Biomass burning and marine aerosol processing over the southeast Atlantic Ocean: a TEM single-particle analysis

• Published in: Atmospheric chemistry and physics Vol. 22; no. 14; pp. 9389 - 9412
• Main Authors: Dang, Caroline, Segal-Rozenhaimer, Michal, Che, Haochi, Zhang, Lu, Formenti, Paola, Taylor, Jonathan, Dobracki, Amie, Purdue, Sara, Wong, Pui-Shan, Nenes, Athanasios, Sedlacek III, Arthur, Coe, Hugh, Redemann, Jens, Zuidema, Paquita, Howell, Steven, Haywood, James
• Format: Journal Article
• Language: English
• Published: Katlenburg-Lindau Copernicus GmbH 21-07-2022; European Geosciences Union; Copernicus Publications, EGU; Copernicus Publications
• Subjects: Aerosol composition; Aerosol-cloud interactions; Aerosols; Aging; Air; Air sampling; Aircraft; Atmospheric processes; Biomass; Biomass burning; Biomass burning plumes; Boundary layers; Burning; Carbon; Chemical composition; Clouds; Composition; ENVIRONMENTAL SCIENCES; Inorganic salts; Marine aerosols; Ocean; Oxidation; Particle analysis; Photolysis; Plumes; Potassium; Potassium salts; Radiation; Radiation-cloud interactions; Salt content; Salts; Sciences of the Universe; Secondary aerosols; Sodium; Troposphere; Uptake; Volatility; Africa
• ISSN: 1680-7324; 1680-7316; 1680-7324
• DOI: 10.5194/acp-22-9389-2022

This study characterizes single-particle aerosol composition from filters collected during the ObseRvations of Aerosols above CLouds and their intEractionS (ORACLES) and CLoud–Aerosol–Radiation Interaction and Forcing: Year 2017 (CLARIFY-2017) campaigns. In particular the study describes aged biomass burning aerosol (BBA), its interaction with the marine boundary layer and the influence of biomass burning (BB) air on marine aerosol. The study finds evidence of BBA influenced by marine boundary layer processing as well as sea salt influenced by BB air. Secondary chloride aerosols were observed in clean marine air as well as in BB-influenced air in the free troposphere. Higher-volatility organic aerosol appears to be associated with increased age of biomass burning plumes, and photolysis or oxidation may be a mechanism for the apparent increased volatility. Aqueous processing and interaction with the marine boundary layer air may be a mechanism for the presence of sodium on many aged potassium salts. By number, biomass burning potassium salts and modified sea salts are the most observed particles on filter samples. The most commonly observed BC coatings are inorganic salts. These results suggest that atmospheric processes such as photolysis, oxidation and cloud processing are key drivers in the elemental composition and morphology of aged BBA. Fresh BBA inorganic salt content, as it has an important role in the particles' ability to uptake water, may be a key driver in how aqueous processing and atmospheric aging proceed.