PM 10 chemical composition at a residential site in the western mediterranean: Estimation of the contribution of biomass burning from levoglucosan and its isomers

The composition of PM , 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 PM concentration was 25.0 μg m , being organic carbon (OC, 6.77 μg m ), NO (2.02 μg m ), SO (1.36 μg m ) and Ca (1.01 μg m ) the main components. Levoglucosan was the dominant anhydrosugar (143 ng m ), 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 PM /Levoglucosan emission ratios for the study area.