AAAR Tutorial Sessions
Monday, October 20, 2008
First Session: 8:00 a.m. - 9:40 a.m.
1. Introduction to Aerosol Mechanics I
William C. Hinds, UCLA, School of Public Health, Center for Occupational and Environmental Health, Department of Environmental Health Science, Los Angeles, CA
Abstract: These two courses (Tutorials 1 and 5) form a sequence that covers basic aerosol mechanics (particle motion) at an introductory level. Topics include: Stokes law, settling velocity, slip correction, aerodynamic diameter, non-spherical particles, acceleration, relaxation time, stopping distance, impaction, isokinetic sampling, diffusion, and coagulation. The course covers theory and applications and is suitable for those new to the field and for others who want to brush up on the basics.
William C. Hinds is a professor of environmental health sciences at the UCLA School of Public Health. He received a bachelor's degree in mechanical engineering from Cornell University and a doctorate in environmental health from Harvard University. Professor Hinds has taught the Introduction to Aerosol Mechanics tutorial for many years as a service to AAAR. This will be his last year teaching this tutorial series.
2. Bioaerosol Sampling and Analyses for Biodefense
Tiina Reponen, Department of Environmental Health, University of Cincinnati, OH and Jana S. Kesavan, Aerosol Sciences Team, U.S. Army Edgewood Chemical Biological Center, Aberdeen Proving Ground, MD
Abstract: Bioaerosols are produced naturally, as a byproduct, or intentionally to harm people. Sampling and detecting harmful aerosols produced by terrorists are important problems. Bioaerosols include viruses and bacteria, and the size of biological particles varies widely, from nanoscale to micron size. The same physical principles that are applied to non-biological particles can be applied to bioaerosol sampling in terms of sampling efficiency of a given particle size range. When sampling to identify a threat, high sample volume, high collection efficiency and accurate detection are important. This tutorial will review the traditional and modern techniques for bioaerosol sampling and analysis. Advantages and disadvantages of various methods in bioaerosol sampling and detection will be discussed.
Tiina Reponen is a professor of environmental health at the University of Cincinnati, Department of Environmental Health. She received her doctoral degree in environmental sciences from Kuopio University, Finland. Her current research efforts are focused on the exposure assessment of biological and non-biological particles in indoor and industrial environments and physical and microbiological characterization of airborne bacteria and fungi.
Jana S. Kesavan is a research physicist at the U.S. Army Edgewood Chemical Biological Center. She received her doctoral degree in environmental health sciences from Johns Hopkins University. She has been characterizing many aerosol samplers, concentrators, and detector systems that are used for biodefense purposes. Next generation and developmental aerosol sampler and detector systems are also characterized in her laboratory.
3. Nanoparticle Synthesis
Mark T. Swihart, Department of Chemical and Biological Engineering, State University of New York at Buffalo, Buffalo, NY
Abstract: The vast majority of commercially produced nanoparticulate materials are made by aerosol processes, based on gas-to-particle conversion. Large volume examples include carbon black, fumed silica, titania, and nickel nanoparticles. In contrast, the vast majority of academic nanoparticle synthesis research has been in solution-phase methods that often provide much better control of product particle size distribution and morphology. A key challenge in aerosol synthesis of nanoparticles is to approach the control of particle size and morphology that is achieved by solution phase methods, while maintaining the important advantages of aerosol processing, including low cost, high throughput, high purity, high crystallinity, and reduced solvent use. This tutorial will provide an overview of methods of aerosol synthesis of nanoparticles, including flame reactors, laser-driven reactors, thermal and non-thermal plasma reactors, spray pyrolysis, and related approaches. Strengths, weaknesses, common features, and differences among these techniques will be highlighted. Aerosol dynamics modeling of nanoparticle synthesis will also be briefly addressed.
Mark T. Swihart is a professor of chemical and biological engineering and director of the UB2020 Integrated Nanostructured Systems Initiative at the State University of New York at Buffalo. He earned a BS in chemical engineering from Rice University, a PhD in chemical engineering from the University of Minnesota and conducted postdoctoral research in the Particle Technology Lab at Minnesota.
