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 / abstract / Mechanical Engineering / Master / Master of Philosophy

This dissertation consists of three chapters on questions in Environmental Economics, addressing policy and health issues in indoor and outdoor environments. In the first chapter, I explores price and quantity policy solutions to externalities that arise from private decisions made over time, focusing on resource extraction as a specific example. In the U.S., mining causes more pollution than any other single industry. I show how tax policy can optimally address a flow externality associated with resource extraction when the policymaker faces asymmetric information in the short run. Chapter 2 investigates whether ordinary exposure to a common indoor air pollutant—Nitrogen Dioxide (NO₂)—affects respiratory health. About 40 percent of occupied homes in the U.S. use gas stoves for cooking, which produce NO₂ as a byproduct of combustion (US Census, 2006), and peak concentrations in homes may reach above 900 ppb when a gas stove is used for cooking (Dennekamp et al., 2001). Permanent or fatal lung damage occurs at NO₂ concentrations greater than 1000 ppb (Samet and Utell, 1990). Previous studies find mixed evidence of negative effects from indoor NO₂ (Basu and Samet, 1999), but exposure may be endogenous in these analyses. I address this problem by developing a physical model of indoor NO₂ concentrations that depends on ventilation decisions and housing characteristics and estimate it using data from the third wave of the National Health and Nutrition Examination Survey. In every model I consider, I find no significant effects of gas stoves on respiratory outcomes. In the final chapter, I combine data on state and local tobacco control ordinances from Americans for Non-smokers Rights Tobacco US Tobacco Control Laws Database with a sample of 35 million births in the U.S. to examine the impact of smoking bans on birth weight and related outcomes. Using difference-in-difference techniques, I identify the effects of state bans net of local bans, as well as the effects of local bans net of state bans. The results suggest less restrictive bans do more to improve birth outcomes than “100% smokefree” bans do, particularly in urban settings. / text

Household air pollution (HAP) is responsible for almost 4 million premature deaths every year, a burden that is primarily carried by women and children in developing countries. The mortality and morbidity impact of HAP can be significantly alleviated through clean cookstove interventions. However, for these interventions to be effective, the new intervention stove must be a substantially cleaner technology and adoption should be high and sustained over time. Woody biomass is the fuel of choice in many developing communities, and contributes substantially to HAP. Several organizations have launched clean cooking interventions to address this issue. However, the majority of those interventions do not address adoption related challenges, that they often face. This thesis explores previous studies on Human-Centered Design (HCD) and the impact of feedback and data access on behavior change. It details a HCD process and methodology applied during the design process of an air quality feedback system, to improve adoption of liquefied petroleum gas (LPG) cookstoves in Rwanda. The feedback system is intended to provide real-time air quality information to stove users and potentially encourage them to abandon traditional biomass cookstoves in favor of the cleaner LPG stoves.

Atomic force microscopy (AFM) is adapted to the measurement of adhesion forces between indoor-air-pollutant bioparticulates and synthetic carpet fiber materials. This novel technology is used to characterize the adhesion and release of a model bioparticulate, the bacterium E. coli on Nylon. This knowledge will lead to expanded studies of a wider range of biocontaminants, and ultimately to the ability to design carpet and rugs upholstery that reduce the spread of indoor air pollutants. Such an advance would improve life significantly for the 20+ million Americans who suffer from asthma, and countless others who are afflicted with allergies and illness spread via bioparticulates.

Poor indoor air quality in schools is associated with diminished learning, health risks to students and staff, and economic costs. This dissertation reports findings from the Texas Elementary School Indoor Air Study (TESIAS). The objective of this investigation is to establish a baseline for indoor environmental parameters. The investigation selected 30 elementary schools from 2 school districts. One school district was located along the Texas/Mexico border in a hot-humid climate region. The other school district was located in central Texas in a mixed-humid climate region. Phase I of the study was a questionnaire completed by 1336 teachers and other school staff. Phase II of the study collected both qualitative and quantitative data in 120 classrooms including continuous monitoring of comfort parameters (carbon monoxide, carbon dioxide, temperature, and relative humidity). Phase III collected more in-depth quantitative data, including fungi and bacteria concentrations, in 12 classrooms. This dissertation investigates potential differences in the study data between school districts and between portable and traditional classrooms. The two major findings of this study concern water leakage from roofs and inadequate ventilation. Roof leaks were the highest reported source of water incursion and correlated with health symptoms. Free-standing small footprint classrooms had fewer roof and wall leaks than traditional classrooms. The simple low pitch roof design and sufficient overhangs typically found on the small footprint buildings studied likely result in less reported roof leaks. The measured carbon dioxide concentrations (both average and peak values) were well in excess of the recommended maximums and fewer than 15% of the classrooms met the recommended maximum concentrations. Relatively higher CO2 concentrations and relative humidity in the border school district were attributed to a greater frequency of blocked outdoor air intakes. Further investigation of novel HVAC systems, such as low velocity displacement ventilation, is needed. Ultimately, this study enables the development of best practices for school design for improved indoor air quality. / text

