Cliff I. Davidson

Public perceptions of energy consumption and savings

In a national online survey, 505 participants reported their perceptions of energy consumption and savings for a variety of household, transportation, and recycling activities. When asked for the most effective strategy they could implement to conserve energy, most participants mentioned curtailment (e.g., turning off lights, driving less) rather than efficiency improvements (e.g., installing more efficient light bulbs and appliances), in contrast to experts’ recommendations. For a sample of 15 activities, participants underestimated energy use and savings by a factor of 2.8 on average, with small overestimates for low-energy activities and large underestimates for high-energy activities. Additional estimation and ranking tasks also yielded relatively flat functions for perceived energy use and savings. Across several tasks, participants with higher numeracy scores and stronger proenvironmental attitudes had more accurate perceptions. The serious deficiencies highlighted by these results suggest that well-designed efforts to improve the publics understanding of energy use and savings could pay large dividends.

An international comparative analysis of sustainability transformation across seven universities

Purpose – The purpose of this paper is to identify the key aspects of transformation of universities towards sustainability, such as the ideal characteristics of the “sustainable university”, and the drivers and barriers in the transformation, by comparing the strategies of seven universities world-wide. nDesign/methodology/approach – A systems transformation analysis of seven case studies has been applied through a self-evaluation based on the tridimensional Framework-Level-Actors (FLA) method. nFindings – The study shows that none of the three dimensions of change is predominant over the others. The main barrier to be overcome is the lack of incentive structure for promoting changes at the individual level. The main drivers for change are the presence of “connectors” with society, the existence of coordination bodies and projects, and the availability of funding, all of which are important for progress. Enhancing interdisciplinarity is a strategic objective at almost all of these universities, while transformative learning is less present. A common characteristic for most of the institutions is establishing and supporting networks of expertise within the universities. These universities show important strategic efforts and initiatives that drive and nucleate change for sustainable development, the result of a combination of drivers. nPractical implications – The FLA-method has proved useful for being used at the level of comparing case-studies through a bird’s-eye perspective. nOriginality/value – The paper demonstrates the application of a simple tool that gives a global perspective on transformational strategies used in seven cases world-wide in the search for commonalities and differences.

Apportionment of Ambient Primary and Secondary Fine Particulate Matter at the Pittsburgh National Energy Laboratory Particulate Matter Characterization Site Using Positive Matrix Factorization and a Potential Source Contributions Function Analysis

Abstract Fine particulate matter (PM2.5) concentrations associated with 202 24-hr samples collected at the National Energy Technology Laboratory (NETL) particulate matter (PM) characterization site in south Pittsburgh from October 1999 through September 2001 were used to apportion PM2.5 into primary and secondary contributions using Positive Matrix Factorization (PMF2). Input included the concentrations of PM2.5 mass determined with a Federal Reference Method (FRM) sampler, semi-volatile PM2.5 organic material, elemental carbon (EC), and trace element components of PM2.5. A total of 11 factors were identified. The results of potential source contributions function (PSCF) analysis using PMF2 factors and HYSPLIT-calculated back-trajectories were used to identify those factors associated with specific meteorological transport conditions. The 11 factors were identified as being associated with emissions from various specific regions and facilities including crustal material, gasoline combustion, diesel combustion, and three nearby sources high in trace metals. Three sources associated with transport from coal-fired power plants to the southeast, a combination of point sources to the northwest, and a steel mill and associated sources to the west were identified. In addition, two secondary-material-dominated sources were identified, one was associated with secondary products of local emissions and one was dominated by secondary ammonium sulfate transported to the NETL site from the west and southwest. Of these 11 factors, the four largest contributors to PM2.5 were the secondary transported material (dominated by ammonium sulfate) (47%), local secondary material (19%), diesel combustion emissions (10%), and gasoline combustion emissions (8%). The other seven factors accounted for the remaining 16% of the PM2.5 mass.

Understanding intra-neighborhood patterns in PM2.5 and PM10 using mobile monitoring in Braddock, PA.

