Plenary Sessions

Plenary I
Tuesday, October 4th 8:00 AM – 9:15 AM
AEESP Lecture: Low-cost Sensors for Exposure and Health Science: How It Started, How It’s Going

John Volckens

Over the past decade, low-cost sensor technologies have become widely popular for quantifying outdoor levels of fine particulate matter. The size, cost, and connectedness of these technologies, along with a renaissance of data science, have enabled measurements at unprecedented scale: from the personal level (what are YOU breathing in?) to a global network of connected devices (e.g., PurpleAir). With air pollution now recognized as the leading environmental cause for premature disease and death across the planet, the need for monitoring is greater than ever. As a result, these sensors show promise for enhancing public health research and practice, whether it be for exposure monitoring, epidemiology, environmental justice, or citizen science. Their application in resource-limited environments is a particularly attractive feature.

The rapid rise of low-cost sensor technologies brings questions about utility, performance and reliability, the future of R&D in this space, and their place in the research community. This plenary will review the state-of-the science of low-cost aerosol sensors (and related technologies), with a focus on public and environmental health. I will discuss their history, their strengths & limitations, their use and misuse, and their prospects for enabling research and discovery in support of public health in the 21st century. I will cover topics ranging from Mie scattering and optics, to global health and air pollution-related disease, calibration, personal exposure, precision medicine, market forces, microelectronics, machine learning, memes, and more!

Bio:
Dr. John Volckens is a professor of Mechanical Engineering and the Director of the Center for Energy Development and Health at Colorado State University (CSU). He holds affiliate appointments in Environmental Health, Biomedical Engineering, the Colorado School of Public Health, and the CSU Energy Institute. His research interests involve air quality, low-cost sensors, exposure science, and air pollution-related disease. He is a founding member of the CSU Partnership for Air Quality, Climate, and Health – an organization that seeks to develop practical, science-vetted solutions to intertwined problems of air quality, climate, and health that we face as a society.

He received a BS in Civil Engineering from the University of Vermont and MS, PhD degrees in Environmental Engineering from the Gillings School of Public Health at the University of North Carolina at Chapel Hill. He was a Postdoctoral Fellow at the U.S. EPA's National Exposure Research Laboratory in Research Triangle Park, NC. At CSU, he has pioneered the development of several new aerosol measurement technologies, which have been deployed for public health research in over 40 different countries and as far away as the International Space Station. He is a co-founder of Access Sensor Technologies, a company started through his research collaborations at Colorado State University. Dr. Volckens is the recipient of 'Best Paper' awards from the American Industrial Hygiene Association (1999, 2017, 2021) and the Journal of Indoor Air (2013). He was a 2018 finalist for the NASA Earth, Space, Air Prize. Perhaps his crowning scientific achievement, however, is that his 2020 work on respiratory aerosol emissions was featured in opening monologue jokes by late-night comedians Stephen Colbert, Jimmy Fallon, and Jimmy Kimmel. In his free time, Dr. Volckens likes to delude himself that he is capable of maintaining his 100+ year-old home in Fort Collins, Colorado.

Plenary II
Wednesday, October 5th 8:00 AM – 9:15 AM
Nonlinear Trajectory: From Aerosol Science to Environmental Public Health

Sarah Henderson

Exposure to ambient particulate matter (PM) has a profound effect on the health of populations. Short-term exposure is associated with a growing list of acute health outcomes, and long-term exposure is associated with a growing list of chronic health outcomes. There seems to be no facet of human health unaffected by our air quality. The available evidence has been the impetus for drastically reducing PM emissions from sources such as vehicles and industry, but we are facing different threats as the climate changes. Smoke from wildfires is starting to dominate lifetime exposures to PM in many regions, and some jurisdictions have identified biomass fuels as climate-friendly energy sources.