4. Conceptual Framework and Application of Receptor Models
Philip K. Hopke, Departments of Chemical Engineering and Chemistry, Clarkson University, Potsdam, NY
Abstract: This course will present the underlying chemical basis for distinct profiles for different types of emission sources and how these differences in profiles then provide a basis for receptor models. The conceptual framework of receptor models, a mass balance approach, will be described and how resulting models can be implemented depending on what a priori information is available. Applications of several types of models to various problems will be described with an emphasis on the practical use of positive matrix factorization for both elemental and organic species data.
Philip K. Hopke is the Bayard D. Clarkson Distinguished Professor at Clarkson University and the director of the Center for Air Resources Engineering and Science. Professor Hopke received his BS in chemistry from Trinity College (Hartford) and his MA and PhD degrees in chemistry from Princeton University.
Second Session: 10:00 a.m. - 11:40 a.m.
5. Introduction to Aerosol Mechanics II
William C. Hinds, UCLA, School of Public Health, Center for Occupational and Environmental Health, Department of Environmental Health Science, Los Angeles, CA
Abstract: These two courses (Tutorials 1 and 5) form a sequence that covers basic aerosol mechanics (particle motion) at an introductory level. Topics include: Stokes law, settling velocity, slip correction, aerodynamic diameter, non-spherical particles, acceleration, relaxation time, stopping distance, impaction, isokinetic sampling, diffusion, and coagulation. The course covers theory and applications and is suitable for those new to the field and for others who want to brush up on the basics.
William C. Hinds is a professor of environmental health sciences at the UCLA School of Public Health. He received a bachelor's degree in mechanical engineering from Cornell University and a doctorate in environmental health from Harvard University. Professor Hinds has taught the Introduction to Aerosol Mechanics tutorial for many years as a service to AAAR. This will be his last year teaching this tutorial series.
6. Numerical Modeling of Multiphase Flows
Sean C. Garrick, Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN
Abstract: This tutorial presents the state-of-the-art in modeling and simulation of multi-phase flows. The models, tools and techniques presented will highlight and delve into both scientific investigation and engineering practice. Specific attention will be given to the need for turbulence models, the coupling of Eulerian and Lagrangian dynamics, and spanning the wide range of length and time scales present in variety of multi-phase flows. In addition, the tutorial will explore the interrelatedness of computational and experimental/physical investigation in the dynamics and chemistry of aerosols and how they may better inform each other.
Sean C. Garrick is an associate professor of mechanical engineering at the University of Minnesota. His research group investigates nanoparticle formation and growth and turbulent reacting multiphase flows. They also develop models for the effects of turbulence on chemical reactions, nanoparticle nucleation, and particle coagulation. Dr. Garrick earned his PhD in mechanical engineering from the State University of New York at Buffalo in 1998.
7. Nanoparticle Applications in Energy Technology
Uwe R. Kortshagen, Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN
Abstract: Semiconductor nanocrystals produced in the gas, liquid, and solid phase are widely studied for applications in energy conversion devices. Applications range from photovoltaics to light-emitting devices to thermoelectrics. This tutorial will present an overview over some of these potential applications and will discuss the potential advantages of nanoparticles compared to bulk materials. It will discuss several schemes for light emitting devices, in which nanocrystals enhance the light emitting properties. It will also discuss the basic physical processes in semiconductor nanocrystals as well as various implementations of nanocrystal-based solar cells: dye-sensitized solar cells, quantum-dot sensitized solar cells, hybrid organic/inorganic solar cells, and ink-jet printed solar cells based on nanocrystal inks.
Uwe R. Kortshagen is a Distinguished McKnight University Professor and director of Graduate Studies in the Department of Mechanical Engineering at the University of Minnesota, and a member of the graduate faculties of physics, chemical engineering, and materials science. He earned his diploma degree in plasma physics in 1988, and his PhD in plasma physics in 1991 from the University of Bochum, Germany. He currently serves as president of the International Plasma Chemistry Society.
