Characteristics of carbonaceous aerosols in Emilia-Romagna (Northern Italy) based on two fall/winter field campaigns

The carbonaceous aerosol in Emilia-Romagna region (Northern Italy) was characterized in two fall/winter monitoring campaigns conducted through the years 2011-2012 and 2012-2013. Nearly 650 PM2.5 samples were collected at three monitoring stations describing urban background (main city Bologna, MS, Parma and Rimini) and one rural background site (San Pietro, SP). OC and EC values were measured by the thermal-optical transmittance method (TOT). Low flow-rate sampling strategy (24 m(3) air volume per day) was used to reduce loading of light absorbing material on the filter surface in order to ensure the correct OC/EC discrimination. The TC values measured in winter 2011-2012 ranged from 9.8 mu gC m(-3) at San Pietro to 12.0 mu gC m(-3) at Parma, consisting of OC from 8.6 mu gC m(-3) at SP to 9.9 mu gC m(-3) at MS and EC from 1.3 mu gC m(-3) at SP to 2.5 mu gC m(-3) at Rimini. In winter 2012-2013, lower values were in general found with TC values ranging from 7.8 to 9.1 mu gC m(-3) consisting of OC from 5.1 to 7.0 mu gC m(-3) and EC from 1.5 to 2.2 mu gC m(-3). Such differences can be likely explained by higher pollutant emissions related to domestic heating in colder fall/winter 2011/2012 (mean temperature approximate to 2 degrees C in comparison with approximate to 7 degrees C in winter 2012/2013). This hypothesis is supported by high levels of levoglucosan, as unambiguous tracer for biomass burning emission, and of polycyclic aromatic hydrocarbons related to combustion (levoglucosan similar or equal to 1000 ng m(-3) and burning PAHs similar or equal to 4 ng m(-3) at MS and SP sites). (C) 2015 Elsevier B.V. All rights reserved.