In February 2017 the "Carbonaceous Aerosol in Rome and Environs (CARE)" experiment was carried out in downtown Rome to address the following specific questions: what is the color, size, composition, and toxicity of the carbonaceous aerosol in the Mediterranean urban background area of Rome? The motivation of this experiment is the lack of understanding of what aerosol types are responsible for the severe risks to human health posed by particulate matter (PM) pollution, and how carbonaceous aerosols influence radiative balance. Physicochemical properties of the carbonaceous aerosol were characterised, and relevant toxicological variables assessed. The aerosol characterisation includes: (i) measurements with high time resolution (min to 1-2 h) at a fixed location of black carbon (eBC), elemental carbon (EC), organic carbon (OC), particle number size distribution (0.008-10 µm), major non refractory PM 1 components, elemental composition, wavelength-dependent optical properties, and atmospheric turbulence; (ii) 24-h measurements of PM 10 and PM 2.5 mass concentration, water soluble OC and brown carbon (BrC), and levoglucosan; (iii) mobile measurements of eBC and size distribution around the study area, with computational fluid dynamics modeling; (iv) characterisation of road dust emissions and their EC and OC content. The toxicological assessment includes: (i) preliminary evaluation of the potential impact of ultrafine particles on lung epithelia cells (cultured at the air liquid interface and directly exposed to particles); (ii) assessment of the oxidative stress induced by carbonaceous aerosols; (iii) assessment of particle size dependent number doses deposited in different regions of the human body; (iv) PAHs biomonitoring (from the participants into the mobile measurements). The first experimental results of the CARE experiment are presented in this paper. The objective here is to provide baseline levels of carbonaceous aerosols for Rome, and to address future research directions. First, we found that BC and EC mass concentration in Rome are larger than those measured in similar urban areas across Europe (the urban background mass concentration of eBC in Rome in winter being on average 2.6 ± 2.5 µg · m −3 , mean eBC at the peak level hour being 5.2 (95% CI = 5.0-5.5) µg · m −3 ). Then, we discussed significant variations of carbonaceous aerosol properties occurring with time scales of minutes, and questioned on the data averaging period used in current air quality standard for PM 10 (24-h). Third, we showed that the oxidative potential induced by aerosol depends on particle size and composition, the effects of toxicity being higher with lower mass concentrations and smaller particle size. Albeit this is a preliminary analysis, findings reinforce the need for an urgent update of existing air quality standards for PM 10 and PM 2.5 with regard to particle composition and size distribution, and data averaging period. Our results reinforce existing concerns about the toxicity of carbonaceous aerosols, suppo...

Road dust (RD), together with surface soils, is recognized as one of the main sinks of pollutants in urban environments. Over the last years, many studies have focused on total and bioaccessible concentrations while few have assessed the bioaccessibility of size-fractionated elements in RD. Therefore, the distribution and bioaccessibility of Fe, Mn, Cd, Cr, Cu, Ni, Pb, Sb and Zn in size fractions of RD and roadside soils (<2.5μm, 2.5-10μm and 10-200μm) have been studied using aqua regia extraction and the Simple Bioaccessibility Extraction Test. Concentrations of metals in soils are higher than legislative limits for Cu, Cr, Ni, Pb and Zn. Fine fractions appear enriched in Fe, Mn, Cu, Pb, Sb and Zn, and 2.5-10μm particles are the most enriched. In RD, Cu, Pb, Sb and Zn derive primarily from non-exhaust sources, while Zn is found in greater concentrations in the <2.5μm fraction, where it most likely has an industrial origin. Elemental distribution across soils is dependent on land use, with Zn, Ni, Cu and Pb being present in higher concentrations at traffic sites. In addition, Fe, Ni and Cr feature greater bioaccessibility in the two finer fractions, while anthropic metals (Cu, Pb, Sb and Zn) do not. In RD, only Zn has significantly higher bioaccessibility at traffic sites compared to background, and the finest particles are always the most bioaccessible; >90% of Pb, Zn and Cu is bioaccessible in the <2.5μm fraction, while for Mn, Ni, Sb, Fe and Cr, values vary from 76% to 5%. In the 2.5-10μm fraction, the values were 89% for Pb, 67% for Zn and 60% for Cu. These results make the evaluation of the bioaccessibility of size-fractionated particles appear to be a necessity for correct estimation of risk in urban areas.

The relative impact of non-exhaust sources (i.e. road dust, tire wear, road wear and brake wear particles) on urban air quality is increasing. Among them, road dust resuspension has generally the highest impact on PM concentrations but its spatio-temporal variability has been rarely studied and modeled. Some recent studies attempted to observe and describe the time-variability but, as it is driven by traffic and meteorology, uncertainty remains on the seasonality of emissions. The knowledge gap on spatial variability is much wider, as several factors have been pointed out as responsible for road dust build-up: pavement characteristics, traffic intensity and speed, fleet composition, proximity to traffic lights, but also the presence of external sources. However, no parameterization is available as a function of these variables. We investigated mobile road dust smaller than 10 μm (MF10) in two cities with different climatic and traffic conditions (Barcelona and Turin), to explore MF10 seasonal variability and the relationship between MF10 and site characteristics (pavement macrotexture, traffic intensity and proximity to braking zone). Moreover, we provide the first estimates of emission factors in the Po Valley both in summer and winter conditions. Our results showed a good inverse relationship between MF10 and macro-texture, traffic intensity and distance from the nearest braking zone. We also found a clear seasonal effect of road dust emissions, with higher emission in summer, likely due to the lower pavement moisture. These results allowed building a simple empirical mode, predicting maximal dust loadings and, consequently, emission potential, based on the aforementioned data. This model will need to be scaled for meteorological effect, using methods accounting for weather and pavement moisture. This can significantly improve bottom-up emission inventory for spatial allocation of emissions and air quality management, to select those roads with higher emissions for mitigation measures.

