COMPARATIVE STUDY OF INDOOR AIR QUALITY BETWEEN PEAK AND NON-PEAK OCCUPANCY PERIOD IN A LIBRARY BUILDING

Abstract

Indoor air quality has increasingly become a growing issue due to its relation with the occupants’ health, comfort and productivity, evidenced by the recent emergence of SS554:2009 Code of Practice for Indoor Air Quality for Air-Conditioned Buildings. This research study aimed to study the indoor air quality of a library, with emphasis on the comparison between the peak and off-peak occupancy variability. Objective and subjective measurements were carried out in the Central Library of the National University of Singapore during the peak and non-peak period, which is namely the examination and non-examination period respectively. Results from the objective measurement indicated that there was an apparent elevation in carbon dioxide during the peak occupancy period which failed to meet the recommended threshold requirement. Another interesting phenomenon is that levels of TVOC and dust particulates were all measured to be consistently higher during the peak occupancy period. These factors suggest that occupants’ activities play a dominant role in contributing to this rise in level of indoor air contaminants. Subjective measurements through the usage of questionnaires reflected that the top three sick building syndromes experienced are dry eyes, dry or irritated throat and dry skin, relating to both peak and non-peak occupancy period. Generally, the overall satisfactory level for the indoor air quality and thermal environment was considered satisfactory despite the varying occupancy level. In conclusion, the role of ventilation contributes to an essential role in maintaining a healthy indoor environment. Ventilation rate is best conformed to the required minimum outdoor air supply in the various standards. Strategies to improve the thermal comfort and indoor air quality have also been made.