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Outdoor Cultural Heritage (CH) suffers severe damage due to the interaction amongst physical and chemical atmospheric factors. To study the mechanisms of degradation and to test the effectiveness of experimental protective treatments, accelerated ageing tests and artificial rains are widely used. In a scenario where climate and tropospheric composition are changing, the compositional variation of atmospheric deposition might strongly contribute to a gap between the results obtained in laboratory and real-world outdoor exposure. To reduce this gap, updated synthetic solutions, representative of changed deposition, seem necessary for material testing so to set up better conservative strategies. This study provides new formulations of ageing solutions representative of changed deposition in southern Europe, obtained through the analysis of trends and sources of ions in atmospheric bulk depositions (1997–2019 period) collected in a highly polluted area (Po Valley, Italy).

With the increasing attempt to empower citizens and civil society in promoting virtuous behaviours and relevant climate actions, novel user-friendly and low-cost tools and sensors are nowadays being developed and distributed on the market. Most of these sensors are typically easy to install with a ready-to-use system, while measured data are automatically uploaded on a mobile application or a web dashboard which also guarantees secure and open access to measurements gathered by other users. However, the quality of the datum and the calibration of these sensors are often ensured against research-grade instrumentations only in the laboratory and rarely in real-world measurement. The discrepancies arising between these low-cost sensors and research-grade instrumentations are such that the first might be impossible to use if a validation (and re-calibration if needed) under environmental conditions is not performed. Here we propose a validation procedure applied to the MeteoTracker, a recently developed portable sensor to monitor atmospheric quantities on the move. The ultimate scope is to develop and implement a general procedure to test and validate the quality of the MeteoTracker data to compile user guidelines tailored for on-the-move sensors. The result will evaluate the feasibility of MeteoTracker (and potentially other on-the-move sensors) to integrate the existing monitoring networks on the territory, improve the atmospheric data local coverage and support the informed decision by the authorities. The procedure will include multi-sensor testing of all the sensor functionalities, validation of all data simultaneously acquired by several sensors under similar conditions, methods and applications of comparisons with research-grade instruments. The first usage of the MeteoTracker will be also presented for different geographical contexts where the sensors will be used for citizen science activities and develop a monitoring network of selected Essential Variables within the HORIZON-EU project I-CHANGE (Individual Change of HAbits Needed for Green European transition).

Events of very high concentrations of 7Be cosmogenic radionuclide have been recorded at low-elevation surface stations in the subpolar regions of Europe during the cold season. With an aim to investigate the mechanisms responsible for those peak 7Be events, and in particular to verify if they are associated with the fast descent of stratospheric air masses occurring during sudden stratospheric warming (SSW) events, we analyze 7Be observations at six sampling sites in Fennoscandia during January–March 2003 when very high 7Be concentrations were observed and the Arctic vortex was relatively unstable as a consequence of several SSW events. We use the GEOS-Chem chemistry and transport model driven by the MERRA-2 meteorological reanalysis to simulate tropospheric 7Be over northern Europe. We show that the model reasonably reproduces the temporal evolution of surface 7Be concentrations observed at the six sampling sites. Our analysis of model simulations, surface 7Be observations, atmospheric soundings of ozone and temperature and surface ozone measurements indicates that the 7Be peak observed in late February 2003 (between 20 and 28 February 2003) at the six sampling sites in Fennoscandia was associated with downward transport of stratospheric vortex air that originated during an SSW that occurred a few days earlier (between 18 and 21 February 2003).