BackgroundBraddock, Pennsylvania is home to the Edgar Thomson Steel Works (ETSW), one of the few remaining active steel mills in the Pittsburgh region. An economically distressed area, Braddock exceeds average annual (>15 μg/m3) and daily (>35 μg/m3) National Ambient Air Quality Standards (NAAQS) for particulate matter (PM2.5).MethodsA mobile air monitoring study was designed and implemented in morning and afternoon hours in the summer and winter (2010–2011) to explore the within-neighborhood spatial and temporal (within-day and between-day) variability in PM2.5 and PM10.ResultsBoth pollutants displayed spatial variation between stops, and substantial temporal variation within and across study days. For summer morning sampling runs, site-specific mean PM2.5 ranged from 30.0 (SDu2009=u20093.3) to 55.1 (SDu2009=u200913.0) μg/m3. Mean PM10 ranged from 30.4 (SDu2009=u20092.5) to 69.7 (SDu2009=u200951.2) μg/m3, respectively. During summer months, afternoon concentrations were significantly lower than morning for both PM2.5 and PM10, potentially owing to morning subsidence inversions. Winter concentrations were lower than summer, on average, and showed lesser diurnal variation. Temperature, wind speed, and wind direction predicted significant variability in PM2.5 and PM10 in multiple linear regression models.ConclusionsData reveals significant morning versus afternoon variability and spatial variability in both PM2.5 and PM10 concentrations within Braddock. Information obtained on peak concentration periods, and the combined effects of industry, traffic, and elevation in this region informed the design of a larger stationary monitoring network.

Particle Resuspension in Turbulent Flow: A Stochastic Model for Individual Soil Grains

A stochastic model for the motion of a particle initially at rest on a surface is explored. Fluid and adhesive forces are quantified based on first principles, and turbulent fluctuations are addressed probabilistically from probability distribution functions. A Monte Carlo process yields the distributions of particle position and velocity under a wide range of wind conditions and soil sizes. Results indicate that particle size and friction velocity are the most important factors in determining if a particle will resuspend and in predicting its subsequent motion. Larger wind speeds produce more violent fluctuations, which have a greater effect on small particles than on large particles. A theoretical analysis of the threshold friction velocity supports earlier experimental findings. The aerodynamic lift force cannot be neglected, and the torque exerted on a particle can be important in some cases. Applying the results of this work may contribute to reducing uncertainty in large-scale aerosol models.

Changing Household Behaviors to Curb Climate Change: How Hard Can it Be?

As part of a recent national survey on public perceptions of energy consumption and savings, we asked 505 participants to rate how difficult it would be for them to implement 15 of Gardner and Stern’s 27 actions. Our question, which was adapted from self-efficacy research in other domains.

A Monte Carlo model for soil particle resuspension including saltation and turbulent fluctuations

This article describes a stochastic model for resuspension that combines both aerodynamic entrainment and momentum transfer from saltating particles. Two case studies are performed based on soil conditions for the topmost layer of soil in Los Angeles County, CA, and Allegheny County, PA. Wind friction velocity, u*, and soil size distribution were found to be the most important factors in predicting mass and number flux. Under a broad range of wind conditions mass and number fluxes agree to within an order of magnitude with the empirical models of Marticorena and Bergametti (1995) and Ginoux et al. (2001) at u* ≤ 0.4 m/s. For u* ≤ 0.60 m s−1 and u* ≥ 0.85 m s−1 aerodynamic forces and splash were the dominant resuspension mechanisms, respectively. Flux was sensitive to wind speed but was not proportional to u*3. The mass and number distributions with height peaked at heights corresponding to the maximum concentration of saltating particles and the maximum concentration of suspended particles, respectively. Particles that are most likely to resuspend in the absence of saltation are < 10 μm or > 100 μm in diameter. The average particle diameter increases with height but is consistently less than the average particle diameter of the parent soil. Simulations reached steady state in approximately 0.01 seconds, and an alternative method of predicting the reduction in near-surface wind speed as a result of saltation is presented as a component of the model.

