Atmospheric Brown Carbon Production: Cloud Chamber Experiments on Methylglyoxal, Methylamine, and Ammonium Sulfate Seed Particles in the Presence of Sunlight and Oxidants
EMSL Project ID
48884
Abstract
The goal of this project is to characterize atmospheric brown carbon production during cloud processing through CESAM cloud/smog chamber simulations involving methylglyoxal, amines, and ammonium sulfate aerosol. These compounds have been found to produce light-absorbing products in dark, aqueous, bulk-phase reactions, but the reactions are thought to be much faster in suspended evaporating droplets. The CESAM chamber, located at the University of Paris – East, Cretiel, will allow the formation of brown carbon during cloud cycling to be directly observed. The chamber can produce 3-5 sequential cloud events, each of ~10 min duration, similar to that of real cloud events. The effects of oxidants and sunlight will be included in the simulations. The project will determine whether light-absorbing compounds and oligomers can be produced by Maillard-type reactions under realistic atmospheric conditions. If so, control of dicarbonyl precursors, primary amines, and ammonia emissions may provide a path to reduce particulate air pollution and short-term mitigation of climate change. EMSL will provide high-resolution nano-desorption electrospray mass spectroscopy (HR-DESI-MS) and environmental scanning electron microscopy (ESEM) analyses of chamber aerosol samples. These techniques allow molecular analysis of very small samples while avoiding liquid extraction, which can destroy oligomers via hydrolysis. Aerosol samples can therefore be taken before and after chamber cloud events, so that the effects of each event can be determined on organic aerosol molecular composition (HR-DESI-MS) and microstructure (ESEM).
Project Details
Project type
Large-Scale EMSL Research
Start Date
2015-10-01
End Date
2017-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Co-Investigator(s)