Light-Induced Formation of Volatile Organic Compounds from Bleach Cleaning in Indoor Environments

Abstract Surface bleach cleaning is a common indoor activity that releases abundant strong oxidants, including hypochlorous acid (HOCl) and chlorine gas (Cl2), which can significantly influence indoor chemistry. While bleach-driven chemical transformations are recognized, the specific role of illumination remains poorly understood. This study combines field measurements and laboratory flow tube experiments to investigate volatile organic compound (VOC) formation from reactions between bleach emissions and surface-sorbed species, e.g., kitchen-derived organic films, under illuminated conditions. In real-world indoor settings, we observed that bleach cleaning under light predominantly generates oxygenated VOCs (OVOCs), accounting for ∼92% of total emissions. Saturated carbonyls contributed the most (∼82%), such as C6H12O, C9H18O, and C2H4O. Flow tube experiments using surrogate compounds and kitchen-collected surface films confirmed that OVOCs are generated via heterogeneous reactions between surface-bound organics (e.g., fatty acids, amides, amino acids) and radicals produced from photolysis of bleach-derived oxidants. VOC production was found to depend on surface accumulation and aging, with more accumulated and aged surfaces producing greater quantities and more diverse products. These findings provide important insights into VOC production from indoor surface chemistry initiated by bleach cleaning under typical indoor lighting conditions, advancing our understanding of volatile byproduct formation from indoor bleach photochemistry.