7th International Aerosol Conference

IAC Tutorials

Sunday, September 10, 2006

First Session: 8:00 a.m. – 9:40 a.m.

1. Introduction to Aerosol Mechanics I
Dr. 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 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 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.

2. Aerosol Thermodynamics
Dr. Athanasios Nenes, Georgia Institute of Technology, Schools of Earth and Atmospheric Sciences and Chemical and Biomolecular Engineering, Atlanta, GA

Abstract: The equilibrium thermodynamic properties of the mixture of acids, salts, and organic compounds present in the atmosphere largely control gas/aerosol equilibrium and the water uptake of soluble aerosol components in response to temperature and relative humidity changes. This course will cover the following fundamentals: the water uptake of different soluble components of aerosols, including organic compounds; the precipitation of solid phases and metastable equilibria; the Phase Rule; Henry’s law; the Kelvin effect; and activity coefficients and deviations from ideal solution behavior. There will be some discussion of predictive methods for thermodynamic properties (notably vapor pressures) of atmospheric organic compounds, activity coefficient models for the liquid phase, and the types and sources of data that can be used in these models.

Athanasios Nenes is an assistant professor in the Schools of Earth and Atmospheric Sciences and Chemical and Biomolecular Engineering at the Georgia Institute of Technology, email nenes@eas.gatech.edu 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. He is the developer of the ISORROPIA aerosol thermodynamic model (http://nenes.eas.gatech.edu/~ISORROPIA) which has been widely used in atmospheric modeling applications.

3. Air Pollution Exposure Assessment: Implications for Particulate Matter Epidemiology
Dr. Jeremy A. Sarnat, Department of Environmental and Occupational Health, Rollins School of Public Health of Emory University, Atlanta, GA

Abstract: Most epidemiologic studies examining the health effects from exposure to ambient particulate matter have used measurements from central site monitors as surrogates of corresponding personal exposures. The validity of this practice and its potential for introducing exposure misclassification bias into the observed epidemiologic results has been widely debated. In 1998 the National Research Council recommended that further research be conducted to characterize personal exposures to PM2.5, including its relationship to ambient PM2.5 and other multi-pollutant exposures. To address these issues, several panel studies were designed and conducted that characterized actual multipollutant personal exposures throughout the United States and Europe. This tutorial reviews the major results from these exposure studies and summarizes the collective findings for their impact on interpreting particulate matter epidemiologic studies. Directions for future exposure assessment and epidemiology research, including characterizing personal exposures to chemically- and sizeresolved PM2.5, will also be discussed.

Jeremy Sarnat is an assistant professor at the Rollins School of Public Health of Emory University specializing in characterizing personal exposure to criteria air pollutants. He received his master’s degree in environmental risk assessment and doctorate in environmental exposure assessment from Harvard University.

4. Aerosol Characterization using Plasma Spectrochemistry
Drs. Martin M. Shafer and James J. Schauer, Environmental Chemistry and Technology Program, University of Wisconsin- Madison, Madison, WI

Abstract: Detailed elemental and chemical speciation analysis of aerosol particulate matter (PM) can provide valuable information on PM sources, transformations, and climate forcing. Certain PM sources may best be resolved using trace metal signatures, and elemental fingerprints can supplement and enhance molecular maker analysis of PM for source apportionment modeling. In the search for toxicologically relevant components of PM, health studies are increasingly demanding more comprehensive characterization schemes. It is also clear that total metal analysis is at best a poor surrogate for the bioavailable component, and analytical techniques that address the labile component or specific chemical species are needed.

However, traditional analytical techniques (XRF, PIXIE, INAA) that have been widely applied in the past to determine the elemental composition of PM do not have the required sensitivity and accuracy to quantify the full suite of trace elements in the microgram masses of samples typical of many fine particle collections. This state of affairs is exacerbated by the current trend toward even smaller sample sizes that is being driven by (1) particle size-resolved sampling; (2) personal sampler collections; and (3) fine temporal scale (1-4 hr) sampling.

Inductively-Coupled Plasma Mass Spectrometry (ICP-MS) is emerging as a powerful tool for the determination of the elemental composition and chemical speciation of atmospheric aerosols. In addition to exhibiting extreme sensitivity and high signal to noise, the technique offers other unique capabilities including: high precision, extremely wide dynamic range, a large element menu, and elemental isotopic capability. These features significantly advance the state-of-the art (making it the method of choice for most applications) over traditional aerosol analysis techniques. However, full realization of these advantages is contingent upon several key factors as prerequisites: 1. Full integration of clean techniques into collection/processing/analysis methods; 2. Application of efficient, unbiased, and precise solubilization methods; and 3. Minimization of polyatomic interferences in the ICP-MS analysis.

