“…In terms of importance, oxidation of phenanthrene to produce phenanthrenequinone (e.g., Wang et al, 2007;Lee and Lane, 2010), which is of much lower volatility than either 1,2-or 1,4-naphthoquinone and is more highly redox-active, may be a greater source of particle-phase redox-active organic species and has been shown to be an atmospherically relevant species (EigurenFernandez et al, 2008b). Certainly, previous apportioning of DTT activity to chemical species has shown phenanthrenequinone to be a much more substantial contributor to redox activity than 1,2-and 1,4-naphthoquinone (Chung et al, 2006;Charrier and Anastasio, 2012). The influence of naphthalene oxidation on redox activity in relation to other redox active species such as 9,10-phenanthrenequinone, transition metals, black carbon, and humic-like substances -particularly in warmer climates when partitioning favours the gas phase for small naphthoquinones -may ultimately depend on the volatility of the unknown redox-active species generated through its photooxidation.…”