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

No description available.

Certain processes in indoor air, such as deposition, partitioning, and heterogeneous reactions, involve interactions with surfaces. To accurately describe the surface-area-to-volume ratio in a room, we have characterized the surface area, volume, shape, and material of objects in five bedrooms, four kitchens, and three offices. Averaged over all types of rooms, the ratio of surface area with contents to that without contents was 1.7 ± 0.2 (mean ± standard error), and the ratio of volume of freely moving air to volume of the entire space was 0.89 ± 0.05. Ignoring contents, the surface-area-to-volume ratio was 1.9 ± 0.3 m-1; accounting for contents, the ratio was 3.7 ± 1.2 m-1. Ratios were not significantly different between room types and were comparable to those measured for 33 rooms in a similar study. Due to substantial differences in the design and contents of kitchens, their ratios had the highest variability among the three room types. On average, the contents of bedrooms, kitchens, and offices increase their surface area by 70% and decrease their volume of freely moving air by 11% compared to an empty room. The most common shape of objects in a room was a flat plate, while each room also had many irregularly-shaped objects. Paint and wood were the two most common materials in each room, although the distribution of materials varied by room type. The results of this study can be used to improve understanding of the behavior of gases and particles in indoor environments. / Master of Science / Since humans spend over 90% of their time indoors on average, understanding indoor air quality is essential for characterizing the relationship between health and the environment. Air pollutants can interact with surfaces in the indoor environment, not just surfaces of the walls, ceiling, and floor, but also of objects in the room. Researchers often combine information about the surface area and volume of a room into a single number, the surface-area-to-volume ratio. Many previous studies have estimated the ratio for an empty room, ignoring furniture, appliances, and other contents. We have characterized the surface area, volume, shape, and material of objects in five bedrooms, four kitchens, and three offices. Averaged over all types of rooms, the ratio of surface area with contents to that without contents was 1.7 ± 0.2 (mean ± standard error), and the ratio of volume of freely moving air (i.e., volume of the empty room minus the volume of all contents) to that of the entire space was 0.89 ± 0.05. On average, the contents increased the room’s surface area by 70% beyond that of the walls, floor, and ceiling alone, and decreased the volume of freely moving air by 11% compared to an empty room. Ignoring contents, the surface-area-to-volume ratio was 1.9 ± 0.3 m⁻¹ , whereas accounting for contents, the ratio was nearly double, 3.7 ± 1.2 m⁻¹ . The most common shape of objects in a room was a flat plate, while each room also had many irregularly-shaped objects. Paint and wood were the two most common materials in each room, although the distribution of materials varied by room type. These results can be used for developing realistic model simulations of air flow indoors, updating previously published models, or improving predictions of losses and gains of pollutants in indoor air.

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

The work started with the clinical observations in patients working in buildings with indoor air problems. Signs of seborrhoeic dermatitis, erythematous facial skin conditions and itching conditions on the trunk were noted. Another point of departure was the attribution of facial skin symptoms to VDT work by patients. A questionnaire-based prevalence study of symptoms compatible with the Sick Building Syndrome (SBS) and facial skin symptoms in 4,943 office workers formed the basis for two case referent studies, one focusing on SBS, the other on facial skin symptoms in VDT workers. The prevalence of SBS was three times higher in women than men. The prevalence was higher in young persons and in atopies. Facial skin symptoms showed the same pattern. Psychosocial work load, paper and VDT work were also risk indicators for SBS and for skin symptoms. The symptom excess in women was analyzed with reference to differences in biological or acquired risks and different illness and reporting behaviour. In spite of inequalities in social conditions at home and at work and differences in physical working conditions, these differences could only explain a small part of the gender difference. The odds ratio for SBS in women was lowered from 3.4 in the crude analysis to 3.0 in the multivariate analysis. Effect modification was in most cases stronger in men and the clinical validation of the questionnaire refuted the hypothesis that women over-report symptoms. The results indicate that the gender difference in symptom prevalence is part of a general pattem common to psychosomatic illnesses. In the case referent study of SBS, atopy, psychosocial work load, buildings built or renovated after 1977, the presence of photocopiers and a low outdoor air flow rate were risk indicators. The association between air quality and the occurrence of SBS symptoms was demonstrated by a flow-response relation between the outdoor air flow rate and SBS symptoms. In the case referent study of skin symptoms in VDT work, psychosocial work load, electric background fields, the presence of fluorescent lights with plastic shields and low cleaning frequency were risk indicators. The clinical findings in the two case groups and their referents supported the applied relevance of the studies. Compared with the referents, the SBS cases had more work- related facial erythema, seborriioeic dermatitis and general pruritus, while skin symptom cases, had more work-related facial erythema than their referents. The results show that SBS symptoms and facial skin symptoms have a multifactorial background with constitutional, psychosocial and physical risk indicators. As the indoor air quality is a determinant of SBS symptoms, and the building itself is but one source of indoor air pollution, it is suggested that the name Sick Building Syndrome (SBS) be replaced by Indoor Air Syndrome (IAS). / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1994, härtill 5 uppsatser.</p> / digitalisering@umu

