Browsing by Author "Cohan, Daniel"

Now showing 1 - 4 of 4
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    Air Quality and Health Benefits from Potential Coal Plant Closures in Texas
    (2017-10-09) Strasert, Brian A; Cohan, Daniel
    As power production from renewable energy and natural gas grows, some analysts anticipate coal-fired power plant closures in Texas. In this study, the potential effects of such closures on air quality, regulatory attainment, and human health for 15 of the state’s largest coal plants were analyzed. The impacts varied significantly across power plants, sometimes by more than a magnitude, even after normalizing by generation or emissions. While some power plants have negligible impacts on concentrations at important monitors, average impacts up to 0.5 ppb and 0.2 μg/m3 and maximum impacts up to 3.3 ppb and 1.3 μg/m3 were seen for ozone and fine particulate matter (PM2.5), respectively. Individual power plants impact average visibility by up to 0.25 dV in Class I Areas. Health impacts normalized by electricity generation range from $7.3/MWh for Fayette Power Project to $134.6/MWh for W A Parish, mostly due to PM2.5 from SO2 emissions.
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    Characterization of Atmospheric Nitrogen Chemistry and the Formation/ Evolution of Particulate Matter in Houston, TX
    (2015-12-04) Leong, Yu Jun; Griffin, Robert; Cohan, Daniel; Biswal, Sibani L
    This thesis covers laboratory experiments to study the homogeneous reduction of nitric acid (HNO₃) to nitrous acid (HONO) in the presence of volatile organic compounds that are surrogates for those emitted by motor vehicles. The results presented in this study focus on the impact of environmental variables on the rate of formation of HONO in this process. The homogeneous conversion of HNO₃ to HONO has significant atmospheric implications due to the “renoxification” of less reactive HNO₃ into more reactive HONO. Consecutively, this thesis describes particulate matter (PM) data collected from a month-long (September 2013) field project in Houston, TX. A mobile laboratory containing state-of-the-art PM instrumentation and auxiliary measurements was deployed. The main focus for the thesis work was to utilize this dataset to better characterize PM pollution in the city of Houston. This was achieved by several analysis approaches including cluster analysis, back-trajectory analysis, and principal component analysis to describe spatial and temporal variations in submicron PM in the Houston region. Finally, this work describes the use of a statistical source apportionment technique, positive matrix factorization, on the field dataset to apportion important constituents of atmospheric aerosols in Houston. This technique allowed the apportionment of four organic aerosol factors, two of which were associated with organic nitrates from biogenic sources. Submicron PM plume events from on-road, industrial, and biomass burning sources in Houston also were chemically characterized. Because sources of PM pollution are still poorly understood, particularly in the highly industrial and urban city of Houston, the results from this thesis will advance PM modeling capabilities and allow improved PM control strategies in polluted urban areas similar to Houston.
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    Houston Air Conference: Introduction
    (Rice University, 2008) Cohan, Daniel; Shell Center for Sustainability
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    Rice Air Curriculum
    (Rice University, 2011-01-11) Venkateswar, Kavita; Cohan, Daniel
    The Rice Air Curriculum, developed by Dr. Daniel Cohan and Kavita Venkateswar of Rice University with funding from the National Science Foundation, aims to engage young children in scientific inquiry and hands-on measurement of the atmosphere. The lessons enable students to apply math and science to explore the challenge of air pollution in their own community. Students measure air pollution and meteorology conditions on their school campuses using protocols developed by the GLOBE program (www.globe.gov). The curriculum is aimed at 5th-grade level science and math classes and consists of 7 lessons: Introduction to the Atmosphere, Physical Properties of the Atmosphere, Atmospheric Gases and Their Cycles, Stratospheric Ozone, Tropospheric Ozone and Other Air Pollution, Climate Change, and Analyzing GLOBE Data. How to Navigate this Collection: Please start with the “Curriculum Introduction,” which serves as an introduction to the other modules of this collection. The 7 lessons each consists of (1) a Teacher Lesson Plan, including information about the topic and a step-by-step lesson plan; (2) a Student Lesson module of activities and questions for the students to complete (including a link to a printable worksheet version); and (3) an Answer Key to each student lesson, available as a link from the Teacher Lesson Plan. The Collection also provides: (1) a GLOBE Overview Instruction Manual describing the GLOBE measurement protocols; (2) a Data Sheet Module with links to printable versions of the measurement data sheets; (3) a list of the Texas Essential Knowledge and Skills (TEKS) learning objectives targeted by this curriculum; and (4) Teacher and Student Surveys, which we request that participating teachers return to Dr. Cohan to help assess and improve this curriculum.