The day-to-day work of environmental public health entails the synthesis, translation, and mobilization of scientific evidence into the sphere of policy and practice. Consider the example of wildfire smoke. Every year we learn more about this complex and dynamic form of air pollution from multiple disciplines: aerosol science; atmospheric science; landscape ecology; toxicology; immunology; clinical research; observational epidemiology; implementation science; and many more. The role of environmental public health is to take all of this information and digest it in response to one overarching question: what do people need to know about wildfire smoke, its health effects, and how to protect themselves?

The trajectory from aerosol science to environmental public health is nonlinear. While we all have different roles to play in reducing the harms caused by PM pollution, we are all united by the fact that our combined work can reduce these significant and modifiable harms. This talk will help aerosol researchers better understand the field of public health and better communicate their work to this key stakeholder group.

Bio:
Dr. Sarah Henderson is the Scientific Director of Environmental Health Services at the British Columbia Centre for Disease Control (BCCDC) and the Scientific Director of the Canadian National Collaborating Centre for Environmental Health (NCCEH). Sarah started her career in the field of air pollution abatement and control engineering, then moved into environmental epidemiology to study the population health effects of air pollution exposures. Sarah is internationally recognized for her work in wildfire smoke exposure, epidemiology, and public health interventions. She also has broader expertise in traffic-related air pollution, industrial emissions, road dust, and residential wood heating. At this point in her career, Sarah spends a lot of time thinking about how to make research outputs accessible and meaningful to users in the field of environmental public health.

Plenary III
Thursday, October 6th 8:00 AM – 9:15 AM
Friedlander Lecture: The Secret Lives of Filters

Jeffrey Siegel

Improving indoor air requires addressing source control, ventilation, and filtration. There is an implicit hierarchy in these measures and a long history surrounding the importance of source control and ventilation, even though source control is often not possible, and ventilation is limited by ambient air pollution. Filtration is a much newer approach that has received much less attention. Part of this arises from the fact that filters are often viewed as static with performance solely determined by efficiency as a function of particle size. However, filters are dynamic as the filter efficiency curve of the same filter will change depending on the application as well as over the filter lifetime. Further, filter performance is often largely a function of the context of how the filter is used as much as the filter itself. This presentation explores filter performance from both aerosol science and building science perspectives with a focus on how theoretical and laboratory-tested filtration efficiencies translate to filtration performance in real buildings. The removal of particulate matter is only part of the filtration story. Filters also have a variety of secondary consequences including emissions of gas-phase compounds and complicated impacts on energy use. These effects need to be considered in overall considerations about filter use. However, some of these secondary effects may have a positive impact, including the ability of filters to offer insight on air quality through filter forensics, the analysis of the particles that accumulate on the filter. Several examples of filter forensics for disease surveillance, exposure assessment, and ambient air quality are used to illustrate the hidden value in used filters. The COVID-19 pandemic has further increased the attention paid to central and portable filtration in buildings and this presentation assesses new challenges and opportunities that arise from this renewed focus.

Bio:
Jeffrey Siegel, Ph.D., is Professor of Civil and Mineral Engineering at the University of Toronto and is a Bahen/Tanenbaum Chair in Civil Engineering. He holds joint appointments at the Dalla Lana School of Public Health and the Department of Physical & Environmental Sciences. He has an M.S. and Ph.D. in Mechanical Engineering from the University of California, Berkeley as well as a B.Sc. from Swarthmore College. He is internationally recognized for his work on indoor air quality generally and air cleaning specifically and is a fellow of ASHRAE and a member of the Academy of Fellows of the International Society for Indoor Air and Climate (ISIAQ). His research interests include healthy and sustainable buildings, filtration and air cleaning, ventilation and indoor air quality in residential and commercial buildings, control of indoor particulate matter, and the impact of building systems on indoor microbiology and chemistry. He has published over 100 peer-reviewed journal articles on indoor air quality and related subjects and has been active in disseminating information about filtration and ventilation solutions for COVID-19.

