Published November 15, 2011
by iris_author
The following appeared in the Tuesday, November 15th edition of YFile.
Andreas Wahner, director of the Institute for Energy and Climate Research – Troposphere in Forschungszentrum Juelich, Germany, will give the 21st Annual Harold I. Schiff Lecture in York’s Senate Chamber on Dec. 2.
Organized by the York University Centre for Atmospheric Chemistry and the Faculty of Science & Engineering, Wahner’s talk, "Atmospheric Trace Gas Degradation and Secondary Pollutant Formation: New Insights from Process Studies", starts at 2pm in the Senate Chamber, N940 Ross Building on York’s Keele campus.
Right: Andreas Wahner
Hydroxyl (OH) radicals play a central role in the chemistry of the troposphere (the lowest level of the Earth’s atmosphere). These radicals are mainly responsible for the chemical degradation of many trace gases and they initiate chemical reactions that may eventually lead to the formation of photochemicals or the depletion of tropospheric ozone.
Wahner posits that recent field measurements of the key radicals hydroxyl and water, and measurements of the turnover rates which determine the radical recycling, are significantly underestimated by current atmospheric chemistry models. At a high load of anthropogenic (human impact) and biogenic (produced by biological processes) volatile organic compounds and low nitric oxide (NO), a significant hydroxyl radical is missing.
The challenging questions Wahner will discuss in the Harold Schiff Lecture are: Which kinds of reactions cause such efficient OH cycling? What does this mean to our understanding of the trace gas degradation and photochemical ozone production, which is normally linked with radical cycling through NO reactions?
The Harold I. Schiff Lecture series was established in honour of late Professor Emeritus Harold I. Schiff, who was York's founding dean of the Faculty of Science in 1968. Among his numerous achievements are his major contributions to the development of techniques for measuring trace constituents in the upper atmosphere and to the interpretation of the physics and chemistry of the stratosphere.
An educator and scientist in the field of chemistry, Schiff began at York in 1964 and was named a member of York’s Founders Society in honour of his contributions to the early development of the University. While at York, Schiff was chair of the Department of Chemistry and director of the Natural Science Program in 1964, dean of the Faculty of Science from 1965 to 1972, and director of the Centre for Atmospheric Chemistry from 1985 to 1989.
The annual Harold I. Schiff Lecture is organized by the Centre for Atmospheric Chemistry at York. For more information, e-mail cac@yorku.ca.
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