Secondary organic aerosol formation from the reaction of D5 with chlorine atoms

Indoor emissions of siloxanes from personal care products often dominate total VOCs in occupied spaces. Indoor bleach cleaning activities that emit molecular chlorine and hypochlorous acid can photolyze to form elevated levels of chlorine atoms (Cl), which reacts efficiently with D5. However, the secondary organic aerosol (SOA) formation potential of D5+Cl reaction has not been studied. Here, we characterized the chemical composition and yield of SOA generated from the Cl oxidation of D5 in an oxidation flow reactor, using an AMS and a Vocus PTR-MS with a heated aerosol inlet. The SOA mass yield of this reaction exceeded 100% following several generations of Cl-initiated oxidative aging. Notably, the SOA yield continually increased with Cl exposure, whereas SOA yields obtained from Cl oxidation of most other VOCs eventually decrease due to fragmentation of the precursor backbone. These results emphasize the importance of secondary chemistry during and after bleach cleaning.