Adapting the social-ecological system framework for urban stormwater management: The case of green infrastructure adoption

Stormwater management has long been a critical societal and environmental challenge for communities. An increasing number of municipalities are turning to novel approaches such as green infrastructure to develop more sustainable stormwater management systems. However, there is a need to better understand the technological decision-making processes that lead to specific outcomes within urban stormwater governance systems. We used the social-ecological system (SES) framework to build a classification system for identifying significant variables that influence urban stormwater governance decisions related to green infrastructure adoption. To adapt the framework, we relied on findings from observations at national stormwater meetings in combination with a systematic literature review on influential factors related to green infrastructure adoption. We discuss our revisions to the framework that helped us understand the decision by municipal governments to adopt green infrastructure. Remaining research needs and challenges are discussed regarding the development of an urban stormwater SES framework as a classification tool for knowledge accumulation and synthesis.

Using Statistical Regressions to Identify Factors Influencing PM2.5 Concentrations: The Pittsburgh Supersite as a Case Study

Using data from the Pittsburgh Air Quality Study, we find that temperature, relative humidity, their squared terms, and their interactions explain much of the variation in airborne concentrations of PM 2.5 in the city. Factors that do not appreciably influence the concentrations over a full year include wind direction, inverse mixing height, UV radiation, SO 2 , O 3 , and season of the year. Comparison with similar studies of PM 2.5 in other cities suggests that the relative importance of different factors can vary greatly. Temperature and relative humidity are important factors in both Pittsburgh and New York City, and synoptic scale meteorology influencing these two sites can explain much of the pattern in PM 2.5 concentrations which peak in the summer. However, PM 2.5 levels in other cities have different seasonal patterns and are affected by a number of other factors, and thus the results presented here cannot be generalized to other locations without additional study.

Sustainable Engineering: A Model for Engineering Education in the Twenty-First Century?

How do we design a sustainable built environment for ten billion people? What policies, economic structures and social structures will move us in this direction? These are questions that challenge contributors to and readers of this journal. They are also questions that challenge engineering educators, training the designers who will create the built environment of the twenty-first century. Engineering educators often describe their curricula with the metaphor of a toolbox. Engineering principles of mass conservation, energy conservation, and thermodynamics, to name just a few, can be viewed as powerful tools for solving problems and designing processes and products. An engineering education makes students proficient users of these tools. Yet if the toolbox is too limited, the designs created using those tools can be ineffective. To repeat an overused cliche, if the only tool you have is a hammer, everything looks like a nail. An engineering education also teaches our future designers to focus. From the earliest stages of an engineering education, students are taught to draw a ‘‘box’’ around the system to be analyzed, and to limit their attention to that boxed system. This is a necessary and powerful concept in engineering education, yet there is an increasing need to teach students to consider factors that are ‘‘out of the box’’. Engineering education needs new approaches that enlarge the box, and that give students the tools to effectively treat more complex problems, like the design of sustainable systems. How can engineering educators, practicing engineers and designers of all sorts, enlarge the box and create new tools? There are no simple answers, but offered here are some basic thoughts, using tools needed for the design of sustainable technologies as an example. As a case study of the process of enlarging the box and creating new tools for engineering design, consider the decisions surrounding how to provide personal mobility. In most of North America, personal mobility is achieved through the automobile. The choice of the automobile as the provider of personal mobility necessitates other decisions involving land use, fuel infrastructures, industrial supply chains, and societal investments in roadways. These levels of impact, associated with mobility decisions, are shown conceptually in Fig. 1. A first set of design questions (represented by the innermost layer of Fig. 1) are the choices faced by a parts engineer. In selecting the materials for a bumper/ front end, for example, the engineer could select galvanized steel or a composite, glass-reinforced plastic. Which bumper is better? Like many engineering decisions, this decision can be viewed from environmental, economic and social perspectives. The galvanized steel can be far more effectively recycled, yet the plastic composite will lead to greater fuel efficiency over the life of the vehicle. The steel bumper may be less costly to repair, resulting in different costs of ownership than the glass composite bumper. And, there may be different levels of passenger safety offered by the two materials. New analysis tools, such as environmental life cycle assessments (Curran 1996), have emerged to allow designers to address some of the multifaceted attributes of their designs. These types of analysis methods should become part of the engineer’s toolbox. The next level of questions and tools, represented by the second layer from the center in Fig. 1, considers supply chain impacts. For automobiles, how are parts manufacturers, automotive repair shops, coal producers, The authors have jointly formed the Center for Sustainable Engineering (http://www.csengin.org), which is dedicated to the development and dissemination of educational materials for incorporating concepts of sustainability into engineering curricula.