Tutorials Information

Abstract: This tutorial is the first of two that introduce the broad field of aerosol science. We begin with the particle size distribution, which provides a concise physical description of the aerosol that determines its size-dependent properties. We then turn our attention to the behavior of individual particles that governs how the aerosol evolves, its impacts, and enables measurements. The drag forces that act on a particle determine its settling velocity and whether it can follow the motions of the surrounding gas. Stokes law describes the drag forces on spherical particles moving at modest velocities, but corrections are needed if the particles are small relative to the mean-free-path of the gas molecules, too large to be in the creeping flow regime, or not spherical. Knowledge of these scaling principles makes it possible to relate particle aerodynamics in seemingly disparate systems. The equations of motion for an aerosol particle reveal a measurable property, the aerodynamic relaxation time, that determines its sedimentation velocity and whether the particle will follow changes in velocity or direction of the gas in which it is entrained. We will examine how these inertial effects lead to deposition of large particles in the respiratory tract, filters, and sampling systems, and how they can lead to biases in aerosol sampling. Inertial effects are also used to determine an inertial size of the aerosol particles. Instruments for measuring this aerodynamic equivalent diameter will be briefly discussed. We will end this first introductory tutorial with a brief look at how inertial effects alter the size distribution of the aerosol released from a cough in a closed, well-mixed room.

Bio: Richard C. Flagan is the McCollum/Corcoran Professor of Chemical Engineering and Environmental Science and Engineering at the California Institute of Technology. He has served as the President of AAAR, and as Editor-in-Chief of Aerosol Science and Technology. His research spans the field of aerosol science, including atmospheric aerosols, aerosol instrumentation, homogeneous nucleation, aerosol synthesis of nanoparticles and other materials, bioaerosols ranging from pollen to the SARS-CoV-2 virus, and aerosols in the atmospheres of other worlds. His many contributions to the field of aerosol science have been acknowledged with the Sinclair Award of the AAAR, the Smoluchowski Award of the Gesellschäft für Aerosolforschung, and the Fuchs Award. He is a member of the National Academy of Engineering.

Abstract: Atmospheric aerosols exist in a wide variety of shapes, sizes, and chemical compositions. Some of these are emitted as aerosols from natural or anthropogenic sources; others are formed in the atmosphere from gases, which can be emitted from natural or anthropogenic sources. All of these aerosols are eventually removed from the atmosphere by wet deposition, e.g., in precipitation, or by dry deposition. In this tutorial, we examine removal of atmospheric aerosol by dry deposition onto different kinds of surfaces, such as natural vegetation, agricultural crops, soil and rock, lakes and oceans, and snowfields, as well as urban hardscape such as buildings, streets and parking lots. We also examine the importance of dry deposition relative to wet deposition for several chemical species under different conditions.

We begin by considering the reasons for studying dry deposition and how dry deposition data can be used. We then describe the physical processes of aerosol dry deposition for different aerosol size ranges and for various types of surfaces. We make use of fluid mechanics and physical and chemical interactions with surfaces to explain aerosol behavior during the deposition process. This is accomplished by considering three separate stages of aerosol transport: (1) Turbulent eddies carry particles from the free atmosphere down to the viscous sublayer containing relatively quiescent air just above the surface, (2) Particles move through the viscous sublayer propelled by Brownian and eddy diffusion for very small particles, interception and inertial impaction for larger particles, or sedimentation for even larger particles, and (3) Particles interact with the surface by sticking to it, bouncing off the surface, or chemically interacting with the surface and changing form. 

Next, we quantify the physical/chemical processes just described and present the basics of mathematical modeling of dry deposition on a few specific surface types. We consider atmospheric turbulence, characteristics of the viscous sublayer, and properties of the surface to develop these models. We also consider the extent to which such modeling is based on fundamentals versus empirical data.

Finally, we consider methods of measuring dry deposition, including direct measurements of particles accumulating on surfaces of interest, measurement of particle fluxes by micrometeorological methods, use of surrogate surfaces for particle deposition, and large-scale mass balance methods. We conclude the tutorial by comparing dry deposition to wet deposition measurements, and reaching conclusions about the importance of aerosol dry deposition for understanding overall aerosol transport and behavior.

