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The absorption and scattering of radiation by atmospheric aerosol particles, especially those originating from anthropogenic activities, is a key component of anthropogenic climate change. Aerosol particles also act as cloud condensation nuclei (CCN) “indirectly” forcing climate through the modification of cloud properties and precipitation efficiency. The activation of particles to form CCN depend highly on particle size and chemical composition and differs upon location and proximity to sources. Particle number size distributions, aerosol chemical composition and CCN measurements were performed at two sites in the Eastern Mediterranean, namely a remote background site at Finokalia, Crete and an urban background location downtown Athens, Greece. The aim of the study is to characterize the levels and distribution of total aerosol particles (CN) and CCN in the different environments and analyse the role of anthropogenic sources in the measured levels.

During the summer of 2012 a coordinated field campaign was conducted in multiple locations in Greece in order to characterize the ambient particulate matter (PM) levels, its chemical composition and the contribution of the regional and local sources. PM1, PM2.5 and PM10 samples were collected simultaneously at seven different sites in Greece: an urban and a suburban station in Patras, a suburban station in Thessaloniki, a suburban and an urban background station in Athens, a rural background station at the Navarino Environmental Observatory (NEO) in southwestern Peloponnese and a remote background site at Finokalia in the northeastern part of Crete. The sites were selected to facilitate the estimation of the contribution of the local emission sources and long range transport. Sulfate and organics were the major PM1 components in all sites suggesting that high sulfate levels still remain in parts of Europe. The photochemistry of the Eastern Mediterranean can convert rapidly the emitted sulphur dioxide to sulfate. Our analysis indicated significant sulfate production over the area, with high sulfate levels, especially in the remote site of Finokalia, associated with air masses that had passed over Turkey. There was high regional secondary organic aerosol production dominating organic aerosol levels even in a major city like Athens. High organic aerosol levels were associated with air masses that had crossed the Balkans with a significant biogenic component. The average PM2.5 concentration ranged from 13 to 18 μg m−3 in the different sites. There were unexpected significant gradients in the concentrations of secondary aerosol components in length scales of a few hundred kilometers. The low concentrations of measured PM2.5 nitrate are mostly organic nitrates and supermicrometer nitrate associated with sea-salt and dust. Dust was a significant PM10 constituent in all areas and was quite variable in space showing the importance of the local sources.

Polycyclic aromatic hydrocarbons (PAHs) are organic pollutants in fine particulate matter (PM) long known to have mutagenic and carcinogenic effects, but much is unknown about the importance of local and remote sources to PAH levels observed in population-dense urban environments. A year-long sampling campaign in Athens, Greece, where more than 150 samples were analyzed for 31 PAHs and a wide range of chemical markers were used in combination with Positive Matrix Factorization (PMF) to constrain the temporal variability, sources and carcinogenic risk associated with PAHs. We find that biomass burning (BB), a source mostly effective during wintertime intense pollution events (observed for 18 % of measurement days in 2017), lead to wintertime PAH levels 7 times higher than in other seasons and was responsible for annual mean PAH concentrations (31 %) comparable to those from diesel/oil (33 %) and gasoline (29 %) sources. The contribution of non-local sources, although limited on an annual basis (7 %), was increased during summer, becoming comparable to that of local sources combined. The fraction of PAHs associated with BB is linked to increased health risk compared to the other sources, accounting for almost half the annual carcinogenic potential of PAHs (43 %). This can result in a larger number of excess cancer cases due to BB-related high PM levels and urges immediate action to reduce residential BB emissions in urban areas facing similar issues.

Polycyclic aromatic hydrocarbons (PAHs) are organic pollutants with proven mutagenic and carcinogenic potential that originate from incomplete combustion, and partition to fine particulate matter. Nitro-PAHs & oxy-PAHs are oxidation products of PAHs with increased toxicity compared to their parent members and may reveal useful information about the aging and oxidation processes of PAHs.In this study, we investigate the seasonal profiles of 31 PAHs and select oxidized forms such as nitro PAHs & quinones in Athens, Greece to understand their sources, levels, toxicity and impacts. PAHs levels were found to be significantly higher during winter, particularly during intense pollution episodes, compared to the other seasons. Chemical markers linked to biomass burning (BB) emissions are found to correlate well with the total amount of PAHs (ΣPAHs) during wintertime, strongly indicating that BB emissions are a significant source of PAHs. Positive Matrix Factorization (PMF) analysis showed that more than 50% of ΣPAHs originate from BB emissions and that a “factor” (composed of a specific mixture of PAHs) characterizes biomass burning emissions – and can potentially be used as a tracer. Analysis of the PMF series suggests that BB aerosol is much more carcinogenic than the effects of gasoline and diesel combustion combined. Finally, the exposure impact during winter is 9 times higher compared with the other seasons. AcknowledgementsThis work has been funded by the European Research Council, CoG-2016 project PyroTRACH (726165) H2020-EU.1.1. – Excellent. We also acknowledge support by the “PANhellenic infrastructure for Atmospheric Composition and climatE change” (MIS 5021516) implemented under the Action “Reinforcement of the Research and Innovation Infrastructure ”, funded by the Operational Programme “Competitiveness, Entrepreneurship and Innovation” (NSRF 2014-2020) and co-financed by Greece and the European Union (European Regional Development Fund).

