Aerosol Chemical Composition at the Mt. Cimone WMO/GAW Global Station

The aerosol chemical composition at Mt. Cimone has been investigated since 2000 during a series of field campaigns. Starting from 2009, systematic measurements on PM₁ filters was conducted as a contribution to the EUSAAR/ACTRIS network. Moreover, first online chemical measurements were conducted at Mt. Cimone (CMN) in summer 2012 using a high-resolution aerosol mass spectrometer (AMS). The analyses show that the concentrations of mineral elements, associated to coarse particles, are largely influenced by long-range transport of desert dust from Africa. The submicron aerosol composition is dominated by sulfate, carbonaceous material and, to a lesser extent, by nitrate. The concentrations of all PM₁ major components followed a yearly cycle with maxima in the summer when the station prevalently resides in the planetary boundary layer (PBL). The organic-to-sulfate ratio is smaller in summer then in winter. A meta-analysis of the whole dataset shows evidence of a decrease of sulfate concentrations in PM₁ from 2000 to 2010. The sources of organic matter at CMN are still subject of investigation, although biogenic secondary organic aerosol seems to play a role in summertime while biomass burning becomes prevalent in winter.