<p>Swimming is the second most common form of recreational activity in the U.S. Swimming pool water and air quality should be maintained to allow swimmers, pool employees, and spectators to use the pool facility safely. One of the major concerns regarding the health of swimmers and other pool users is the formation of disinfection by-products (DBPs) in swimming pools. Previous research has shown that volatile DBPs can adversely affect the human respiratory system. DBPs are formed by reactions between chlorine and other compounds that are present in water, most of which are introduced by swimmers, including many that contain reduced nitrogen. Some of the DBPs formed in pools are volatile, and their transfer to the gas phase in pool facilities is promoted by mixing near the air/water interface, caused by swimming and pool features.</p> <p><a>Swimming pool water treatment processes can play significant roles in governing water and air quality.</a> Thus, it is reasonable to hypothesize that water and air quality in a swimming pool facility can be improved by renewing or enhancing one or more components of water treatment.</p> <p>The first phase of the study was designed to identify and quantify changes in water and air quality that are associated with changes in water treatment at a chlorinated indoor pool facility. Reductions of aqueous NCl₃concentration were observed following the use of secondary oxidizer with its activator. This inclusion also resulted in significant decreases in the concentrations of cyanogen chloride (CNCl) and dichloroacetonitrile (CNCHCl₂) in pool water. The concentration of urea, a compound that is common in swimming pools and that functions as an important precursor to NCl₃ formation, as well as a marker compound for introduction of contaminants by swimmers, was also reduced after the addition of activator.</p> <p>The second phase of this study involved field measurements to characterize and quantify the dynamic behavior of indoor air quality (IAQ) in indoor swimming pool facilities, particularly as related to volatile compounds that are transferred from swimming pool water to air. Measurements of water and air quality were conducted before, during, and after periods of heavy use at several indoor pool facilities. The results of a series of measurements at different swimming pool facilities allowed for examination of the effects of swimmers on liquid-phase DBPs and gas-phase NCl₃. Liquid-phase NCl₃ concentrations were observed to gradually increase during periods of high swimmer numbers (<i>e.g.</i>, swimming meets), while liquid-phase CHCl₃ concentration was nearly constant in the same period. Concentrations of urea displayed a steady increase each day during these periods of intensive use. In general, the highest urea concentrations were measured near the end of each swimming meet. </p> <p>Measurements of IAQ dynamics during phase 2 of the study demonstrated the effects of swimmers on the concentrations of gas-phase NCl₃and CO₂, especially during swimming meets. The measured gas-phase NCl₃ concentration often exceeded the suggested upper limits of 300 µg/m³ or 500 µg/m³during swimming meets, especially during and immediately after warm-up periods, when the largest numbers of swimmers were in the pool. Peak gas-phase NCl₃ concentrations were observed when large numbers of swimmers were present in the pools; measured gas-phase concentrations were as high as 1400 µg/m³.Concentrations of gas-phase NCl₃ rarely reached above 300 µg/m³ during regular hours of operation. Furthermore, the types of swimmers were shown to affect the transfer of volatile compounds, such as NCl₃, from water to airin pool facilities. In general, adult competition swimmers promoted more rapid transfer of these compounds than youth competition swimmers or adult recreational swimmers. The measured gas-phase CO₂ concentration often exceeded 1000 ppm_v during swimming meets, whereas the gas-phase CO₂ concentration during periods of non-use of the pool tended to be close to the background (ambient) CO₂ concentration or slightly more than 400 ppm_v. This phenomenon was largely attributed to the activity of swimmers (mixing of water and respiratory activity) and the normal respiratory activity of spectators. </p> <p>IAQ models for gas-phase NCl₃ and CO₂ were developed to relate the characteristics of the indoor pool environment to measurements of IAQ dynamics. Several assumptions were made to develop these models. Specifically, pool water and indoor air were assumed to be well-mixed. The reactions that were responsible for the formation and decay of the target compounds were neglected. Two-film theory was used to simulate the net mass-transfer rate of volatile compounds from the liquid phase to the gas phase. Advective transport into and out of the air space of the pool were accounted for. The IAQ model was able to simulate the dynamic behavior of gas-phase NCl₃ during regular operating hours. Predictions of gas-phase NCl₃ dynamics were generally less accurate during periods of intensive pool use; however, the model did yield predictions of behavior that were qualitatively correct. Strengths of the model include that it accounts for the factors that are believed to have the greatest influence on IAQ dynamics and is simple to use. Model weaknesses include that the model did not account liquid-phase reactions that are responsible for formation and decay of the target compounds. The IAQ model for NCl₃ dynamics could still be a useful tool to form the basis for recommendations regarding the design and operation of indoor pool facilities so as to optimize IAQ.</p><p>Measurements of CO₂ dynamics indicated qualitatively similar dynamic behavior as NCl₃. Because of this, it was hypothesized that CO₂ may represent a surrogate for NCl₃ for monitoring and control of IAQ dynamics. To examine this issue in more detail, a conceptually similar model of CO₂dynamics was developed and applied. The model was developed to allow for an assessment of the relative contributions of liquid®gas transfer and respiration by swimmers and spectators to CO₂ dynamics. The results of this modeling effort indicated that the similarity of CO₂ transfer behavior to NCl₃ may allow use of CO₂ as a surrogate during periods with few to no spectators in the pool; however, when large numbers of spectators are present, the behavior of CO₂ dynamics may not be representative of NCl₃ dynamics because of spectator respiration.</p><p></p> <br>

