Traditional equilibrium-based models often fail to accurately predict the fate and exposure risks of semi-volatile organic compounds (SVOCs) in indoor environments due to dynamic conditions and continuous emissions. Our research establishes a novel steady-state theory that better describes the multi-media partitioning behavior of SVOCs under real-world indoor scenarios. By integrating field measurements across various microenvironments with mechanistic modeling, we demonstrate that SVOCs frequently exist in a non-equilibrium, steady-state condition governed by emission rates, ventilation, and surface interactions. This theory enables more accurate prediction of SVOC concentrations in air, dust, and settled particles. Furthermore, we apply this framework to assess human exposure pathways and health risks. The steady-state approach provides a scientific basis for improved indoor air quality management and exposure mitigation strategies, particularly for vulnerable populations.

SVOCs, steady-state theory, multi-media partitioning, health risks