The Surratt Research Group is located within the Department of Environmental Sciences and Engineering, part of The Gillings School of Global Public Health at UNC-Chapel Hill.
Our research is mainly focused on understanding the chemical formation and evolution of secondary organic aerosol (SOA) in the Earth’s atmosphere. Since numerical models currently underestimate the amount of SOA mass observed in fine aerosol collected from several locations, which indicates that significant sources of SOA are not yet identified or well characterized, we chemically characterize both smog chamber-generated and ambient SOA in order to more adequately describe sources (e.g., heterogeneous chemistry) of SOA in the troposphere. By using this approach, Professor Surratt has helped to elucidate the chemical pathways leading to organic aerosol formation from the atmospheric oxidation of isoprene, which is the most abundant non-methane hydrocarbon emitted annually into the Earth’s atmosphere that was previously thought not to be a significant source of SOA.
We employ advanced on- and off-line mass spectrometric techniques to chemically characterize organic aerosol samples produced in smog chamber experiments and collected from locations around the world. We chemically speciate organic aerosol constituents from filter samples using GC/MS and LC/MS techniques. In addition, we are now using on-line aerosol mass spectrometry techniques (i.e., the Aerodyne Aerosol Chemical Speciation Monitor (ACSM)) to chemically speciate ambient aerosols, and thus, determine their specific sources. Furthermore, our research group has two smog chamber facilities that are used for understanding the formation and evolution of fine organic aerosols; specifically, an outdoor dual smog chamber located in Pittsboro, NC, and a new 10 m3 indoor smog chamber located in Hooker Lab. With the outdoor smog chamber we use natural sunlight to drive reactions that lead to organic aerosol formation; with our indoor chamber we conduct both dark reactive uptake experiments and nighttime (i.e., NO3-initiated) oxidation reactions. We chemically analyze both the gas- and aerosol-phase constituents in order to elucidate the detailed reactions leading to fine organic aerosol in the atmosphere.