Smoke is a suspension of airborne particulates and gases emitted when a material undergoes combustion or pyrolysis, together with the quantity of air that is entrained or otherwise mixed into the mass. It is commonly an unwanted by-product of fires, but may also be used for pest control (fumigation), communication, defensive and offensive capabilities in the military, cooking, or smoking. It is used in rituals where incense, sage, or resin is burned to produce a smell for spiritual or magical purposes. It can also be a flavoring agent and preservative.
An aerosol is a suspension of fine solid particles or liquid droplets in air or another gas. Aerosols can be generated from natural or human causes. The term aerosol commonly refers to the mixture of particulates in air, and not to the particulate matter alone. Examples of natural aerosols are fog, mist or dust. Examples of human caused aerosols include particulate air pollutants, mist from the discharge at hydroelectric dams, irrigation mist, perfume from atomizers, smoke, dust, sprayed pesticides, and medical treatments for respiratory illnesses.
Soot is a mass of impure carbon particles resulting from the incomplete combustion of hydrocarbons. Soot is considered a hazardous substance with carcinogenic properties. Most broadly, the term includes all the particulate matter produced by this process, including black carbon and residual pyrolysed fuel particles such as coal, cenospheres, charred wood, and petroleum coke classified as cokes or char. It can include polycyclic aromatic hydrocarbons and heavy metals like mercury.
Cloud condensation nuclei (CCNs), also known as cloud seeds, are small particles typically 0.2 μm, or one hundredth the size of a cloud droplet. CCNs are a unique subset of aerosols in the atmosphere on which water vapour condenses. This can affect the radiative properties of clouds and the overall atmosphere. Water vapour requires a non-gaseous surface to make the transition to a liquid; this process is called condensation.
Particulates or atmospheric particulate matter are microscopic particles of solid or liquid matter suspended in the air. The term aerosol refers to the particulate/air mixture, as opposed to the particulate matter alone, though it is sometimes defined as a subset of aerosol terminology. Sources of particulate matter can be natural or anthropogenic. They have impacts on climate and precipitation that adversely affect human health, in ways additional to direct inhalation.
An ice nucleus, also known as an ice nucleating particle (INP), is a particle which acts as the nucleus for the formation of an ice crystal in the atmosphere.
Veronica Vaida is a Romanian-Hungarian-American chemist and professor at the University of Colorado Boulder. She is an expert in environmental chemistry and aerosols.
Heather Cecile Allen is a research chemist and Professor of Chemistry, who leads the Allen Group at The Ohio State University. Allen's research focuses on interfacial phenomena, particularly those involving water and air. Her work has broad application ranging from medicine to climate change. She also develops nonlinear optical spectroscopy and microscopy instruments for the examination of interfacial surfaces.
Barbara J. Finlayson-Pitts is a Canadian-American atmospheric chemist. She is a professor in the chemistry department at the University of California, Irvine and is the Director of AirUCI Institute. Finlayson-Pitts and James N. Pitts, Jr. are the authors of Chemistry of the Upper and Lower Atmosphere: Theory, Experiments, and Applications (1999). She has been a member of the National Academy of Sciences since 2006 and is the laureate for the 2017 Garvan–Olin Medal. In 2016 she co-chaired the National Academy of Science report "The Future of Atmospheric Chemistry Research"
Roy Michael Harrison is a British environmental scientist. He has been Queen Elizabeth II Birmingham Centenary Professor of Environmental Health at the University of Birmingham since 1991, and is a distinguished adjunct professor at King Abdulaziz University in Jeddah, Saudi Arabia.
Vicki H. Grassian is a distinguished professor in the department of chemistry and biochemistry at the University of California, San Diego. She also holds the distinguished chair in physical chemistry.
Hind Al-Abadleh is a professor of chemistry at Wilfrid Laurier University in Waterloo, Ontario, Canada. She studies the physical chemistry of environmental interfaces, aerosols and climate change.
Colette L. Heald is a Canadian-born professor at ETH Zurich who is an expert in atmospheric chemistry.
Kimberly A. Prather is an American atmospheric chemist. She is a distinguished chair in atmospheric chemistry and a distinguished professor at the Scripps Institution of Oceanography and department of chemistry and biochemistry at UC San Diego. Her work focuses on how humans are influencing the atmosphere and climate. In 2019, she was elected a member of the National Academy of Engineering for technologies that transformed understanding of aerosols and their impacts on air quality, climate, and human health. In 2020, she was elected as a member of the National Academy of Sciences. She is also an elected Fellow of the American Philosophical Society, American Geophysical Union, the American Association for the Advancement of Science, American Philosophical Society, and the American Academy of Arts and Sciences.
Lynn Russell is a professor of atmospheric chemistry at the Scripps Institute of Oceanography a division of the University of California, San Diego in La Jolla, California.
Julia Yvonne Schmale is a German environmental scientist. She is a specialist in the micro-physical makeup of the atmosphere, in particular aerosols and their interaction with clouds. She is a professor at EPFL and the head of the Extreme Environments Research Laboratory (EERL). She is a participant in the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expeditions.
Vivian Faye McNeill is an American atmospheric chemist who is professor of chemical engineering at Columbia University. She leads the University's initiative Clean Air Toolbox for Cities. McNeill provided expert guidance on aerosols and ventilation throughout the COVID-19 pandemic.
Chiara Giorio is an Italian atmospheric chemist who is an Assistant Professor in the Yusuf Hamied Department of Chemistry at the University of Cambridge, a Fellow of Christ's College and a Fellow of the Community for Analytical Measurement Science.
Nga Lee Ng is the Love Family Professor at the Georgia Institute of Technology, holding appointments in both the School of Chemical and Biomolecular Engineering and the School of Earth and Atmospheric Sciences. Her research focuses on atmospheric chemistry, particularly in the study of organic aerosols and their effects on air quality, climate, and human health.
Richard Charles Flagan is an American chemical engineer known for his research on aerosols, both in atmospheric science studies and in the processing of materials. He is the McCollum-Corcoran Professor of Chemical Engineering and Environmental Science and Engineering at the California Institute of Technology.
