AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Isoprene Effects on Biogenic and Inorganic New Particle Formation
LEE TISZENKEL, Ryan Haley, Shanhu Lee, University of Alabama Huntsville
Abstract Number: 509 Working Group: Aerosol Chemistry
Abstract New particle formation (NPF) via gas-to-particle conversion is a ubiquitous event that is responsible for about 50% of the global CCN production. Oxidized organic species such as alpha-pinene and inorganic species such as sulfuric acid and ammonia have been observed to participate in NPF in areas with a sufficient concentration of these precursors. However, the presence of high concentrations of isoprene, which is the most abundant biogenic volatile organic compound (BVOC) globally, may suppress the NPF process, although the chemical mechanisms behind this suppression processes are not yet known. Here we present the results of laboratory studies of both organic and inorganic nucleation in the presence of varying ozone levels, isoprene and pure hydrogen gas acting as a hydroxyl radical scavenger, using a fast flow nucleation reactor. These experiments are conducted with a flow tube nucleation reactor monitored by a particle size magnifier (PSM) that produces size distributions between 1 and 3 nm, a scanning mobility particle sizer (SMPS) that produces size distributions from 3 to 100 nm, and chemical ionization mass spectrometers (CIMS) that monitor sulfuric acid and amine/ammonia concentrations. Varying ozone during these experiments allows for varying concentrations of highly oxidized molecules (HOMs) that participate in biogenic NPF and HOMs concentrations are calculated using the steady state condition in the flow tube. Isoprene effects on nucleation in the presence of both organic and inorganic precursors at atmospherically relevant concentrations will be discussed.