Ultrasonic or acoustic cavitation involves the use of high-frequency sound waves in water to generate highly reactive species, particularly the hydroxyl (•OH), hydrogen (H•), hydroperoxyl (HO2•), and superoxide anion (•O2-) radicals and hydrogen peroxide (H2O2). We have previously demonstrated the utility of the Taguchi statistical method to design experiments and optimize the sonochemical removal of carbon disulfide in aqueous solutions. The effects of temperature, ultrasonic intensity, irradiation gas and frequency on the sonochemical oxidation process were studied. In the current work we have, for the first time, applied the method to a gas-liquid sonochemical system under ultrasonic irradiation. This technique will help us gain an insight into the relative significance of the various experimental factors necessary for the effective removal of NOx in a sonochemical scrubber under actual operating levels.