Organic molecular markers and signature from wood combustion particles in winter ambient aerosols: aerosol mass spectrometer (AMS) and high time-resolved GC-MS measurements in Augsburg, Germany

摘要

The impact of wood combustion on ambient aerosols was investigated inAugsburg, Germany during a winter measurement campaign of a six-week period.Special attention was paid to the high time resolution observations of woodcombustion with different mass spectrometric methods. Here we present andcompare the results from an Aerodyne aerosol mass spectrometer (AMS) and gaschromatographic – mass spectrometric (GC-MS) analysed PM₁ filters on anhourly basis. This includes source apportionment of the AMS derived organicmatter (OM) using positive matrix factorisation (PMF) and analysis oflevoglucosan as wood combustion marker, respectively.During the measurement period nitrate and OM mass are the main contributorsto the defined submicron particle mass of AMS and Aethalometer with 28%and 35%, respectively. Wood combustion organic aerosol (WCOA) contributesto OM with 23% on average and 27% in the evening and night time.Conclusively, wood combustion has a strong influence on the organic matterand overall aerosol composition. Levoglucosan accounts for 14% of WCOAmass with a higher percentage in comparison to other studies. The ratiobetween the mass of levoglucosan and organic carbon amounts to 0.06.This study is unique in that it provides a one-hour time resolutioncomparison between the wood combustion results of the AMS and the GC-MSanalysed filter method at a PM₁ particle size range. The comparison ofthe concentration variation with time of the PMF WCOA factor, levoglucosanestimated by the AMS data and the levoglucosan measured by GC-MS is highlycorrelated (R2 = 0.84), and a detailed discussion on the contributorsto the wood combustion marker ion at mass-to-charge ratio 60 is given. Atthe end, both estimations, the WCOA factor and the levoglucosanconcentration estimated by AMS data, allow to observe the variation withtime of wood combustion emissions (gradient correlation with GC-MSlevoglucosan of R2 = 0.84). In the case of WCOA, it provides theestimated magnitude of wood combustion emission. Quantitative estimation ofthe levoglucosan concentration from the AMS data is problematic due to itsoverestimation in comparison to the levoglucosan measured by the GC-MS.