Browsing by Subject "air quality"
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Item 3D Printing in the Wild: A Preliminary Investigation of Air Quality in College Maker Spaces(University of Texas at Austin, 2016) McDonnell, Bill; Jimenez Guzman, Xavier; Dolack, Matthew; Simpson, Timothy W.; Cimbala, John M.Additive manufacturing is a popular method for prototyping and manufacturing custom parts, especially on college campuses. While there is widespread use of 3D printers as part of many engineering classwork, there is little regulation or knowledge regarding emissions. Many plastics, including polycarbonates, ABS, and PLA are known to emit high counts of volatile organic compounds (VOCs) and particulate matters (PMs). This study focuses on VOC and PM counts in several natural environments and dedicated “maker spaces” on a large college campus to gauge the exposure that students and operators experience. Emissions were measured using a photoionization detector and two particle sizers. The photoionization detector measured total VOCs, and the particle size counters measured both total nanoparticles and individual micro-particles based on relative particle diameter. Measurements were taken in hourly increments and then analyzed to determine the degree with which desktop printers emitted VOCs and PM. Our data can be used to determine whether additional ventilation or filtration is needed when 3D printing “in the wild” to enhance operator and bystander safety.Item Air quality impacts of plug-in hybrid electric vehicles in Texas: Evaluating three battery charging scenarios(IOP Publishing, 2011-04-19) Thompson, Tammy M.; King, Carey W.; Allen, David T.; Webber, Michael E.; King, Carey W.; Allen, David T.; Webber, Michael E.The air quality impacts of replacing approximately 20% of the gasoline-powered light duty vehicle miles traveled (VMT) with electric VMT by the year 2018 were examined for four major cities in Texas: Dallas/Ft Worth, Houston, Austin, and San Antonio. Plug-in hybrid electric vehicle (PHEV) charging was assumed to occur on the electric grid controlled by the Electricity Reliability Council of Texas (ERCOT), and three charging scenarios were examined: nighttime charging, charging to maximize battery life, and charging to maximize driver convenience. A subset of electricity generating units (EGUs) in Texas that were found to contribute the majority of the electricity generation needed to charge PHEVs at the times of day associated with each scenario was modeled using a regional photochemical model (CAMx). The net impacts of the PHEVs on the emissions of precursors to the formation of ozone included an increase in NOx emissions from EGUs during times of day when the vehicle is charging, and a decrease in NOx from mobile emissions. The changes in maximum daily 8 h ozone concentrations and average exposure potential at twelve air quality monitors in Texas were predicted on the basis of these changes in NOx emissions. For all scenarios, at all monitors, the impact of changes in vehicular emissions, rather than EGU emissions, dominated the ozone impact. In general, PHEVs lead to an increase in ozone during nighttime hours (due to decreased scavenging from both vehicles and EGU stacks) and a decrease in ozone during daytime hours. A few monitors showed a larger increase in ozone for the convenience charging scenario versus the other two scenarios. Additionally, cumulative ozone exposure results indicate that nighttime charging is most likely to reduce a measure of ozone exposure potential versus the other two scenarios.Item Air Quality in the National Parks: Outcome of a Citizen Science Course Project Outcomes(2020) Chen, Anna; Sullivan, Colleen; Betts, Nicole; Hammons, Emilie; Illingworth, Parker; Sears, Libby; Johnson, Kristina; Larson, RowdyItem Austin Area Environmental Handbook(City of Austin, 1987) Austin Department of Environmental ProtectionItem Changing the spatial location of electricity generation to increase water availability in areas with drought: A feasibility study and quantification of air quality impacts in Texas(IOP Publishing, 2013-08-20) Pacsi, Adam P.; Alhajeri, Nawaf S.; Webster, Mort D.; Webber, Michael E.; Allen, David T.; Pacsi, Adam P.; Alhajeri, Nawaf S.; Webber, Michael E.; Allen, David T.The feasibility, cost, and air quality impacts of using electrical grids to shift water use from drought-stricken regions to areas with more water availability were examined. Power plant cooling represents a large portion of freshwater withdrawals in the United States, and shifting where electricity generation occurs can allow the grid to act as a virtual water pipeline, increasing water availability in regions with drought by reducing water consumption and withdrawals