Effect of aqueous phase cloud chemistry on tropospheric ozone

The sensitivity of tropospheric O-3 to aqueous HOx (OH + HO2) phase chemistry in clouds is examined using photochemical model calculations of the O-3 production efficiency per unit NOx and the chemical lifetime of O-3, combined with estimates for the residence time of air in clouds. It is found that the maximum perturbation to O-3 from cloud chemistry in the tropics and midlatitudes summer is less than 3%. This result is supported by calculations using a three-dimensional, continental-scale model for North America.