Plenary Sessions

Electronic Cigarettes: Evidence, Uncertainty and Policy

JONATHAN SAMET, Department of Preventive Medicine, Keck School of Medicine of USC, University of Southern California, Los Angeles, California

Over a five-year span, use of electronic cigarettes (e-cigarettes), which deliver an aerosol generated by a battery-powered vaporizer, has rapidly increased, particularly among adolescents and young adults. Because e-cigarettes can deliver nicotine without the combustion-generated carcinogens and toxins of tobacco smoke, they have been proposed as potentially useful for harm reduction, if substituted for conventional cigarettes. However, the potential for harm reduction needs to be balanced against the potential for e-cigarettes to increase nicotine addiction among adolescents and young adults, to reduce cessation among cigarette smokers, and to “renormalize” use of tobacco products. With the Food and Drug Administration poised to take regulatory authority over e-cigarettes under the Family Smoking Prevention and Tobacco Control Act, the public health impact standard of the Act becomes relevant—that is, what is the overall public health impact of availability of e-cigarettes? This presentation addresses the evidence needed to gauge the public health impact of e-cigarettes and the use of models to estimate the balance between potential harms and benefits. Research to generate the needed evidence is challenged by the highly dynamic pattern of use of tobacco products subsequent to the addition of e-cigarettes to the marketplace. Models must project future scenarios of use that are quite uncertain. Nonetheless, policies are being developed at local, state, and national levels that draw on the limited evidence available and the application of principles of risk management. Research targeted at key uncertainties and careful surveillance are requisite in order to maintain the evidence base needed to minimize public health impact.

Biosketch:
Dr. Samet, a pulmonary physician and epidemiologist, is Distinguished Professor and Flora L. Thornton Chair, Department of Preventive Medicine at the University of Southern California Keck School of Medicine and Director of the USC Institute for Global Health. Previously, he was chair of the Department of Epidemiology of the Johns Hopkins Bloomberg School of Public Health. His career has centered on epidemiologic research on threats to public health and using research findings to support policies that protect population health. His research has addressed indoor and outdoor air pollution, smoking, radiation risks, cancer etiology and outcomes, and sleep. He has been involved with numerous committees related to use of scientific evidence in characterizing risks and making decisions, including chairing the Clean Air Scientific Advisory Committee of the U.S. EPA and the FDA’s Tobacco Products Scientific Advisory Committee (TPSAC). For three decades he has authored and edited the reports of the Surgeon General on smoking and health, including serving as Senior Scientific Editor for the 50^th Anniversary 2014 report. Dr. Samet received the 2004 Prince Mahidol Award for Global Health awarded by the King of Thailand, the Surgeon General’s Medallion in 1990 and 2006. He is a member of the National Academy of Medicine.

 

Nanocarbon in Flames: From Unwanted Particulate Emissions to Useful Materials

HAI WANG, Mechanical Engineering, Stanford University

Formation of particulate carbon is ubiquitous in many combustion and flame phenomena. Particulate carbon formed in flames or emitted from combustion sources is usually in the form of an aerosol. As a byproduct of combustion, particulate carbon or soot is a major source of air pollutants. Its emission is responsible for a wide range of human health problems. Soot emission is also a major cause of uncertainties in modeling global climate change. On the other hand, particulate carbon has a very long history as a useful material. It found its use prehistorically in cave paintings and provided the black pigment for India ink as early as the Neolithic age. Today, the same versatile material finds myriad uses, from rechargeable batteries as a chemically resistant electrical conductor to fuel cells as a cathode catalyst or catalyst support. This talk aims to provide an overview of the relationship between the properties of carbon particles and conditions of flames in which they are generated. It will provide an in-depth discussion about the reaction mechanism and kinetics of carbon formation in flames.

Biosketch:
Hai Wang is Professor of Mechanical Engineering at Stanford University. His interests are in renewable energy conversion, catalysis and combustion. His current research focuses on theories and applications of nanoparticles and nanostructures for rechargeable batteries and supercapacitors, combustion simulations and nanocatalysis. He is the author and coauthor of numerous papers in scholarly journals. He is currently the Editor-in-Chief of Progress in Energy and Combustion Science.