COVID-19 is evolving into one of the worst pandemics in recent history, claiming a death toll of over 1.5 million as of December 2020. In an attempt to limit the expansion of the pandemic in its initial phase, nearly all countries imposed restriction measures, which resulted in an unprecedented reduction of air pollution. This study aims to assess the impact of the lockdown effects due to COVID-19 on in situ measured aerosol properties, namely spectral-scattering (bsca) and absorption (babs) coefficients, black carbon (BC) concentrations, single-scattering albedo (SSA), scattering and absorption Ångström exponents (SAE, AAE) in Athens, Greece. Moreover, a comparison is performed with the regional background site of Finokalia, Crete, for a better assessment of the urban impact on observed differences. The study examines pre-lockdown (1–22 March 2020), lockdown (23 March–3 May 2020) and post-lockdown (4–31 May 2020) periods, while the aerosol properties are also compared with a 3–4 year preceding period (2016/2017–2019). Comparison of meteorological parameters in Athens, between the lockdown period and respective days in previous years, showed only marginal variation, which is not deemed sufficient in order to justify the notable changes in aerosol concentrations and optical properties. The largest reduction during the lockdown period was observed for babs compared to the pre-lockdown (−39%) and to the same period in previous years (−36%). This was intensified during the morning traffic hours (−60%), reflecting the large decrease in vehicular emissions. Furthermore, AAE increased during the lockdown period due to reduced emissions from fossil-fuel combustion, while a smaller (−21%) decrease was observed for bsca along with slight increases (6%) in SAE and SSA values, indicating that scattering aerosol properties were less affected by the decrease in vehicular emissions, as they are more dependent on regional sources and atmospheric processing. Nighttime BC emissions related to residential wood-burning were slightly increased during the lockdown period, with respect to previous-year means. On the contrary, aerosol and pollution changes during the lockdown period at Finokalia were low and highly sensitive to natural sources and processes.

Two-sized aerosol samples were obtained from a rural site located close to Sinop on the south coastline of the Black Sea. In addition, bulk deposition samples were collected at Varna, located on the west coastline of the Black Sea. Both aerosol and deposition samples were analyzed for the main macronutrients, NO3−, NH4+, and PO43−. The mean aerosol nitrate and ammonium concentrations were 7.1 ± 5.5 and 22.8 ± 17.8 nmol m−3, respectively. The mean aerosol phosphate concentration was 0.69 ± 0.31 nmol m−3, ranging from 0.21 to 2.36 nmol m−3. Interestingly, phosphate concentration over Sinop was substantially higher than those of most Mediterranean sites. Comparison of the atmospheric and riverine inputs for the Black Sea revealed that atmospheric dissolved inorganic nitrogen (DIN) only ranged between 4% and 13%, while the atmospheric dissolved inorganic phosphorus (DIP) fluxes had significantly higher contributions with values ranging from 12% to 37%. The molar N:P ratios in atmospheric deposition for Sinop and Varna were 13 and 14, respectively, both of which were lower than the Redfield ratio (16). The atmospheric molar N:P ratios over the Black Sea were considerably lower than those reported for riverine fluxes (41) and the Mediterranean region (more than 200). The atmospheric P flux can sustain 0.5%–5.2% of the primary production, whereas the N flux can sustain 0.4%–4.8% of the primary production. The contribution of the atmospheric flux may enhance by 2.6 when the new production is considered.

Long-range transportation of air pollutants from industrial and urban environments can significantly affect the quality of the air in remote regions. In this study, we investigate episodes of particulate transport (PT) from Eurasia to the remote environment of Northeastern Mediterranean, i.e., the region of the North Aegean Sea (NAS), during the summer when the synoptic Etesian wind conditions prevail. A temporary monitoring station was set up at a remote region on the island of Lemnos, which is located at the center of the NAS at a distance of ca. 250 km from the continent. Measurements of the aerosol particle size distributions, the total number and mass concentrations, as well as the chemical composition of the particles were conducted from 27 August to 10 September 2011. During this period, the wind speeds were high (typically higher than 5.5 ms −1 ) with a direction that mostly ranged from north to northeast (68% frequency). Winds having direction ranging from northwest to south were less frequent (7% frequency), while the rest of the cases were characterized as calm (i.e., wind speeds less than 1 m s −1 ; 25% frequency). Seven PT episodes were observed during the sampling period. When the wind direction was northeastern we observed up to a six-fold increase in particle number concentration of nucleation mode, while the peak size of the particles decreased from 100 to 20 nm. Interestingly, the nucleation-mode particles grew from ca. 15 to 25 nm with rates of ca. 9.0 nm h −1 , which are representative of polluted areas. Analysis of the chemical composition of particle samples collected on filters during the PT episodes shows that the concentration of sulfates and nitrates increased by ca. 60%, while the OC/EC ratio increased by ca. 22% compared to the rest of the sampling period. Back-trajectory analysis for the period during the episodes shows that the air masses arriving at the station passed over the greater Istanbul area and the Black Sea 9 to 12 h before reaching our station. These observations provide strong evidence that the air quality in the remote region of the NAS can be significantly affected by the transportation of particulate pollution during the summer period, having potentially important effects upon human health and climate in the region.

