Beatrice Moroni

Microbial growth and air pollution in carbonate rock weathering

Preliminary results on limestone weathering caused by air pollution and microbial colonization are presented in this study. Outdoor exposure experimental assays were performed on Scaglia limestone samples. Samples were exposed in two areas in Perugia (Italy) that differ for degree of urban air pollution. At different times of exposure, ranging from 1 to 12 months, microbial contamination and textural modifications of sampled surfaces were evaluated by microbiological procedures, X-ray diffraction, and scanning electron microscopy. After one year of exposure a significant fungal colonization and the presence of weathering products (i.e. gypsum) were detected on sampled surfaces.

Vertical Profiles and Chemical Properties of Aerosol Particles upon Ny-Ålesund (Svalbard Islands)

Size-segregated particle samples were collected in the Arctic (Ny-Alesund, Svalbard) in April 2011 both at ground level and in the free atmosphere exploiting a tethered balloon equipped also with an optical particle counter (OPC) and meteorological sensors. Individual particle properties were investigated by scanning electron microscopy coupled with energy dispersive microanalysis (SEM-EDS). Results of the SEM-EDS were integrated with particle size and optical measurements of the aerosols properties at ground level and along the vertical profiles. Detailed analysis of two case studies reveals significant differences in composition despite the similar structure (layering) and the comparable texture (grain size distribution) of particles in the air column. Differences in the mineral chemistry of samples point at both local (plutonic/metamorphic complexes in Svalbard) and remote (basic/ultrabasic magmatic complexes in Greenland and/or Iceland) geological source regions for dust. Differences in the particle size and shape are put into relationship with the mechanism of particle formation, that is, primary (well sorted, small) or secondary (idiomorphic, fine to coarse grained) origin for chloride and sulfate crystals and transport/settling for soil (silicate, carbonate and metal oxide) particles. The influence of size, shape, and mixing state of particles on ice nucleation and radiative properties is also discussed.

Aerosol dynamics upon Terni basin (Central Italy): results of integrated vertical profile measurements and electron microscopy analyses

In this work, aerosol size distribution measurements along with individual particle analyses were performed along the vertical profile in the atmosphere, to shed some light on the dynamics of evolution of aerosol properties upon a basin valley. The case study is the Terni basin, one of the most polluted urban and industrial sites in central Italy. Aerosol vertical profile measurements were performed using a helium-filled tethered balloon equipped with an optical particle counter (OPC), a miniaturized cascade impactor with particle collection filter, and a portable meteorological station. Combined OPC number size measurements and single particle analyses by scanning electron microscopy were employed to reconstruct the pattern and evolution of aerosol properties over the basin. Moreover, the CHIMERE chemistry-transport model was applied over a selected computing domain to obtain a general overview of the driving forces of the aerosol dynamics. Scanning electron microscopy methods along with chemical transport modeling revealed distinct distributions of number, size and geochemical properties of different particles classes in the aerosols. These reflect distinct behaviours and spatial/temporal evolution of the constituent particles, along with the common occurrence of dust inputs from regional to long range sources (e.g., Saharan dust inputs). All these features have to be taken into consideration when approaching the modeling of atmospheric processes, particularly in basin valleys located in Central and Southern Italy where the influence of Saharan dust outbreaks is more pronounced.

Determination of travertine provenance from ancient buildings using self-organizing maps and fuzzy logic

This work is focused on determining provenance of travertine stones employed in the construction of some important monuments in Umbria (Italy) using two systems that use concepts and algorithms inherent to Artificial Intelligence: Kohonen self-organizing maps and fuzzy logic. The two systems have been applied to travertine samples belonging to quarries known to be sites of excavation from ancient times and monuments. Tests on quarry samples show a good discriminative power of both methods to recognize the exact provenance of most samples. The application of the systems to monument samples show that most of employed travertine stones were quarried from outcrops occurring in areas close to the towns where monuments have been erected. Results are in good agreement with historical data.

