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Wet and dry aerosol deposition samples were collected from September 2010 to August 2012 at a remote background site in the Mallorca Isle (Western Mediterranean). Ions and major and trace elements were determined in soluble and insoluble fractions. Temporal variations of chemical components are discussed and interpreted. The overall pattern associated to long-range-transport air masses is studied: Dry/Wet deposition ratios, charges and composition depend clearly on the meteorological scenario. E.g. Dry/Wet ratio is 1:1 when air comes from North Africa, in contrast to a 1:9 ratio under the mainland Europe influence. Moreover, an innovating source apportionment study was conducted integrating both dry and wet deposition samples. Six sources were revealed, including marine aerosols (32%); two different mineral factors, African dust (15%) and regional dust (12%); two anthropogenic factors, one related to road traffic (8%) and another to regional sources (17%); and a mixed factor having biomass burning emissions and others sources (17%). Temporal variations and influence from long-range-transport air masses are also investigated. Fertilization deposition trends have also been explored, observing nutrients settling, as well as nitrate and sulphate, due to their agricultural interest. An important peak during January–February 2012 is studied in depth. Having in mind the strong impact of African dust on the global deposition budget, the analysis of elemental ratios between key dust components was investigated in order to identify major source areas affecting Western Mediterranean: Western Sahara, Algeria-Hoggar Massif and Tunisia-Libya. Differences among these regions are evident. E.g. the impact of industrial emissions is well-detected under outbreaks from Tunisia-Libya, with relatively high content of Ni and Pb. Unlabelled Image • Dry Vs Wet, Soluble Vs Insoluble, Deposition fluxes in the Western Mediterranean • Source apportionment study integrating Dry and Wet Deposition results • Comparative of Western Mediterranean Depositions • African dust and nutrients deposition in the Western Mediterranean, case studies • Dry and Wet chemical composition from Northern African Dust Source Areas [ABSTRACT FROM AUTHOR]

The present study discloses the results of a comprehensive 3-years campaign (2010−2012) of air pollution measurements over an regional island background area (Can Llompart-Balearic Islands, Spain), contextualized with other measurements in the western Mediterranean region. Gaseous pollutants and particulate matter fractions were measured in real time; and PM 10 and PM 1 daily samples were obtained regularly from which chemical analyses were performed. Furthermore, during three intensive observation periods, real-time concentrations of particle number, black carbon and ammonia were additionally measured. Our results display particular diurnal and seasonal patterns for certain pollutants such as O 3 and particle number concentration. Our study reveals that concentrations of air pollutants and aerosol chemical composition are rather similar all over the central and western Mediterranean basin. The most abundant chemical components in PM 10 were mineral dust, followed by organic matter, sea spray and SO 4 2−; in PM 1 organic matter and SO 4 2− dominated, with significant contribution of mineral dust. Furthermore, a source apportionment Positive Matrix Factorization analysis was conducted. Natural sources exert most of the impact on the coarse-mode fraction, while most of fine-mode aerosols are linked to anthropogenic sources coming from local, regional or long range transport emissions. Prevalence of Atlantic air masses in 2010 had a positive effect in air quality, lowering mineral dust, SO 4 2− and EC concentrations. On the contrary, the high incidence of African dust and regional recirculation situations during the 2012 warm season favoured an overall PM load increase governed by mineral dust, SO 4 2− and trace elements associated to dust aerosols. The continuous increase in tourists in the Balearic Islands, and in general all around the Mediterranean, is clearly changing air quality patterns: while urban air pollution has strongly decreased since 2010, such downward trend is less pronounced at the regional scale, thus related to crescent sources such as maritime and air transport. Unlabelled Image • Air pollution and sources in the insular regional background of the WMED • Comparison with other sites in the region is presented. • Insular and pan-regional aerosol phenomenology is discussed and revised. • Local to regional sources are increasing, while long-range transport is decreasing. • Level of background air pollution remain due to boosted maritime and air transport. [ABSTRACT FROM AUTHOR]

Here we present an environmental magnetic study of atmospheric deposition collected by a multi-site network in Spain that covers fourteen locations representative of urban, industrial, agricultural, and natural environments across southwestern Europe. We have combined magnetic methods with scanning electron microscopy and geochemical data to characterize the magnetic mineral assemblages of particulate matter across different types of sites and phenomenological scenarios, and to unravel their environmental significance in terms of the most important anthropogenic and natural components of atmospheric deposition. Our results enable identification of two magnetite/maghemite components of anthropogenic origin, derived mostly from vehicular traffic, plus a hematite component associated with a baseline supply of north African dust, in all the studied sites regardless of their type. The ubiquitous presence of anthropogenic magnetite/maghemite particles in pristine natural environments, albeit in lower concentrations, point to their arrival from neighbouring urban areas through atmospheric mixing processes. Samples including particulate matter deposited during distinctively intense periods of north African dust supply are characterized by a fourth component, represented also by coarser-grained hematite, that is likely derived from a different source area within the Sahara Desert. The concomitant increase observed in these cases in the amounts of magnetite/maghemite particles suggests strongly that part of the magnetite/maghemite load attributed to anthropogenic sources for the rest of the phenomenological scenarios is aeolian in origin. This seems to explain the overall moderate correlation observed between magnetite/maghemite contents and proxies for vehicular traffic, and demonstrates the need for caution when interpreting environmental magnetic proxies for magnetite/maghemite abundances in terms of anthropogenic loads. This is especially the case in southern European cities where a steady supply of north African dust occurs throughout most of the year. Our results show a good correlation between hematite abundances and geochemical proxies for north African dust, which collectively delineate broad maxima during the summer and large peaks during distinctive dust breakouts. Thus, environmental magnetic proxies of hematite abundances can be used to monitor the contribution of natural sources to atmospheric deposition. • Magnetic characterisation of atmospheric deposition in a multi-site network in Spain. • 15 sites typifying urban, industrial, agricultural and natural areas of SW Europe. • Magnetite/maghemite of anthropogenic origin occurs at all sites. • Aeolian hematite is a reliable proxy for the supply of North African dust. • Aeolian magnetite/maghemite weakens the use of these minerals as a pollution proxy. [ABSTRACT FROM AUTHOR]