The thesis analyses heat loss caused by ventilation for various volumes of ventilated air. Number of model cases were analyzed (class room, fit center, auditorium in the cinema and an apartment). Every scenario was analyzed with the heat recuperation and without it. Annual energetic balance and influence of heat recuperation was evaluated for every model case thereafter. Simulations of ventilation energy consumption were carried out in the TRNSYS 16 program.

Doctor of Philosophy / Department of Mechanical and Nuclear Engineering / Zhongquan Zheng / A nano-material filter is an efficient device for improving indoor environmental quality (e.g. smoke reduction, air purification in buildings). Studying the effectiveness of nano-materials used in the device by computer simulation is challenging because very different size scales are involved. Therefore, numerical methods have to be developed to accommodate varying magnitudes of scales. In the current study, the simulation has been divided into three scales: macro-, micro- and nano-scale. The numerical schemes at each scale are targeted at a particular scale; however, the relationship of the general transport phenomena, physical mechanisms and properties among different scales are uniquely linked at the same time. The objective of the macro-scale simulation was to design and study a gas filter constructed with nano-material pellets. The filter was considered a packed-bed tube filled with manufactured nano-material pellets. Commercial computational fluid dynamics (CFD) packages were used along with the embedded programming macros. In the filtration process, we focused on the flow and species transport phenomena through the porous substrate. The mathematical/numerical models were built and tested based on the physical models used in the experimental setups for different materials that were tested. The results from the numerical models were validated and compared well to experimental data obtained from the pressure drop measurements and the adsorption (breakthrough) tests. In the micro-scale simulation, a modified immersed-boundary method (IBM) with the Zwikker-Kosten (ZK) porous model and the high-order schemes was validated and applied to simulate a representative porous unit that represented a periodic array of solid/porous cylinders. In the periodic unit, the solid cylinder case was used to validate the high-order schemes by comparing it to the results obtained from the commercial CFD software. The relationship between the pressure gradient and the porosity (Blake-Kozeny equation) was determined from this level and fed back to the macro-scale simulation, which provided a link between the two scales. In the porous cylinder case, both flow field and species transport were investigated with a porous model similar to the one used in the macro-scale. The species concentration change was calculated and found to be nonlinearly related to the adsorption coefficient. In the nano-scale simulation, a molecular dynamics (MD) simulation and a coupled molecular-continuum scheme were applied to solve the momentum and the mass transport problems at the molecular level at which the traditional continuum theory is no longer applicable. Both schemes were verified from the surface slip behavior study compared to the literature. The scale and shear effects in the Coutte flow were investigated, showing that in the micro-scale and macro-scale, the slip behavior could be neglected since it was only important in much smaller scales. The same hybrid scheme was then applied to a diffusion model with nano-pores constructed in the solid substrate. The adsorptions between various gases and the carbon substrate were simulated. The mass fluxes cross the fluid/solid interfaces were counted and both self-diffusivity and transport diffusivity were estimated and compared to their respective values found in the literature. The transport properties are closely related to the species transport (Fick’s law) in the macroscopic simulations. Linear concentration profiles in the channel were obtained based on those transport properties for various gases going through different sizes of nano-pores, which, as a connection to the continuum model, were to be used as boundary conditions in the continuum simulation.