Local vs. long-range sources of aerosol particles upon Ny-Ålesund (Svalbard Islands): mineral chemistry and geochemical records

Aerosol samplings were performed both at ground level and at different heights upon the Ny-Ålesund polar station in June–July 2012 using a tethered balloon equipped with a sampling pump and meteorological sensors. The samples were analyzed by ion chromatography and scanning electron microscopy to characterize the sources and the evolution of the aerosol particles in the planetary boundary layer. The results show the main contribution of long-range over local/regional transported particles and sediments in the aerosols in the period of interest. Among the long-range sources, a main contribution was represented by Siberian local soils and regional wildfires which provided typical particles (metal oxides, calcareous grains), and ion species (nss-K+, nss-SO42−) to the aerosols. Among the local sources, a main contribution was represented by fly ash emitted by the cruise ships frequently landing around Ny-Ålesund during summer. Another aspect which results from aerosol particle characterization is the clear stratification of the planetary boundary layer upon Ny-Ålesund. This typical feature, which has been already documented in spring on the same site (Moroni et al. 2015), is quite effective also in summertime despite the higher potential of local dust production and the lower atmospheric stability characterizing this period.

Corrosion of limestone in humid air containing sulphur and nitrogen dioxides: A model study

Publisher Summary Dry deposition of pollutants, such as SO2 and NO2, is the most active process in urban areas because it affects large extents of material for long periods of time. This chapter describes the mode of interaction of SO2 and NO2 with limestone and to derive a general model of sulfation. Laboratory experiments were performed within a testing apparatus simulating dry deposition of pollutants and by exposing limestone samples to the corrosive action of sulfur dioxide (SO2)and nitrogen dioxide (NO2) at constant temperature (25˚C), relative humidity (about 100%), and dynamic flow conditions (300cc/min). The obtained results confirm a marked slowdown of the sulfation process in short time, and to an apparent resumption of sulfation after about twenty days from the beginning of the experiments.. Two empirical fitting equations, logarithmic form and simple linear form, were determined. The former is to describe the initial period, whereas the latter fits the subsequent period of resumption of sulfation. X-ray diffraction shows that calcium sulphite hemihydrate is the main reaction product in the presence of SO2 alone, whereas gypsum is the only reaction product in the presence of SO2 and NO2. A multistep genetic model was formulated by taking into account the influence of nucleation, and growth of the reaction products in the progress of sulfation.

Trace elements in surface sediments from Kongsfjorden, Svalbard: occurrence, sources and bioavailability

ABSTRACT Concentration levels, potential sources and bioavailability of trace elements in marine sediments from Kongsfjorden (Svalbard Islands, Norwegian Arctic) were assessed and discussed. Surface sediments were collected by a Ponar grab and characterised in terms of mineralogical composition, grain-size distribution, total organic carbon and nitrogen percentage contents, and major and trace elements concentrations. Anthropogenic and natural sources of trace elements were inferred from lead isotope ratios, while the potential metal bioavailability was evaluated by size-fractionation and solid-phase speciation studies and by the analysis of acid-volatile sulphides (AVS) and simultaneously extracted metals (SEM). Concentrations of metals, their enrichment factors and solid speciation patterns collectively indicated that the anthropogenic impact of trace elements in the fjord is generally low, with a minor enrichment with respect to crustal values (by a factor of 2–11) for As, Cr, Ni and V. The lead isotope ratios (208Pb/207Pb: 2.474–2.498 and 206Pb/207Pb: 1.206–1.212) were close to the natural signature except in the outer fjord, due to the influence of the Atlantic marine circulation. Many elements of toxicological concern (e.g. Pb, V, Zn) were enriched in the finest sediment fraction, which was by far the preponderant one, especially in the inner fjord. However, less than 15% of most trace elements (exceptions Cd and Mn) in the finest fraction was actually associated with easily leachable sediment phases. Finally, the high SEM/AVS ratios determined on samples from sites close to the glacier fronts (11–15), due to low AVS content, highlighted that the sediment in that zone cannot remove additional inputs of heavy metals by sulphide precipitation.

