Submicron aerosol source apportionment of wintertime pollution in Paris, France by double positive matrix factorization (PMFsup2/sup) using an aerosol chemical speciation monitor (ACSM) and a multi-wavelength Aethalometer

摘要

Online non-refractory submicron aerosol mass spectrometer (AMS) measurementsin urban areas have successfully allowed the apportionment of specificsources and/or physical and chemical properties of the organic fraction.However, in order to be fully representative of PM pollution, acomprehensive source apportionment analysis is needed by taking into accountall major components of submicron aerosols, creating strengthened bondsbetween the organic components and pollution sources. We present here anovel two-step methodology to perform such an analysis, by taking advantageof high time resolution of monitoring instruments: the aerosol chemicalspeciation monitor (ACSM) and the multi-wavelength absorption measurements(Aethalometer AE31) in Paris, France. As a first step, organic aerosols (OA)were deconvolved to hydrocarbon-like OA (HOA), biomass burning OA (BBOA)and oxygenated OA (OOA) with positive matrix factorization (PMF), and black carbonwas deconvolved into its wood burning and fossil fuel combustion fractions.A second PMF analysis was then carried out with organic factors, BCfractions and inorganic species (nitrate, sulfate, ammonium, chloride),leading to a four-factor solution allowing highly time-resolvedcharacterization of the major sources of PM₁. Outputs of thisPMF2 include two dominant combustion sources (wood burningand traffic) as well as semi-volatile and low-volatile secondary aerosols.While HOA is found to be emitted by both wood burning and traffic, thelatter sources occurred to significantly contribute also to OOA.