Bio: Cliff Davidson is the Thomas and Colleen Wilmot Professor of Engineering in the Department of Civil and Environmental Engineering at Syracuse University in Syracuse, NY. He also serves as Director of Environmental Engineering Programs, and Director of the Center for Sustainable Engineering. He received his B.S. in Electrical Engineering from Carnegie Mellon University, and his M.S. and Ph.D. degrees in Environmental Engineering Science from California Institute of Technology.  Following his PhD, he was a member of the Carnegie Mellon faculty for 33 years before moving to Syracuse University in 2010. Davidson’s research areas are in measurement of atmospheric aerosol chemical species, long-range transport of aerosol from sources to receptor sites, and ultimate fate of aerosol by dry and wet deposition. He has led several field campaigns in U.S. National Parks and on the Greenland Ice Sheet. More recently, he has broadened his interests to include environmental sustainability in urban areas, especially the use of green roofs and other green infrastructure projects. He is a long standing member of the AAAR, and served as AAAR President in 1999-2000.

Abstract: Microfluidics is a powerful platform for precise, high-throughput, low-cost measurements with small volumes of sample. The microscale platform is already widely established in fields of biology, medicine, chemistry, and rheology, and, as highlighted in this tutorial, is rapidly emerging as an important platform for aerosol science measurements. This tutorial on aerosol measurements with microfluidics will involve three main sections:

• Basic operating principles of microfluidic flows, with emphasis on two-phase flows for aerosol science applications. General techniques for generating, detecting, trapping, sorting, filtering, and manipulating droplets and particles in microscale flows will be presented.
• Current and emerging aerosol science microfluidic measurements, with comparison to conventional aerosol experimental methods where applicable. In addition, methods for sample collection will be discussed.
• Step-by-step guidance on designing, fabricating, and operating devices, with a practical hands-on demonstration of assembling a device and generating fluid flows.

Bio: Cari Dutcher: Dr. Cari S. Dutcher is an Associate Professor of Mechanical Engineering (ME) and Chemical Engineering and Materials Science (CEMS) at the University of Minnesota, Twin Cities, with research interests in aerosol science and multiphase fluids. Cari has served on the AAAR board of directors, AAAR aerosol physics working group chair, and currently serves as secretary on the AAAR Executive Board. She has received a number of early faculty awards, including the 3M Non-Tenured Faculty Award, NSF CAREER and AAAR Kenneth T. Whitby Award. Cari received her Ph.D. from the University of California, Berkeley in Chemical Engineering and was a postdoc at the University of California, Davis in the Air Quality Research Center.

Bio: Andrew Metcalf: Dr. Andrew R. Metcalf is an Assistant Professor in Environmental Engineering and Earth Sciences at Clemson University. Andrew’s research interests are in atmospheric aerosols, with a focus on black carbon aerosol, and on developing new technologies for detecting airborne particles, including using microfluidics. Andrew is the PI for the SP2 NSF community instrument facility. Andrew received his Ph.D. from Caltech and was a postdoc at the Combustion Research Facility at Sandia National Lab and at the University of Minnesota.

Abstract: In this tutorial, we will discuss the status, gaps, and opportunities pertaining to global air quality monitoring. The role of Earth Observing Satellites (EOS) in global air quality monitoring will be discussed. Specific emphasis will be given to ground and satellite aerosol datasets. Aerosol retrievals, dataset access, and satellite missions will be discussed. The role of low-cost air-quality monitor networks in understanding spatial and temporal gradients in column and surface particle loading will also be discussed. The tutorial will include lecture material and hands-on exercises.  Lectures will cover the fundamentals of satellite atmospheric aerosol datasets, introduction to AERONET datasets, and best research practices on spatiotemporal collocation of space and ground datasets for validation studies. Hands-on exercises will be geared towards accessing data, spatiotemporal collocation, and validating against ground measurements (Participants should bring a laptop or tablet to participate in the hands-on exercises).

Bio: Dr. Gupta is a senior scientist at NASA Goddard Space Flight Center, Greenbelt, MD. He co-leads NASA’s AERONET program and has been leading the air quality training team under NASA’s Applied Remote Sensing Training (ARSET). He has provided online and in-person training workshops worldwide for the past 13 years. Dr. Gupta has more than 20 years of experience in satellite aerosol retrieval and application for air quality and climate change research.

