Understanding the evolution of organic aerosols (OA) from daily human activities is crucial for mitigating indoor air pollution. Here we characterized the changes in sources and composition of OA from five controlled experiments using high-resolution aerosol mass spectrometer combined with positive matrix factorization. Our results demonstrate that indoor OA composition is highly dynamic, influenced by factors such as indoor sources, surface interactions, ventilation, and air purification. The burning of ghee lamps and incense emits a significant quantity of OA that decays rapidly within the room. However, the aged OA, formed through gas-particle partitioning and chemical oxidations emerges as a significant contributor to indoor OA. Although the mass spectra are similar, the temporal variations of cigarette smoke OA (CSOA) exhibit significant variability among different cigarettes and environmental conditions. Particularly, the aged CSOA can persist for an extended period in the room, and the gaseous compounds adsorbed on indoor surfaces can greatly influence secondary OA formation during cleaning processes. The impact of indoor cleaning activities on OA composition was also explored, highlighting the role of surface interactions and chemical reactions in shaping indoor air quality. The disinfection with chlorine tablets and cleaning with oxalic acid produces a large amount of chloride, ammonium, and two nitrogen-containing OA factors associated with third-hand smoke, characterized by prominent C2H4N+, C5H10N+, C3H8N+ ions. Overall, our results highlight the rapid and dynamic changes in concentrations and compositions of OA arising from common indoor human activities, providing critical insights for evaluating the impact of indoor OA on human health. Display omitted •The rapid and dynamic impact of human activities on indoor POA and SOA was explored.•Ghee lamps and incense OA decays quickly but contributes to aged OA via oxidation.•Cigarette smoke produces OA with variable decay rates based on conditions and types.•Chlorine disinfection and oxalic acid cleaning increase third-hand smoke exposure.