This tutorial will address each of these three areas in detail, providing practical solutions and recommendations for a variety of real-world applications. It will be stressed that ultratrace ICP-MS analysis cannot be performed in isolation, but must be part of a complete package of contamination and interference control. The importance and practical implementation of method blanks and use of standard reference materials in protocol validation will be covered. Metrics of ICP-MS performance will be compared with those from more traditional methods as specifically relates to ambient aerosol characterization.

Contamination control strategies for specific steps (substrate preparation, field sampling, post-collection processing, and ICP-MS analysis) of the overall method will be discussed. Lack of suitable solubilization methods for the complete suite of elements comprising atmospheric particulate matter has been a barrier to the use of solution nebulization techniques, including ICP-MS, for the analysis of aerosols. Concerns have included extraction efficiency, volatilization losses, contamination, and issues of dilution and sensitivity. This short course will detail digestion protocols that our research group (and others) have developed to effectively address these issues. Microwave-based methods will be emphasized. Various “selective” dissolution approaches for aerosols will also be covered – focusing on methods that target the labile metals/components. A host of interference control approaches for ICP-MS analysis will be discussed, including: (1) the use of high efficiency desolvating nebulizers; (2) collision/reaction cell ICP-MS; and (3) high mass resolution ICP-MS.

The tutorial will conclude with a discussion of several advanced applications of ICP-MS in the context of aerosol characterization. These will include chemical speciation analysis (oxidation state speciation, HPLC-ICP-MS), high precision isotope ratio analysis and applications, and direct solids/particle analysis using laser-ablation-ICP-MS.

Second Session: 10:00 a.m. – 11:40 a.m.

5. Introduction to Aerosol Mechanics II
Dr. William C. Hinds, UCLA, School of Public Health, Center for Occupational and Environmental Health, Department of Environmental Health Science, Los Angeles, CA

6. Atmospheric Nucleation
Dr. Markku Kulmala, University of Helsinki, Department of Physical Sciences, Helsinki, Finland

Abstract: In order to be able to better understand the health and climatic effects of atmospheric aerosols, the formation and growth processes of atmospheric aerosols should also be better understood. Nucleation, the formation of ultrafine particles detected at a few nm, and subsequent growth to ~100 nm in 1- 2 days, has been observed frequently all around the world, particularly in the continental boundary layer. Such observations span from Arctic and Antarctic areas, over the remote boreal forest, and urban and suburban areas in Scandinavia, to industrialized agricultural regions in Europe and North America, to coastal environments around Europe, and to Asian and American megacities. Our recent overview summarized the formation and growth properties from a global point of view, quantifying especially the formation and growth rates of nucleation events where available. It has been proposed and also observed that atmospheric new particle formation depends on the sulfuric acid concentration. On the other hand some observations support the idea that atmospheric ions are participating in new particle formation. In this tutorial, different atmospheric nucleation mechanisms - including barrierless (kinetic), binary, ternary and ion induced nucleation as well as recently proposed cluster activation mechanisms - are explained and compared with atmospheric observations and laboratory experiments.

Markku Kulmala is an academy professor and professor in physics at University of Helsinki, Finland. He acts also as a director of the Division of Atmospheric Sciences in the Department of Physical Sciences in Helsinki. He received master’s and doctorate degrees in physics from the University of Helsinki.

7. Human Aerosol Exposure: Toward a Mechanistic Understanding
Dr. William W Nazaroff, Department of Civil and Environmental Engineering, University of California, Berkeley, CA

Abstract: This tutorial explores the relationships between particle sources and human inhalation exposure. The tools and techniques are those of the physical sciences and engineering, stressing causal connections. The lecture 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 Nazaroff is professor of environmental engineering and chair of the Energy and Resources Group 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).

8. Basics of Light Absorbing Carbon
Dr. Tami C. Bond, Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL

Abstract: Although carbon particles contain thousands of compounds, one type of carbon is routinely separated in modeling and analysis: the kind that appears black because it absorbs light strongly. What makes this compound so special? This tutorial will briefly discuss flame formation and important sources of light-absorbing carbon. Carbon that absorbs light weakly will also be covered. I will review factors that affect absorption and scattering by these particles, including changes that occur during the time between emission and removal. This discussion leads to an overview of the role of black particles in the Earth’s radiative balance. Finally, I will review common measurement methods, with particular emphasis on how light absorption can aid in or confound interpretation.