Abstract: This tutorial continues the basic introduction to aerosol science, continuing the discussion of the physics of a single particle, and then examining particle diffusion, and finally turning our attention to the dynamics of aerosol populations. While large particles can be separated due to their inertia, inertial methods are difficult to use for small ones, but aerodynamic drag can be used for small particles if they are first charged and then subjected to an electric field. This method is applied in differential mobility analysis to obtain the particle size distribution in terms of a mobility equivalent diameter in the scanning mobility particle sizer (SMPS). Small particles can also deviate from the gas motion because Brownian motion causes them to diffuse, enhancing deposition of small particles in the respiratory tract, sampling systems, and filters. Diffusion also degrades the performance of the SMPS for small particles, which will be discussed. Aerosol particles can change size due to diffusion of vapors to or from them. Vapors can alter the particles and their size distribution by condensing on them or evaporating from them. We will examine the thermodynamics and vapor transport processes, their use in aerosol particle counting in the condensation particle counter (CPC), and examine effects on the particle size distribution. Under extreme conditions, vapors form new particles directly from the vapor phase through homogeneous nucleation of one or more vapor species, which we shall briefly examine. The particle size distribution is also altered by coagulation in which two particles combine through collision to form one large particle. These diverse processes can be combined to form a general dynamic equation for aerosols, which will be the final topic of these introductory aerosols.

Bio: Richard C. Flagan is the McCollum/Corcoran Professor of Chemical Engineering and Environmental Science and Engineering at the California Institute of Technology. He has served as the President of AAAR, and as Editor-in-Chief of Aerosol Science and Technology. His research spans the field of aerosol science, including atmospheric aerosols, aerosol instrumentation, homogeneous nucleation, aerosol synthesis of nanoparticles and other materials, bioaerosols ranging from pollen to the SARS-CoV-2 virus, and aerosols in the atmospheres of other worlds. His many contributions to the field of aerosol science have been acknowledged with the Sinclair Award of the AAAR, the Smoluchowski Award of the Gesellschäft für Aerosolforschung, and the Fuchs Award. He is a member of the National Academy of Engineering.

Please note that this tutorial will begin at 10:15 to allow for travel time from the Convention center to the PSU campus; suggestions for travel arrangements will be provided to registered participants by email in advance.

Abstract: In recent years, indoor aerosol filtration and air cleaning has transformed from a relatively staid sub-field of the air quality-related disciplines to a topic of great public interest, demonstrated societal need, and political and legal contest. In this tutorial session, we aim to provide a broad survey of the science, standards, practice, and societal implications of aerosol filtration and air cleaning in buildings. This tutorial will include approximately equal parts classroom-style lecture and hands-on experiential learning; the tutorial will be held in the Engineering Building of Portland State University to facilitate the latter. The tutorial will begin with an overview of air cleaning fundamentals and aerosol filtration metrics. Filtration theory will be reviewed and underlying particle removal mechanisms presented. Guidelines and standards of high importance to size-resolved indoor particle removal and filter loading will be reviewed, including ASHRAE 52.2, ANSI/AHAM AC-1, and ISO 16890. The lecture component will conclude with a discussion of material balance modeling of air cleaning at the building-scale and practical considerations in predicting and measuring air cleaning effectiveness. The tutorial will include demonstrations and tours. A laboratory demonstration will enable attendees to conduct (in-part) an air cleaner “pull-down” test, observe and handle air cleaners with various particle removal strategies, and explore filter pressure drop-airflow relationships. The tutorial will conclude with a tour of an institutional air handling system and in-duct filter bank, with relevant components of the system identified and practical considerations discussed. Attendees should leave this tutorial with an understanding of air cleaning scientific principles, an improved working language to discuss air cleaning systems in scientific and practical contexts, and hands-on experience with full-scale aerosol filters and air cleaners and several important strategies for evaluating air cleaners and components of air cleaners.

Bio: Elliott Gall: Dr. Elliott Gall is an associate professor at Portland State University (PSU) in the department of Mechanical and Materials Engineering.  His lab at PSU, the Healthy Buildings Research Laboratory (www.pdx.edu/healthy-buildings), conducts fundamental and applied research exploring the many factors that impact our exposure to air pollution inside buildings.  Current research areas include the study of air pollution exposures during wildfires and the design and evaluation of air cleaning technologies. 

Bio: Brandon Boor: Dr. Brandon E. Boor is an Associate Professor of Civil Engineering and Environmental and Ecological Engineering (by courtesy) at Purdue University. Dr. Boor conducts research on the physics and chemistry of indoor air. His group applies state-of-the-art measurement techniques to explore the dynamics of indoor air pollutants in diverse indoor environments. Dr. Boor teaches courses on indoor air quality, thermodynamics, and architectural engineering and advises an undergraduate air quality engineering service learning team.

