Characterizing the regional contribution to PM10 pollution over northern France using two complementary approaches: Chemistry transport and trajectory-based receptor models.

Abstract Atmospheric pollution is a striking regional issue for public health and ecosystems and has major global impacts on climate. Particulate matter (PM) can be of primary or secondary origin and its sources, both natural and anthropogenic, are very heterogeneous in space and time. Hence, many efforts have been made worldwide to get a better knowledge of PM sources, in order to set effective reduction strategies. To this end, several distinct approaches may be used among which: (i) the localization of potential source areas with trajectory-based statistical receptor models (TRMs) which combine PM concentrations observed at receptor sites with computed back trajectories (BTs) of air masses, and (ii) the estimation of PM source contribution and chemical speciation with deterministic chemistry transport models (CTMs) based on emission inventories and detailed chemistry-transport processes. This study aims at testing the coherence between two independant approaches, CTMs and TRMs, for the geographical localization of the sources impacting a region of study. The case study refers to PM 10 pollution in the Hauts-de-France region (HdF) in the North of France for the year 2010. The considered TRMs are multi-site Concentration Field (CF) and Potential Source Contribution Function (PSCF) applied to 12 receptor sites using the Zefir package. The considered CTM is CHIMERE using detailed EDGAR European emission data. First, TRMs showed that some given far-located European countries (named "Far-East" countries) could have a strong but infrequent impact on PM 10 levels in the study region, while some given nearer European countries (named "Near-East" countries) had a frequent and predominant impact. Then, the contributions of each of these TRM-highlighted regions to PM 10 concentrations over the study area were analyzed by CHIMERE simulations. The potential influence of another non TRM-highlighted region (i.e. the "British Isles") was also studied for comparison. The CTM results confirmed the prevalence of the Near-East source area in terms of mass contribution throughout the year and particularly during high-concentration periods. Therefore results obtained from CHIMERE CTM and multi-site CF and PSCF TRMs showed consistency, highlighting the interest for further comparison of both CTMs and TRMs independent approaches in other regions as well as for other pollutants. Highlights • The continental and regional sources of pollutants impacting northern France are identified and quantified. • Two independent approaches, statistical sources-receptor and deterministic chemistry-transport models are used. • Both approaches showed consistency, highlighting the influence of several areas on the northern France pollution. [ABSTRACT FROM AUTHOR]