8. Aerosol Nucleation: Bridging Subnanoscale Processes to Global-Scale Climate Change
Fangqun Yu, Department of Earth and Atmospheric Sciences, State University of New York at Albany, Albany, NY
Abstract: Nucleation, the molecular process that drives the formation of new particles in the nanometer size range, is a key source of the atmospheric aerosol. Nanoparticles that grow to the sizes of cloud condensation nuclei contribute to the aerosol indirect radiative forcing of the climate system. Exposure to high concentrations of nanoparticles can lead to adverse health effects. A clear understanding of the physical and chemical processes and parameters controlling aerosol nucleation is thus crucial for assessing future climate change, and a range of climate-related health and environmental impacts associated with airborne particulates. Topics to be covered in this tutorial will include: (1) Nucleation fundamentals: A historical overview; (2) Recent advances in atmospheric nucleation (quantum-mechanical investigation of molecular interactions relevant to nucleation, measurements of pre-nucleation clusters, multiple-instrument characterization of nucleation events, and kinetic nucleation models); (3) Well-constrained case studies of particle formation and growth in the atmosphere; (4) Nucleation rate parameterizations suitable for multi-dimensional simulations; (5) Global modeling and observations of atmospheric nucleation; (6) Nucleation and climate change (aerosol indirect radiative forcing, positive and negative climate feedback mechanisms, and links between solar variability and climate change).
Fangqun Yu is a faculty member at the State University of New York at Albany. He has earned degrees from Peking University and the Chinese Academy of Sciences, and a PhD in atmospheric sciences at UCLA. Yu's research focuses on the fundamental theory of nucleation mechanisms, the development and application of nucleation models, the analysis of field and laboratory measurements related to particle formation, and the global implications of aerosol nucleation for climate change, air quality, and health impacts. He has published about 50 peer-reviewed scientific journal papers.
Third Session: 1:00 p.m. - 2:40 p.m.
9. Atmospheric-Surface Exchange: Dry Deposition and Resuspension
Cliff I. Davidson, Departments of Civil and Environmental Engineering/Engineering and Public Policy, Carnegie Mellon University, Pittsburgh, PA
Abstract: This tutorial reviews current understanding of aerosol exchange between the atmosphere and surfaces, focusing on the interacting processes of dry deposition and resuspension. First, the process of dry deposition is described physically and mathematically, considering the three sequential steps aerodynamic transport, boundary layer transport, and interaction with the surface. Second, the process of resuspension is described, including some newly developed models. Finally, a number of important measurement techniques for dry deposition and resuspension are summarized. These include direct measurements of material accumulated on surfaces as well as methods of inferring the flux using atmospheric data.
Cliff I. Davidson is a professor in the Department of Civil and Environmental Engineering and the Department of Engineering and Public Policy at Carnegie Mellon. He is the founding director of the Center for Sustainable Engineering at that university. He received his BS in electrical engineering from Carnegie Mellon and MS and PhD degrees in environmental engineering science from the California Institute of Technology.
10. Secondary Aerosol Formation
Paul J. Ziemann, Department of Environmental Sciences, University of California, Riverside, CA
Abstract: Secondary aerosol is an important component of atmospheric fine particles that generally consists of organics, sulfates, and nitrates. The processes that lead to the formation of this material are often complex and can involve gas and particle phase chemistry, nucleation, and gas-particle partitioning. In this course, Dr. Ziemann will discuss the major chemical reactions and partitioning processes involved in the formation of secondary organic and inorganic aerosol (with a strong emphasis on organic aerosol) using examples from laboratory and field studies.
Paul J. Ziemann is a professor of atmospheric chemistry at the University of California, Riverside. He received a doctorate in chemistry from Penn State University and was a postdoctoral researcher in the Particle Technology Laboratory at the University of Minnesota.