A new eco-friendly process is reported, the implementation of which at the EU level could reduce ammonia and greenhouse gas emissions from fermented biowaste by over 1 Gt yr −1 . The present work reports the case study of municipal biowaste (MBW). The process is based on the use of soluble bio-organic substances (SBOs) as auxiliaries in the anaerobic fermentation of MBW to produce biogas and digestate with reduced ammonia content. The SBO-assisted process enables a virtuous biowaste cycle, where MBW is sequentially fermented under anoxic conditions, the digestate is composted, and the compost generated is hydrolyzed, yielding SBO, which is recycled to the anaerobic fermentation reactor at 0.2% concentration. The results show that depending on the MBW source, fermentation inoculum, and SBO concentration in the fermentation slurry, about 40% reduction of ammonium in the digestate is achieved, whereas the control fermentation without SBO exhibits up to 11% ammonia increase. The microbial community and biogas production are not significantly affected by SBO addition. The data are consistent with biological and chemical processes occurring in SBO-assisted fermentation. These comprise ammonia production by protein hydrolysis catalyzed by proteolytic bacteria and ammonia oxidation to N 2 catalyzed by SBOs. The results confirm the benefit provided by the use of SBOs to reduce the environmental impact of biowaste. These encourage the implementation of SBO-assisted fermentation in the real operational environment.

The results on elemental composition of aerosol (PM10) sampled during 2011 in Piedmont region (Italy) are interpreted using meteorological data, Enrichment Factors (EF), chemometric processing by Principal Component Analysis (PCA), Factor Analysis (FA) and Hierarchical Cluster Analysis (HCA).Daily concentrations of about 30 elements were measured using HR-ICP-MS in five monitoring sites. A clear seasonal pattern, with higher concentrations in autumn and winter, was observed, particularly in the urban sites. Levels of As, Cd, Ni and Pb in most of the samples were within the limits imposed by the European legislation. Spatial differences in PM10 and metal concentrations were significant, with rural and urban sites showing different metal patterns, indicating different sources. K and Ca were used, respectively, as marker of biomass burning and industrial marker (cement plant); EFs showed that Ca was enriched just in one area and K was enriched only in the winter period considered and in some stations.Data analysis through PCA, FA and HCA allowed us to identify correlations among the investigated elements and similarities between sampling sites in order to individuate specific emission sources, such as non-exhaust vehicle emission. Keywords PiedmontTrace elements in PM10 Spatial variability Chemometric processingInductively coupled plasma-mass spectrometry

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This experiment was aimed at verifying the usefulness of phytoremediation using Short Rotation Coppice (SRC) in an urban Zn-contaminated site. Besides elemental uptake and reclamation, the SRC method was applied to evaluate the additional benefits of a green infrastructure. Nine different plants with rapid growth and large biomass production were selected: three Populus clones, three Salix hybrids, and three Robinia genotypes. Annual and biennial coppicing were evaluated. Poplar clones were more productive using annual coppicing, while Salix and Robinia produced higher biomass in blocks not coppiced. Poplar had the highest phytoextraction rate during the second year, with 1077 g/ha. Salix clones S1 and S3 extracted similar quantities using biennial coppicing. After two years, the bioavailable fraction of Zn decreased significantly using all species, from the 26% decrease of Robinia to the 36% decrease of Salix. The short rotation coppice method proved to be useful in an urban context, for both landscape and limiting the access to the contaminated area. Improving the biomass yield through the phytomanagement options (fertilization, irrigation, coppicing, etc.) could make SRC phytoremediation an economic and effective solution to manage urban contaminated areas, coupling the added values of biomass production to the landscape benefits.

Mining activities have led to the introduction of high levels of potentially toxic elements (PTE) concentrations in soils. This has attracted governmental and public attention due to their nonbiodegradable nature and hazards posed to human health and the environment. However, total concentrations of PTE are poor indicators of actual risk hazard to human health and can lead to overestimation of risk. In this study, oral bioaccessibility, the fraction available for absorption via oral ingestion, was used to refine human health risk assessment at an abandoned mine site from Campello Monti, northwest Italy. The solid phase distribution was performed to characterise the distribution and the behaviour of PTE within the extractive waste streams and impacted soil nearby. Mineralogical information was obtained from micro-XRF and SEM analysis used to identify elemental distibution maps. The results showed that the total concentrations of PTE were high, up to 7400 mg/kg for Ni due to the presence of parent material, however, only 11% was bioaccessible. Detailed analysis of the bioaccessible fraction (BAF) showed that As, Cu and Ni varied from 7 to 22%, 14 to 47%, 5 to 21%, respectively. The variation can be attributed to the difference in pH, organic matter content and mineralogical composition of the samples. The non-specific sequential extraction also showed that the non-mobile forms of the PTE were associated with the clay and Fe oxide components of the enviromental matrices. The present study demonstrates how bioaccessibility, solid phase distribution and mineralogical analysis can help decision making and inform the risk assessment of abandoned mine sites.