The composition of atmospheric aerosols is dynamic and influenced by their emission sources, organic and inorganic composition, transport pathways, chemical and physical processes, microorganisms' content and more. Characterization of such factors can improve the ability to evaluate air quality and health risks under different atmospheric scenarios. Here we investigate the microbial composition of the atmospheric particulate matter (

In an attempt to take effective action towards mitigating pollution episodes in the Greater Athens Area (GAA), precise knowledge of PM 2.5 composition and their sources is a prerequisite. Thus, a two year chemical composition data set from aerosol samples collected in an urban-background site of central Athens, from December 2013 till March 2016, has been obtained and Positive Matrix Factorization (PMF) was applied in order to identify and apportion fine aerosols to their sources. A total of 850 aerosol samples, were collected on a 12 to 24 h basis and analyzed for major ions, trace elements, organic and elemental carbon, allowing us to further assess the impact of residential heating as a source of air pollution over the GAA. The ionic and carbonaceous components were found to constitute the major fraction of the PM 2.5 aerosol mass. The annual contribution of the Ion Mass (IM), Particulate Organic Mass (POM), dust, Elemental Carbon (EC) and Sea Salt (SS) were calculated at 31 %, 34 %, 18 %, 8 % and 3 %, respectively. However, carbonaceous aerosols (POM + EC) and IM exhibited considerable seasonal variation. In winter, IM was estimated down to 23 %, with POM + EC being the dominant component accounting for 48 % of the PM 2.5 mass, while in summer IM was the dominant component (42 %), followed by carbonaceous aerosols 37 %. Results from samples collected on a 12 h basis (day and night) during the 3 intensive winter campaigns indicated the impact of heating on the levels of a series of compounds. Indeed PM 2.5 , EC, POM, NO 3 − , C 2 O 4 2− , nssK + and selected trace metals including Cd and Pb were increased by almost a factor of 4 during night compared to day, highlighting the importance of heating on air quality of the GAA. Furthermore, in order to better characterize winter-time aerosol sources in the city centre of Athens and quantify the input of biomass burning as a source to winter night-time PM 2.5 concentrations, source apportionment was performed. Τhe data can be interpreted on the basis of six sources namely biomass burning (32 %), vehicular emissions (19 %), heavy oil combustion (7 %), regional secondary (20 %), marine aerosol (9 %) and dust particles (8 %). With specific emphasis on night to day contrasts their contributions shifted from 19, 19, 8, 30, 11 and 9 % of the PM 2.5 mass during day to 39, 19, 6, 14, 7 and 6 % during night, underlining the significance of biomass burning as the main contributor to fine particle levels during night-time.

International audience; Aerosol samples (PM10) were collected at Finokalia monitoring station in a remote area of Crete in the Eastern Mediterranean over a two-year period. They were analyzed for total organic carbon (OC), water-soluble organic carbon (WSOC), and the molecular distribution of sugars. WSOC comprised 45% of OC while the contribution of sugars to the OC and WSOC content in the PM10 particles averaged 3 ± 2% (n = 218) and 11 ± 6% (n = 132), respectively. The total concentration of sugars ranged between 6 and 334 ng m−3 with the two most abundant sugars over the two-year period being glucose and levoglucosan, contributing about 25% each to the total carbohydrate pool. Primary saccharides (glucose, fructose, and sucrose) peaked at the beginning of spring (21, 17, and 15 ng m−3, respectively), indicating significant contributions of bioaerosols to the total organic aerosol mass. On the other hand, higher concentrations of anhydrosugars (biomass burning tracers levoglucosan, mannosan, galactosan) were recorded in winter (19, 1.4, and 0.2 ng m−3 respectively) than in summer (9.1, 1.1, and 0.5 ng m−3 respectively). Levoglucosan was the dominant monosaccharide in winter (37% of total sugars) while the low concentration measured in summer (19% of total sugars) was probably due to the enhanced photochemical oxidation by hydroxyl (OH) radicals which impact anhydrosugars. Based on levoglucosan observations, biomass burning was estimated to contribute up to 13% to the annual average OC measured at Finokalia. Annual OC, WSOC, and carbohydrate dry deposition fluxes for the two-year sampling period were estimated at 414, 175, and 9 mg C m−2 y−1, respectively. Glucose and levoglucosan accounted for 34% and 2% of the total sugar fluxes. According to our estimations, atmospheric OC and WSOC inputs account for 0.70% and 0.71%, respectively of the carbon in the annual primary production in the Cretan Sea. Considering the entire Mediterranean, dry deposition of OC can provide at least 3 times more C than riverine inputs of Rhone. Carbohydrate dry deposition flux represents a small fraction of total carbon flux up to 0.04% of the C used for the primary production in the Cretan Sea, while this value is

LC3-associated phagocytosis (LAP) is a non-canonical autophagy pathway regulated by Rubicon, with an emerging role in immune homeostasis and antifungal host defence. Aspergillus cell wall melanin protects conidia (spores) from killing by phagocytes and promotes pathogenicity through blocking nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-dependent activation of LAP. However, the signalling regulating LAP upstream of Rubicon and the mechanism of melanin-induced inhibition of this pathway remain incompletely understood. Herein, we identify a Ca2+ signalling pathway that depends on intracellular Ca2+ sources from endoplasmic reticulum, endoplasmic reticulum-phagosome communication, Ca2+ release from phagosome lumen and calmodulin (CaM) recruitment, as a master regulator of Rubicon, the phagocyte NADPH oxidase NOX2 and other molecular components of LAP. Furthermore, we provide genetic evidence for the physiological importance of Ca2+-CaM signalling in aspergillosis. Finally, we demonstrate that Ca2+ sequestration by Aspergillus melanin inside the phagosome abrogates activation of Ca2+-CaM signalling to inhibit LAP. These findings reveal the important role of Ca2+-CaM signalling in antifungal immunity and identify an immunological function of Ca2+ binding by melanin pigments with broad physiological implications beyond fungal disease pathogenesis., I.K.’s work is supported by the Onassis Foundation under the ‘Special Grant and Support Program for Scholars’ Association Members’ (Grant no. R ZM 003-1/2016-2017); G.C. was supported by grants from the Greek State Scholarship Foundation (I.K.Y.), the Hellenic General Secretariat for Research and Technology-Excellence program (ARISTEIA) and a Research Grant from Institut Mérieux; J.P.L. was supported by European Community’s Seventh Framework Programme (FP7/2007-2013) under grant agreement 260338 ALLFUN and ANR-10-BLAN-1309 HYDROPHOBIN, and the Association Vaincre La Mucoviscidose (RF20140501052/1/1/141); H.F. and N.M.N. were supported by the project FROnTHERA (NORTE-01-0145-FEDER-000023), supported by Northern Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF), and by Fundação para a Ciência e Tecnologia (FCT) project SPARTAN (PTDC/CTM-BIO/4388/2014), funded through the PIDDAC Program. A.C. and C.C. were supported by NORTE 2020, under the Portugal 2020 Partnership Agreement, through the ERDF (NORTE-01-0145-FEDER-000013), and by FCT (IF/00735/2014 and SFRH/BPD/96176/2013). G.S.D. and J.L.F. were supported by NIH grant AI-106269. K.J.K-C is supported by the Division of Intramural Research (DIR), NIAID, NIH, info:eu-repo/semantics/publishedVersion