 

Optical Characterization of Atmospheric Aerosols: From Fundamental Electromagnetism to Satellite Missions

MICHAEL I. MISHCHENKO, NASA Goddard Institute for Space Studies, New York, NY

The strong influence of tropospheric and stratospheric aerosols on the environment, as well as on the global and regional climates, is well recognized. This explains the utmost scientific and societal importance of detailed and accurate knowledge of physical and chemical properties of these particles. More often than not it is impracticable to collect actual aerosol samples and subject them to a laboratory test. Therefore, in most cases one has to rely on theoretical analyses of in situ and/or remote-sensing measurements of light scattered by aerosol particles. Fortunately, certain scattering properties of small particles can exhibit a strong dependence on the particle microphysics and composition. This factor makes measurements and analysis of electromagnetic scattering an extremely useful and often the only practicable means of physical and chemical particle characterization. Addressing growing ecological and climate-change concerns requires the development and application of remote-sensing instrumentation and data analysis methodologies enabling accurate characterization of key components of the exceedingly complex atmospheric environment. The accumulated body of evidence shows that addressing this challenging task requires the following: (1) The development of measurement concepts that provide adequate sensitivity to specific macro- and microphysical parameters of atmospheric particulates and their composition. These concepts must be based on modern physics of light–matter interactions; the broadest possible spectral range extending from near-UV to near-IR wavelengths; the use of all four Stokes parameters of the detected radiation rather than just the first one (intensity); and active as well as passive observation strategies. (2) The development of advanced physically-based retrieval algorithms fully accounting for the extreme morphological complexity of the vast majority of aerosol and cloud particles. (3) Synergistic use of ground-based, aircraft, and satellite instrumentation and data

Biosketch:
A graduate of the Moscow Institute of Physics and Technology, Michael Mishchenko is a Senior Scientist at the NASA Goddard Institute for Space Studies in New York. His research interests include aerosol and cloud remote sensing, atmospheric radiation, and ocean optics. He managed the NASA/GEWEX Global Aerosol Climatology Project and served as Project Scientist for the NASA Glory Space Mission. Dr. Mishchenko has authored four research monographs and published 290 peer-reviewed journal papers and book chapters. He is Editor-in-Chief of the Journal of Quantitative Spectroscopy and Radiative Transfer and previously served as Topical Editor for Applied Optics. An elected Fellow of AGU, OSA, AMS, and The Institute of Physics (UK), Dr. Mishchenko is the recipient of many professional awards including the AMS Henry G. Houghton Award, Hendrik C. van de Hulst Award from Elsevier, and two NASA Exceptional Scientific Achievement Medals.

 

Fire Aerosols: Exceptionally Common

CHRISTINE WIEDINMYER, Scientist, Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research

Fire emissions and the downwind chemistry in and out of biomass burning plumes degrade air quality, impact regional climate, and contribute to negative human health outcomes. Fires, and specifically the burning of biomass, produce aerosols from incomplete combustion processes and contribute substantially to the global atmospheric burden of carbonaceous aerosol in terms of both mass and number. These fire aerosols are ubiquitous in the atmosphere and have been identified at all scales from the indoor environment to the stratosphere. Despite great advances in the ability to identify and quantify emissions from biomass burning, the techniques used to predict emissions and understand their fate and transport in the in the atmosphere are uncertain, and the subsequent estimates of the impacts are difficult to assess. Global change driven by climate, policy, and social behaviors alter fire activity and its impacts. Quantification of the feedbacks and interactions between fire activity and global change remain critical open questions. This presentation will detail efforts to identify and quantify biomass burning emissions across scales, and highlight their importance and confounding factors in air quality, health, and climate impact assessments.

Biosketch:
Dr. Christine Wiedinmyer is a Scientist in the Atmospheric Chemistry Observations & Modeling Laboratory of the National Center for Atmospheric Research. Dr. Wiedinmyer’s research emphasizes the identification and quantification of various emission sources and modeling the transport and fate of emitted pollutants in the atmosphere. She is the creator of the Fire INventory from NCAR (FINN) model that estimates emissions of pollutants from open burning globally; the FINN emissions estimates have been applied in numerous air quality and climate studies to evaluate their impacts. Further, Dr. Wiedinmyer is an expert in interdisciplinary research to connect her research to other areas of societal relevance, such as public health, land management, and climate. She is the recent recipient of the Walter Orr Roberts Lecturer for Interdisciplinary Sciences from the American Meteorological Society in 2014 “for research on biomass burning and its impact on the atmosphere and terrestrial biosphere, and bridging atmospheric science, biology, engineering, public health and other disciplines.” She holds a BS in chemical engineering from Tulane University, and an MS and PhD in chemical engineering from the University of Texas at Austin.