Tami Bond earned bachelor’s and master’s degrees in the combustion side of mechanical engineering before her 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 and is now an assistant professor at the University of Illinois. Most of her research involves measuring and estimating emissions for climate applications. She still likes to burn things.

Third Session: 1:00 p.m. – 2:40 p.m.

9. Aerosol Sampling and Transport
Dr. John E. Brockmann, Principal Member, Technical Staff, Sandia National Laboratories, Albuquerque, NM

Abstract: It is desirable that the sampled aerosol be representative of the aerosol in its original environment. Sampling and transport can alter
the ambient aerosol distribution. This tutorial will provide the tools to evaluate aerosol sampling and transport systems. The mechanisms that enrich or deplete particle concentration will be identified and discussed, and correlations from the literature will be given.

Dr. Brockmann received his PhD in mechanical engineering from the University of Minnesota in 1981 and works at Sandia National Laboratories. His areas of research include nuclear aerosols, microcontamination, particle sampling and transport, and instrumentation.

10. Measurements of Aerosol Radiative Properties
Dr. John A. Ogren, Physical Scientist, NOAA Earth System Research Laboratory, Boulder, CO

Abstract: This tutorial will cover the methods used for measurement of aerosol radiative properties, with an emphasis on in-situ measurements of aerosol light scattering, absorption, and extinction coefficients. Approaches for determining the dependence of these properties on particle size, wavelength, and relative humidity will be described, along with an overview of the results from their application in NOAA’s longterm aerosol monitoring program.

Dr. Ogren received his PhD in 1983 from the University of Washington. He leads NOAA’s long-term aerosol monitoring program, which emphasizes the radiative properties of aerosols.

11. Biokinetics and Toxicology of Nanoparticles
Dr. Günter Oberdörster, Professor of Toxicology, University of Rochester, Department of Environmental Medicine, Rochester, NY

Abstract: The rapidly developing field of nanotechnology holds many promises and benefits for developments in structural engineering, electronics, optics, consumer products, alternative energies, soil and water remediation and nanomedicine. However, engineered nanoparticles (NP, <100 nm) are also likely to result in human exposure through inhalation, ingestion, skin uptake, and injection of engineered nanomaterials. Information about safety and potential hazards is urgently needed. The new field of nanotoxicology, which can be defined as safety evaluation of engineered nanostructures and nanodevices, addresses this need by identifying NP-cell interactions through specific in vivo and in vitro tests. When inhaled, certain sizes of NP are efficiently deposited by diffusional mechanisms in all regions of the respiratory tract. The small particle size facilitates uptake into cells, transcytosis across epithelial and endothelial cells into the blood and lymph circulation to reach potentially sensitive target sites such as bone marrow, lymph nodes, spleen, and heart. Access to the central nervous system and ganglia via translocation along axons and dendrites of neurons has also been observed. NP penetrating the skin distribute via uptake into lymphatic channels. Endocytosis, and biokinetics are largely dependent on NP surface chemistry (coating) and in vivo surface modifications. The greater surface area per mass compared to larger-sized particles of the same chemical structure renders NP more active biologically. This activity includes a potential for inflammatory and pro-oxidant, but also anti-oxidant, activity. Evidence of mitochondrial distribution and oxidative stress response following NP endocytosis points to a need for basic research about their interactions with subcellular structures. Considerations for assessing safety of engineered NP include careful selections of appropriate and relevant doses/concentrations, the likelihood of increased effects in a compromised organism, and the development of new specific tests. This should be balanced with the benefits of possible desirable effects in medical and other applications. An interdisciplinary team approach (e.g., toxicology, materials science, medicine, molecular biology, and bioinformatics, to name a few) is mandatory for nanotoxicology research to arrive at an appropriate risk assessment.

Dr. Oberdörster received a DVM in veterinary medicine and PhD in pharmacology from the University of Giessen, Germany.

12. Secondary Aerosol Formation
Dr. Paul J. Ziemann, Air Pollution Research Center and 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, I 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 Ziemann is an associate 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.

Fourth Session: 3:00 p.m. – 4:40 p.m.