During the last years the atmosphere of the Great Athens Area (GAA) and other Greek cities is burdened from extended residential biomass burning for heating purposes. In this work, a series of near real-time and off-line biomass burning tracers are analyzed during intense wood burning events in Athens. The measurements were conducted at an urban background site located in the center of Athens, and in the heart of wood burning activities (winter 2013–2014). The measured tracers include high resolution measurements of non-sea salt potassium (nss-K+), wood burning black carbon (BCwb), the m/z 60 fragment associated with levoglucosan and monosaccharide anhydrides (levoglucosan, mannosan and galactosan) determined on selected filter samples. The suitability of these tracers was evaluated when the prevailing meteorological conditions with low dispersion and deposition mechanisms (low wind speed, absence of precipitation) were associated with high biomass burning emissions at nighttime. During the severe smog periods, the levels of K+, BCwb, m/z 60 and levoglucosan were up to 2.2 μg m−3, 12.5 μg m−3, 3.4 μg m−3 and 8.6 μg m−3, respectively, higher by a factor of at least two, relatively to the non smog periods due to biomass burning. Correlations between biomass burning tracers as well as between monosaccharide anhydrides provided information about the type of material and wood being burned.

Atmospheric deposition provides significant amounts of nutrients to the continental and marine ecosystems. Using the mesoscale WRF/CMAQ modeling system, the nitrogen (N) and sulfur (S) atmospheric deposition fluxes over the Mediterranean and the Black seas and continental Europe are evaluated for the year 2008. The annual N and S deposition fluxes are calculated to be 4.89 Tg(N) yr −1 and 2.07 Tg(S) yr −1 over continental Europe, 0.92 Tg(N) yr −1 and 0.52 Tg(S) yr −1 over West Mediterranean, 1.10 Tg(N) yr −1 and 0.84 Tg(S) yr −1 over East Mediterranean and 0.36 Tg(N) yr −1 and 0.17 Tg(S) yr −1 over the Black Sea. Inorganic N deposition fluxes are calculated to be about 3 times higher than gaseous organic N deposition fluxes. Comparison to available observations associates the annual mean model estimates with about 40 ± 30% of uncertainty depending on location. Dry deposition dominates over wet deposition for both N and S in agreement with the observations. Results suggest that an important fraction of the N deposited over the Mediterranean basin can be attributed to transported N species while S deposition is dependent more on the local emissions. In Black Sea and West Mediterranean Sea waters the calculated atmospheric N inputs are comparable to the N export measured by sediment traps whereas in the East Mediterranean N input exceeds by a factor of about 5 the N export. Our simulations show that the critical N load of 1 g(N) m −2 yr −1 is exceeded over 84% of the European forested areas.

To assess the origin and transformation of carbonaceous material in the marine boundary layer of the Eastern Mediterranean, a total of 111 size segregated aerosol samples have been collected using a 12-stage Small-Deposit-area low-volume-Impactor (SDI) covering an almost 3 year period. The samples have been analyzed for organic (OC), elemental (EC), water-soluble organic carbon (WSOC) and ionic components. Maxima of OC, EC and WSOC mass size distributions were found in the accumulation mode (0.449 μm) with occasionally a minor, secondary peak in the coarse mode (2.68 μm). OC and WSOC concentrations peak during summertime due to photochemistry, while EC during autumn, and spring. In general, almost 2/3 of OC and EC concentrations are found in the PM 1 fraction of the aerosol with OC being mostly secondary and therefore highly oxidized and water-soluble to a great extent (∼70%). Using the EC-tracer method, it was found that 83 ± 11% of the PM 10 organic carbon is secondary, with the percentage reaching ∼70% for the PM 1 fraction, a value in very good accordance to WSOC/OC ratio. Ammonium sulfate accounts for 75.5 ± 21.7% and 9.3 ± 1.9% of the aerosol mass in the fine and coarse fraction respectively, exhibiting maximum concentrations also in the accumulation mode. It was estimated that, on average, sea salt and mineral dust account for 33% and 45% of the coarse inorganic mass fraction, respectively.

This study examines the chemical composition of aerosols over Athens. To achieve this, particulate matter sampling has been conducted on a 6–24 h basis from January 2013 until now. More than 700 aerosol samples were collected at downtown Athens, in Thissio and after mass quantification, were analyzed for major ions (Cl−, Br−, \( {\text{NO}}_{3}^{ - } \), \( {\text{SO}}_{4}^{2 - } \), \( {\text{PO}}_{4}^{ - 3 } \), \( {\text{C}}_{2} {\text{O}}_{4}^{ - 2 } \), \( {\text{NH}}_{4}^{ + } \), K+, Na+, Mg2+, Ca2+), trace elements (Al, As, Ca, Cd, Co, Cr, Cu, Fe, V, Zn, Mn, Ni, Pb, P, S, Sb), organic carbon (OC) and elemental carbon (EC). Aerosol chemical mass closure calculations indicated that carbonaceous aerosol constitutes a major component, along with nitrate and sulfate anions, dust, cations and EC. Principal component analysis (PCA) was also applied to better constrain the aerosol sources over Athens with specific emphasis during the winter time, period characterized by intense biomass burning.

