A. Genga

Source apportionment of size-segregated atmospheric particles based on the major water-soluble components in Lecce (Italy).

Atmospheric aerosols have potential effects on human health, on the radiation balance, on climate, and on visibility. The understanding of these effects requires detailed knowledge of aerosol composition and size distributions and of how the different sources contribute to particles of different sizes. In this work, aerosol samples were collected using a 10-stage Micro-Orifice Uniform Deposit Impactor (MOUDI). Measurements were taken between February and October 2011 in an urban background site near Lecce (Apulia region, southeast of Italy). Samples were analysed to evaluate the concentrations of water-soluble ions (SO4(2-), NO3(-), NH4(+), Cl(-), Na(+), K(+), Mg(2+) and Ca(2+)) and of water-soluble organic and inorganic carbon. The aerosols were characterised by two modes, an accumulation mode having a mass median diameter (MMD) of 0.35 ± 0.02 μm, representing 51 ± 4% of the aerosols and a coarse mode (MMD=4.5 ± 0.4 μm), representing 49 ± 4% of the aerosols. The data were used to estimate the losses in the impactor by comparison with a low-volume sampler. The average loss in the MOUDI-collected aerosol was 19 ± 2%, and the largest loss was observed for NO3(-) (35 ± 10%). Significant losses were observed for Ca(2+) (16 ± 5%), SO4(2-) (19 ± 5%) and K(+) (10 ± 4%), whereas the losses for Na(+) and Mg(2+) were negligible. Size-segregated source apportionment was performed using Positive Matrix Factorization (PMF), which was applied separately to the coarse (size interval 1-18 μm) and accumulation (size interval 0.056-1 μm) modes. The PMF model was able to reasonably reconstruct the concentration in each size-range. The uncertainties in the source apportionment due to impactor losses were evaluated. In the accumulation mode, it was not possible to distinguish the traffic contribution from other combustion sources. In the coarse mode, it was not possible to efficiently separate nitrate from the contribution of crustal/resuspension origin.

Source apportionment of PM2.5 in the harbour-industrial area of Brindisi (Italy): identification and estimation of the contribution of in-port ship emissions.

Harbours are important for economic and social development of coastal areas but they also represent an anthropogenic source of emissions often located near urban centres and industrial areas. This increases the difficulties in distinguishing the harbour contribution with respect to other sources. The aim of this work is the characterisation of main sources of PM2.5 acting on the Brindisi harbour-industrial area, trying to pinpoint the contribution of in-port ship emissions to primary and secondary PM2.5. Brindisi is an important port-city of the Adriatic Sea considered a hot-spot for anthropogenic environmental pressures at National level. Measurements were performed collecting PM2.5 samples and characterising the concentrations of 23 chemical species (water soluble organic and inorganic carbon; major ions: SO4(2-), NO3(-), NH4(+), Cl(-), C2O4(2-), Na(+), K(+), Mg(2+), Ca(2+); and elements: Ni, Cu, V, Mn, As, Pb, Cr, Sb, Fe, Al, Zn, and Ti). These species represent, on average, 51.4% of PM2.5 and were used for source apportionment via PMF. The contributions of eight sources were estimated: crustal (16.4±0.9% of PM2.5), aged marine (2.6±0.5%), crustal carbonates (7.7±0.3%), ammonium sulphate (27.3±0.8%), biomass burning-fires (11.7±0.7%), traffic (16.4±1.7 %), industrial (0.4±0.3%) and a mixed source oil combustion-industrial including ship emissions in harbour (15.3±1.3%). The PMF did not separate the in-port ship emission contribution from industrial releases. The correlation of estimated contribution with meteorology showed directionality with an increase of oil combustion and sulphate contribution in the harbour direction with respect to the direction of the urban area and an increase of the V/Ni ratio. This allowed for the use of V as marker of primary ship contribution to PM2.5 (2.8%+/-1.1%). The secondary contribution of oil combustion to non-sea-salt-sulphate, nssSO4(2-), was estimated to be 1.3 μg/m(3) (about 40% of total nssSO4(2-) or 11% of PM2.5).

Chemical characterisation of ancient pottery from south of Italy by inductively coupled plasma atomic emission spectroscopy (ICP-AES) statistical multivariate analysis of data

Chemical characterisation has been carried out on 58 fragments of archaeological pottery from pre-classical sites in Apulia and Lucania, regions in southern Italy. Fourteen elements were determined by atomic emission spectroscopy by using inductively coupled plasma source. Statistical techniques, such as principal component analysis and clustering analysis, have been utilised to define grouping of different pottery items. Tests performed showed that the analysed shards were differentiable mainly by age and provenance.

