The role and fate of oxidized nitrogen in the atmosphere. A story of 3 decades of (off and on) research

Dr. Frank Flocke

Senior Scientist, National Center for Atmospheric Research

Atmospheric oxidized nitrogen plays a key role in the gas phase chemistry of the troposphere. The photochemical processes that lead to the formation of ozone are dependent on the availability of NOx (NO + NO2) and its ratio to volatile organic compounds (VOC), the other ingredient to ozone formation. While NOx serves as the catalyst in the ozone formation cycle, termination reactions of this cycle result in the formation of nitrates, both in inorganic and organic form. Organic nitrates in both the gas phase and the condensed phase can reveal details about the ozone production efficiency in different polluted environments but they can also serve as transport media to deliver NOx to remote areas, changing the photochemical balance there. I will try and give an overview of what we know and don’t know about organic nitrates and their role in tropospheric photochemical cycles.

Bio: Frank is a Senior Scientist at the National Center for Atmospheric Research (NCAR) in Boulder, Colorado. He came to Boulder in 1992 as a PostDoc and has worked at NCAR ever since. In his nearly 3 decades at NCAR he has participated in more than 20 aircraft-based and several more ground-based field projects aimed at understanding atmospheric chemistry and air quality both in and outside of the U.S. His work focuses on the formation and fate of organic nitrates and the role they play in the production of tropospheric ozone, and the impact of anthropogenic emissions on regional air quality, for example the contributions of oil and gas extraction and transportation emissions to ozone formation in the Colorado Front Range. Recent work has also included the investigation of the atmospheric chemical transformation of emissions from large western wildfires.