On-line, measurements of inorganic ions were performed at Thissio station (December 2014–October 2015), in order to comprehend the sources and the factors that affect variability of fine inorganic aerosol in Athens, Greece. Atmospheric air is sampled through a 1 μm cut-size impactor, to a particle-into-liquid sampler, coupled with ion chromatography. Simultaneously, fine aerosol (PM2.5) is collected daily on quartz filters, and further analysed by ion chromatography. The concentrations of Cl−, \({\text{NO}}_{3}^{ - }\) and \({\text{SO}}_{4}^{2 - }\) measured by PILS average 0.29 ± 0.20, 0.69 ± 0.35 and 1.86 ± 1.6 μg m−3, respectively, and are in accordance with the corresponding concentrations obtained by filter analysis. The seasonal variability of nss-\({\text{SO}}_{4}^{2 - }\) presents maxima during summer, while minimum appears in winter, due to the enhanced summer photochemistry combined with limited precipitation and intensive regional transport. During both seasons, sulfate presents no distinct diurnal variability according to its regional character. On the contrary, nitrate presents an opposite seasonality with winter maxima and summer minima, since high temperatures tend to dissociate fine mode ammonium nitrate into nitric acid and ammonia. Additionally, a clear diurnal variation is observed for both seasons with maximum values during nighttime due again to lower temperatures occurred during nighttime compared to daytime.

Aerosol particles in coastal areas result from a complex mixing between sea spray aerosols locally generated at the sea surface by the wind-waves interaction processes and a continental component resulting from natural and/or anthropogenic sources. This paper presents a physical and chemical analysis of the aerosol data acquired from May to September 2014 in the Adriatic Sea. Aerosol distributions were measured on the Acqua Alta platform located 15 km off the coast of Venice using two Particle Measuring System probes and a chemical characterization was made using an Ion Chromatography analysis (IC). Our aim is to study both the sea-spray contribution and the anthropogenic influence in the coastal aerosol of this Mediterranean region. To this end, we focus on a comparison between the present data and the aerosol size distributions measured south of the French Mediterranean coast. For air masses of marine origin transported by southern winds on the French coast and by the Sirocco in the Adriatic, we note a good agreement between the concentrations of super-micrometer aerosols measured in the two locations. This indicates a similar sea surface production of sea-spray aerosols formed by bubble bursting processes in the two locations. In contrast, the results show larger concentrations of submicron particles in the North-Western Mediterranean compared to the Adriatic, which result probably from a larger anthropogenic background for marine conditions. In contrast, for a coastal influence, the chemical analysis presented in the present paper seems to indicate a larger importance of the anthropogenic impact in the Northern Adriatic compared to the North-Western Mediterranean. (C) 2016 Elsevier Ltd. All rights reserved.

The synthesis and magnetic properties of 13 new homo- and heterometallic Co(II) complexes containing the artificial amino acid 2-amino-isobutyric acid, aibH, are reported: [Co(II)(4)(aib)(3)(aibH)(3)(NO(3))](NO(3))(4)·2.8CH(3)OH·0.2H(2)O (1·2.8CH(3)OH·0.2H(2)O), {Na(2)[Co(II)(2)(aib)(2)(N(3))(4)(CH(3)OH)(4)]}(n) (2), [Co(II)(6)La(III)(aib)(6)(OH)(3)(NO(3))(2)(H(2)O)(4)(CH(3)CN)(2)]·0.5[La(NO(3))(6)]·0.75(ClO(4))·1.75(NO(3))·3.2CH(3)CN·5.9H(2)O (3·3.2CH(3)CN·5.9H(2)O), [Co(II)(6)Pr(III)(aib)(6)(OH)(3)(NO(3))(3)(CH(3)CN)(6)]·[Pr(NO(3))(5)]·0.41[Pr(NO(3))(3)(ClO(4))(0.5)(H(2)O)(1.5)]·0.59[Co(NO(3))(3)(H(2)O)]·0.2(ClO(4))·0.25H(2)O (4·0.25H(2)O), [Co(II)(6)Nd(III)(aib)(6)(OH)(3)(NO(3))(2.8)(CH(3)OH)(4.7)(H(2)O)(1.5)]·2.7(ClO(4))·0.5(NO(3))·2.26CH(3)OH·0.24H(2)O (5·2.26CH(3)OH·0.24H(2)O), [Co(II)(6)Sm(III)(aib)(6)(OH)(3)(NO(3))(3)(CH(3)CN)(6)]·[Sm(NO(3))(5)]·0.44[Sm(NO(3))(3)(ClO(4))(0.5)(H(2)O)(1.5)]·0.56[Co(NO(3))(3)(H(2)O)]·0.22(ClO(4))·0.3H(2)O (6·0.3H(2)O), [Co(II)(6)Eu(III)(aib)(6)(OH)(3)(NO(3))(3)(CH(3)OH)(4.87)(H(2)O)(1.13)](ClO(4))(2.5)(NO(3))(0.5)·2.43CH(3)OH·0.92H(2)O (7·2.43CH(3)OH·0.92H(2)O), [Co(II)(6)Gd(III)(aib)(6)(OH)(3)(NO(3))(2.9)(CH(3)OH)(4.9)(H(2)O)(1.2)]·2.6(ClO(4))·0.5(NO(3))·2.58CH(3)OH·0.47H(2)O (8·2.58CH(3)OH·0.47H(2)O), [Co(II)(6)Tb(III)(aib)(6)(OH)(3)(NO(3))(3)(CH(3)CN)(6)]·[Tb(NO(3))(5)]·0.034[Tb(NO(3))(3)(ClO(4))(0.5)(H(2)O)(0.5)]·0.656[Co(NO(3))(3)(H(2)O)]·0.343(ClO(4))·0.3H(2)O (9·0.3H(2)O), [Co(II)(6)Dy(III)(aib)(6)(OH)(3)(NO(3))(2.9)(CH(3)OH)(4.92)(H(2)O)(1.18)](ClO(4))(2.6)(NO(3))(0.5)·2.5CH(3)OH·0.5H(2)O (10·2.5CH(3)OH·0.5H(2)O), [Co(II)(6)Ho(III)(aib)(6)(OH)(3)(NO(3))(3)(CH(3)CN)(6)]·0.27[Ho(NO(3))(3)(ClO(4))(0.35)(H(2)O)(0.15)]·0.656[Co(NO(3))(3)(H(2)O)]·0.171(ClO(4)) (11), [Co(II)(6)Er(III)(aib)(6)(OH)(4)(NO(3))(2)(CH(3)CN)(2.5)(H(2)O)(3.5)](ClO(4))(3)·CH(3)CN·0.75H(2)O (12·CH(3)CN·0.75H(2)O), and [Co(II)(6)Tm(III)(aib)(6)(OH)(3)(NO(3))(3)(H(2)O)(6)]·1.48(ClO(4))·1.52(NO(3))·3H(2)O (13·3H(2)O). Complex 1 describes a distorted tetrahedral metallic cluster, while complex 2 can be considered to be a 2-D coordination polymer. Complexes 3-13 can all be regarded as metallo-cryptand encapsulated lanthanides in which the central lanthanide ion is captivated within a [Co(II)(6)] trigonal prism. dc and ac magnetic susceptibility studies have been carried out in the 2-300 K range for complexes 1, 3, 5, 7, 8, 10, 12, and 13, revealing the possibility of single molecule magnetism behavior for complex 10.

