Quantitative analysis of indoor CO2 and PM levels during violin performance in a music practice room

Indoor air quality significantly impacts public health as high CO₂ levels impair cognition, and elevated particulate matter (PM) increases respiratory diseases. Music practice rooms, often enclosed spaces where musicians spend extended time, are seldom assessed for air quality. This study investigates CO₂ and PM levels during violin practice in a music practice room using home-built low-cost air quality box (AQB) systems. Without ventilation, CO₂ levels increase nearly linearly, frequently exceeding the 1000 ppm threshold. Simulations of CO₂ profiles retrieve the exhaled minute volume of (9 ± 0.7) × 10^-3 m³ min^-1 person^-1 for the violinist. The PM levels vary across five experiments, influenced by factors such as music tempo, rosin, and bow. In the simulation of PM profiles, the deposition rate constants are evaluated as 2.3×10^-2, 2.6×10^-2, and 9.8×10^-2 min^-1 for PM₁, PM_1-2.5, and PM_2.5-10, respectively, higher than the gravitational deposition rate constants likely due to advection and turbulence. Smaller particles show higher deposition ratios due to their lower inertia. A model accounting for a decreasing PM generation rate over time, linked to rosin consumption during playing, offers improved prediction accuracy. This variation in rosin is further corroborated by scanning electron microscopy images. Infrared spectroscopy further identified functional groups of rosin and bow hair as factors affecting PM levels across experiments. Additional tests in a room with external circulation systems suggest strategies to maintain low CO₂ and PM levels. These findings highlight the importance of adequate ventilation and proper material maintenance to mitigate CO₂ and PM levels, thereby improving indoor air quality in music practice rooms to provide healthier environments for musicians, enhancing their well-being and performance.