Organic aerosol constitues a major part of particulate matter (PM) accounting for about 20 60% of the total mass. OA is still poorly understood due to the complexity and the diversity of the PM sources (anthropogenic and biogenic) and processes involved (primary and secondary). The aim of this work was to refine the PM source apportionment using specific primary and secondary organic molecular markers. Field measurements were performed at both locations in France (Grenoble, 2013 and at the SIRTA station, 2015 (25 km SW from Paris)) over 1 year with PM10 samplings, every third day. Intensive observations at SIRTA have been also performed with PM10 samples collected every 4 hour during a period of severe PM pollution event (PM>50 μg m 3 for several days) in March 2015. Following an extended chemical characterization (from 139 to 216 species quantified), the use of key primary and secondary organic molecular markers in positive matrix factorization (PMF) model allowed to deconvolve 9 and 11 sources (Grenoble and SIRTA, respectively), including common ones (biomass burning, traffic, dust, sea salt, secondary inorganics and nitrate), as well as uncommon resolved sources such as primary biogenic OA (fungal spores and plant debris), biogenic SOA (marine, isoprene) and anthropogenic SOA (nitro PAHs, oxy PAHs, phenolic oxidation). Discussion will further underline the details of the chemical and temporal/seasonal profiles of each source, and their relative contributions. In addition, the high timeresolution filter dataset obtained at SIRTA allowed the study of the diurnals of the identified sources and the better understanding of the chemical processes involved.