To identify the relative contribution of local versus regional sources of particulate matter (PM) in the Greater Athens Area (GAA), simultaneous mass and chemical composition measurements of size segregated particulate matter (PM: PM1, PM2.5 and PM10) were carried out from September 2005 to August 2006 at three locations: one urban (Goudi, Central Athens) and one suburban (Lykovrissi, Athens) in GAA and the third in a regional background site (Finokalia, Crete). The two stations in GAA exceeded the EU-legislated PM10 limit values, both in terms of annual average (59.0 and 53.6 μg m−3 for Lykovrissi and Goudi, respectively) and of 24-h value, while the concentration levels at the remote site of Finokalia indicated an elevated background. High levels of PM2.5 and PM1 were also found at all locations (23.5 and 18.6 for Lykovrissi, while 29.4 and 20.2 μg m−3 for Goudi, respectively). Significant correlations were observed between same PM fractions at both GAA sites indicating important spatial homogeneity within GAA. During the warm season, the PM1 ratio between the GAA and the background site ranged from 1.1 to 1.3. On the other hand this ratio was significantly higher (1.6–1.7) during the cold season highlighting the role of long-range transport and local sources during the warm and cold seasons respectively. Similar seasonal and geographical patterns were observed for nss-SO42−, a secondary compound characteristic of regional sources, confirming the above hypothesis. Regarding the coarse fraction no such seasonal trend was observed for both GAA sites with their ratio (GAA site/Finokalia) being higher than 2 indicating significant contribution from local sources such as road dust and/or constructions as confirmed by Ca2+ measurements. Chemical speciation data showed that on a yearly basis, ionic and crustal mass represent up to 78% of the gravimetrically determined mass for PM10 samples in GAA. The unidentified mass might be attributed to organic carbon (OC) and elemental carbon (EC), in agreement with the results reported by earlier studies in central Athens. The contribution of local sources at both GAA sites was also estimated by considering mass and chemical composition measurements at Finokalia as representative of the regional background. Carbonaceous material, Particulate Organic Matter (POM) and EC, seemed to be the main contributor of the local PM mass within GAA (up to 62% in PM1). Dust from local sources (mainly resuspension) contributed also significantly to the local PM10 mass (up to 33%).

Primary productivity of continental and marine ecosystems is often limited or co-limited by phosphorus. Deposition of atmospheric aerosols provides the major external source of phosphorus to marine surface waters. However, only a fraction of deposited aerosol phosphorus is water soluble and available for uptake by phytoplankton. We propose that atmospheric acidification of aerosols is a prime mechanism producing soluble phosphorus from soil-derived minerals. Acid mobilization is expected to be pronounced where polluted and dust-laden air masses mix. Our hypothesis is supported by the soluble compositions and reconstructed pH values for atmospheric particulate matter samples collected over a 5-yr period at Finokalia, Crete. In addition, at least tenfold increase in soluble phosphorus was observed when Saharan soil and dust were acidified in laboratory experiments which simulate atmospheric conditions. Aerosol acidification links bioavailable phosphorus supply to anthropogenic and natural acidic gas emissions, and may be a key regulator of ocean biogeochemistry.

