We Do Not Have Much Time Left
Yuan-Tseh LEE Nobel Laureates
Academia Sinica, Taiwan
In the past fifty years, explosion in human population and per capita consumption, we have changed the relationship between the humanity and nature. We are changing the atmosphere. With the increase of greenhouse gases, there is more energy coming in than going out, and the temperature of the surface of the earth is continuing to rise. Our efforts to keep the temperature rise to within 1.5 ℃ of that of pre-industrial era, is apparently falling way behind.
For many of us, 2 to 3 degree temperature rise seem still quite tolerable. However, with the accumulation of enormous amount of energy on the surface of the earth, the consequent climate change and extreme whether events, such as heat wave, hurricane, flood and forest fire, will seriously threaten the survival of humanity on earth.
generation has not done well, and time is running out on us fast. If we fail to
reduce the emission of greenhouse gases by 40 to 50 percent in the next ten
years, it will not be possible to reach carbon neutral by 2050, to keep the
temperature rise to 1.5 degree and for humanity to develop sustainably on
earth. We need to work together with tremendous efforts, since we don’t have
much time left.
Born in 1936, Yuan Tseh Lee received his B.S. degree from Taiwan University in 1959, M.S. from Tsing Hua University in 1961, and Doctorate from UC-Berkeley in 1965. He joined Dudley Herschbach’s group at Harvard as a research fellow in 1967. After being appointed Assistant Professor at the University of Chicago in 1968, Dr. Lee rapidly made his laboratory a major center for molecular beam study in North America. He returned to Berkeley as Professor of Chemistry in 1974. He was University Professor and Principal Investigator at the Lawrence Berkeley Laboratory, UC Berkeley, before he became President of Academia Sinica in 1994. In 2006 he became President Emeritus and Distinguished Research Fellow at the same institution. In 2008 he was elected president of the International Council for Science (ICSU) and took up the appointment in 2011 for a period of three years.Dr. Lee has received numerous awards and honors, including the 1986 Nobel Prize in Chemistry, the U.S. National Medal of Science, Peter Debye Award from American Chemical Society, Faraday Medal and Prize from the Royal Chemical Society of Great Britain, and the Jawaharlal Nehru Birth Centenary Medal from the Indian National Science Academy. He is a fellow of the U.S. National Academy of Sciences, the American Academy of Arts and Science, and Academia Sinica; a foreign member of Göttingen Academy of Sciences, Indian National Academy of Sciences, Japan Academy, Korean Academy of Science and Technology, Royal Swedish Academy of Engineering Sciences, The World Academy of Sciences, etc. Dr. Lee has received Doctor Honoris Causa from 42 universities throughout the world.
The Roles of Aerosol Inhalation in SARS-CoV-2 Transmission
The University of Hong Kong, Hong Kong
The roles of aerosol inhalation in SARS-CoV-2 transmission were only recognized more than one year into the COVID-19 pandemic when more than 150m people were infected and 3m people died from the virus infection. I shall describe the new concepts of respiratory infection as redefined during the pandemic, and new hypothesis of the predominance of short-range inhalation transmission following investigating more than 20 COVID-19 outbreaks and the major observed transmission phenomena in the pandemic. The roles of building ventilation, filtration, and virus deactivation on both short- and long-range aerosol inhalation transmission will be discussed. I shall present a new equal CO2 exposure method to derive a set of minimum ventilation rates and associated maximum CO2 concentrations in indoor settings with various activity levels (sleep or nap, sedentary/passive, light exercise, moderate exercise, and heavy exercise) and breathing modes (breathing, speaking, singing, and loudly speaking).
