Dark Chemistry during Bleach Cleaning Enhances Oxidation of Organics and Secondary Organic Aerosol Production Indoors

Bleach can oxidize volatile organic compounds (VOCs) and contribute to secondary organic aerosol (SOA) indoors. During the House Observations of Microbial and Environmental Chemistry (HOMEChem) campaign, we observed indoor terpene mixing ratios decrease during bleach cleaning periods, with simultaneous increases in oxidized VOC (OVOC) products. Cooking just prior to bleach cleaning significantly increased SOA due to uptake of bleach-related OVOCs onto cooking aerosols. While SOA formation occurred, it was small (<3%) relative to total organic aerosol mass concentrations. Bleach cleaning chemistry also produced several potentially toxic chlorinated and nitrogenated VOCs indoors, including isocyanates, cyanogen chloride, and chlorocarbons. Observed volatile chlorinated organic acids were likely impurities from the bleach. The bleach-induced terpene oxidation, SOA formation, and chlorinated/nitrogenated VOC production were independent of indoor illumination, consistent with dark chemical production. These observations add to previous studies that demonstrate bleach as a source of potentially harmful primary and secondary pollutants to indoor air.