Investigation of impacts of air-conditioning and mechanical ventilation (acmv) system on indoor bio-aerosol level

Singapore is a country with an all year tropic climate. The effects of global warming has led to the increased usage of air-conditioning throughout the years with no clear understanding about the importance of clean air. Studies have shown the devastating effects due to poor quality of air on the human body. Thus, this study serves to compare the effects between natural ventilation and mechanical ventilation, to identify whether the Air Conditioning and Mechanical Ventilation (ACMV) unit could be a source of bio-aerosol deposition indoors. Samples of indoor airborne bio-aerosols such as bacteria and fungi particles were taken in different indoor conditions, followed by incubation and colony counting to compare the differences. In order to compare the difference between natural and mechanical ventilation, the ACMV unit in the room was installed with the High Efficiency Particulate Arrestance (HEPA) filter near the entrance of the duct in order to isolate the emissions of bio-aerosols from the fresh air ventilation duct. The experiment is repeated without the use of the ACMV unit as well as repeating the experiment at different altitudes. This study focuses on the importance of the different factors that may affect the amount of airborne particles. Factors such as temperature, humidity, rainfall, carbon dioxide concentration as well as human activity prove to be significant in affecting the amount of airborne particles. This study has provided new insights about the emission of airborne bacterial and fungal particles from the ACMV unit, which the amount of airborne particles needs to be controlled and monitored for air- conditioned buildings, especially in the case for the all year tropical Singapore.Bachelor of Engineering (Mechanical Engineering