Connecting the Physicochemical Properties with Ice Nucleation Properties of Secondary Organic Aerosols (SOAs) Formed from Multiphase Chemical Processes
EMSL Project ID
51942
Abstract
Organic aerosols (OA), especially secondary organic aerosols (SOA), make up a large fraction of tropospheric fine particulate matter (PM) and up to 80% of the total fine PM in the upper troposphere. A significant portion of the SOA (40% or higher in certain regions of the world) are formed through the multiphase chemical processes. Recent studies that the PI Zhang led have been the first to demonstrate that multiphase chemical processes may convert the inorganic sulfates of the particles into organosulfates and other multifunctional organic species, which have drastic different chemical composition and physicochemical properties, leading to significant changes in their climate properties. In addition, preliminary work by the PI shows that multiphase chemical reactions of biogenic volatile organic compound (BVOC)-derived oxidation products also change the ice nucleation properties of the particles, though the mechanisms are not clear due to challenges in simultaneously characterize the chemical and microphysical properties of aerosols with their climate effects. The difficulty in connecting chemical transformations, compositions, and physicochemical properties of SOA with their ability to form clouds is a major gap that needs to be addressed. This study aims to address the above scientific gap by hypothesizing that common multiphase reaction process can lead to inorganic to organic conversion and the formation of organosulfates and multifunctional SOA components, which in turn poses changes to the cloud microphysical properties through altering the phase state, mixing state, and INP properties of aerosols. This study will first focus on examining the chemical composition and physicochemical properties of SOA produced from multiphase reactions with acidic inorganic sulfate seed particles during laboratory studies using advanced characterization instruments from EMSL, such as the inductively coupled plasma spectrometry (ICP-MS), ion chromatography (IC), Nanospray Desorption Electrospray Ionization (nano-DESI), and atomic force microscope (AFM). Then in the second year, the study will examine the abilities for these aerosols to promote ice nuclei (IN) by using SPLAT II data to analyze the ice residue with a PCVI. The SPLAT data will be crossed compared with the physiochemical characterization results obtained from the first year to understand the role of chemical composition, morphology, and mixing state in governing the ice nucleation abilities of aerosols generated from multiphase reactions.
The project will provide new, important information on how organosulfates generated from the multiphase reactions will impact aerosol physiochemical properties and their cloud formation properties. Furthermore, the outcome will be useful for improving model parameterizations in predicting aerosol transformation and aerosol-cloud interactions. The results will be of significance to our understanding of current atmospheric processes, in addition to estimates of future climate consequences regarding interactions among the physical, chemical, and biological processes of the Earth.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2021-10-01
End Date
2023-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members