Diurnal variations of ambient particulate wood burning emissions and their contribution to the concentration of Polycyclic Aromatic Hydrocarbons (PAHs) in Seiffen, Germany

摘要

Residential wood burning is becoming an increasingly important cause of airquality problems since it has become a popular source of alternative energyto fossil fuel. In order to characterize the contribution of residentialwood burning to local particle pollution, a field campaign was organized atthe village of Seiffen (Saxony, Germany). During this campaign, an AerosolMass Spectrometer (AMS) was deployed in parallel to a PM high volumefilter sampler. The AMS mass spectra were analyzed using Positive MatrixFactorization (PMF) to obtain detailed information about the organic aerosol(OA). Biomass-burning organic aerosol (BBOA), Hydrocarbon-like organicaerosol (HOA), and Oxygenated Organic Aerosol (OOA) were identified andrepresented 20%, 17% and 62% of total OA, respectively.Additionally, Polycyclic Aromatic Hydrocarbons (PAH) were measured by theAMS with an average concentration of 10 ng m and short term events ofextremely high PAH concentration (up to 500 ng m) compared to themean PAH value were observed during the whole measurement period. Acomparison with the results from PM filter samples showed that theBBOA factor and the AMS PAH are good indicators of the total concentrationof the different monosaccharide anhydrides and PAH measured on the filtersamples. Based on its low correlation with CO and the low car traffic, theHOA factor was considered to be related to residential heating using liquidfuel. An influence of the time of the week (week vs. weekend) on the diurnalprofiles of the different OA components was observed. The weekdays werecharacterized by two maxima; a first one early in the morning and a strongerone in the evening. During the weekend days, the different OA componentsprincipally reached only one maximum in the afternoon. Finally, the PAHemitted directly from residential wood combustion was estimated to represent1.5% of the total mass of the BBOA factor and around 62% of the totalPAH concentration measured at Seiffen. This result highlights the importantcontribution of residential wood combustion to air quality and PAH emissionsat the sampling place, which might have a significant impact on humanhealth. Moreover, it also emphasizes the need for a better time resolutionof the chemical characterization of toxic particulate compounds in order toprovide more information on variations of the different sources through thedays as well as to better estimate the real human exposure.