Building environmental conditions such as ventilation and contaminant concentrations are important factors that influence occupant health and comfort. The objective of the present work is to investigate how personal exposure to gaseous and particulate pollutants depends on indoor airflow, source characteristics, and occupant activity in commercial and residential environments. The study examines airflow and pollutant transport using experimental measurements in conjunction with computational fluid dynamics (CFD). The results demonstrate that breathing has a measurable influence on the airflow in an occupant breathing zone, but it has very small impacts on the occupant thermal plume. The results also show that breathing can significantly affect inhaled particle concentrations, even though the influence varies with source position and particle size. Also, localized hand motions of a sitting manikin do not significantly disrupt the upward thermal plume. In typical US residences, forced convection driven mixing airflow or buoyancy driven stratified airflow occurs depending on the HVAC fan operation (fan on or fan off, respectively). The measured transition period between mixing flow (fan on) and stratified flow (fan off) is approximately one minute, implying that most airflow in the residence is either dominated by mixing or stratification. A high level of exposure to short-term pollutant sources, such as resuspension of particles from floor surfaces due to human activity, more likely occurs with stratified flow than with highly mixed airflow. This is due to the strong influence of the occupant thermal plume that transports the pollutants into the breathing zone. Furthermore, by transporting air containing ozone across the reactive occupant surface, the occupant thermal plume has a large effect on exposure to ozone reaction products. Due to the reaction of ozone with the skin oils and clothing surfaces, the occupant surface boundary layer becomes depleted of ozone and conversely enriched with ozone reaction products. The parameter ventilation effectiveness quantifies the effectiveness of airflow distribution and can be used for assessment of exposure to gaseous pollutants. Based on the study results, the usefulness of ventilation effectiveness as an indicator of exposure to particulate pollutants depends on the particle size. For small particles (~1 [mu]m), an increase of ventilation effectives caused a decrease in occupant exposure, while for large particles (~7 [mu]m), source location and airflow around the pollutant source are significant factors for the exposure, and the ventilation effectiveness has very little to no effect. / text

In South Africa one of the strongest influences on domestic indoor air quality is the type of energy used for heating, cooking and other household purposes. Emissions from fuel combustion, along with housing factors, can result in respiratory infections, a leading cause of death in the country. In this study I examine the relationships between energy types, patterns of use, housing conditions such as improper ventilation and overcrowding, indoor air quality and respiratory health in poorer communities of Msunduzi Municipality, South Africa. These variables were examined using an ecohealth perspective through the integration of data concerning individual time-activity budgets, housing materials and structure, energy sources used for heating, cooking and lighting, respiratory symptoms and continuous real time monitoring of indoor air pollutants (particulate matter (PM), carbon dioxide (CO2), carbon monoxide (CO) and sulphur dioxide (SO2)). A total of 20 dwellings, displaying large variability in housing structure and energy patterns, were sampled for 24 hours (hr) over a period of 60 days. The mean 24-hr average indoor concentrations measured were as follows: PM2.5= 16 ± 11 µg/m3, PM10= 78 ± 46 µg/m3, CO= 5 ± 6 ppm and SO2= 0.18 ± 0.27 ppm. Mean indoor concentrations measured were significantly greater than mean outdoor concentrations (p<0.0001 (PM2.5), p=0.017 (PM10), p<0.0001 (CO), p<0.0001 (SO2)). Although PM concentrations increased with the use of increasingly inefficient-burning fuel types (gas < paraffin < wood), no significant differences in the means were found across these fuel types. It is thought that the high degree of variability among dwellings and the small sample size in this study obscured any statistically significant relationships. No significant differences in mean concentrations were found across different housing types either. Indoor exposures were, on average, highest among very young children (ages 0-5) and elders (ages 51+). All age groups reported experiencing high levels of respiratory symptoms, with the elder group (ages 51+) reporting the highest percentages for each symptom. This study will be used to inform local governments and NGOs of local indoor air pollution and exposure risks, so that policy and resources can be allocated accordingly to improve physical environments. / Thesis (Master, Environmental Studies) -- Queen's University, 2007-09-27 08:52:05.443