1 research outputs found
Aqueous Processing of Atmospheric Organic Particles in Cloud Water Collected via Aircraft Sampling
Cloudwater and below-cloud atmospheric
particle samples were collected
onboard a research aircraft during the Southern Oxidant and Aerosol
Study (SOAS) over a forested region of Alabama in June 2013. The organic
molecular composition of the samples was studied to gain insights
into the aqueous-phase processing of organic compounds within cloud
droplets. High resolution mass spectrometry (HRMS) with nanospray
desorption electrospray ionization (nano-DESI) and direct infusion
electrospray ionization (ESI) were utilized to compare the organic
composition of the particle and cloudwater samples, respectively.
Isoprene and monoterpene-derived organosulfates and oligomers were
identified in both the particles and cloudwater, showing the significant
influence of biogenic volatile organic compound oxidation above the
forested region. While the average O:C ratios of the organic compounds
were similar between the atmospheric particle and cloudwater samples,
the chemical composition of these samples was quite different. Specifically,
hydrolysis of organosulfates and formation of nitrogen-containing
compounds were observed for the cloudwater when compared to the atmospheric
particle samples, demonstrating that cloud processing changes the
composition of organic aerosol