Photodegradation of atmospheric chromophores: changes in oxidation state and photochemical reactivity

Abstract. Atmospheric chromophoric organic matter (COM) plays a fundamental role in photochemistry and aerosol aging. However, the effects of photodegradation on chemical components photochemical reactivity COM remain unresolved. Here, we report potential carbon contents, optical properties, fluorophore aerosol. After 7 d photodegradation, fluorescent intensity absorption coefficient decrease by 71.4 % 32.0 %, respectively. Photodegradation makes difference to component chromophore degree Low-oxidation humic-like substance (HULIS) is converted into high-oxidation HULIS due photooxidation. also changes reactivity. The generation triplet-state (3COM*) decreases slightly ambient particulate (ambient PM) but increases primary (POA) following photodegradation. results highlight that opposite effect POA PM. singlet-oxygen (1O2) obviously PM, which could be attributed precursors 1O2. combination property, reactive oxygen species has an important impact air quality. new insights reinforce importance studying dissolved (DOM) related with