Improvement of PMF methodology using an extended suite of specific organic tracers : What benefits/what drawbacks ?
Résumé
Receptor models (RMs) as Positive Matrix Factorization (PMF) have become, one of the most used methodology for PM source apportionment in Europe. Evidence for this is given by the recent common protocol for RMs users, proposed by JRC of the European Commision in 2014. These last decades, the chemical composition of Particulate Matter (PM) is increasingly important in order to understand their atmospheric behavior and their emission sources. With this respect, the interest in the individual organic constituents of PM has grown, all the more since most of them can also be used as tracers in source apportionment models. Currently, many research groups try to include additional chemical compounds as PMF input data to better constraint the particles emission sources. Indeed, the contribution made by organic tracers on the PMF output increases the ability to identify some PM sources. Several recent French programs were developed in this regard. For these programs PM have been collected on quartz filters over one year period at several site types, and a large chemical speciation has been performed on samples. In this presentation, a review of these PMF studies including a wide range of specific organic tracers is proposed. New organic markers such as polyols (arabitol, mannitol, sorbitol), methane sulfonic acid (MSA), hopanes, or PAH and sulfured PAH (BNT) were quantified for each site. These organic compounds allowed to improve the factor identification and the quantification of PM sources in PMF studies (Waked et al. 2014). The identified sources, comprise biogenic (marine and soil) factors, secondary aerosols (nitrate and sulfate factors), fresh and aged sea salt particles and various anthropogenic sources (industrial factor, traffic exhaust, biomass burning…). In a first part, the different sources and their chemical profiles (such as those presented in Figure 1) will be compared and discussed. The presentation will also focus on the benefits and the drawbacks to use organic compounds within PMF analysis. This will includes discussion on the sources clearly identified and the factors still presenting evident indication of mixing.