Selective real-time monitoring of respiratory droplets for indoor air safety in educational environments

Respiratory aerosol transmission represents an important pathway for the spread of infectious diseases in indoor educational environments. Real-time monitoring of respiratory droplets was performed using the AeroDrops respiratory droplet detector in multiple educational settings, including kindergarten and a primary school classroom, a university lecture hall, and experimental chemistry workshops. Measurements were conducted under different environmental conditions, including different ventilation regimes, seasonal conditions, and groups of preschool children, school children, and young adults. The detector selectively detected respiratory droplets while remaining insensitive to particulate matter and other non-respiratory aerosol sources. Distinct temporal variations in droplet concentrations were observed which correlated with participant activities, occupancy levels, vocalization, and movement. The results demonstrate that selective real-time monitoring of respiratory droplets provides information unavailable from conventional indoor air quality indicators and offers a promising approach for ventilation management and indoor air safety assessment.