11. Challenges to Ensuring the Safety of Emerging Nanomaterials
Andrew D. Maynard, Project on Emerging Nanotechnologies, Woodrow Wilson International Center for Scholars, Washington, DC
Abstract: Many engineered nanomaterials demonstrate scale-specific functionality that may be exploited in new products and applications. But there is evidence that scale-specific properties might also lead to new risks to humans and the environment. Avoiding undue release, dispersion of and exposure to nanoscale aerosols is a significant challenge if safe and successful nanotechnologies are to be developed and commercialized. This tutorial considers the challenges to understanding and managing potential nanomaterial risks from an aerosol perspective. Starting from an exploration of how nanoscale size and structure might influence biologically-relevant behavior, the tutorial will consider how aerosol science and technology can inform the development of safe nanotech products and practices, and where some of the greatest future challenges lie.
Andrew D. Maynard is chief science advisor to the Project on Emerging Nanotechnologies. He received his bachelor's degree in physics from the University of Birmingham, U.K., and his doctorate in ultrafine particle analysis from the University of Cambridge, U.K. For many years, he worked on aerosol measurement and characterization at the U.K. Health and Safety Laboratory and the U.S. National Institute for Occupational Safety and Health. Before leaving bench science for science policy in 2005, Dr. Maynard was co-chair of the U.S. government National Nanotechnology Initiative Nanotechnology Environment and Health Implications working group.
12. Aerosol-Cloud Interactions: The Elusive Component of Climate Change
Athanasios Nenes, Schools of Earth and Atmospheric Sciences and Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA
Abstract: The effects of aerosols on clouds (known as the "aerosol indirect climatic effect") are thought to have a net climatic cooling effect, which partially offsets greenhouse gas warming. Regional impacts of aerosol-cloud interactions on the radiation budget and precipitation can be very strong. Despite its importance, the complex and multiscale nature of aerosol-cloud interactions makes it one of the most uncertain components of anthropogenic climate change. This tutorial will provide an overview of what aerosol-cloud interactions are and present the approaches used to observationally study them and represent them in models. We will provide an assessment of what has been learned and point out key research challenges for the future.
Athanasios Nenes is an associate professor in the Schools of Earth and Atmospheric Sciences and Chemical and Biomolecular Engineering at the Georgia Institute of Technology. He received a diploma in chemical engineering from the National Technical University of Athens, a master's degree in atmospheric chemistry from the University of Miami, and a doctorate in chemical engineering from the California Institute of Technology.
Fourth Session: 3:00 p.m. - 4:40 p.m.
13. Human Aerosol Exposure: Toward a Mechanistic Understanding
William W Nazaroff, Department of Civil and Environmental Engineering, University of California, Berkeley, CA
Abstract: This tutorial explores the relationships between aerosol emission sources and human inhalation exposure. The tools and techniques are those of the physical sciences and engineering, stressing causal connections. The tutorial draws on key chemical and physical knowledge from atmospheric aerosol science, focusing on human exposure as the outcome of concern leads to an emphasis on the proximity between sources and receptors. Most exposure occurs while people are in enclosed spaces, so issues that influence indoor aerosols enter strongly into this lecture.
William W Nazaroff is a professor of environmental engineering at UC Berkeley. His research group studies indoor air pollutant chemistry and physics. They also develop and apply methods for assessing human exposure to air pollutants from major exposure sources, such as motor vehicles, power plants, and cigarettes. Dr. Nazaroff earned a PhD in environmental engineering science at Caltech (1989).
