AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Comparison of the Sources of Organic Aerosol (OA) Using Aerosol Mass Spectrometry at Two Mediterranean Islands: Corsica and Mallorca
H. LANGLEY DEWITT, Jorge Pey, Stig Hellebust, Brice Temime-Roussel, Aurelie Mizzi, Dalia Salameh, Alexandre Sylvestre, Miriam Elser, N. Pérez, José Carlos Cerro, Jean-Luc Jaffrezo, Grisa Mocnik, Andre Prévôt, Nicolas Marchand, Aix-Marseille Université, CNRS, LCE FRE 3416
Abstract Number: 179 Working Group: Source Apportionment
Abstract The atmosphere above the Mediterranean Sea is heavily impacted by a mix of continental aerosol sources as well as primary (e.g., sea salt) and secondary (e.g., sulfate, organic sulfate) marine aerosols. Although the region is typically calm with low surface biological activity, periods of high wind speeds and/or plankton blooms increase marine aerosol; anthropogenic emissions could also affect the formation rate of secondary marine aerosol by increasing available oxidants in the atmosphere. During the summer, the long hours of sunlight and dry weather accelerate the photochemical processing of aerosol and gas-phase species. As part of the Chemistry-Aerosol Mediterranean Experiment (ChArMEx) field campaign, two high-resolution aerosol mass spectrometers (HR-ToF-AMS), co-located with other instrumentation such as a PTR-ToF-MS, an Aethalometer/MAAP, a SMPS, and high-volume samplers (for off-line analysis of organic markers, trace metals, OC/EC, and major ions), were deployed on the islands of Corsica (on an isolated ridge 10 km from the sea) and Mallorca (seaside) to measure the chemical composition, concentration, and size of aerosol in the western Mediterranean basin. Back-trajectories of air masses, pollution outflow forecasts, MODIS satellite chlorophyll data, and dust aerosol maps were used for interpretations of aerosol sources, and the marine aerosol influence at different locations and heights (sea-level and above) was investigated. Higher levels of organic sulfur species, generally used as tracers for secondary marine aerosol, were observed at the Mallorca site compared to concentrations measured at the hilltop Corsica site. Recent improvements in the source apportionment approach based on AMS measurements made it possible to separate and identify different aerosol sources (e.g., SOA, marine aerosol). Separating anthropogenic from natural aerosol influences in this heavily human-impacted environment will increase our understanding of the interaction of anthropogenic aerosol, gases, and oxidants with naturally occurring aerosol and gas-phase emissions in these marine environments.