An analytical method for the determination of total and water soluble carbon in fine aerosol particles

Carbonaceous aerosol (TC) represents a relevant part of total aerosol both in urban and rural areas1 and it is mainly composed by organic matter (OC), while a minor fraction is due to so called Black Carbon (BC). OC and BC affect the hygroscopicity of aerosol particles and play an active role in several atmospheric processes, in particular in nucleation and droplets growth2. All these things considered it appears important to set up fast and reliable protocols for the determination of TC and of the water soluble fraction of carbon (WSOC), which can be an index of the hygroscopic nature of TC for a given aerosol. The main problems of such a determination are: i) the limited amount of sample, usually a portion of a 47 mm filter, ii) the non availability of an useful reference material; iii) the need to perform instrumental calibration at very low level of analyte quantity, hence at the instrumental sensitivity limit. Both methods have been set-up adopting the most recent ISO international standards related to calibration and quality control. Results obtained from real samples collected in the Po Valley will be presented.