14. Methods for the Semicontinuous Measurement of Particle and Gas Chemical Composition
Rodney J. Weber, School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA
Abstract: A wide variety non-mass spectrometric methods have been developed recently for automated on-line measurements of particle chemical composition in real, or near real-time. Many of these techniques collect ambient particles in a manner that permits them to be directly coupled to existing analytical devices. Although these approaches generally only provide measurements of bulk chemical composition, they often have unique advantages. Some are highly quantitative and are capable of measuring a wide range of chemical compounds, including gas phase species. Others are relatively low in cost and/or can operate unattended for extended periods making them suitable for network monitoring sites. A review attempting to convey the breadth of these types of approaches will be presented. This will include approaches that convert particles to gases for analysis and liquid-based systems. Methods for measuring a wide range of compounds will be discussed, including inorganic ions, total organic mass and water-soluble organic mass, organic acids, reactive oxygen species (ROS), aerosol pH, and specific water-soluble metals. Consideration will be given to the application of newer analytical devices, such as microchip electrophoresis, ion selective electrodes, and liquid waveguide capillary cells with spectroscopic detection. The goal will be to provide resource information and insights into the many research opportunities afforded by these types of systems.
Rodney J. Weber is a professor in the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology. He received a bachelor's degree in mechanical engineering from the University of Waterloo, and masters and doctorate degrees in mechanical engineering from the University of Minnesota.
15. Aerosol Filtration for Fine and Nano Particles
Da-Ren Chen, Department of Energy, Environmental and Chemical Engineering, Washington University, St. Louis, MO
Abstract: Nanoparticles comprise a key foundation for nanotechnology. Nanoparticles of different materials have been synthesized for industrial applications using a variety of physical and chemical methods. The presence of synthetic nanoparticles and the potential for releasing them into the environment have raised public concern over how these nanoparticles could impact the public health and our environment. Large increases in demand and production in the future could lead to unintended exposures to nanoparticles by occupational workers and/or end product users via inhalation, dermal absorption, and gastrointestinal tract absorption. Aerosol filtration is the conventional technique to remove particles from gas streams. Concern about the filtration efficiency of filters is often raised when applying the technique for controlling releases of nanoparticles. This tutorial will review published works in nanoparticle filtration, fundamental filtration theories and simulation techniques for nanoparticle filtration, the experimental validation of theories, and issues/common mistakes in the experimental evaluation of filter performance for nanoparticles.
Da-Ren Chen, PhD, is an associate professor in the Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, MO. He received his PhD from the Particle Technology Laboratory, University of Minnesota. He has received the Sheldon K. Friedlander Award (1997), Smoluchowski Award (2002) and Kenneth T. Whitby Award (2005) for his contributions to nanoparticle instrumentation. He has also been involved in aerosol filtration research for more than 17 years. His filtration work includes filter pleating design; dust cake filtration; filter behavior under particle loadings; pulsed reserve-flow systems for filter cleaning; and modeling of filtration systems.
16. From Emission to Direct Forcing: Single Source Contributions to Climate Change
Tami C. Bond, Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL
Abstract: This tutorial will examine direct climate forcing by aerosols from a slightly different perspective. Instead of looking at how single chemical species affect the Earth's radiative balance, we'll discuss total effects of individual sources. The tutorial will begin with a brief overview of the major players in direct radiative forcing. A simple one-dimensional box model of radiative transfer will be presented and made available to the tutorial participants. (Bring a laptop if you desire.) The important aerosol characteristics that come from aerosol characterization, including hygroscopicity and optical properties will be discussed. Dr. Bond will then discuss the simplifications required to incorporate these aerosols into global models of transport and radiative-transfer models. Two case studies of sources that emit significant amounts of black carbon—diesel engines and biofuel cookstoves— showing the path from direct emission measurements to estimates of climate forcing by these sources will be presented. A discussion of future research needs to fill in the missing steps in the path from emission to forcing will conclude the tutorial.
Tami C. Bond earned bachelor's and master's degrees in the combustion side of mechanical engineering before turning to an interdisciplinary PhD from the University of Washington (atmospheric sciences, mechanical engineering and civil engineering). She was a NOAA Climate and Global Change post-doctoral fellow, a visiting scientist at NCAR, and is now an assistant professor at the University of Illinois. She measures emission properties that are relevant to understanding the climatic impact of anthropogenic aerosols in the laboratory and field and runs microphysical and global models.