A CASE STUDY ON THE IMPACT OF FILTERS ON EXPOSURE TO PM, BACTERIA AND FUNGI FOR CONVENTIONAL ACMV SYSTEMS IN AN OFFICE BUILDING

Abstract

Most people spend a large proportion of their time in the office. The quality of the indoor air in the office is therefore critical, as it affects the well-being of the occupant. According to the hierarchy of hazard control, the removal of the source and the substitution of any process or equipment that is a source of such indoor pollutants are the 2 most effective steps to control the hazard of bad indoor air quality. However, it is impossible for us remove or substitute all the sources of indoor pollutants. Hence, the next best alternative is to implement engineering controls. In the context of our dissertation, the engineering control would be the combination of MERV-rated filters in the AHU. The presence of high enough MERV-rated filters would reduce the amount of pollutants in the indoor air. Hence, the main aim of this dissertation is to study the impact of filters and filter configuration on the concentration of PM, bacteria and fungi. The filter configurations tested during the course of this dissertation included different permutations of MERV 7 primary filters and MERV 11 or MERV 14 secondary filters. Through the experiments, it was found that the combination of a MERV 7 primary filter and a MERV 14 secondary filter has the best overall performance in removing PM, bacteria and fungi. One of the limitations of this study was the inability to conduct this experiment under controlled conditions, which meant that there were differences in the occupancy level on different days of the experiment.