This paper concerns an in-depth analysis of an exceptional incursion of mineral dust over southern Europe in late March 2020 (27–30 March 2020). This event was associated with an anomalous circulation pattern leading to several days of PM10 (particulate matter with an aerodynamic diameter less than 10 µm) exceedances in connection with a dust source located in central Asia; this is a rare source of dust for Europe, which is more frequently affected by dust outbreaks from the Sahara Desert. The synoptic meteorological configuration was analyzed in detail, and the aerosol evolution during the transit of the dust plume over northern Italy was assessed at high time resolution by means of optical particle counting at three stations, namely Bologna, Trieste, and Mt. Cimone, allowing for the revelation of the transport timing among the three locations. Back-trajectory analyses supported by Copernicus Atmosphere Monitoring Service (CAMS) maps allowed for the location of the mineral dust source area in the Aralkum region. Therefore, the event was analyzed by observing the particle number size distribution with the support of chemical composition analysis. It is shown that the PM10 exceedance recorded is associated with a large fraction of coarse particles, which is in agreement with mineral dust properties. Both the in situ number size distribution and the vertical distribution of the dust plume were cross-checked using lidar ceilometer and aerosol optical depth (AOD) data from two nearby stations and showed that the dust plume (in contrast to those originating from the Sahara Desert) traveled close to the ground (up to a height of about 2 km). The limited mixing layer height caused by high concentrations of absorbing and scattering aerosols caused the mixing of mineral dust with other locally produced ambient aerosols, thereby potentially increasing its morbidity effects.

The assessment of potential radon-hazardous environments is nowadays a critical issue in planning, monitoring, and developing appropriate mitigation strategies. Although some geological structures (e.g., fault systems) and other geological factors (e.g., radionuclide content, soil organic or rock weathering) can locally affect the radon occurrence, at the basis of a good implementation of radon-safe systems, optimized modelling at territorial scale is required. The use of spatial regression models, adequately combining different types of predictors, represents an invaluable tool to identify the relationships between radon and its controlling factors as well as to construct Geogenic Radon Potential (GRP) maps of an area. In this work, two GRP maps were developed based on field measurements of soil gas radon and thoron concentrations and gamma spectrometry of soil and rock samples of the Euganean Hills (northern Italy) district. A predictive model of radon concentration in soil gas was reconstructed taking into account the relationships among the soil gas radon and seven predictors: terrestrial gamma dose radiation (TGDR), thoron (220Rn), fault density (FD), soil permeability (PERM), digital terrain model (SLOPE), moisture index (TMI), heat load index (HLI). These predictors allowed to elaborate local spatial models by using the Empirical Bayesian Regression Kriging (EBRK) in order to find the best combination and define the GRP of the Euganean Hills area. A second GRP map based on the Neznal approach (GRPNEZ) has been modelled using the TGDR and 220Rn, as predictors of radon concentration, and FD as predictor of soil permeability. Then, the two GRP maps have been compared. Results highlight that the radon potential is mainly driven by the bedrock type but the presence of fault systems and topographic features play a key role in radon migration in the subsoil and its exhalation at the soil/atmosphere boundary.

A multi-parametric experimental campaign was performed in Agri Valley (Basilicata, southern Italy) from July 2017 to January 2018. The investigated area, though basically rural and devoted to agricultural activities, hosts a huge onshore oil reservoir, i.e. Centro Olio Val d'Agri (COVA), bringing substantial environmental modifications and impacts to the district landscape. Daily concentrations of PM1 aerosol samples, Equivalent Black Carbon and number size distributions were evaluated. Chemical aerosol speciation based on elemental and ion analyses were carried out and source apportionment by Positive Matrix Factorization (PMF) was applied to reconstruct PM1 source profile. The most significant emission sources found are torches from the oil treatment facility (37 % w/w), an unresolved factor constituted by soil resuspension, Saharan dust, and biomass burning (24 % w/w), ammonium sulphate (23 % w/w), emissions from the oil desulfurization (Claus process) (13 % w/w), and traffic +road dust (3 % w/w). SEM analysis on PM1 single particles allowed to confirm the finding from PMF including the occurrence of elemental sulfur associated with the Claus process. The novelty of the present study consists in the identification of this latter fingerprint.

