Concrete pavements containing TiO 2 can be used for air pollution control by oxidizing NO X under UVbearing sunlight. This study employed a bench-scale photoreactor to estimate NO oxidation rates for varied environmental conditions. Rates correlated positively with NO inlet concentration and irradiance and negatively with relative humidity. No correlation occurred with flow rate. A decrease in slab moisture (previously unstudied) positively correlated with NO oxidation rate at 0-2% loss of saturated mass, but negatively correlated at losses greater that 2%. Although prior researchers deemed temperature insignificant, data indicated a positive correlation. Overall, rates ranged from 9.8-64 nmol•m-2 •s-1 .