Atmospheric Chemistry Program Seminar
April
12
Mon
2021
12:30 pm
Open to Public
OS and pH estimation from AMS measurements and OH oxidation of phenolic compounds in wildfire smoke
Melinda Schueneman,
ANYL 3rd year student, [cires1.colorado.edu/jimenez-group/ Jimenez Group]
"This talk will focus on two unrelated research projects: the first will highlight a paper recently published in AMT, and the second will introduce and show preliminary results for a biomass burning project. Shortened abstracts are included here for reference.
Part I: Sulfate can be present in aerosols as inorganic (mainly ammonium sulfate, AS) or organosulfate (OS). Although OS is thought to be a smaller fraction of total sulfate in most cases, recent literature argues that this may not be the case in more polluted environments. Two new methods have been proposed to quantify OS separately from AS with AMS data. We use observations collected during several airborne field campaigns covering a wide range of sources and air mass ages and targeted laboratory experiments to investigate the proposed OS methods. Four chemical regimes are defined. In polluted areas with high ammonium nitrate concentrations and in remote areas with high aerosol acidity, the decomposition and fragmentation of sulfate in the AMS is influenced by multiple complex effects, and estimation of OS does not seem possible with current methods. In regions with lower acidity (pH > 0) and ammonium nitrate (fraction of total mass