Plenary IV
Friday, October 7th 11:00 AM – 12:15 PM
AAAR's First 40 Years: Its Origins and Evolution

Susanne Hering

At the time AAAR was founded in 1982, the term “aerosol” was most often used by the lay public to refer to a spray can – whether it be hair spray or insect repellant.  Now, 40 years later, a greater fraction of the public understands the term “aerosol” to mean fine airborne particles that can act as a pathway for transmission of respiratory disease, and even as a type of air pollutant.

Aerosol technology emerged from an unrecognized field to an important discipline during the latter half of the twentieth century. In 1960 the US Atomic Energy Commission (now subsumed into DOE) created the Inhalation Toxicology Research Institute to study late-occurring health risks from inhaling small amounts of radioactive particles. In 1970s the State of California funded the “Aerosol Characterization Experiment”, an expansive field experiment to unravel the science, and sources of the visibility-reducing smogs in Los Angeles. Around the same time the military’s interest in obscuration smokes for lasers led the development of an aerosol research program at the Edgewood Chemical Biological Center. Critical advances were made in aerosol instrumentation including automated condensation particle counters, single particle optical counters and the electrical mobility analyzer.

At this time, aerosol research was published in a number of journals, and presented at a variety of conferences.  Kenneth Whitby’s famous work on the multimodal nature of Los Angeles smog was first presented at an American Chemical Society Symposium and published in the Journal of Colloid and Interface Science. Other papers appeared in Atmospheric Environment, and Environmental Science and Technology. 1970 saw the birth of the Journal of Aerosol Science, published by Pergamon Press under the editorship of C.N. Davies. In the US, conference presentations were spread between annual meetings of the Air Pollution Control Association, the American Chemical Society, and American Institute of Chemical Engineers (AIChE), supplemented by a few less formal meetings including the Aerosol Technology Meetings, and the Edgewood Aerosol Conferences.  Aerosol science was a growing field in Europe as well, with annual aerosol meetings at the University of Mainz and at Battelle-Frankfurt, leading to the formation of the Gesellschaft fur Aerosol Forschung in 1972. Yet in the US there was no common home.

We think of professional organizations starting first, and then producing a journal.  For AAAR the order was the opposite. AAAR was founded to support its journal. In 1978 David Shaw published not one, but two, books on aerosol science and technology based on an aerosol symposium held under the auspices of the AIChE. Given his success, Elsevier Science Publishing Co. approached him to start an aerosol journal.If there were to be a journal, it was decided there needed to be a professional organization behind it. The decision to form AAAR was made by Sheldon Friedlander, David Ensor, Benjamin Liu and David Shaw at a meeting held in Research Triangle Park, NC in the fall of 1981. Our first conference was held the following February in Santa Monica, CA, with 300 attendees. The first abstract submitted to that conference came from David Sinclair, for whom the AAAR Sinclair Award is named. The first issue of our journal, Aerosol Science and Technology, appeared that same year, directed by its founding editors, Ensor, Liu and Shaw.

In the early years, AAAR was run through the volunteer efforts of its leading members. In the ensuing period, as the AAAR grew, it adopted a formal structure, with codified by-laws, governing procedures and management. Likewise, the journal evolved, driven by the vision of its editors, increasing its scope and presence. Throughout its forty years, the traditions of AAAR and its journal continue to be driven by dedicated volunteers within its membership.

Bio:
Dr. Susanne V. Hering is founder of Aerosol Dynamics Inc., a small research firm specializing in the development of measurement methods for fine, airborne particles. Her firm is known for the development of a motion-tolerant, water-based condensation methods for particle counting and collection, and for their work in collaboration with the University of California to develop a thermal desorption gas chromatography system for on-line, hourly analysis of organic matter in atmospheric aerosols. After completing he PhD in Physics at the University of Washington, she entered the field of aerosol research through postdoctoral studies at the California Institute of Technology. She is a founding AAAR Fellow, a recipient of AAAR’s BYH Liu Award, and has served twice as President of the American Association for Aerosol Research, and several years as an Editor for Aerosol Science and Technology. She has been involved with AAAR since its founding in 1982.