Comprehensive IoT-based Monitoring of Air Quality and Thermal Comfort: An Indoor-Outdoor University Campus Case Study

Indoor environmental quality is a critical factor influencing human health, comfort, and productivity, yet systematic and continuous monitoring in large, multipurpose buildings such as university campuses remains limited. This study addresses this gap through a comprehensive Internet of Things (IoT)-based monitoring system, investigating air quality and thermal comfort across both indoor and outdoor spaces at the State University of New York College of Environmental Science and Forestry. The objective is to evaluate spatial and temporal variations in environmental parameters and assess how different indoor spaces perform under different occupancy and outdoor climatic conditions. The system integrated 28 low-cost and in-house-developed devices, including sensors for Particulate Matter (PM), carbon dioxide (CO2), dry bulb temperature, humidity, Total Volatile Organic Compounds, human audible noise, light, globe temperature and wind speed for outdoor, connected via microcontrollers to enable continuous data logging. Indoor and outdoor locations were selected to capture a diverse range of occupancy use types and exposure conditions. Data analysis revealed that some indoor environments exhibited elevated levels of CO2 and PMs during peak occupancy, whereas outdoor conditions were strongly influenced by diurnal and seasonal temperature and humidity fluctuations as well as city-wide factors such as adjacent highway construction. Indoor thermal comfort, estimated using a Simplified Predicted Mean Vote (sPMV) model, indicated that some classrooms and offices frequently experienced conditions outside the optimal comfort range, particularly during afternoon hours and summer periods. These results highlight the potential of IoT-based environmental monitoring in identifying trends that are often missed through fixed sensors measurements or occupant surveys. The findings highlight opportunities for targeted interventions, including optimized indoor ventilation schedules and outdoor shading or landscaping strategies. The study also demonstrates that IoT-based monitoring system provides a scalable, cost-effective approach for assessing environmental quality, supporting sustainability goals, facilities management, and occupant well-being.