RADICAL-MEDIATED OXIDATION OF VOLATILE ORGANIC COMPOUNDS IN INDOOR ENVIRONMENTS: DYNAMIC UNDERSTANDINGS AND MITIGATION PROPOSITIONS.

Volatile organic compounds (VOCs) are pervasive indoor air pollutants, originating from building materials, consumer products, and occupant activities. Once released, VOCs undergo oxidation reactions mediated by radicals such as hydroxyl (*OH), nitrate (NO3*), and peroxy radicals (RO2*), forming secondary pollutants including formaldehyde, organic aerosols, and ozone. These processes significantly degrade indoor air quality and contribute to adverse health outcomes. This study investigates the mechanistic pathways of radical-mediated oxidation of representative VOCs -- formaldehyde, toluene, and limonene -- within controlled indoor environments. Kinetic modelling, radical probe analysis, and simulation of photolysis-driven reactions were combined to map dynamic reaction networks. Five governing equations describing reaction kinetics, radical steady-state approximations, and secondary aerosol yields are developed. Results highlight that indoor radical concentrations are highly dynamic, strongly influenced by light exposure, surface deposition, and human activities. Mechanistic findings suggest that mitigation strategies must combine source reduction, advanced filtration, and photocatalytic oxidation to effectively control VOC transformations. The study proposes an active model of mitigation which includes chemical, physical, and architectural interventions which can be implemented to maintain the quality of indoor air. [ABSTRACT FROM AUTHOR]