Abstract: In recent years, tools such as low-cost sensor networks and mobile laboratories have enabled intensive monitoring of our real-world surroundings to better understand complex air pollution environments. These newer monitoring approaches generate large and complex datasets that benefit from expertise in data processing, QA/QC, statistical computing and visualization. This tutorial will review strategies for managing and interpreting complex real-world air quality data sets along the pipeline of data collection, cleaning, statistical analysis and visualization. As part of this tutorial, we will explore real-world case studies of data collected from actual monitoring campaigns, discussing common pitfalls and suggested best practices I’ve learned over the past 15 years. Participants do not need to have any formal training in data science in advance of the tutorial; resources for learning the demonstrated software tools including SQL, R, Jupyter Notebooks, Github, and Grafana will be provided.

Bio: Dr. Naomi Zimmerman is an Assistant Professor in the Dept. of Mechanical Engineering at the University of British Columbia and Canada Research Chair in Sustainability. Prior to joining UBC she was a postdoctoral fellow at the Center for Atmospheric Particle Studies at Carnegie Mellon University and also holds a Ph.D. in Chemical Engineering from the University of Toronto. Her research focuses on the measurement of air pollutants in complex environments to better understand the health and climate impacts of new technologies and policies, with a focus on the transportation and energy sectors.

Abstract: The chemical properties of atmospheric aerosol particles impact their role on the climate and air quality. Tremendous progress has been made recently that advances our ability to measure the components of aerosol particles both in the field and the laboratory. This tutorial will review methods for both on-line and off-line aerosol analysis with mass spectrometry. A focus will be placed on real-time measurement methods with the aerosol mass spectrometer (AMS) along with offline characterization with the AMS and other complementary techniques.

Topics will include instrument components used in aerosol mass spectrometers including vacuum systems, inlets, and ionization sources. Mass spectrometer types and their characteristics will also be compared for the AMS and across different offline mass spectrometry options. This tutorial will also review current lab and field measurements and provide a brief introduction to data processing from AMS measurements.

Bio: Dr. Rachel O’Brien is an Assistant Professor of Civil and Environmental Engineering at the University of Michigan. Her primary research interests have focused on characterizing complex organic mixtures with mass spectrometry techniques with a focus on aerosol particles and indoor surface films. Rachel currently serves as the secretary elect for AAAR and has been awarded an NSF CAREER award. She received her Ph.D. in Chemistry from UC Berkeley, and she worked as a postdoc at Lawrence Berkeley National Lab and MIT. She joined the faculty as an assistant professor in the chemistry department at William & Mary in 2017 and she moved to the CEE department at the University of Michigan in fall 2022. Email: reobrien@umich.edu

Abstract: The public health consequences of exposure to ambient particulate matter (PM) have been well-documented by more than four decades of epidemiologic, toxicologic and clinical studies. The global burden of disease attributable to ambient PM is at a historical high and is estimated to be greater than 5 million deaths per year, including an estimated 100,000 deaths in the United States. In addition to increases in mortality, air pollution exposure is associated with adverse cardiovascular, respiratory and neurological outcomes and diseases. Cardiovascular effects identified through epidemiological studies include increases in the rate of myocardial infarction and atherosclerosis and decreases in heart rate variability. Respiratory effects associated with exposure include increases in pulmonary infections, cough, wheeze, chronic obstructive pulmonary disease (COPD) as well as the incidence and severity of asthma. Reproductive health effects include increases in pregnancy complications and pre-term birth and decreases in birth weight. More recent evidence has shown associations between PM exposure and neurological outcomes including Alzheimer’s disease, Parkinson’s disease and autism. This tutorial will provide an overview of epidemiologic evidence for PM health effects and biological mechanisms linking exposure to outcomes. In addition, we will discuss methodologies for assessing health response including biomarker evaluation, biometric screening, wearable technologies, and emerging -omics based tools for examining changes in biological state related to environmental exposure.

Bio: Roby Greenwald is an Associate Professor in the School of Public Health at Georgia State University in Atlanta. He received a PhD in Environmental Engineering in 2005 from the Georgia Institute of Technology and completed a post-doctoral fellowship in Pediatric Pulmonology at the Emory University School of Medicine. He subsequently joined the faculty in the Rollins School of Public at Emory University in 2009 before moving to Georgia State University in 2014. His research expertise focuses on human health effects related to air pollution exposure, often in difficult-to-measure settings including in-vehicle exposure assessment for persons driving on major roadways, personal exposure measurements for individuals in near-road environments, evaluating the role of physical activity in air pollution exposure, and examining air pollution exposures in child care settings. His research experience additionally includes evaluation of the role the built environment plays on environmental exposures and physical activity levels, and his research group conducts human subjects research with study participants of all ages from toddlers to pediatric asthma patients to senior citizens.

