Wood combustion contribution to PM: results of five years campaign (2005-2009) in Lombardy (Italy)

In this work, a methodology based on the macro-tracer approach was improved to obtain a more reliable estimate of the wood burning impact on PM and OC concentrations. Indeed, emission factors taken from the literature but tailored to the wood consumption data available for the investigated region were used for the calculation. Moreover, an alternative approach was introduced using the Positive Matrix Factorization (PMF) source profile to derive real-world emission ratios in ambient air. In this work – at our knowledge for the first time - these data have been used in the macro-tracer approach to obtain more reliable estimates of the wood burning impact on atmospheric aerosol. A critical comparison of these methods with average wood smoke emission factors reported in the literature was carried out. These results indicate that PMF-derived emission ratios can be a feasible alternative to the most traditional approach with wood smoke emission factors measured at the source, which show a high variability. The proposed methodology was applied to a trial dataset of wintertime PM10 samples - characterised for anhydrosugars, organic, and elemental carbon contents – collected in the frame of a regional project. The results gave a preliminary estimate of the wood smoke contribution to PM10 and the organic fraction in different sites in Lombardy (Northern Italy).