Factor-driven urban sensory equity: parallel auditory and olfactory perceptual models of spatial experience in urban environments for people with visual impairment

Visually impaired people constitute a large proportion of the population, and audition and olfaction serve as vital media through which they perceive urban environments. However, few studies have focused on parallel auditory and olfactory perceptual models of visually impaired individuals to comprehensively describe how they understand the environment, thus providing evidence-based urban spatial design interventions. This study aimed to construct a parallel auditory and olfactory perceptual model of the visually impaired in urban environments to characterise perceptual dimensions of spatial experience and explore the relationships among different perceptual factors. First, indicators of auditory and olfactory environmental perceptions specific to the visually impaired were extracted through interviews. Subsequently, a laboratory experiment was conducted to investigate the evaluations of the visually impaired (participants were adults with visual impairment defined as best-corrected visual acuity below 0.1) under different combinations of auditory and olfactory variables, based on which a perceptual model was constructed. This study identified 17 indicators of auditory environment perception and 10 indicators of olfactory environment perception through interviews. Through factor analysis, these indicators were grouped into five perceptual factors of the auditory environment (auditory affect, auditory spatiotemporality, auditory discriminability, auditory awareness, and auditory curiosity) and three perceptual factors of the olfactory environment (olfactory affect, olfactory awareness, and olfactory spatiality). The distributions of auditory and olfactory environment perceptions under different auditory and olfactory variables were analysed. Furthermore, the correlations between these indicators were examined to assess the feasibility of simplifying the indicator framework. This study provides a practical, evidence-based guideline, which offer tangible utility for the researchers and practitioners in urban environmental design.