The purpose of this report was to find out if there were any differences in how the indoor environment was experienced in environmentally certified school buildings compared with similar conventional buildings. For that two certified school buildings, Vegaskolan in Vännäs and Hedlunda preschool in Umeå was compared with two conventional preschools in Umeå, Solbacken and Skattelden, in terms of how the indoor environment was experienced. This was done using a questionnaire and interviews. The results of the survey showed that Vegaskolan had the lowest percentage among the staff that was bothered by various environmental factors, while Hedlunda preschool had the largest share. Hedlunda also had the highest percentage amongst the staff with health problems. All four buildings surveyed, however, had smaller percentages who were disturbed by noise than preschools in general, and the environmentally certified buildings had an even lower percentage. If this is due to the certification is however difficult to say. Since there were more differences between the two certified buildings, it is difficult to draw general conclusions depending on the building type. Most of the differences showed in this study do not depend on the certification of the buildings, but of other causes. However the environmentally certified buildings are more complex than the conventional buildings, with more things that can go wrong. Therefore it requires more monitoring of the indoor environment after the building is put into use, as well as more information to operators and users in order to prevent adverse health effects, which seems to be the case at Hedlunda.

Commercial energy use in Arizona is different from the rest of the United States because of their high demand for air conditioning. Nearly half of the energy used in commercial buildings goes to heating, cooling, and ventilation. In an attempt to reduce overall every use in buildings, looking at these categories led to an examination of ventilation in buildings, which is the main cause for high heating and cooling costs. Ventilation of fresh air is required in order to provide a safe, healthy environment, with acceptable indoor air quality. Indoor air quality and pollution has continuously come to light as a major health concern for building occupants. Chemicals used in manufacturing allow consumers to buy and expose themselves to toxic substances such as volatile organic compounds on a daily basis. With minimal regulations on indoor air, it is important to find ways to better filter and clean it. The traditional solution is ventilation, but more fresh air ventilation means more heating and cooling. This paper explores the research that has been done on plants and phytoremediation and the applicability to indoor air quality. With the proof that certain combinations and amounts of plants can filter the air of volatile organic compounds, systems are explored for indoor air filtration instead of mechanical ventilation. This type of system can greatly reduce heating and cooling costs in buildings due to the reduction of outdoor air being brought in and requiring conditioning. A system of this type is a feasible solution to indoor air quality and can lead to a significant reduction in energy use. The proposed AIRMAPS is a system that in certain quantities can reduce the need for fresh air ventilation by 25%, which in turn has shown through the validation by eQUEST, that the energy used for heating, cooling, and ventilation fans can also be reduced by approximately the same amount. The plants used are spider plant, dumb cane, English ivy, and golden pothos. The average formaldehyde removal by each of these plants is a low approximation of 75% per cubic meter. This paper also considers the growing materials used for the plants; activated carbon, potting soil mix, and grow-stones, as well as their formaldehyde removal capabilities.