Measurement report: A 1-year study to estimate maritime contributions to PM₁₀ in a coastal area in northern France

Abstract

This work focuses on filling the knowledge gap associated with the contribution of natural and anthropogenic marine emissions to PM10 concentrations in northern France. For this purpose, a 1-year measurement and sampling campaign for PM10 has been conducted at a French coastal site situated at the Strait of Dover. The characterization of PM10 samples was performed considering major and trace elements, water-soluble ions, organic carbon (OC), elemental carbon (EC), and organic markers of biomass burning and primary biogenic emissions. Furthermore, the source apportionment of PM10 was achieved using the constrained weighted non-negative matrix factorization (CW-NMF) model. The annual average PM10 was 24.3 µg m−3, with six species contributing 69 % of its mass (NO3-, OC, SO42-, Cl−, Na+, and NH4+). The source apportionment of PM10 led to the identification of 9 sources. On average yearly, fresh and aged sea salts contributed 37 % of PM10, while secondary nitrate and sulfate contributed 42 %, biomass burning contributed 8 %, and heavy-fuel-oil (HFO) combustion from shipping emissions contributed almost 5 %. Additionally, monthly evolution of the sources' contribution evidenced different behaviors with high contributions of secondary nitrate and biomass burning during winter. In the summer season, 15-times-higher concentrations for HFO combustion (July compared to January) and the predominance of aged sea salts versus fresh sea salts were observed.The concentration-weighted trajectory model showed that the sources contributing more than 80 % of PM10 at Cap Gris-Nez are of regional and/or long-range origins, with the North Sea and the English Channel as hotspots for natural and anthropogenic marine emissions and Belgium, the Netherlands, and the west of Germany as hotspots for secondary inorganic aerosols.