Healthier Indoor Environments for Vulnerable Occupants: Analysis of Light, Air Quality, and Airborne Disease Risk

This study evaluates indoor environmental quality (IEQ) in childcare facilities, focusing on air quality and lighting—key factors affecting children’s health and development. The analysis examines a nursery in Seville, Spain, where continuous monitoring revealed challenges in maintaining suitable indoor conditions. Carbon dioxide (CO₂) levels often surpassed Spanish standards (770 ppm) and stricter thresholds (550 ppm) for sensitive groups, peaking at nearly 1900 ppm. These concentrations are linked to possible cognitive impairments and increased airborne pathogen risks, with Attack Rates (ARs) exceeding 70%. Passive ventilation strategies, such as window openings, proved insufficient, emphasizing the need for Controlled Mechanical Ventilation (CMV) systems to ensure consistent air renewal while maintaining thermal comfort. Lighting assessments identified insufficient circadian stimulus during key periods. Excessive lighting during nap times disrupted rest, while morning daylight levels failed to provide adequate circadian stimulation. These findings stress the importance of integrating solar protection and dynamic daylight and electric lighting systems to align with children’s biological rhythms. This research highlights the urgent need for comprehensive IEQ strategies in childcare settings, combining advanced ventilation, hygrothermal management, and circadian-friendly lighting to create safer and healthier environments for young children.