CAREER: Budget and Impacts of Atmospheric Organic Acids from Ground and Space-based Observations

Formic and acetic acids are the dominant carboxylic acids in the atmosphere. They exert an important influence on atmospheric aqueous chemistry through their effect on precipitation acidity, aqueous hydroxyl radical concentrations, and possibly secondary organic aerosol formation. This CAREER award focuses on understanding seasonal sources of organic acids and their atmospheric impacts. The research will be guided by the following key questions: What is the global importance of direct emissions versus secondary production from biogenic, biomass burning, and anthropogenic sources? Is there a significant source of formic and acetic acids during aging of organic aerosols? What is the role of formic and acetic acids in governing the acidity of precipitation and clouds around the world? How does this vary geographically and seasonally? The experimental approach combines new process-oriented measurements with new global observations from space, interpreted in the framework of an atmospheric model. Specific steps will include carrying out new field and laboratory measurements to quantify key controls on organic acid abundance in the atmosphere, applying new satellite retrievals of formic acid from the Tropospheric Emission Spectrometer and the Infrared Atmospheric Sounding Interferometer in targeted process studies on the global scale, and using the GEOS-Chem chemical transport model to interpret the new space-borne and in situ measurements in terms of quantitative constraints on global sources and chemical impacts organic acids in the atmosphere.

The broader impacts of this work will include: 1) Enhanced learning in air pollution and Earth Science for local public elementary students; 2) Training graduate and postdoctoral researchers in cutting-edge atmospheric chemistry measurement and modeling tools; 3) Building the research and education capacity of the new Land and Atmospheric Science program at the University of Minnesota; 4) Better understanding of organic acid sources and impacts for more accurate air quality and climate predictions; 5) Active dissemination of scientific findings through scientific presentations and publications. Finalized measurement data, satellite retrievals, and model code will be made public and readily available online.