Comparison of five methodologies to apportion organic aerosol sources during a PM pollution event

This study presents a comparison of five methodologies to apportion primary (POA) and secondary organic aerosol (SOA) sources from measurements performed in the Paris region (France) during highly processed PM pollution event. POA fractions, estimated EC-tracer method positive matrix factorization (PMF) analyses, conducted on PM10 filters, chemical speciation monitor (ACSM) offline mass spectrometry (AMS), were all comparable (2.2–3.7 ?g m?3 as carbon (POC)). Associated relative uncertainties (measurement + model) POC estimations ranged 8 50%. The best apportionment traffic OA was achieved using key markers (EC 1-nitropyrene) speciation-based PMF showing more pronounced rush-hour peaks greater correlation with NOx than other related factors. All biomass burning-related factors good agreement, typical diel profile night-time increase linked residential heating. If applied ACSM data showed agreement outputs corrected dust-related (coarse PM), discrepancies observed between individual (traffic, burning) directly SOA oxidized OA. Similar (SOC) concentrations (3.3 ± 0.1 m?3) obtained approaches, except SOA-tracer (1.8 m?3). 14 52% larger for PMF-chemical data, EC- methods. latter significantly underestimated total loadings, even including burning SOA, due missing classes precursors. None approaches able identify formation mechanisms and/or precursors responsible fraction associated nitrate- sulfate-rich aerosols (35% OA). We recommend use combination different POC/SOC concentrations/contributions get highest level confidence estimates obtained.