Zhiwen, LuoAl Qutub, Rahaf2025-06-262025https://hdl.handle.net/20.500.14154/75683The quality of indoor environments significantly influences the well-being and performance of the occupants, particularly in schools where specific environmental factors are crucial for effective learning experiences. This is particularly relevant for autistic pupils, whose sensory sensitivities and behavioural responses to environmental stimuli differ significantly from those of non-autistic individuals. Autism, a complex developmental condition characterised by social and communication differences, repetitive behaviours, sensory reactivity differences, and a need for consistency and routines, necessitates careful consideration of the indoor environment. The prevalence of autism has risen both globally and in Saudi Arabia; this rise is attributed to better awareness and earlier diagnosis, though challenges remain regarding diagnosis, intervention, and support systems such as schools. This research investigates the relationship between Indoor Environment Quality (IEQ) and autistic pupils in autism schools in Saudi Arabia, which currently is non-existent. This study firstly proposes a comprehensive framework for understanding the interaction between IEQ parameters—such as lighting, acoustics, and thermal comfort—and autistic sensory reactivity and behaviours. A systematic review of eleven relevant studies highlights a growing body of studies between specific IEQ factors, particularly lighting and acoustics, and various autistic behaviours. However, the impact of parameters like thermal comfort and air quality remains under-researched, and there is a notable lack of quantitative studies that could inform architectural practices for designing classrooms tailored to the needs of autistic pupils. The IEQ conditions in two autism schools in the Eastern region of Saudi Arabia were evaluated, measuring factors such as air temperature, relative humidity, particulate matter (PM2.5 and PM10) concentrations, CO2 levels, sound, and lighting in classrooms during both winter and summer. The findings reveal significant IEQ challenges, including PM2.5 and PM10 concentrations exceeding WHO guidelines, with PM2.5 averaging 51 µg/m³ in School A and 30 µg/m³ in School B. PM10 levels were even higher, peaking at 116 µg/m³ in School A and 101 µg/m³ in School B. The main sources contributing to high concentration are classroom activity and cleaning practices. These findings underscore the need for the development of autism-friendly IEQ standards to guide future educational spaces, ultimately aiming to improve learning outcomes and well-being for autistic pupils in Saudi Arabia. Furthermore, the study linked the measured IEQ conditions with behavioural outcomes in 37 autistic pupils (aged 5–12 years) attending autism schools. A multidisciplinary approach was used to assess the effects of IEQ parameters on externalising behaviours, alongside sensory reactivity. Significant correlations emerged between PM10 concentration and both adaptive behaviours (p = 0.04) and maladaptive behaviours (p = 0.05), sound levels and maladaptive behaviours (p = 0.05), and relative humidity and adaptive behaviours (p = 0.03). A regression model was developed to quantify the relationship between PM10 concentrations and externalising behaviours, serving as a predictive tool for understanding how indoor air quality (IAQ) influences behavioural outcomes. These findings emphasise the importance of tailoring environmental conditions in autism schools to accommodate the sensory sensitivities of autistic pupils, contributing to better learning experiences. The findings of the study highlight the negative impact of poor IAQ on autistic behaviour outcomes, suggesting that improving IAQ could significantly enhance behavioural outcomes in autism classroom in Saudi Arabia. Using a simulation modelling approach, the study evaluated the effectiveness of air purifiers in reducing PM10 levels and their impact on both adaptive and maladaptive behaviours. The intervention demonstrated that air purifiers reduced the indoor PM10 level by 45.6%, 53.5%, and 65%, which, in turn, led to significant improvements in adaptive behaviours (10%, 14%, and 19%) and reductions in maladaptive behaviours (13%, 16%, and 19%). These results indicate that air purifiers can be a valuable intervention for improving classroom environments, thereby enhancing behavioural outcomes for autistic pupils. In conclusion, this research highlights the need for a holistic approach to IEQ in autism schools, offering evidence-based recommendations to improve environmental conditions for autistic pupils. Further investigation is needed to explore the long-term effects of the impact of IEQ parameters and interventions on different outcomes for autistic pupils, such as health.191enAutismindoor environmentschoolsbehavioursThesis