Atmospheric Particle Formation in Two Systems: Sulfuric Acid (H2SO4)/Water (H2O) plus Ammonia (NH3) and/or Amines, and Oxidation Products from Organic Compounds

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This project involves the conduct of new laboratory experiments to study fundamental processes underlying new particle formation in the atmosphere with a particular focus on the formation and growth of nanoparticles. There still exist uncertainties and knowledge gaps related to new particle formation, and this work will provide insights into new particle formation and enhance our understanding of the formation of clouds, as well as the impacts on a changing climate and human health. The experiments will be performed in two reactors developed in previous NSF-funded work. Undergraduate students, including those from underrepresented groups, will be trained and taught laboratory techniques over the course of this project.Two flow reactors, developed in previous NSF-funded work, will be used in this project: a Photolytic Flow Reactor (PhoFR) and a Growth Flow Reactor (GroFR). The experiments will provide fundamental knowledge pertaining to Gibbs energy, van der Waals effects, and the impact of particle phase composition of a H2SO4/NH3 system, as well as focus on organic particle formation from biogenic volatile organic compound oxidation. The experiments with the PhoFR include: (1) study the nucleation rates and cluster Gibbs energies in H2SO4/H2O and ternary (with NH3) systems under various temperatures; and (2) study the growth of seed particles by H2SO4 uptake as a function of seed particle size and composition, as well as determine the effects of van der Walls forces and the hygroscopicity of nanoparticles. The experiments with the GroFR include: (1) study the effect of seed particle size and growth during the photooxidation of monoterpenes; (2) study the synthesis of first-generation oxidation products of monoterpenes and related compounds; and (3) the deployment of a mass spectrometer.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.