10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Single Particle Analysis of Samples Collected During the Actris-2 Field Campaign at the Mt. Cimone Station
TYLER CAPEK, Swarup China, Daniel Veghte, Angela Marinoni, Douglas Orsini, Claudio Mazzoleni, Michigan Technological University
Abstract Number: 1389 Working Group: Aerosol Transport and Transformation
Abstract Atmospheric particles influence the Earth’s radiative balance directly by scattering and absorbing solar radiation and indirectly by affecting the formation of clouds and altering the overall albedo of clouds. Due to many socio-economic and environmental reasons, the Mediterranean region is considered a hot spot for climate change and air quality issues. In July 2017 we measured the optical properties and collected samples of atmospheric particles at Monte Cimone as part of an Aerosol Cloud and Trace Gases Research Infrastructure (ACTRIS-2) field campaign. Monte Cimone, the highest mountain in the northern Apennines of Italy, is ideally situated to study the physical and chemical properties of atmospheric particles in the Mediterranean free troposphere as well as the heavily polluted Po Valley (just to the north).
Atmospheric particles ranging in aerodynamic diameter from 0.25-1µm were collected using a 4-stage cascade impactor from the O. Vittori Observatory near the summit of Mt. Cimone. We utilized scanning and transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy (EDS) to determine the abundance, morphology, elemental composition, and mixing state of single particles. We determined the abundance of size-resolved particle classes from the elemental composition of numerous particles. Furthermore, we performed dynamic hydration experiments using an environmental SEM to study the hygroscopic behavior of different particle classes. We observed a considerable fraction of aged sea-salt, sulfates, calcium-rich dust particles, and other carbonaceous particles such as soot and tar balls. On July 19th, 2017 the microscopy analysis showed that 15% of the atmospheric particles were tar ball aggregates, a carbonaceous particle typically associated with biomass burning. Our results indicate that biomass burning plumes and marine sources influenced the air masses sampled at the station. This study provides information on the morphology and composition of single particles at high altitudes where this kind of data is scarce. The results can enhance the understanding of the optical properties of aged particles.