Abstract: Secondary organic aerosol (SOA) is an important component of atmospheric fine particles that is formed by processes that can involve gas- and particle-phase chemistry, nucleation, and gas-particle partitioning. In this tutorial I will discuss laboratory methods that are commonly used to investigate SOA formation and composition. The presentation will describe methods of SOA generation from reactions of volatile organic compounds (VOC) with OH and NO3 radicals, O3, and Cl atoms in environmental chambers and flow reactors; gas and aerosol sampling with online and offline analysis; identification and quantitation of gas and aerosol products; experimental design considerations and procedures for accurately measuring yields of SOA and individual products; use of simple box models for data analysis; and methods for developing explicit, quantitative VOC oxidation and SOA formation mechanisms. The methods will be illustrated with examples from studies conducted in my laboratory over more than twenty-five years and by others. I will also provide references for the various components of the presentation.

Bio: Paul Ziemann is a Professor in the Department of Chemistry and a Fellow in the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado Boulder. 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. His research interests include laboratory studies of the kinetics, products, and mechanisms of organic oxidation reactions and their effects on the composition of gases, particles, and surfaces in outdoor and indoor air. He was a recipient of the AAAR Whitby Award in 2001 and served as President of AAAR from 2009–2010.

Abstract: Aerosol physical chemistry influences aerosol formation, growth, transport, heterogeneous reaction rates, and aerosol-cloud interactions. This tutorial covers the chemical thermodynamics of the aerosol phase, including theoretical development and important applications in aerosol science. Researchers interested in heterogeneous reactions or the dynamics of the aerosol size distribution will be especially interested in this tutorial. We will cover phase equilibria of condensed mixtures, activity models, and acidity. These concepts will then be applied to aerosol phase, which differs from that of bulk materials in a number of ways. For example, surface tension increases vapor pressure, increases internal pressure, suppresses liquid-liquid phase separation, and modulates viscosity. We will explore how these properties vary with temperature, diameter, and mixing state.

Bio: Sarah Petters is an atmospheric chemist studying the chemical and physical properties of aerosols, in particular their phase states and their interaction with water. Her current project focuses on nano- and microplastic aerosols. She was recognized in 2022 with the Paul J. Crutzen Award for Early Career Scientists for her contributions to establishing the range and complexity of cloud condensation nucleus (CCN) activity of atmospheric organic aerosols, and for combining thermodynamics from aerosol microphysics with organic chemistry to propose how Laplace pressure in aerosols influences heterogeneous reactions and microstructure. She received a BS in physics and a PhD in atmospheric sciences, both from North Carolina State University, and was awarded the NSF Postdoctoral Fellowship to work in environmental chemistry at the University of North Carolina Chapel Hill. Since 2022 she works with Professor Merete Bilde's atmospheric physical chemistry group at Aarhus University, working on the Green Transition project ‘Plastic in the Air’, funded by Independent Research Fund Denmark.

Abstract: As the pandemic showed so vividly, communication plays a critical role in shaping public and policy responses to risks from infectious disease, pollution, climate change and more - for better or worse.  But what are best practices for communicating science for public benefit when the communication environment is one of the only things changing faster than the biogeophysical one? The task can seem overwhelming given the contraction of traditional news media, the power of social media to distort and distract, and the turbulence around platforms like Twitter or Tiktok. But turning away simply cedes the space to those with ill intent and to algorithms that are designed to distract, titillate, divide more than inform.  In a special workshop and brainstorming session connected to his AAAR keynote at the Science Communication event on Monday evening, longtime journalist and Columbia Climate School communication advisor Andy Revkin will describe strategies, practices and tools that can help scientists and their institutions navigate the online communication arena with impact and the fewest regrets. He’ll also solicit and address participants’ questions about particular challenges they face.

You can send questions or case studies in advance if you'd like to ar667@columbia.edu. Put AAAR question in the heading.