13. Preparation of Nanoparticles and Nanostructured Powders by Spray Method for Their Applications in Nanotechnology
Dr. Kikuo Okuyama, Department of Chemical Engineering, Graduate School of Engineering, Hiroshima University, Higashi- Hiroshima, Japan

Abstract: Recently nanoparticles and nanostructured powders are attracting a great interest in science and engineering as functional materials for use in electronics, biotechnology and so on. Spray methods are promising routes to produce single and multicomponent nanoparticles and nanostructured powders. In this Tutorial, I would like to talk about: 1) General scope of particles preparation by spray pyrolysis and spray drying methods; 2) Preparation of nanoparticles using physical and chemical methods (electrospray pyrolysis, lowpressure expansion method and so on); 3) Dispersing technology for agglomerated nanoparticles; 4) Preparation of ordered porous powders as well as particles composite by spray drying method; 5) and finally, The application of nanoparticles and nanostructured powders in nanotechnology.

Prof. Kikuo Okuyama is the professor in the Department of Chemical Engineering, Graduate School of Engineering at Hiroshima University. He received his BS (1971) and MS (1973) degrees in chemical engineering from Kanazawa University, and he received his doctorate of engineering (1978) in chemical engineering at University of Osaka Prefecture. He is the president of the Japan Association of Aerosol Science and Technology (JAAST), and serves as the editor of the Journal of the Society of Powder Technology Japan, Journal of Nanoparticle Research and Aerosol Science and Technology.

14. Aerosol Technology for Drug Delivery
Dr. Warren Finlay, University of Alberta, Department of Mechanical Engineering, Edmonton, AB, Canada

Abstract: The number of technologies under development for delivering therapeutic aerosols to the respiratory tract has increased dramatically in recent years, yielding a surprisingly large array of aerosol delivery devices and formulations. However, the fundamental principles governing these systems are relatively few, and understanding these principles allows the scientist or engineer to much more easily understand the many competing pharmaceutical aerosol delivery systems. The focus of this tutorial is thus on the underlying mechanics of inhaled pharmaceutical aerosol delivery devices, including existing aqueous systems, dry powder inhalers, propellant driven metered dose inhalers, as well as new systems under development.

Warren Finlay is a professor of mechanical engineering at the University of Alberta, where he holds the distinguished title of Killam Annual Professor. He received bachelor’s and master’s degrees in electrical engineering from the University of Alberta and a doctorate in mechanical engineering from Stanford University. He is the author of the book Mechanics of Inhaled Pharmaceutical Aerosols, Academic Press, 2001.

15. Instrumentation and Theory of Cloud Condensation Nuclei Measurements
Dr. Athanasios Nenes, Georgia Institute of Technology, Schools of Earth and Atmospheric Sciences and Chemical and Biomolecular Engineering, Atlanta, GA

Abstract: The past few years have seen a significant and growing interest in measuring the potential of aerosols to act as cloud condensation nuclei (CCN). Numerous techniques over the years have been developed for this purpose; they all involve exposing an aerosol sample to a controlled water vapor supersaturation and optically detect the size and concentration of droplets that form. We will review the diverse set of designs and detection approaches, as well as theoretically analyze the methodology embodied by each CCN instrument. Results from laboratory and field experiments will be presented to demonstrate the capabilities of these instruments and highlight their importance for quantitative understanding of aerosol-cloud interactions.

Athanasios Nenes is an assistant 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.

16. Making Use of Satellite-derived Aerosol Amounts, Distributions, and Properties
Dr. Ralph Kahn, Jet Propulsion Laboratory, Caltech, Pasadena, CA

Abstract: Space-borne instruments are providing increasing amounts of data relating to global aerosol spectral optical depth, horizontal and vertical distribution, and micro-physical properties. The data sets, and many of the underlying techniques, are new. They represent a vast amount of information, potentially useful to the AAAR community. However, there are also issues, some quite subtle, that scientific users must take into consideration. This tutorial will provide one view of the answers to the following four questions: 1.) What satellite-derived aerosol products are available?; 2.) What are their strengths and limitations?; 3.) How are they being used now?; and 4.) How might they be used in conjunction with each other, with sub-orbital measurements, and with models to address cutting edge aerosol questions?

Ralph Kahn is a principal scientist in the Earth and Space Sciences Division at JPL. He is the aerosol scientist for the Multi-angle Imaging SpectroRadiometer (MISR) instrument, which flies aboard the NASA Earth Observing System’s Terra satellite. Kahn received his PhD in applied physics from Harvard University.