On the use of organic molecular markers for the apportionment of aerosols - Insight from PMF analysis at 3 French urban sites

Organic molecular compounds are used as markers of many anthropogenic and biogenic sources. Some ambient air biogenic aerosols sources could be identified and quantified using organic markers such as arabitol, mannitol, sorbitol and methane sulfonic acid (MSA) into receptor models such as Positive Matrix Factorization model (US EPA PMF v3.0). The quantification of these biogenic sources is still only performed in very few studies in the literature. In this work, source apportionments of ambient particulate matter (PM10) collected over one year period at three urban background sites (Lens, Bordeaux and Lyon) in France were conducted using PMF. The components measured and used in these PMF solutions included soluble ionic species, trace elements, sugar alcohols, sugar anhydride, organic carbon OC and elemental carbon EC. The sources identified in those sites were secondary organic aerosols (Sulfate-rich and Nitrate-rich), primary biogenic emissions and marine biogenic emissions, fresh and aged sea salt, mineral dust, traffic and biomass burning as well as petrochemical and metallurgical industries. The results obtained showed an important contribution for the biogenic aerosols sources in the 3 urban sites and a comparable temporal variations with contributions exceeding 10% of the total PM10 mass. In addition, a strong seasonal variation was also observed for these sources accounting for more than 20% of the total PM10 mass in summer. It indicates that these sources are not negligible and calls for more investigations using source apportionments studies in general