Rethinking clean air – How the composition of indoor air may differ and change based on four ventilation strategies

In recent years, heightened public awareness of indoor air quality (IAQ) and building energy consumption has spurred a growing demand for novel ventilation strategies to deliver clean air to indoor environments cost-effectively. However, uncertainties persist regarding the adequacy of fresh air provided by different ventilation methods and whether the air quality achieved by these methods is comparable. We conducted a twin-chamber study to investigate the impact of four common ventilation modes on IAQ: 1) mechanical ventilation using a filtering section incorporated with physical-chemical technologies (MV-1); 2) mechanical ventilation via a residential ventilator equipped with HEPA; 3) portable air cleaners (PACs) incorporated with HEPA (PV-1); and 4) PACs employing negative ions technology incorporated with HEPA (PV-2). Natural ventilation serves as the baseline for comparison. The study focused on particles, ozone, and volatile organic compounds (VOCs) as key criteria. Preliminary findings suggest that all ventilation modes effectively reduced particle concentrations, irrespective of size, with slightly weaker efficacy observed in PVs. Introducing clean air not only lowered ozone concentrations but also mitigated concentration fluctuations. Further analysis is ongoing to assess the overall performance and equivalence of different ventilation strategies. There were no differences observed in VOCs.