Impact of indoor environmental quality on autistic occupants: A multi-domain analysis

The well-being of autistic occupants should be carefully considered in the design of indoor environments. Autism spectrum condition (ASC) is often associated with different perceptions of environmental stimuli and synesthesia (cross-over of senses), with implications for multi-domain perceptions. This study investigated the differences in indoor environmental quality (IEQ) perception between autistic and non-autistic individuals, focusing on multi-domain aspects. The research involved 17 autistic and 20 control participants exposed to six different thermal and visual conditions in an office-like living lab. Environmental measurements were coupled with subjective questionnaires in the four comfort domains (thermal, visual, indoor air quality, and acoustic). The findings revealed that autistic individuals experienced greater discomfort under non-optimal IEQ conditions, particularly in the acoustic domain (large or very large effect sizes, with average satisfaction scores around 2.50 compared to 4.00 in the Control Group). A natural view out mitigated thermal and Indoor Air Quality (IAQ) discomfort for the autistic participants, aligning their perception more with the Control Group, and reducing the difference in satisfaction and acceptability scores between groups by up to 1 scale units. However, acoustic discomfort remained regardless of the view. Thermal-visual, thermal-IAQ, and visual-IAQ correlations were stronger for the autistic group, while visual-acoustic and IAQ-acoustic correlations were stronger for the controls. The results suggest that autistic occupants have more stringent and individually variable IEQ requirements, emphasizing the importance of tailored solutions for indoor design. These findings can contribute to the development of guidelines and standards aimed at enhancing indoor well-being for autistic individuals.