In a collaboration with PNNL, Sergey Nizkorodov and his students have found that cloud water accelerates aerosol aging. 

Natural organic aerosols have astonishingly complex chemical composition, which continuously evolves as aerosols age. A collaborative study involving scientists from the University of California, Irvine and Pacific Northwest National Laboratory found that cloud water significantly accelerates this aging process. Aerosol organics dissolve in cloud water, undergo efficient photochemical processing, and once the cloud dissipates, a completely different aerosol is left behind. This change in the chemical composition alters how the aerosol particles behave, a topic of interest to health scientists and climate modelers