Sources of PM₁₀ ionic species in the South-West Mediterranean (Algeria)

The contents of water-soluble major's ions (MSA, Cl^-, NO₃^-, SO₄^2-, Na⁺, NH₄⁺, K⁺, Mg²⁺, and Ca²⁺) in the PM₁₀ particle fraction were investigated thanks to detailed measurements of the main chemical constituents of PM₁₀ in remote coastal areas in Bou-Ismail; in the South-West of the Mediterranean Sea (Algeria), during a 2-year period; from July 2011 to August 2013, under the framework of the ChArMEx project (Chemistry-Aerosol Mediterranean Experiment, http://charmex.lsce.ipsl.fr ). The total water-soluble ion concentrations in PM₁₀ at the Bou-Ismail measurement station varied from 3.3 µg/m³ (July 2011) to 49.6 µg/m³ (March 2012). The annual mean mass concentrations of ions in the PM₁₀ particulate fraction were Cl^-  > Na⁺  > SO₄^2- > Mg²⁺  > NO₃^-  > Ca²⁺  > K⁺  > NH₄⁺  > Oxalate. The change in potassium nss-K + concentrations in PM₁₀ over the course of a year reveals that biomass burning (BB) has an effect on three separate seasons: the beginning of winter (February and March), the end of summer (August), and the autumn (September and October). The origin periods of biomass burning BB identified employing the mapping of hotspots and fires during periods of August and September 2011, 2012, and 2013 underlined the important fires in the surrounding areas of the Mediterranean Sea (Sardinia Islands from Italy, Corsica from France).