Theoretical Threshold for Estimating the Impact of Ventilation on Materials' Emissions

In new buildings, nonoccupant VOC emissions are initially high but typically decrease within months. Increased ventilation is commonly used to improve indoor air quality, assuming it speeds up VOC off-gassing from materials. However, previous research presents inconsistent results. This review introduces a simplified analytical model to understand the ventilation-emission relationship. By combining factors such as diffusivity, emitting area, and time, the model suggests the existence of a theoretical ventilation threshold beyond which enhanced ventilation has no further influence on emission rates. A threshold of approximately 0.13 L s^-1 m^-2 emitting area has been found for various VOCs documented in the existing literature, with which the conflicting results are explained. It is also shown that the threshold remains notably consistent across different boundary conditions and model resolutions, indicating its suitability for real-world applications.