Assessing Indoor and Outdoor Particulate Matter Dynamics in Daycare Center: A Case Study in Dubai, United Arab Emirates

Abstract

This study examines the dynamics of indoor and outdoor particulate matter concentrations in childcare facilities in Dubai, UAE, with a focus on particle size-specific behavior under varying occupancy conditions. Measurements were conducted in a daycare room for three-year-olds over five consecutive days, capturing realworld activity scenarios. The study employed an Optical Particle Counter to measure particulate matter concentrations for six particle sizes (0.3 µm, 0.5 µm, 1 µm, 3 µm, 5 µm, and 10 µm), along with indoor carbon dioxide (CO₂) levels as an indicator of source intensity. The findings reveal a strong correlation between indoor and outdoor concentrations for smaller particles (0.3 µm, 0.5 µm, and 1 µm), regardless of occupancy, indicating the dominance of outdoor sources. Conversely, larger particles (3 µm, 5 µm, and 10 µm) displayed significant variability in Indoor/Outdoor (I/O) ratios, with indoor activities such as movement and bedding preparation contributing to elevated concentrations during occupancy. For particles measuring 10 µm, no correlation with outdoor sources was observed under either condition, emphasizing the predominance of indoor factors. Additionally, the positive correlation between CO₂ levels and concentrations of larger particles (3 µm, 5 µm, and 10 µm) confirms that occupant activities significantly contribute to their generation and resuspension. These results underscore the importance of targeted strategies for air quality management, including the implementation of enhanced filtration systems for smaller particles and design interventions to minimize resuspension for larger particles. This research provides actionable insights for creating healthier childcare environments, addressing the unique challenges posed by Dubai’s environmental conditions.