Alternative methods for identification of Fe3+ and Mn 2+ in atmospheric particulate aerosols during their transport over the eastern coast of the English Channel

The present work is a physicochemical study of atmospheric particulates at Wimereux, a French station located on the eastern coast of the English Channel, with special emphasis on Fe and Mn aerosols. GFAAS has been used to access on the metal concentrations. EPR spectroscopy has been introduced for one of the first times in the field of atmospheric particulate matter with the goal to follow the evolution of the chemical forms of Mn. Fe and Mn mean concentrations were estimated respectively to 189±164 and 86±152 ng.m^-3 . Fe values are common one in North Sea sites but Mn values are far higher due to the presence of an important local source of Mn. EPR spectra have evidenced isolated Fe³⁺ and Mn²⁺ ions and carbonaceous products with variable intensities according to the wind directions. Amounts of paramagnetic species and carbonaceous products are maximum for continental winds and minimum for marine winds. Three Mn types were identified depending on the sampling distance front the source of emission and on the size of particles. The authors also confirm that atmospheric particles have different properties in accordance with their size