Yuguo Li is a Chair Professor of Building Environment at Department of Mechanical Engineering, The University of Hong Kong. His current research topics include city climate, environment studies of infection and indoor environment. He serves as Editor-in-Chief of Indoor Air. Since early 2020, he has collaborated with WHO, Guangdong CDC, Hunan CDC, Jiangsu CDC, and Hong Kong various Government departments, and studied the transmission routes of SARS-CoV-2 in buildings. The redefinition of the inhalation transmission route of SARS-CoV-2 has been accepted by major health authorities. He is a member of the WHO IPC Guidelines Development Group (GDG) and WHO Environment and Engineering Control Expert Advisory Panel (ECAP) for COVID-19. He received 2021 Louise and Bill Holladay Distinguished Fellow Award and also Medal of Honour (MH) in 2021 by Chief Executive of Hong Kong SAR Government “in recognition of his valuable contribution to leading his team to examine the potential airborne transmission pathways through tracer gas testing and assess the risk of virus infection during the COVID-19 epidemic.”
Aerosol Science and Technology: Enabling Applications in Energy, Environment and Medicine
University of Miami, USA
Aerosols, particles that are suspended in a gaseous medium, are ubiquitous and found in nature and engineered systems. They occur in a range of sizes, shapes and compositions and are relevant to important phenomena such as climate change, human health, environmental and energy processes. These particles are both inadvertently and intentionally produced in a variety of systems. The inadvertently produced particles maybe problematic and their emissions need to be controlled. The intentionally produced particles have applications in a variety of fields, and form the backbone of the field of nanotechnology. The presentation will describe an understanding of the formation of these particles in gas-phase processes, and report on recent scientific advances. A description of aerosol science and engineering that enables fundamental studies both mechanistically, and by the availability of well controlled particles to understand property-function relationships will be presented.
The second part of
the talk will focus on aerosol science and engineering enabling environmental,
energy and medical technologies. For the
inadvertently produced particles, approaches to develop effective control
technologies to prevent emissions to the atmosphere will be described. The ability to use the fundamental knowledge
of aerosol science and engineering, coupled with reaction engineering
principles to produce particles with strictly controlled sizes, morphologies
and composition in aerosol reactors will be described. The use of semiconducting oxides for both
photo-catalytic and light harvesting (solar energy) applications will be
discussed. Examples will include the use
of nanomaterials in environmental technologies for remediation of various
pollutants and conversion of carbon dioxide to value-added products. Innovative applications in the area of
medicine from cancer treatment to delivery to the brain will also be
discussed. The presentation will address
important aerosol science related issues relative to COVID-19: from airborne
transmission to the methodology of vaccine.
Dr. Pratim Biswas received his B.Tech. degree from the Indian Institute of Technology, Bombay in 1980; his M.S. degree from the University of California, Los Angeles in 1981 and his doctoral degree from the California Institute of Technology in 1985. After a long stint at Washington University in St. Louis as the Lucy and Stanley Lopata Professor, Chair of the Department of Energy, Environmental and Chemical Engineering and Assistant Vice Chancellor, International Programs, he recently moved to the University of Miami as the Dean, College of Engineering.
Pratim Biswas has won
several Teaching and Research Awards: a few recent ones include the Simon Frees
Environmental Engineering Award in 2022, Fuchs Award for outstanding
contributions by a senior scientist in the world in 2018, Lawrence K. Cecil
Award in Environmental Chemical Engineering by AIChE in 2015; and the White
Award in 2016 for pioneering work in electrostatic precipitation of aerosols.
He is a Fellow of the American Association for Aerosol Research, the Saint
Louis Science Academy, the American Association for Environmental Engineering
and Science Professors and the International Aerosol Research Assembly. In
2019, he was elected to the National Academy of Engineering. His research and educational interests are
in aerosol science and technology, nanoparticle technology, energy and
environmental nanotechnology, air quality and pollution control and the thermal
sciences. He has published more than 450
refereed journal papers with his 60 PhD graduates, and presented more than 200
invited talks all across the globe.
