The effect of the properties of activated carbons with varying pore size distributions (Activated Carbon Fiber Cloth (ACFC)-10, ACFC-20, Darco FGD, and Calgon F400) on NO oxidation was studied. Steady-state NO oxidation efficiency ranged from 32-56% for these carbons, and the carbons with the smallest average pore width (ACFC-10) were most efficient as NO oxidation catalysts. Average micropore width was more influential than total micropore volume for catalyzing NO oxidation. It was proposed that acidic surface functionalities, e.g., oxygen groups added to carbon via nitric acid treatment, improved desorption kinetics for formed NO2, which decreases the total time necessary to reach steady-state NO oxidation. Acidic oxygen functionalities added to the carbon surface make for a more practical NO oxidation catalyst, since their presence decreased the time required to reach steady-state conversion without significantly impacting the conversion efficiency. This is an abstract of a paper presented at the 105th AWMA Annual Conference and Exhibition 2012 (San Antonio, TX 6/19-22/2012).