10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Measurements of Black Carbon Concentration and Aerosol Light Absorption during the Finokalia Aerosol Measurement Experiment (FAME-16)
ANTONIOS TASOGLOU, Kalliopi Florou, Evangelos Louvaris, Aikaterini Liangou, Georges Saliba, Spyros Pandis, Carnegie Mellon University
Abstract Number: 503 Working Group: Remote/Regional Atmospheric Aerosol
Abstract A month of continuous air monitoring took place at the Finokalia Atmospheric Observatory in Crete, Greece during the summer of 2016. No significant human activities occur within 15 km of the station. The sampled air masses originated from the Balkans, northern Africa and the Mediterranean Sea. This study focused on the measurement of the aerosol light absorption in a remote area characterized by highly oxidized organic aerosol and also high sulfate levels.
In addition to a high-resolution Aerosol Mass Spectrometer (HR-ToF-AMS) and a Scanning Mobility Particle Sizer (SMPS) for size distributions and chemical composition measurements, a suite of instruments for the measurement of the light absorption and the refractory black carbon (rBC) mass concentration was deployed. This included an aethalometer, a photoacoustic extinctiometer (PAX405), a Multi-angle Absorption Photometer (MAAP), and a Single Particle Soot Photometer (SP2).
The fine aerosol mass concentration ranged from 0.3 to 8 μg m-3, with the sulfate and organics accounting for almost 80% of the total mass. The organic aerosol was quite oxidized with an average O:C equal to 0.7. The rBC concentration ranged from 0.04 to 0.3 μg m-3, representing from 2 to 15% of the fine aerosol mass. The measured light absorption was two or more times higher than that of fresh BC. Mie theory was used to evaluate if the effect of the coatings of BC cores by organics and sulfate could explain this absorption enhancement. The role of brown carbon and also other non-BC light-absorbing material was investigated. A thermodenuder was used to link the volatility of the organic aerosol with the observed BC absorption enhancement.