Odorous VOC profiles and odor perception of typical indoor sources

Volatile organic compounds (VOCs) emitted from indoor sources are primary contributors to odor nuisance and can affect indoor perceived air quality (PAQ) and occupant comfort. However, odor perception depends on multicomponent mixtures, and the relationship between indoor VOC concentrations and human olfactory perception remains unclear. In this study, we measured VOC emissions from nine typical odor sources, including occupants, pets, furniture, and building materials and assessed odor intensity (OI) by a trained sensory panel. A total of 31 odor-active VOCs were identified, with aldehydes and acids being the dominant odor contributors, accounting for 36%–100% and 1%–45% of the sum of odor activity value (OAV_sum), respectively. Across the nine source categories, odor-active VOC profiles differed markedly in composition and relative contribution patterns. Further, multivariable models linking odor profiles with perceived OI were developed, using Elastic Net Regression with variable selection (R² = 0.64), and partial least squares regression (PLSR) based on full VOC profiles, which showed improved performance (R² = 0.84). 2-butanone oxime, 2-butanone, 2,3-butanedione, m-xylene, acetaldehyde, and 6-methyl-5-hepten-2-one (6-MHO) were further identified to be closely related with OI perception. These findings support a shift from total-concentration metrics to profile-based odor assessment for indoor PAQ monitoring and evaluation.