Andy offers some advance reading for those with time:

How to Use Twitter Without Being Abused by it

https://revkin.substack.com/p/how-to-use-twitter-without-being

Can Innovative Imagery Overcome Big-Number Numbness Stalling Action on Covid and Climate? https://revkin.substack.com/p/can-innovative-imagery-overcome-big-22-05-18

Andrew Revkin, one of America’s most honored and experienced environmental journalists, is the founding director of the Initiative on Communication and Sustainability at Columbia University’s Climate School. There he is building programs, courses, tools and collaborations bridging communication gaps between science and society to cut climate risk and boost societal and environmental resilience. Revkin has written on climate change for more than 30 years, reporting from the North Pole to the White House, the Amazon rain forest to the Vatican - mostly for The New York Times. He has held positions at National Geographic and Discover Magazine and won the top awards in science journalism multiple times, along with a Guggenheim Fellowship. Revkin has written acclaimed books on the history of humanity’s relationship with weather, the changing Arctic, global warming and the assault on the Amazon rain forest, as well as three book chapters on science communication. The Golden-Globe-winning HBO film “The Burning Season” was based on Revkin’s biography of slain rain forest defender Chico Mendes. His 1992 proposition that humans have entered a “geological age of our own making” got him invited onto the Anthropocene Working Group, the expert team assessing evidence that Earth’s fate is being markedly reshaped by humans. A lifelong musician, he was a frequent accompanist of Pete Seeger and is a performing songwriter. His Sustain What webcast (j.mp/sustainwhatlive) has reached some 3 million viewers through nearly 400 episodes. Subscribe to his Sustain What newsletter to keep track. Learn more and get in touch here: https://j.mp/revkinlinks.

Abstract: This tutorial will enable the participants to get an "under the hood" look at a broad spectrum of currently available aerosol instruments. Whether you are an experimentalist, modeler, or both, this is an opportunity to learn how fundamental aerosol science principles are used in actual aerosol measurement technologies. Key capabilities, as well as limitations, of each technique will be described in order to instill a better appreciation of what different instruments can and cannot do. In this session, six aerosol instrumentation suppliers will present the concepts and engineering design processes that led to the successful development of different aerosol instruments. The tutorial is not a marketing and sales opportunity for participating vendors; this is an education session with an emphasis entirely on technology and the key physical concepts employed by the instruments. The goal is that by the end of the tutorial, participants no longer consider the instruments a "black box," but rather have some understanding of the principles and design consideration that went into the development of the various instruments. Furthermore, the information presented on measurement uncertainties and limitations will help the participants better interpret (avoid over-interpreting) measurement results.

Aethlabs
microAeth AL50

Brechtel
Scanning Electrical Mobility Sizer (SEMS)

Durag Group
Grimm 11-D Spectrometer

Particle Plus
Particle Plus 12000 Series

Palas GmbH
AQ Guard Smart System

Ionicon
PTR-TOF 4000 High-Resolution PTR-TOF-MS – Trace VOC Analyzer

Abstract: This tutorial will overview biological aerosols and methods for their measurement and study. Specifically, this tutorial will cover three primary areas: bioaerosol measurement, laboratory techniques, and field studies. Each topic will be covered from environmental bioaerosol and infectious aerosol perspectives. Both real-time and offline techniques for bioaerosol measurement will be covered, as well as laboratory techniques for bioaerosol study. Field studies will cover a range of situation from outdoor measurements to studies in clinical settings.

Bio: Alex Huffman is an Associate Professor of Analytical and Environmental Chemistry at the University of Denver after having earned his Ph.D. in Analytical/Atmospheric Chemistry from the University of Colorado. His research group focuses on the development and application of new scientific approaches to detecting bioaerosols in the atmosphere, characterization and application of techniques for ultrafine particle detection, and heterogeneous chemical reactions on bioaerosol surfaces. During the COVID-19 pandemic Dr. Huffman added research focus on transmission and removal of aerosols in indoor environments, including relevant aerosol modeling, mitigation, and monitoring efforts. Dr. Huffman has more than 20 years of experience with atmospheric aerosol science and has published more than 45 papers related to bioaerosols. Dr. Huffman has been involved with AAAR since 2005, currently serves on the board, and has previously served as bioaerosol working group chair and organizer for multiple special symposia and conference committees.

