A Comparison of Indoor Pollution using Different Ventilation Methods

A Case Study

Abstract

One of the essential aspects of healthy buildings is the air quality that people breathe indoors, as it directly impacts their comfort, health, and well-being. Achieving an acceptable indoor air quality (IAQ) has become an essential design objective for newly constructed and renovated buildings as well as for the operational system in existing buildings. The COVID-19 pandemic, which began in 2019, highlighted the need for better IAQ. The quality of indoor air space is not only affected by ambient or external pollution but also by indoor sources and inadequate ventilation. For instance, the build-up of pollutants may differ for the same space due to the ventilation method. This paper uses a case study of an open-plan office in Loughborough, UK, simulated under two ventilation schemes, mechanical ventilation (MV) and natural ventilation (NV), for the same weather file to diagnose and examine the difference in the IAQ. The results of the simulations were compared with monitored data using an IAQ sensor located in the centre of the open-plan office. The air parameters measured were indoor temperature (Ta), relative humidity (RH), carbon dioxide (CO2), formaldehyde (CH2O) and particulate matter (PM2.5). It was found that the average CO2 levels were better by 10% under MV than in NV because higher ventilation rates were achieved during occupied hours. The average PM2.5 was twofold better under NV than MV, as well as CH2O was also better under NV than MV by 26% in the simulated scenarios. The open-plan office was ventilated at all times
under NV; unlike in MV, the air handling unit was only operating during the occupied hours, which contributed to better IAQ. The simulation results for this study revealed that both mechanical and natural ventilation could achieve acceptable IAQ for this specific case study and location. The ventilation control strategy is the manipulator of jeopardising the IAQ in the space.