Functional exploratory data analysis for high-resolution measurements of urban particulate matter

In this work we propose the use of functional data analysis (FDA) to deal with a very large dataset of atmospheric aerosol size distribution resolved in both space and time. Data come from a mobile measurement platform in the town of Perugia (Central Italy). An OPC (Optical Particle Counter) is integrated on a cabin of the Minimetrò, an urban transportation system, that moves along a monorail on a line transect of the town. The OPC takes a sample of air every six seconds and counts the number of particles of urban aerosols with a diameter between 0.28 μm and 10 μm and classifies such particles into 21 size bins according to their diameter. Here, we adopt a 2D functional data representation for each of the 21 spatiotemporal series. In fact, space is unidimensional since it is measured as the distance on the monorail from the base station of the Minimetrò. FDA allows for a reduction of the dimensionality of each dataset and accounts for the high space-time resolution of the data. Functional cluster analysis is then performed to search for similarities among the 21 size channels in terms of their spatiotemporal pattern. Results provide a good classification of the 21 size bins into a relatively small number of groups (between three and four) according to the season of the year. Groups including coarser particles have more similar patterns, while those including finer particles show a more different behavior according to the period of the year. Such features are consistent with the physics of atmospheric aerosol and the highlighted patterns provide a very useful ground for prospective model-based studies.

Modelling spatio-temporal air pollution data from a mobile monitoring station

ABSTRACT Environmental data is typically indexed in space and time. This work deals with modelling spatio-temporal air quality data, when multiple measurements are available for each space-time point. Typically this situation arises when different measurements referring to several response variables are observed in each space-time point, for example, different pollutants or size resolved data on particular matter. Nonetheless, such a kind of data also arises when using a mobile monitoring station moving along a path for a certain period of time. In this case, each spatio-temporal point has a number of measurements referring to the response variable observed several times over different locations in a close neighbourhood of the space-time point. We deal with this type of data within a hierarchical Bayesian framework, in which observed measurements are modelled in the first stage of the hierarchy, while the unobserved spatio-temporal process is considered in the following stages. The final model is very flexible and includes autoregressive terms in time, different structures for the variance-covariance matrix of the errors, and can manage covariates available at different space-time resolutions. This approach is motivated by the availability of data on urban pollution dynamics: fast measures of gases and size resolved particulate matter have been collected using an Optical Particle Counter located on a cabin of a public conveyance that moves on a monorail on a line transect of a town. Urban microclimate information is also available and included in the model. Simulation studies are conducted to evaluate the performance of the proposed model over existing alternatives that do not model data over the first stage of the hierarchy.

Airborne bacteria and persistent organic pollutants associated with an intense Saharan dust event in the Central Mediterranean

In this paper, we present a comprehensive taxonomic survey of the bacterial community and accurate quantification of polycyclic aromatic hydrocarbons (PAHs) associated with an intense Saharan dust advection, which impacted Central Mediterranean area in the whole 2014-2015 period. This work is part of an intensive field campaign at the EMEP regional background site of Monte Martano (Central Italy), considered well representative of long-range transport in the Central Mediterranean area. 22 samples have been characterized in their provenance region and have been considered for the chemical and biological characterization. The event described in the present paper was exceptionally intense at the sampling site allowing a detailed evaluation of the dust load on a regional scale, an estimation of the impact of PAH based on the Toxic Equivalency Factor methodology and a thorough characterization of the airborne bacterial fraction performed by High Throughput Sequencing approach. Afterward, we cultured viable bacteria and evaluated several enzymatic activities and conducted UV survival tests. Principal findings include: (i) the striking evidence that, during the Saharan dust event, a highly diverse and abundant bacterial community was associated with PAH concentrations higher than the yearly mean; (ii) the tangible presence of cultivable microbes; (iii) the proof that the isolates recovered from Saharan dust had the potential to be metabolically active and that almost all of them were able to persist following UV radiation exposure. Comparisons of results for the present case study with mean values for the 2014-2015 experimental campaign are presented. The bacterial community and chemical speciation associated with the Saharan dust advection were specific and very different from those associated with other air masses. The particular case of North-Western Atlantic, which represents one of the most typical advection route reaching the sampling site is discussed in detail.