A Dispersion model for ozone inside the rectangular duct of an indoor air quality pilot plant was simulated. Using this the concentration profiles of ozone at several points downstream of ozone insertion were simulated and they matched well with experimental results. Recommendations for future work are cited. A thermodynamic study was conducted to check the levels of concentration in which certain toxic compounds could be present due to the oxidation of pre-determined chlorinated compounds. STANJAN, a package which solves for equilibrium concentrations using the element potential method, was used. Recommendations for future work are cited. A Reaction model was developed for the global oxidation reactions occurring in the catalyst bed which is situated downstream of the ozone insertion. Once this was done, the effect of moisture and temperature were studied qualitatively and recommendations for further work are Cited. / Master of Science

Experiments were conducted to determine the photocatalytic degradation of three types of gas-phase compounds, NOX, VOCs, and chloramines, by TiO2 impregnated tiles. The oxides of nitrogen NO and NO2 (NOx) have a variety of negative impacts on human and environmental health ranging from serving as key precursors for the respiratory irritant ozone, to forming nitric acid, which is a primary component of acid rain. A flow tube reactor was designed for the experiments that allowed the UV illumination of the tiles under exposure to both NO and NO2 concentrations in simulated ambient air. The reactor was also used to assess NOx degradation for sampled ambient air. The PV values for NO and NO2 were 0.016 cm s-1 and 0.0015 cm s-1, respectively. For ambient experiments a decrease in ambient NOx of ~ 40% was observed over a period of roughly 5 days. The mean PV for NOx for ambient air was 0.016 cm s-1 and the maximum PV was .038 cm s-1. Overall, the results indicate that laboratory conditions generally simulate the efficiency of removing NOx by TiO2 impregnated tiles. Volatile organic compounds (VOC's) are formed in a variety of indoor environments, and can lead to respiratory problems (US EPA, 2010). The experiments determined the photocatalytic degradation of formaldehyde and methanol, two common VOCs, by TiO2 impregnated tiles. The same flow tube reactor used for the previous NOX experiments was used to test a standardized gas-phase concentration of formaldehyde and methanol. The extended UV illumination of the tiles resulted in a 50 % reduction in formaldehyde, and a 68% reduction in methanol. The deposition velocities (or the photocatalytic velocities, PV) were estimated for both VOC's. The PV for formaldehyde was 0.021 cm s-1, and the PV for methanol was 0.026 cm s-1. These PV values are slightly higher than the mean value determined for NO from the previous experiments which was 0.016 cm s-1. The results suggest that the TiO2 tiles could effectively reduce specific VOC levels in indoor environments. Chlorination is a widespread form of water disinfection. However, chlorine can produce unwanted disinfection byproducts when chlorine reacts with nitrogen containing compounds or other organics. The reaction of chlorine with ammonia produces one of three chloramines, (mono-, di-, and tri-chloramine). The production of chloramines compounds in indoor areas increases the likelihood of asthma in pool professionals, competitive swimmers, and children that frequently bath in indoor chlorinated swimming pools (Jacobs, 2007; Nemery, 2002; Zwiener, 2007). A modified flow tube reactor in conjunction with a standardized solution of monochloramine, NH2Cl, determined the photocatalytic reactions over the TiO2 tiles and seven concrete samples. The concrete samples included five different concrete types, and contained either 5 % or 15 % TiO2 by weight. The PV for the tiles was 0.045 cm s-1 for the tiles manufactured by TOTO Inc. The highest PV from the concrete samples was 0.054 cm s-1. Overall the commercial tiles were most efficient at reducing NH2Cl, compared to NOX and VOC compounds. However, the concrete samples had an even higher PV for NH2Cl than the tiles. The reason for this is unknown; however, distinct surface characteristics and a higher concentration of TiO2 in the concrete may have contributed to these findings.

