This research will focus on novel methods for the speciation of organic nitrate compounds and the quantification of organic nitrate formation during volatile organic carbon (VOC) oxidation, generally by the hydroxyl (OH) and nitrate (NO3) radicals. Because VOC oxidation mechanisms are complex and depend on the specific VOC in question, the production of organic nitrates varies both in terms of species and abundance. Laboratory studies will help elucidate nitrate species from specific VOC compound oxidation pathways (e.g., isoprene oxidation in the presence of OH). Field samples will be obtained at a pine forest site during the Biosphere Effects on Aerosols and Photochemistry Experiment (BEARPEX) campaign and analyzed with gas chromatography/mass spectrometry (GC/MS) and other techniques. The field phase of the project will focus on measuring the wide range of organic nitrate compounds present, most of which have previously only been detected as a sum of total organic nitrates. The investigators will attempt to identify and quantify larger and more complex nitrates than has been possible in past studies, as well as nitrate compounds in aerosols. This project will test and demonstrate a novel technique for the detection of speciated organic nitrates. Results from this research should also help improve understanding of fundamental oxidation pathways and the production of reactive nitrogen containing species. These species can impact regional abundances of nitrogen oxides (NOx) and thus tropospheric ozone. A postdoctoral research associate will be partially supported through this project.
