Residential building ventilation in situations with outdoor PM2.5 pollution

Affordable ventilation of residential buildings in situations with outdoor PM2.5 pollution is a challenge. This investigation used the validated EnergyPlus software program to model ventilation performance in a newly constructed residential apartment in five different climate zones in China. The evaluated ventilation modes were natural ventilation, balanced mechanical ventilation, and hybrid ventilation, together with indoor particle filtration. Both indoor-generated particles due to cooking and ventilation-drawn particles from the outdoor environment were considered. Different heat recovery modes for mechanical ventilation were also compared. The evaluated parameters included indoor CO2 (carbon dioxide), PM2.5 (fine particulate matter), formaldehyde, and TVOC (total volatile organic compound) concentrations, energy consumption, and operating costs. The natural ventilation mode was found to be the cheapest, but it may provide an insufficient ventilation rate for 27%-79% of the occupied time. Mechanical ventilation can ensure good indoor air quality continuously, but the associated utility cost may be more than twice that for natural ventilation. Indoor particulate filtration should be utilized in situations with severe outdoor PM2.5 pollution. Heat recovery is not recommended in residential buildings due to the high initial investment cost at present. The least energy-consuming ventilation mode for residential buildings with maximum potential to use natural ventilation is recommended.