Chan Pui-Ling. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 169-182). / Text in English; abstracts in English and Chinese. / Chan Pui-Ling. / Acknowledgements --- p.i / Abstracts --- p.ii / Table of Contents --- p.v / List of Plates --- p.ix / List of Figures --- p.xii / List of Tables --- p.xiv / Abbreviations --- p.xviii / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Indoor Air Quality (IAQ): An overview --- p.1 / Chapter 1.1.1 --- Importance of indoor air quality --- p.2 / Chapter 1.1.2 --- Common indoor air pollutants --- p.2 / Chapter 1.1.3 --- Airborne bacteria --- p.4 / Chapter 1.1.3.1 --- Possible sources of airborne bacteria --- p.4 / Chapter 1.1.3.2 --- Health effects of the airborne bacteria --- p.5 / Chapter a. --- Sick building syndromes --- p.5 / Chapter b. --- Building-related illness --- p.7 / Chapter 1.1.4 --- Importance of studying airborne bacteria --- p.12 / Chapter 1.2 --- Situation in Hong Kong --- p.13 / Chapter 1.2.1 --- Outdoor air quality --- p.14 / Chapter 1.2.2 --- Indoor air quality --- p.14 / Chapter 1.2.2.1 --- Hong Kong studies --- p.16 / Chapter 1.2.3 --- Air quality objectives in Hong Kong --- p.18 / Chapter 1.3 --- Different sampling methods --- p.18 / Chapter 1.4 --- Identification of bacteria --- p.24 / Chapter 1.5 --- Site selection --- p.26 / Chapter 2 --- Objectives --- p.28 / Chapter 3 --- Materials and methods --- p.29 / Chapter 3.1 --- Samples collection --- p.29 / Chapter 3.1.1 --- Sampling site --- p.29 / Chapter 3.1.2 --- Complete Biosampler System --- p.29 / Chapter 3.1.3 --- Sampling preparation --- p.33 / Chapter 3.1.4 --- Sampling procedures --- p.33 / Chapter 3.2 --- Recovery of the airborne bacteria --- p.36 / Chapter 3.2.1 --- Cultural medium --- p.36 / Chapter 3.2.2 --- Recovery procedures --- p.36 / Chapter 3.2.3 --- Frozen stocks --- p.37 / Chapter 3.3 --- Indentification of bacterial strains --- p.37 / Chapter 3.3.1 --- Gram stain --- p.37 / Chapter 3.3.1.1 --- Chemical reagents --- p.37 / Chapter 3.3.1.2 --- Gram stain procedures --- p.38 / Chapter 3.3.2 --- Oxidase test --- p.38 / Chapter 3.3.2.1 --- Chemical reagents --- p.38 / Chapter 3.3.2.2 --- Oxidase test procedures --- p.41 / Chapter 3.3.3 --- Midi Sherlock® Microbial Identification System (MIDI) --- p.41 / Chapter 3.3.3.1 --- Culture medium --- p.41 / Chapter 3.3.3.2 --- Chemical reagents --- p.41 / Chapter 3.3.3.3 --- MIDI procedures --- p.41 / Chapter 3.3.4 --- Biolog MicroLogTM system (Biolog) --- p.41 / Chapter 3.3.4.1 --- Culture medium --- p.41 / Chapter 3.3.4.2 --- Chemical reagents --- p.44 / Chapter 3.3.4.3 --- Biolog procedures --- p.44 / Chapter 3.3.5 --- DuPont Qualicon RiboPrinter® Microbial Characterization System (RiboPrinter) --- p.46 / Chapter 3.3.5.1 --- Culture medium --- p.46 / Chapter 3.3.5.2 --- Chemical reagents --- p.46 / Chapter 3.3.5.3 --- RiboPrinter procedures --- p.46 / Chapter 4 --- Results --- p.50 / Chapter 4.1 --- Sample naming system --- p.50 / Chapter 4.2 --- Interpretation of results --- p.50 / Chapter 4.2.1 --- Midi Sherlock® Microbial Identification System (MIDI) --- p.51 / Chapter 4.2.2 --- Biolog MicroLog´ёØ System (Biolog) --- p.51 / Chapter 4.2.3 --- DuPont Qualicon RiboPrinter® Microbial Characterization System (RiboPrinter) --- p.52 / Chapter 4.3 --- Sample results --- p.53 / Chapter 4.3.1 --- Sample 1 (Spring) --- p.53 / Chapter 4.3.2 --- Sample 2 (Summer-holiday) --- p.62 / Chapter 4.3.3 --- Sample 3 (Summer-school time) --- p.71 / Chapter 4.3.4 --- Sample 4 (Autumn) --- p.81 / Chapter 4.3.5 --- Sample 5 (Winter) --- p.90 / Chapter 4.4 --- Bacterial profile of the student canteen --- p.100 / Chapter 4.5 --- The cell and colony morphology of the dominant bacteria --- p.100 / Chapter 4.6 --- Comparison between samples --- p.121 / Chapter 4.6.1 --- Spatial variation --- p.121 / Chapter 4.6.1.1 --- Spatial effect on bacterial abundance --- p.121 / Chapter 4.6.1.2 --- Spatial effect on species diversity --- p.121 / Chapter 4.6.2 --- Daily variation --- p.126 / Chapter 4.6.2.1 --- Daily effect on bacterial abundance --- p.126 / Chapter 4.6.2.2 --- Daily effect on species diversity --- p.126 / Chapter 4.6.3 --- Seasonal variation --- p.126 / Chapter 4.6.3.1 --- Seasonal effect on bacterial abundance --- p.126 / Chapter 4.6.3.2 --- Seasonal effect on species diversity --- p.130 / Chapter 4.7 --- Temperature effect on individual airborne bacterial population --- p.130 / Chapter 4.7.1 --- Gram positive bacteria --- p.130 / Chapter 4.7.2 --- Gram negative bacteria --- p.130 / Chapter 4.8 --- Effect of relative humidity on individual airborne bacterial population --- p.137 / Chapter 4.8.1 --- Gram positive bacteria --- p.137 / Chapter 4.8.2 --- Gram negative bacteria --- p.137 / Chapter 5 --- Discussion --- p.143 / Chapter 5.1 --- Bacterial profile --- p.143 / Chapter 5.1.1 --- Bacterial diversity --- p.143 / Chapter 5.1.2 --- Information of the identified bacteria from the student canteen --- p.144 / Chapter 5.1.3 --- Pathogenicity --- p.153 / Chapter 5.1.4 --- Summary on the bacterial profile --- p.153 / Chapter 5.2 --- Comparison between samples --- p.160 / Chapter 5.2.1 --- Spatial variation (Sampling point 1 against Sampling point 2) --- p.160 / Chapter 5.2.2 --- Daily variation (Morning against Afternoon) --- p.161 / Chapter 5.2.3 --- Seasonal variation --- p.162 / Chapter 5.2.4 --- Summer holiday against Summer school time --- p.163 / Chapter 5.2.5 --- Summary on the factors affecting the bacterial content --- p.164 / Chapter 5.3 --- Summary on indoor air quality of the student canteen in terms of bacterial level. --- p.166 / Chapter 6 --- Conclusions --- p.168 / Chapter 7 --- References --- p.169 / Appendix 1 --- p.183 / Appendix 2 --- p.187

published_or_final_version / Radioisotope / Doctoral / Doctor of Philosophy

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management