Face Masks and Prevention of Respiratory Viral Infections: an Overview
National Taiwan University, Taiwan
Bioaerosols released from infected individuals are a major source of transmission of respiratory viruses. The virus transmission consists of three steps: (1) release of respiratory fluids in the form of droplets from the nose and mouth of an infected person, (2) transport of the droplets in air, and (3) entry of the droplets into the nose and mouth of an uninfected individual. Talking, coughing, and sneezing emit respiratory droplets across a spectrum of sizes. Evaporation of the water in droplets leads to size reduction. The rate at which a droplet evaporate depends on its chemical composition, ambient temperature, and relative humidity. As a result of evaporation, most of the droplets emitted during speech are smaller than 10 micrometers in diameter.
Face masks are effective for capturing droplets just released from the nose and mouth of an infected person. Studies indicate that more than 50% of community transmission of SARS-CoV-2 is from asymptomatic and pre-symptomatic cases. Use of face masks by the public can effectively reduce the chance of infected individuals unknowingly spreading the virus. In addition to being a device for source control, face masks can also protect the wearers from inhaling virus-laden droplets which have been transported into their breathing zones. Cloth masks and disposable masks provide reasonable protection for the public, while surgical masks and N95 respirators give higher levels of protection as needed in healthcare settings. Made with varied materials, these masks have different structural characteristics. The collection efficiency of a mask is a function of droplet size, face velocity (the velocity of the air just before it enters the mask), and the structural characteristics of the mask. For a given mask, the efficiency for capturing droplets during exhalation is higher than during inhalation. Pressure drop across the mask is an important factor to consider when selecting a face mask. The best face mask is the one that gives the highest collection efficiency with the least pressure drop. The fit of the mask is essential for an effective aerosol protection. While face masks have helped preventing the spread of respiratory diseases such as COVID-19, there are rooms for improvement.
Dr. Chiu-sen Wang began his academic career studying Chemical Engineering at National Taiwan University followed by graduate studies, first at Kansas State University and then at the California Institute of Technology, where he received his Ph.D. in 1966. He embarked on research in inhaled particles when he was appointed an assistant professor at the New York University Institute of Environmental Medicine in 1968. Between 1969 and 1984, he taught and conducted research in inhaled particles and aerosol filtration at the Syracuse University Department of Chemical Engineering and Materials Science. He moved back to National Taiwan University as a professor of public health in 1991 and in the following years served as the Chairman of the Department of Public Health and the Dean of the College of Public Health. He became a professor emeritus when he retired in 2003.
Dr. Wang’s research interests include aerosol science and technology, inhaled particles, occupational health, and process optimization. He has authored and co-authored several books, including Inhaled Particles and The Discrete Maximum Principle: a Study of Multistage Systems Optimization (co-authored with L. T. Fan). He served as the Founding President of Taiwan Association for Aerosol Research (1992-1994), President of International Aerosol Research Assembly (2002-2006), President of Taiwan Public Health Association (1997-1999), the Founding Editor-in-Chief of Aerosol and Air Quality Research (1999-2003), and Chairman of the Editorial Board of the Journal of Occupational Safety and Health, Taipei, Taiwan (1994-2000). He was elected an Honorary Member of Japan Association of Aerosol Science and Technology and received the Distinguished Achievement Award from Taiwan Association for Aerosol Research and the 50th Anniversary Award from Society of Powder Technology, Japan.
Aerosol Technology for Controlling Airborne Nanoparticles
Kanazawa University, Japan
Ambient aerosol is a complex mixture of various chemical component such as organic/inorganic carbon, salts, metals and metal oxides, as well as bioaerosols. Transport dynamics and health impacts are significantly influenced by size and chemical composition of aerosol particles. The inhaled airborne particles may deposit at the different position in the respiratory tract and lung as a function of particle size. In order to mimic aerosol dynamics and deposition process at the respiratory system, particularly at the alveoli, air-liquid-interface (ALI) cell exposure system has been developed. In the Extracellular Fine Particles project (CREST, JST, Japan), in vitro cell exposure system, composed of model particle generator, classifier, condensation growth device, and ALI cell exposure chamber, has been newly developed. The effects of size and chemical composition on the aerosol-cell interactions (cell viability, cytokines expression, and phagocytosis process etc.) are investigated by coupling this system with bioimaging/analysis techniques. In addition, interactions (cross talk) of extracellular vecicles (EVs such as exosomes) and nanoparticles that may play a key role in the immunological system are studied. Finally, recent progresses and future aerosol technology such as measurement of sub 3-nm particles, nanofiltration, control of indoor air quality and total solution for human comfort will be discussed.
