Mapping Domain-Specific IEQ Exposure-Outcome Pathways: A Systematic Review and Standardized Research Framework of Objective Human Health Responses

Indoor Environmental Quality (IEQ), including indoor air quality (IAQ), thermal comfort, visual quality, and acoustic quality, is increasingly recognized as a critical determinant of human physiological and psychological health and well-being. The expanding body of research in this field now enables mapping of the relationship between IEQ parameters and objective human health responses. Nevertheless, progress was impeded by the absence of standardized frameworks. Inconsistent selection of environmental parameters, divergent methods for assessing objective outcomes, and fragmented approaches to analyzing interactions and combined effects have significantly limited cross-study comparability and the application of research findings to evidence-based environmental design. To address these limitations, this study systematically reviewed 229 peer-reviewed studies that jointly measured IEQ parameters and assessed occupants’ physiological and psychological responses using objective indices, and identified distinct domain-specific research patterns. Thermal studies primarily investigated temperature, thermoregulatory and cardiovascular responses, while IAQ studies concentrated on particulate matter, respiratory outcomes, and associated physiological indicators. Visual and acoustic studies remained comparatively less represented. In addition, only 35 studies investigated combined or interactive effects across IEQ domains, with most focusing on pairwise exposures. Based on these findings, a research framework was proposed to support more consistent objective assessment and future investigation of multi-domain IEQ interactions.