One year intensive PM2.5 bound polycyclic aromatic hydrocarbons monitoring in the area of Tuscany, Italy. Concentrations, source understanding and implications.

Polycyclic aromatic hydrocarbons (PAHs) associated to PM(2.5) particles were monitored at three sites in the region of Tuscany, Italy, during the period March 2009-March 2010. PAH concentrations ranged between 0.92 ng m(-3) and 13 ng m(-3). The spatial and seasonal differences observed at the three sites are discussed and attributed to specific PAH sources. Benzo[a]Pyrene average annual values were below the EU limit value of 1.0 ng m(-3). The results of this study suggest that emissions from commuting and work related traffic play an important role for the city of Florence, whereas for the city of Livorno, the harbor activities seem to impact the PAH burden substantially, as well. The PAH cancer risk (expressed as the "BaPE index") has shown a 6-fold decline compared to early 1990's concentrations and 2- to 3-fold decline compared to the late 1990's.