Dr. Seto Takafumi is currently working as a Professor in the Faculty of Frontier Engineering, Institute of Science and Engineering, Kanazawa University, Japan. His research interests include Chemical Engineering, Aerosol, Nanoparticle, Laser. He is serving as an editorial member and reviewer of several international reputed journals. He is also the member of Present member of the board of directors, Japanese Association of Aerosol Science and Technology (JAAST) and the society of Powder Technology, Japan. He has authored of many research articles/books related to Chemical Engineering, Aerosol, Nanoparticle, Laser.
Three Dimensional Nanoprinting via Charged Aerosols
Seoul National University, Korea
Aerosols can become fundamental units in manufacturing three dimensional materials or structures that exhibit unique properties once they could be accurately controlled to have desired size, morphology and crystalline phase, and also manipulated to be positioned into the exact position in three dimensional space. Although three dimensional printing (3D printing) that is an additive manufacturing has emerged as a revolutionary technology during last decade, there still lacks a technology satisfying all requirements such as nanoscale resolution, fast speed, high purity and capability producing intricate 3D geometry for manufacturing nanoscale 3D structures in a practical way. In this presentation, I show that aerosol technology enables to develop the unique 3D nanoprinting named as EAAL (Electric-field assisted aerosol lithography) which can produce 3D nanostructure array with nanoscale resolution, high purity and versatile geometry under atmospheric conditions in a parallel fashion. In this aerosol 3D nanoprinting, charged aerosol nanoparticles are focused by nanoscopic electrostatic lens on the surface of a hole containing mask under a given electric field and then guided by controlling electric field lines to be printed into three dimensional nanostructures. Electric field line is a drawing tool to manipulate charged aerosols with three dimensional shape controllability to finally design and manufacture desired 3D structures. Controlled generation of nanoparticles is a prerequisite for successful operation of our aerosol 3D nanoprinting. In this regard, I will also summarize different approaches that we developed that can generate a few nanometre sized unagglomerate metal nanoparticles. Our technique exhibits two complementary modes: tip-directed growth and surface writing modes that can print versatile 3D nanostructures including nanohelices, nanopillar-like structures. horizontal ring and letter structures. As applications, I will show 3D vertical split-ring magnetic metamaterial resonators, 3D nanosensors and 3D solar cells. Unlike the existing 3D printing methods, our technique involves a completely dry process without polymers or inks. Theoretical simulations for the technique will be also presented.
Mansoo Choi is currently a Professor of Mechanical Engineering of Seoul National University. He received his B.S. (1980) and M.S. (1982) from Seoul National University and Ph.D. (1987) from University of California, Berkeley, all from mechanical engineering. After working as an assistant engineer at Argonne National Laboratory until 1991, he joined in Seoul National University as a faculty. His research interests include aerosol manufacture of nanoparticles and nanostructures, nano-manufacturing and their applications to sensors and multiscale energy systems including nanostructured solar and fuel cells. Since 2011, he has been leading the Global Frontier Center for Multiscale Energy Systems aiming to develop new conceptual solar and fuel cells utilizing nanotechnology. His early research in the field of aerosol science includes flame aerosol synthesis, control of nanoparticle size, morphology and crystalline phase, non-spherical aerosol dynamics modelling and measurements, aerosol charging, spark discharge aerosol generation technique. Recently, he has been focusing on the development of a new 3D nanoprinting technology based on charged aerosols and has applied aerosol technology for developing novel 3D gas sensors, 3D plasmonic devices, nanostructured solar cells and fuel cells. He had been a Co-Editor-in-Chief of Journal of Aerosol Science from 2004 to 2018.