for power generation. During a 2006 drought, shifting electricity generation out of the most impacted areas of South Texas ( 10% of base case generation) to other parts of the grid would have been feasible using transmission and power generation available at the time, and some areas would experience changes in air quality. Although expensive, drought-based electricity dispatch is a potential parallel strategy that can be faster to implement than other infrastructure changes, such as air cooling or water pipelines.Item Environmental Federalism when Numbers Matter More than Size(The Center for Global Energy, International Arbitration, and Environmental Law, 2014-11-05) Adelman, David E.Two elements of the Clean Air Act are viewed as essential to its many successes: the health-based national ambient air quality standards (NAAQS), which restrict emissions of six widely released air pollutants, and the statute’s hybrid form of cooperative federal-state regulation. This Article will show that these programs are far less important to the operation of the statute than conventional wisdom would have you believe. An amalgam of parallel programs and external constraints, both political and practical, have marginalized the NAAQS framework and limited state action, such that in practice the law is more federal than it is cooperative.Item Grandfather's Last Days?: Voluntary Permits and Economically Sustainable Air Quality in Texas(Bureau of Business Research, The University of Texas at Austin, 2000-02) Groberg, DavidDaunting air quality problems in Texas have brought state government under increasing public pressure to enact strict controls on air emissions. The Texas Natural Resources Conservation Commission (TNRCC) launched a voluntary emissions reduction (VERPs) program to encourage plants to reduce their emissions. If the program does not produce significant reductions, the legislature will likely subject these plants to strict standards.Item Indoor air quality(2009-11) Kamholz, Jenna; Montry, MatthewRecent studies have shown that indoor air pollutant levels are often greater than the outdoor levels. This paper looks at types of pollutants and their causes, and describes various methods for improving indoor air quality.Item Presentation: Is Your House Killing You?(Environmental Science Institute, 2008-10-10) Environmental Science Institute; Corsi, RichardItem Public Policies Affecting Lignite Development in Texas, PRP 20(LBJ School of Public Affairs, 1977) Blissett, Marlan; Groat, Charles G.; Folger, A. Gray; Spurr, Stephen H.Item Richard L. Corsi Named Next Dean of Engineering at Portland State University(The University of Texas at Austin, 2018-06-12) News, UTItem Standards of human comfort: relative and absolute(2009-10) Fincher, Warren; Boduch, MichaelAn examination of the factors that affect the quality of comfort in an architectural environment, including temperature, lighting, humidity, and air quality. The paper also considers the variability of individual and cultural perceptions of comfort in determining how designers might create an optimal living or work space.Item Using market-based dispatching with environmental price signals to reduce emissions and water use at power plants in the Texas grid(IOP Publishing, 2011-11-23) Alhajeri, Nawaf S.; Donohoo, Pearl; Stillwell, Ashlynn S.; King, Carey W.; Webster, Mort D.; Webber, Michael E.; Allen, David T.; Alhajeri, Nawaf S.; Stillwell, Ashlynn S.; King, Carey W.; Webber, Michael E.; Allen, David T.The possibility of using electricity dispatching strategies to achieve a 50% nitrogen oxide (NOx) emission reduction from electricity generating units was examined using the grid of the Electricity Reliability Council of Texas as a case study. Simulations of a hypothetical policy demonstrate that imposing higher NOx prices induces a switch from some coal-fired generation to natural gas generation, lowering NOx emissions. The simulation is for a day with relatively high electricity demand and accounts for transmission constraints. In addition to the lowering of the NOx emissions, there are co-benefits of the redispatching of generation from coal to natural gas, including reductions in the emissions of sulfur oxides (24%–71%), Hg (16%–82%) and CO2 (8.8%–22%). Water consumption was also decreased, by 4.4%–8.7%. Substantial reductions of NOx emissions can be achieved for an increased generation cost of 4–13%, which is due to the higher fuel price of gas relative to coal (assuming a price of $3.87 per MMBTU (MMBTU: million British thermal units) for natural gas, and $1.89 per MMBTU for coal). However, once the system has reduced NOx emissions by approximately 50%, there is little incremental reduction in emissions due to further increases in NOx prices.