PM10 chemical composition at a residential site in the western mediterranean: Estimation of the contribution of biomass burning from levoglucosan and its isomers.

Abstract The composition of PM10, including molecular markers of biomass burning (levoglucosan, mannosan and galactosan), was determined at a residential site in southeastern Spain during winter and early spring. The average PM10 concentration was 25.0 μg m–3, being organic carbon (OC, 6.77 μg m–3), NO3– (2.02 μg m–3), SO42– (1.36 μg m–3) and Ca2+ (1.01 μg m–3) the main components. Levoglucosan was the dominant anhydrosugar (143 ng m–3), accounting for 81% of the total concentration of monosaccharide anhydrides. The average contribution of biomass combustion to OC, estimated from the levoglucosan data, was 23%. This value agreed well with that calculated by Positive Matrix Factorization (PMF, 25%). The PMF model resolved six factors that were assigned to road traffic (28%), secondary aerosols (27%), soil dust (14%), fresh sea salt (13%), aged sea salt (10%) and biomass burning (8%). This model was used to estimate the OC/Levoglucosan and PM10/Levoglucosan emission ratios for the study area.