Bio: Dr. Joshua L. Santarpia is an Associate Professor in the Department of Pathology and Microbiology program director for Biodefense and Health Security Degree Program at the University of Nebraska Medical Center. Additionally, he is both the Associate Director of Academic Affairs and a Scholar for the Global Center for Health Security. He is also the Science and Technology Advisor for the National Strategic Research Institute at the University of Nebraska. He completed his graduate studies at Texas A&M University and has held past positions at the Edgewood Chemical and Biological Center, the Johns Hopkins University Applied Physics Laboratory, and immediately prior to joining UNMC was a distinguished staff member at the Sandia National Laboratories. His work is generally in the field of aerobiology, the study of airborne microorganisms.  He has worked extensively on biological sensors, building and facility sensing networks, and has developed aerosol measurement tools, including those for unmanned aerial vehicles and for biodetection/collection activities for both the U.S. Department of Defense and Department of Homeland Security. He has worked extensively to understand optical and other signatures that can be used to detect and identify biological aerosol and study how those signatures change over time. He has developed novel methods to study bioaerosol hazards in medical environments. Most recently, he has applied these methods to characterizing SARS-CoV-2 aerosol in the patient environment and characterizing aerosol risk in public spaces.

Abstract: Three-dimensional Chemical Transport Models (CTMs) are mathematical representations of physical and chemical processes relevant to trace gas and particle pollutants and are used to support policy actions to mitigate negative human health impacts and understand climate change. Here we discuss three different aspects of using CTMSs to address atmospheric aerosol science and applications. First, CTMs integrate all our understanding of complex processes governing aerosols based on decades of work combining laboratory and field measurements with theoretical parameterizations. Yet, when they are challenged to predict aerosol states within a new region, model-measurement differences provide clues about processes that are not understood or well-represented in models. To be particularly useful for diagnosing key missing processes in models, applying a high resolution 3D CTM to a new field experiment requires careful design and characterization of the region of interest, which often requires significant efforts. We will discuss broadly the key considerations for careful design of a modeling study to explain field measurements of secondary organic aerosols.

Second, we will discuss CTMs with different levels of complexity, which forecast the 3D concentrations of different aerosol and other chemical constituents on regional and global scales. Some of these CTMs are integrated with operational weather models to provide smoke forecasts critical for informing susceptible populations or responding to emergency events like wildland fires. NOAA’s high-resolution coupled smoke-weather model simulates smoke transport by incorporating a real-time biomass burning emissions algorithm, fire plume rise parameterization, advection and turbulent mixing, and removal processes of the aerosol. High aerosol loadings in the atmosphere also affect weather and visibility. We will present some examples of how coupled aerosol-meteorology models simulate these processes, and how simulating aerosols explicitly in the numerical weather prediction models can help us to improve weather forecasting. The offline CTMs that forecast primary and secondary aerosol pollution from anthropogenic and other sources will be discussed. Additionally, we will present NOAA's global aerosol forecast model and its application to some long-range aerosol transport case studies.

Lastly, we will survey a number of analysis techniques that leverage CTM predictions along with data from other sources (e.g. ambient monitoring data, satellite retrievals, health data, etc.) to understand the impact of particle air pollution on public health. The results of these analysis techniques provide necessary support for driving air pollution policy decisions. Through a discussion of each of these examples, this tutorial will offer context for how large-scale models can be used to demonstrate the impact of aerosol research findings and how they may further support prioritization of future research efforts.

Bio: Manish Shrivastava: Dr. Manish Shrivastava is currently a senior Earth Systems Scientist at the Pacific Northwest National Laboratory (PNNL). His research bridges measurements and modeling of secondary organic aerosols (SOA), and their interactions with clouds, radiative forcing and human health. Over the past decade, he has developed and implemented several new model formulations of SOA within community regional and global models based on laboratory and field measurements. In 2018, he was awarded the highly prestigious and competitive U.S. Department of Energy Early Career Award to conduct research on finding missing links associated with aerosol-cloud interactions.

Bio: Ben Murphy: Dr. Ben Murphy is a physical scientist at the U.S. EPA where he develops chemical transport models for regulatory applications. A member of the Community Multiscale Air Quality (CMAQ) model development team, he primarily focuses on formation, processing and loss of organic aerosol and ultrafine particles. He is also interested in developing models for quantifying the atmospheric fate and transport of Per- and PolyFluoroAlkyl Substances (PFAS).

Bio: Ravan Ahmadov: Dr. Ahmadov is a research scientist at CU Boulder CIRES, working for NOAA’s Global Systems Laboratory. His main research areas are air quality modeling, atmospheric model development, and impact of fire emissions on air quality and weather. Dr. Ahmadov is the primary developer of NOAA’s operational smoke forecasting model HRRR-Smoke.

