Renyi Zhang

zhang Nucleation and Growth of Atmospheric Aerosols —
Progress and Challenges

About the Presenter:

Renyi Zhang joined the faculty at Texas A&M University (TAMU) in 1997 and is Professor in the Departments of Atmospheric Sciences of College of Geosciences and Chemistry of College of Science. He earned a Ph.D. from MIT and completed postdoctoral work at Caltech/NASA Jet Propulsion Laboratory. He is holder of the Harold J. Haynes Endowed Chair in Geosciences and University Distinguished Professor at TAMU. His early research contributed to the understanding of stratospheric ozone depletion and formation of the “Antarctic Ozone Hole”. His research at TAMU has led to important advances in several atmospheric fields—photochemical oxidation of hydrocarbons; formation, growth, and properties of aerosols; urban and regional air pollution; ambient measurements of trace gases and aerosols; and assessment of aerosol-cloud-climate interaction—and provided critical insights into the impacts of human activities on the environment, weather, and climate. He has published more than 180 papers in peer-refereed journals. Currently, Zhang is editor for Journal of the Atmospheric Sciences and senior editor for Oxford Research Encyclopedia – Environmental Science, Oxford University Press, and is a member of the International Commission on Atmospheric Chemistry and Global Pollution. He served as editor of the Journal of Geophysical Research – Atmospheres (2009-2013) and chaired the American Meteorological Society’s Atmospheric Chemistry Committee (2010-2014). He has received several awards, including honorary professorships at Peking University and Fudan University, the Outstanding International Collaboration Researcher Award from the China National Science Foundation, The Association of Former Students Distinguished Achievement Award—Research at TAMU, the Bush Excellence Award for Faculty in International Research at TAMU, and the Cheung-Kong Distinguished Scholar Award from the Ministry of Education–China. He is an elected Fellow of the American Geophysical Union and American Meteorological Society.

Full Presentation:

Abstract:

Atmospheric aerosols impair visibility and human health, alter cloud formation, and interfere with the Earth’s radiative transfer. The major contributors include secondary sulfate and organic aerosols from anthropogenic and biogenic activities, which are produced through a multitude of complex multiphase atmospheric processes by photochemical oxidation of emitted sulfur dioxide and volatile organic compounds (VOCs) into less volatile forms and gas-to-particle conversion. Aerosol nucleation events have been frequently observed under various tropospheric conditions and account for a major fraction of the total aerosol population, but the fundamental chemical processes responsible for aerosol nucleation and growth remain poorly understood. New particle formation occurs in two distinct stages, i.e., nucleation to form the critical clusters and subsequent growth of the newly nucleated clusters by condensation or heterogeneous reactions to larger particles. Although sulfuric acid has been identified as a key species in aerosol nucleation and growth, it is commonly recognized that sulfuric acid alone is inefficient enough to explain measured atmospheric aerosol formation. Considerable uncertainty exists regarding
the mechanisms and identity of other condensable species responsible for nucleation and growth of atmospheric aerosols. This talk focuses on nucleation and growth of aerosols in the atmosphere, focusing on the fundamental chemical processes at the molecular levels.