SEM-EDS investigation on PM10 data collected in Central Italy: Principal Component Analysis and Hierarchical Cluster Analysis

BackgroundPrincipal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) were applied on PM10 particle data in order to: identify particle clusters that can be differentiated on the bases of their chemical composition and morphology, investigate the relationship among the chemical and morphological parameters and evaluate differences among the sampling sites. PM10 was collected in 3 different sites in central Italy characterized by different conditions: yard, urban and rural sites. The concentration of 20 chemical parameters (C, O, Na, Mg, Al, Si, P, Cd, Cl, K, Ca, Sn, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn) were determined by Scanning Electron Microscopy – Energy Dispersive X-ray Spectroscopy (SEM-EDS) and the particle images were processed by an image analysis software in order to measure: Area, Aspect Ratio, Roundness, Fractal Dimension, Box Width, Box Height and Perimeter.ResultResults revealed the presence of different clusters of particles, differentiated on the bases of chemical composition and morphological parameters (aluminosilicates, calcium particles, biological particles, soot, cenosphere, sodium chloride, sulphates, metallic particles, iron spherical particles). Aluminosilicates and Calcium particles of rural and urban sites showed a similar nature due to a mainly natural origin, while those of the yard site showed a more heterogeneous composition mainly related to human activity. Biological particles and soot can be differentiated on the bases of the higher loads of Fractal Dimension, which characterizes soot, and content of Na, Mg, Ca, Cl and K which characterize the biological ones. The soot of the urban site showed higher loadings of Roundness and Fractal Dimension than the soot belonging to the yard and rural sites, this was due to the different life time of the particles. The metal particles, characterized mainly by the higher loading of iron, were present in two morphological forms: spherical and angular particles. The first were generated by a fusion process at high temperature, while the second one had crustal origin (those characterized by typical terrigenous elements) and also human origin.ConclusionIn this work a protocol for the morphological-chemical characterization of single particles has been developed. SEM analysis allows to classify particles in 10 different families and PCA and HCA have provided information about the sources of PM and similarities and differences among the sites.

LB multilayers of highly conjugated porphyrin dimers: differentiation of properties and behaviour between the free base and the metallated derivatives

Abstract Meso,meso′ -buta-1,3-diyne-bridged Ni(II), Cu(II) and free base and meso,meso ′-ethene-bridged Ni(II) and free base have been deposited in mixture with arachidic acid as thin films by the Langmuir–Blodgett technique. The floating layers and the film so fabricated have been characterised. Moreover, interesting gas sensing properties have been manifested by the two metallated butadiyne derivatives, evidencing high stability, reversibility, selectivity and sensitivity to nitric oxide. On the contrary, the free bases and the metallated ethene-bridged derivative do not exhibit such behaviour. A rationale of these different characteristics has been proposed on the basis of the existence of different bisporphyrin conformers in the films that reverberates also on the multilayer order and structure.

X-Ray photoelectron spectroscopy characterisation of Langmuir–Blodgett films containing TiO2 nanoparticles grown by room-temperature hydrolysis of TiO(C2O4)22−

Abstract A new approach to the preparation of TiO2 nanoparticles embedded in organic films is described. This room-temperature method is based on a Langmuir–Blodgett standard procedure using an aqueous subphase in which TiO(C2O4)22− is dissolved. Spectroscopic investigations on the subphase show that TiO2 nanoparticles are dispersed in the solution. Careful X-ray photoelectron spectroscopy characterisation of Langmuir–Blodgett films reveals that those particles are transferred into the interior of the films during growth of the n-octadecylamine layers.

Cadmium Concentration in Grains of Durum Wheat (Triticum turgidum L. subsp. durum)

Heavy metal excess in soil represents a critical problem for crop productivity. Among these pollutants, cadmium (Cd) is one of the most dangerous in terms of food-chain contamination. Two durum wheat near-isogenic lines (NILs) and 12 commercial varieties (cultivars Arcangelo, Aureo, Aziziah, Cappelli, Cirillo, Creso, Iride, Maestrale, Parsifal, Russello, Strongfield, and Svevo) of durum wheat were exposed to a nontoxic level of Cd to evaluate its concentration in grains, roots, and shoots, as well as effects on biomass production. Cultivar Iride showed the most interesting behavior because it stored large amounts of Cd in the roots, preventing its translocation to grains. On the contrary, Cirillo and Svevo genotypes were characterized by a high Cd concentration in the grains. Furthermore, a molecular characterization employing the ScOPC20 marker associated with the Cd uptake locus has shown the absence of the expected fragment in the Iride variety and in other varieties characterized by low Cd concentration, as well as the presence of it in high Cd-accumulating cultivars.

Individual particle SEM-EDS analysis of atmospheric aerosols in rural, urban, and industrial sites of Central Italy

PM10 samples were collected simultaneously at three representative areas (urban, industrial, and rural areas). Their morphology and elemental composition were determined by scanning electron microscopy coupled with energy-dispersive analysis (SEM-EDS). Twenty-four chemical parameters (C, O, Na, Mg, Al, Si, P, Cd, Cl, K, Ca, S, Sn, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, W, and Pb) were determined and three morphological parameters (area, roundness, and fractal dimension) were measured by Image Pro Analyzer 6.3. The particles were classified into ten groups based on morphology and elemental composition: Ca-rich and metal particles, soot aggregates, cenosphere, alumosilicates, sea salt, calcium sulfate, spherical particles of iron, biological carbonaceous particles, and various. Particles of natural origin were predominantly found in the coarse size fraction and particles of anthropogenic origin in the fine size fraction. The greatest contribution to particulate matter belonged to aluminum-silicates and calcium-rich particles. The cenosphere were recognized only in the coastal urban site, while all the other particles were present in each site. The coastal industrial site was characterized by the prevalence of alumosilicates and Ca-rich particles, due to construction activity in this site during the sampling period (movement of vehicles, transport of terrigenous materials, and use of construction products). The coastal urban site was characterized by a higher amount of soot and by the presence of cenosphere, due to the presence of vehicular traffic.