Design selection and evaluation method of PM2.5 filters for fresh air systems

Abstract Because of the frequent occurrence of outdoor haze in China, fresh air systems are being used in an increasing number of buildings for indoor and outdoor air circulation. However, there is no uniform method of selecting and evaluating filters for fresh air systems to control indoor PM2.5. In this study, a fresh air system filter selection method was established for this purpose. Based on the ‘guarantee rate’' concept, which guarantees that the vast majority of days are within recommended air pollution limits, a scientific method of calculating the outdoor PM2.5 concentration is proposed, which can be used to determine the comprehensive filter efficiency required for PM2.5 pollution management in different regions scientifically. A PM2.5 filtration performance test was performed for different filter grades, and the comprehensive filtration efficiencies and service lives of different filter combinations were analysed. Finally, the applicable filter combinations for PM2.5 pollution management in different regions of China were determined. The system performances, technology, service lives, and costs were comprehensively evaluated, and the optimal combination was identified. The fresh air system filter design, selection, and evaluation method proposed in this article provides a scientific basis for filter selection.