Please use this identifier to cite or link to this item: http://hdl.handle.net/10397/85059
Title: An indoor air quality monitoring and assessment protocol for air-conditioned offices in subtropical climates
Authors: Hui, Pui-shan
Degree: Ph.D.
Issue Date: 2009
Abstract: Maintaining good Indoor Air Quality (IAQ) aimed at meeting human requirements on health and comfort of a space. Wellbeing concerns related to the IAQ are complex and IAQ is targeted as a minimum provision of statutory control in practice. Indeed, no agreed monitoring and assessment protocol is available for practical environmental control measures in air-conditioned offices in subtropical climates. Investigations through continuous air sampling could provide thorough understanding, and ultimately could help setting up practical IAQ strategies for the environment. It is, however, too expensive to continuously monitor all air pollutants of the general community. Resources justified sampling tactics for a practical IAQ monitoring and assessment protocol including the assessment parameters, sampling locations and time period with quantified uncertainties for correct results interpretation must be worked out. The objectives of this study are to develop a practical IAQ monitoring and assessment protocol for promoting better IAQ of air-conditioned offices in subtropical climates. The protocol presents IAQ assessment results with a simple IAQ benchmark, using the selected representative pollutant levels obtained from a number of alternative sampling schemes at acceptable assessment uncertainties regarding sampling locations and times. The development and feasibility of the protocol are demonstrated using a comprehensive cross-sectional survey on common indoor air parameters from a long-term measurement in air-conditioned offices of Hong Kong. Regarding the choice of assessment parameters, it was shown that selecting representative parameters by identifying a small number of dominant contributors of unsatisfactory IAQ would provide acceptable accuracy with reduced measurement effort. Concurrently, reasonable predictions could be made by another proposed model with assessed carbon dioxide (CO2), respirable suspended particulates (RSP), and total volatile organic compounds (TVOC) levels. These three parameters were judged to be indicative for the performance of IAQ control through dilution, removal, or source control respectively. Furthermore, the uncertainties of various sampling schemes were analysed using the year-round longitudinal measurement results. For a selected representative parameter, the required measurement period by a proposed scheme of two random sample average from two time-equal sessions with an opposite reverse time sequence within the occupied period would have potential reductions up to 30%. And reducing the number of sampling points by 50% would decrease the probability of obtaining the sample-spatial average concentration at the same confidence level by 10% only. In view of the technical difficulties in applications of the schemes, feasibility of accuracy improvement with the epistemic approach was analysed. The use of past information and assessment accuracies to improve present understanding for judging IAQ acceptance from a test sample and regional monitoring were demonstrated. Finally, a simple IAQ index compiled by the representative indicators were used as a benchmarking parameter for air-conditioned offices of Hong Kong to distinguish the relative performance of IAQ, presented in a widely adopted star rating system. The benchmark system was demonstrated to be an effective indication of IAQ in air-conditioned offices. Taking the assessment uncertainties into account, this study provided a useful tool for setting up an efficient IAQ monitoring and assessment programme, and ultimately can help promote better IAQ.
Subjects: Hong Kong Polytechnic University -- Dissertations.
Indoor air quality.
Indoor air quality -- Monitoring.
Pages: xix, 211 leaves : ill., 1 map ; 30 cm.
Appears in Collections:Thesis

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