Atmospheric loadings of the aerosols coarse (particles of AED > 1.5 μm) and fine fractions (particles of AED

A month (4 May to 8 June 2008) of ambient aerosol, air ion and gas phase sampling (Finokalia Aerosol Measurement Experiment 2008, FAME-08) was conducted at Finokalia, on the island of Crete, Greece. The purpose of the study was to characterize the physical and chemical properties of aged aerosol and to investigate new particle formation. Measurements included aerosol and air ion size distributions, size-resolved chemical composition, organic aerosol thermal volatility, water uptake and particle optical properties (light scattering and absorption). Statistical analysis of the aerosol mass concentration variations revealed the absence of diurnal patterns suggesting the lack of strong local sources. Sulfates accounted for approximately half of the particulate matter less than 1 micrometer in diameter (PM1) and organics for 28%. The PM1 organic aerosol fraction was highly oxidized with 80% water soluble. The supermicrometer particles were dominated by crustal components (50%), sea salt (24%) and nitrates (16%). The organic carbon to elemental carbon (OC/EC) ratio correlated with ozone measurements but with a one-day lag. The average OC/EC ratio for the study period was equal to 5.4. For three days air masses from North Africa resulted in a 6-fold increase of particulate matter less than 10 micrometers in diameter (PM10) and a decrease of the OC/EC ratio by a factor of 2. Back trajectory analysis, based on FLEXPART footprint plots, identified five source regions (Athens, Greece, Africa, other continental and marine), each of which influenced the PM1 aerosol composition and properties. Marine air masses had the lowest PM1 concentrations and air masses from the Balkans, Turkey and Eastern Europe the highest.

The aerosol chemical composition in air masses affected by wildfires from the Greek islands of Chios, Euboea and Andros, the Dalmatian Coast and Sicily, during late summer of 2012 was characterized at the remote background site of Finokalia, Crete. Air masses were transported several hundreds of kilometers, arriving at the measurement station after approximately half a day of transport, mostly during nighttime. The chemical composition of the particulate matter was studied by different high-temporal-resolution instruments, including an aerosol chemical speciation monitor (ACSM) and a seven-wavelength aethalometer. Despite the large distance from emission and long atmospheric processing, a clear biomass-burning organic aerosol (BBOA) profile containing characteristic markers is derived from BC (black carbon) measurements and positive matrix factorization (PMF) analysis of the ACSM organic mass spectra. The ratio of fresh to aged BBOA decreases with increasing atmospheric processing time and BBOA components appear to be converted to oxygenated organic aerosol (OOA). Given that the smoke was mainly transported overnight, it appears that the processing can take place in the dark. These results show that a significant fraction of the BBOA loses its characteristic AMS (aerosol mass spectrometry) signature and is transformed to OOA in less than a day. This implies that biomass burning can contribute almost half of the organic aerosol mass in the area during periods with significant fire influence., Atmospheric Chemistry and Physics, 14 (9), ISSN:1680-7375, ISSN:1680-7367

Bulk aerosol samples were collected from three different coastal rural sites located around the Eastern Mediterranean, (i) Erdemli (ER), Turkey, (ii) Heraklion (HR), Crete, Greece, and (iii) Tel Shikmona (TS), Israel, during two distinct mineral dust periods (October, 2007 and April, 2008) in order to explore the temporal and geographical variability in the aerosol chemical composition. Samples were analyzed for trace elements (Al, Fe, Mn, Ca, Cr, Zn, Cu, V, Ni, Cd, Pb) and water-soluble ions (Cl-, NO3-, SO42-, C2O42-, Na+, NH4+, K+, Mg2+ and Ca2+). The dust events were categorized on the basis of Al concentrations > 1000 ng m(-3), SKIRON dust forecast model and 3-day back trajectories into three groups namely, Middle East, Mixed and Saharan desert. ER and TS were substantially affected by dust events originating from the Middle East, particularly in October, whilst HR was not influenced by dust transport from the Middle East. Higher AOT values were particularly associated with higher Al concentrations. Contrary to the highest Al concentration: 6300 ng m(-3), TS showed relatively lower Al and AOT. Al concentrations at ER were similar for October and April, whilst OMI-Al and AOT values were similar to 2 times higher in April. This might be attributed to the weak sensitivity of the TOMS instrument to absorbing aerosols near the ground and optical difference between Middle East and Saharan desert dusts. The lowest enhancement of anthropogenic aerosol species was observed at HR during dust events (nssSO(4)(2-)/nssCa(2+) similar to 0.13). These species were particularly enhanced when mineral dust arrived at sites after passing through populated and industrialized urban areas. (c) 2012 Published by Elsevier Ltd.

To investigate the relation between aerosol optical properties and their chemical composition, scattering and absorption of aerosols have been recorded on a routine basis during the last 4 years (2008–2011) at the Aerosol Monitoring Station of the National Observatory of Athens, at Penteli’s premises, Athens, Greece. In parallel, monitoring of PM2.5, PM2.5–10, and PM10 fractions of particulate matter was performed. Samples were analysed for complete chemical characterization of aerosols, by means of ionic chromatography and the thermal–optical transmission method for EC/OC.

PM10 aerosol samples were collected in Durg City, India from July 2009 to June 2010 using an Andersen aerosol sampler and analyzed for eight water-soluble ionic species, namely, Na+, NH4 +, K+, Mg2+, Ca2+, Cl−, NO3 − and SO4 2− by ion chromatography. The annual average concentration of PM10 (253.5 ± 99.4 μg/m3) was four times higher than the Indian National Ambient Air Quality Standard of 60 μg/m3 prescribed by the Central Pollution Control Board, India. The three most abundant ions were SO4 2−, NO3 −, and NH4 +, with average concentrations of 8.88 ± 4.81, 5.63 ± 2.22, and 5.18 ± 1.76 μg/m3, respectively, and in turn accounting for 27.1 %, 16.5 %, and 15.5 % of the total water-soluble ions analyzed. Seasonal variation was similar for all secondary ions i.e., SO4 2−, NO3 −, and NH4 +, with high concentrations during winter and low concentrations during monsoon. Varimax Rotated Component Matrix principal component analysis identified secondary aerosols, crustal resuspension, and coal and biomass burning as common sources of PM10 in Durg City, India.

