Authors
Maxwell Lee, Daniel Katz, Bri Dobson, Ellie Browne (CIRES)
Abstract
Understanding the factors that govern particle growth is important for improving our comprehension of how new particle formation (NPF) contributes to the production of particles of sufficient size to act as cloud condensation nuclei. In continental locations, particle growth is typically driven by organic compounds, however the identity of these compounds is highly uncertain due to insufficient ambient measurements. Agricultural areas are a particular area of interest, as they account for approximately 42% of global land use. The Department of Energy Southern Great Plains atmospheric observatory has continuously made atmospheric measurements since 1992 in a rural agricultural area, and the high frequency of new particle formation events make it an ideal place to study how agricultural volatile organic compound (VOC) emissions affect the growth of new particle formation events. Previous research done by the Browne group has identified the importance of sesquiterpene derived organonitrates for particle growth in the fall, but recent analysis of data collected during spring of 2022 shows the importance of monoterpene derived organonitrates to particle growth, as opposed to sesquiterpenes. In this work, we analyze this data using binned positive matrix factorization and generalized Kendrick analysis to gain chemical information and temporal variation of detected ions, revealing insights into the role of agricultural biogenic VOCs in NPF at the research site. Analysis shows the importance of night-time NO3 radical oxidation of monoterpenes and sesquiterpenes, the presence of night-time H2SO4 formation via Creigee-Intermediates, and the role of transported biomass burning products.