19.24x 10(-5) mol/g at 35 degrees C. Adsorption of C3H6 cannot be correlated with either NO or SO2. However, there is a significant positive correlation between NO and SO2 adsorptions. The long chain hydrocarbons are preferentially adsorbed on activated lignites as compared to the short chain hydrocarbons. The results also suggest a positive correlation between surface area and the content of telohuminite maceral subgroup above the level of 45%. (C) 2008 Elsevier B.V. All rights reserved.