Water-soluble ions (Cl−, NO 3 − , SO 4 2 − , C 2 O 4 − , Na+, NH 4 + , K+, Mg2+,Ca2+), water soluble organic carbon (WSOC), organic and elemental carbon (OC, EC) and trace metals (Al, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Cd and Pb) were measured in aerosol PM10 samples above the megacity of Istanbul between November 2007 and June 2009. Source apportionment analysis using Positive Matrix Factorization (PMF) indicates that approximately 80% of the PM10 is anthropogenic in origin (secondary, refuse incineration, fuel oil and solid fuel combustion and traffic). Crustal and sea salt account for 10.2 and 7.5% of the observed mass, respectively. In general, anthropogenic (except secondary) aerosol shows higher concentrations and contributions in winter. Mean concentration and contribution of crustal source is found to be more important during the transitional period due to mineral dust transport from North Africa. During the sampling period, 42 events exceeding the limit value of 50 μg m−3 are identified. A significant percentage (91%; n = 38) of these exceedances is attributed to anthropogenic sources. Potential Source Contribution Function analysis highlights that Istanbul is affected from distant sources from Balkans and Western Europe during winter and from Eastern Europe during summer. On the other hand, Istanbul sources influence western Black Sea and Eastern Europe during winter and Aegean and Levantine Sea during summer.

This study examines the chemical composition of aerosols over the Greater Istanbul Area. To achieve this 325 (PM(10)) aerosol samples were collected over Bosphorus from November 2007 to June 2009 and were analysed for the main ions, trace metals, water-soluble organic carbon (WSOC), organic (OC) and elemental carbon (EC). PM(10) levels were found to be in good agreement with those measured by the Istanbul Municipality air quality network, indicating that the sampling site is representative of the Greater Istanbul Area. The main ions measured in the PM(10) samples were Na(+), Ca(2+) and non-sea-salt sulphates (nss-SO(4)(2-)). On average, 31% of Ca(2+) was found to be associated with carbonates. Trace elements related to human activities (as Pb, V, Cd and Ni) obtained peak values during winter due to domestic heating, whereas natural origin elements like Al, Fe and Mn peaked during the spring period due to dust transport from Northern Africa. Organic carbon was found to be mostly primary and elemental carbon was strongly linked to fuel oil combustion and traffic. Both OC and EC concentrations increased during winter due to domestic heating, while the higher WSOC to OC ratio during summer can be mostly attributed to the presence of secondary, oxidised and more soluble organics. Factor analysis identified six components/sources for aerosol species in PM(10), namely traffic/industrial, crustal, sea-salt, fuel-oil combustion, secondary and ammonium sulfate.

The importance of dust and biomass burning episodes on the atmospheric concentration of water-soluble reactive phosphate (SRP) was determined in the eastern Mediterranean. SRP was measured with a new rapid real-time automated analytical system with a time resolution of a few minutes per sample and with an extremely low detection limit. The average atmospheric concentration of SRP during the sampling campaign was estimated at 0.35 & nbsp;+/- 0.25 (median 0.30) nmol P m(-3). The maximum concentration of SRP (3.08 nmol P m(-3)) was recorded during an intense dust episode, and was almost ten times higher than the campaign average, confirming that Saharan dust was an important primary source of bioavailable P to the eastern Mediterranean, especially during the spring period when 60% of the events occurred. Predicted increases in the frequency and intensity of dust storms in the area will enhance the role of the atmosphere as a source of bioavailable P for the Mediterranean marine ecosystem. During the warm period, when Northerly winds prevailed, biomass burning processes contributed significantly to soluble phosphorus delivered from atmospheric sources to the eastern Mediterranean. These inputs during warm periods are especially important for the Eastern Mediterranean, where biological productivity is strongly limited by nutrient availability.

Summarization: Particulate matter measurements were performed at the Akrotiri research station on the island of Crete (Greece) using an 8-stages Andersen non-viable impactor. The main purpose of the current work was to measure the ambient levels of PM 10 particulate matter as well as the concentrations of metals and ions in 8 different PM size fractions with aerodynamic diameter cutoff at 9, 5.8, 4.7, 3.3, 2.1, 1.1, 0.7, 0.4 and a back-up filter for particles below 0.4 µm. The mean PM 10 concentration during the first sampling period of August 2007 was equal to 28.2 ± 14.0 µg m -3 (10/08/2007 – 26/08/2007), whereas during the second sampling period (09/07/2008 – 16/07/2008) was 40.2 ± 16.9 µg m -3 . Moreover, mean concentrations of PM 2.1 particulate matter were measured on the average equal to a 41.0 % and 37.2 % of PM 10 , respectively for the two corresponding sampling periods. The measurements showed high concentration of fine particles (with aerodynamic diameter less than 0.9 µm), whereas the mass concentration peak was located at an aerodynamic diameter close to 4 -5 µm. Sulphate was the most abundant anion PM 10 , whereas sea production ions, such as chlorine, sodium and nitrate, were also in elevated concentrations presented. In addition, the crustal element Fe was in higher concentrations in comparison to the measured heavy metals. Παρουσιάστηκε στο: Global Nest Journal