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Phthalates are ubiquitous in the built environment and are used across various fields, despite known endocrine disruptive properties, and other associated health hazards, including abnormalities in reproductive health and development. I investigated the presence of phthalates in the built environment using the Health Product Declaration (HPD) repository to survey for products containing these chemicals, investigated the literature for possible health effects and alternatives to phthalates, and conducted a laboratoy-based feasibility study of urinary biomarkers associated with phthalates using wastewater-based epidemiology (WBE) on a US university campus at the building-scale. Of the 5,278 products in the HPD repository, 73 contained phthalates and were most commonly found in windows, doors, flooring, sealants, insulations, and furnishings. Alternative plasticizers (cardanol, epoxidized soybean oil, hydrogenated castor oil) usage were identified in 10 products from HPD repository. The two wastewater samples analyzed by liquid chromatography-tandem mass spectrometry (LC-MS-MS) showed that dimethyl phthalate (DMP) was detectable, as well as its human metabolite, monomethyl phthalate (MMP), observed at a concentration of 163-202 ng/L. These results indicate low human exposure from the building materials in the limited convenience sample investigated. Future studies of building scale wastewater-based epidemiology are recommended to investigate these and other phthalates commonly found in the built environment, including diisononyl phthalate (DINP) and diisononyl hexahydrophthalate (DINCH).
Environmental releases of neonicotinoid and fipronil insecticides via U.S. wastewater infrastructure
Trees serve as a natural umbrella to mitigate insolation absorbed by features of the urban environment, especially building structures and pavements. For a desert community, trees are a particularly valuable asset because they contribute to energy conservation efforts, improve home values, allow for cost savings, and promote enhanced health and well-being. The main obstacle in creating a sustainable urban community in a desert city with trees is the scarceness and cost of irrigation water. Thus, strategically located and arranged desert trees with the fewest tree numbers possible potentially translate into significant energy, water and long-term cost savings as well as conservation, economic, and health benefits. The objective of this dissertation is to achieve this research goal with integrated methods from both theoretical and empirical perspectives.
This dissertation includes three main parts. The first part proposes a spatial optimization method to optimize the tree locations with the objective to maximize shade coverage on building facades and open structures and minimize shade coverage on building rooftops in a 3-dimensional environment. Second, an outdoor urban physical scale model with field measurement is presented to understand the cooling and locational benefits of tree shade. The third part implements a microclimate numerical simulation model to analyze how the specific tree locations and arrangements influence outdoor microclimates and improve human thermal comfort. These three parts of the dissertation attempt to fill the research gap of how to strategically locate trees at the building to neighborhood scale, and quantifying the impact of such arrangements.
Results highlight the significance of arranging residential shade trees across different geographical scales. In both the building and neighborhood scales, research results recommend that trees should be arranged in the central part of the building south front yard. More cooling benefits are provided to the building structures and outdoor microclimates with a cluster tree arrangement without canopy overlap; however, if residents are interested in creating a better outdoor thermal environment, open space between trees is needed to enhance the wind environment for better human thermal comfort. Considering the rapid urbanization process, limited water resources supply, and the severe heat stress in the urban areas, judicious design and planning of trees is of increasing importance for improving the life quality and sustaining the urban environment.