Abstract
As the main source of atmospheric sulfate aerosol, the aqueous-phase oxidation of SO2 has been of great concern. Traditionally, the aqueous-phase oxidation of SO2 is considered a consumption process of atmospheric oxidation capacity; however, we report here that •OH radicals and other reactive oxygen species (ROS) can be generated in the photochemical reactions of bulk HSO3− solution. This •OH production pathway results in the fast sulfate formation in the photooxidation of dissolved SO2. The photochemical process is determined to be pH-dependent in which sulfate formation is promoted by decreasing pH. Hence, a light - driven acidic positive feedback mechanism is proposed that the oxidation of dissolved SO2 and the formation of •OH radicals have a synergistic promoting effect. These results indicate that the photochemistry of dissolved SO2 could be a missing source of aqueous •OH radicals as well as sulfate at regional to global scales.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