Abstract: In this tutorial I will teach you the fundamentals of particulate light scattering and absorption in the context of aerosol science. The approach will be empirical, descriptive and largely non-mathematical; hence, significant physical intuition for the scattering and absorption processes will be gained. This approach is largely based on my recently published book, Light Scattering and Absorption by Particles: The Q-space Approach, which in turn is based on a career studying this subject. It starts with simple wave diffraction and then incrementally evolves to include the electromagnetic character of light by increasing both the real and imaginary parts of the refractive index. In a similar manner the particle shape will evolve from particles so small shape doesn’t matter, to spheres, various perturbations on spheres, dusts, ice crystals and fractal aggregates. The path through this expansive variety is what I have termed Q-space analysis guided by two fundamental, unifying parameters that our group has developed. The tutorial will include examples of experimental set-ups and data analysis.

Bio: Chris Sorensen is the Vice President for Research & Development at Hydrograph Clean Power, Inc., a startup based on his patents to make graphene aerosol gel materials. He is also University Distinguished Professor & etc. Emeritus in Physics at Kansas State University. He received a BS in physics in 1969, was drafted and served in Vietnam in military intelligence 1970 -71, and earned a PhD in physics from the University of Colorado in 1976. His research interests include particulate light scattering. He is a Fellow of the AAAR, APS and AAAS.

He is a past president of the AAAR and a recipient of the Sinclair and the AS&T Outstanding Publication awards. In 2007 he was named the CASE/Carnegie Foundation United States Professor of the year for doctoral universities. He recently published a book, Light Scattering and Absorption by Particles: The Q-space Approach.

Abstract: Metrology is the scientific study of measurement and its application. In this tutorial, I will a provide a quick historical overview of metrology followed by some statistical basics including uncertainty analysis. Next, we will apply these basics to data collection, handling, and reporting with an emphasis on calibration, validation, and confidence in novel data. As an example of this workflow, we will discuss the calibration and validation of the measurement of mass absorption coefficients (MAC; m² g^-1) by a method developed at NIST that utilizes a tandem differential mobility analyzer, aerosol particle mass analyzer, photoacoustic spectrometer, and condensation particle counter. We will then apply this data towards NIST’s specific contribution in a photoacoustic spectrometer intercomparison study so that we can discuss the importance of reference materials and the relationship between a single lab-based instrument and the broader field of aerosol science. We’ll conclude with discussion on why intercomparison studies represent the pinnacle of metrology (different research groups/instruments can implement their own best practices and measure similar quantities whether co- or dis-located) and ideas for moving the field forward.

Bio: Dr. James Radney (who goes by Jimmy) received a BS in Biochemistry in 2006 from Georgia Tech and a PhD in Environmental Sciences and Resources: Chemistry (a now expired program) in 2012 from Portland State University for developing instrumentation to measure the humidity dependent optical properties of aerosol particles. After graduating, Jimmy continued his research developing aerosol metrology and instrumentation by serving as a post-doctoral research associate under Dr. Mike Zachariah through the University of Maryland at the National Institute of Standards and Technology (NIST) working with Dr. Chris Zangmeister. In 2014, Jimmy received a 2-year National Research Council post-doctoral fellowship to continue his research at NIST with Chris and has been at NIST ever since. Jimmy has received multiple awards and recognitions at NIST for his research in aerosols and outreach through the Post-doctoral and Early Career Association of Researchers (PEAR).

Abstract: This tutorial will enable the participants to get an "under the hood" look at a broad spectrum of currently available aerosol instruments. Whether you are an experimentalist, modeler, or both, this is an opportunity to learn how fundamental aerosol science principles are used in actual aerosol measurement technologies. Key capabilities, as well as limitations, of each technique will be described in order to instill a better appreciation of what different instruments can and cannot do. In this session, six aerosol instrumentation suppliers will present the concepts and engineering design processes that led to the successful development of different aerosol instruments. The tutorial is not a marketing and sales opportunity for participating vendors; this is an education session with an emphasis entirely on technology and the key physical concepts employed by the instruments. The goal is that by the end of the tutorial, participants no longer consider the instruments a "black box," but rather have some understanding of the principles and design consideration that went into the development of the various instruments. Furthermore, the information presented on measurement uncertainties and limitations will help the participants better interpret (avoid over-interpreting) measurement results.

Aerosol Devices/Handix Scientific
BioSpot Bioaerosol Sampler

Aerosol/Magee Scientific
Carbonaceous Aerosol Speciation System (CASS)

Cambustion
AF10 Aerosol Flowmeter

Particle Instruments LLC/Dekati Ltd.
Dekati Oxidation Flow Reactor (DOFR)

TSI
Flow Focusing Monodisperse Aerosol Generator (FMAG)

URG Corporation
Ambient Ion Monitor