Climate change phenomena represent the most serious threats to human well-being and sustainable development. This affects several dimensions of human life from individual health issues to economic growth, passing through civil protection, with strong impacts on European territories and in several other world regions. The I-CHANGE (Individual Change of HAbits Needed for Green European transition, 2021-2025) project faces the challenge of engaging and promoting the active participation of citizens for addressing climate change, sustainable development and environmental protection in the framework of the European Green Deal , the European Climate Pact and the European Biodiversity Strategy for 2030. The overall driving concept is that citizens and civil society have a central role in the definition of environmental protection and climate action and their direct involvement is essential to drive a true shift and promotion of changes of behaviors towards more sustainable patterns. I-CHANGE represents a change of paradigm achievable through a multi-disciplinary and participatory approach: improvement of data usability - citizen awareness raises through the observation of the environmental impacts of human activities; active participation of citizens - the active involvement of citizens through a set of Living Labs (LLs) located in different socio-economic contexts (Europe, Middle-East and Africa); climate change awareness - the development of clear understanding for citizens of the scientific processes underlying climate change and environmental protections. First year of I-CHANGE activities will be presented and discussed.

An experimental field campaign is designed to unveil mechanisms responsible for turbulent exchange processes when mechanical and thermal effects are entwined. The focus is an urban street canyon with a mean aspect ratio H/W of 1.65 in the business centre of a mid-size Italian city (H is the mean building height and W is the mean canyon width). The exchange processes can be characterized by time scales and time-scale ratios specific to either mechanical or thermal process. Time scales describe the mixing caused by momentum and heat exchange within different canyon layers, while their rates are surrogates of their efficacy. Given that homogeneous mixing does not always occur within the canyon, several time scales are estimated at different levels, showing that mechanical and thermal processes may both contribute to enhance mixing. By computing mechanical time scales, it is found that the fastest mixing occurs at the canyon rooftop level for perpendicular or oblique wind directions, while slow mixing occurs for parallel directions. Thermal processes are faster than the mechanical ones and are particularly efficient for perpendicular wind directions. By calculating the time-scale ratios, exchange processes are found to facilitate mixing for most wind directions and to regulate the pollutant-concentration variability in the canyon. This variability can be associated with the local-circulation regime, demarcated as thermally driven or inertially driven using a buoyancy parameter, i.e., the ratio between thermal and inertial forcings. Using this approach, a generalization of the results is proposed, enabling the extension of the current investigation to different street-canyon aspect ratios.

Terrestrial gamma radiation is mostly due to radionuclides in soil and rocks, primarily the 238U, 235U and 232Th radioactive families and 40K. This radiation contributes 15% to public exposure from all ionizing radiation sources, considering global population. Moreover, it can be used to estimate radon flux and included as one of the quantities relevant to the geogenic radon hazard model. Therefore, effort has been put into developing maps of terrestrial gamma dose rate at the regional, national or European scale, using different input data and methods. In the present work, two distinct approaches to map terrestrial gamma dose rate have been tested in the Euganean Hills district of NE Italy. The first one is based on 41 in situ measurements of ambient dose equivalent rates using a rate meter equipped with a NaI scintillator probe. The second one estimates terrestrial gamma dose rate from the U, Th and K activity concentrations in rock samples collected at the same locations of the dose rates measurements. The results obtained indicate good agreement between the two approaches, and as such suggest that the UNSCEAR 2008 prescription to derive ambient dose equivalent rate from laboratory gamma measurements produces reliable data, provided that cosmic and fall-out contributions are included. Moreover, the study proved that mapping the ambient dose equivalent rate (or terrestrial gamma dose rate) using only one database – i.e. either measured data or estimates derived from radionuclide activity concentration – yields valid results.

The natural radionuclide beryllium-7 (Be-7) is produced in the upper levels of the atmosphere and is transported to the surface on carrier aerosols. Therefore, among other factors, the abundance of Be-7 in the surface air is governed by the rate of its production and large-scale air transport. The North Atlantic Oscillation (NAO) index, which quantifies the surface sea-level pressure difference between the Subtropical (Azores) High and Subpolar low, exerts large effects on precipitation and circulation patterns in Europe. With an aim to look closely into the interrelations between the Be-7 specific activity in the surface air, sunspot number (as a proxy for the production signal), and NAO index, this paper investigates their long-term time series over 28 years, between February 1987 and December 2014. The Be-7 specific activity was recorded in Vienna (48.22 ºN; 16.35 ºE; 193 m a.s.l.), Austria, and stored in the Radioactivity Environmental Monitoring databank (REMdb) that is created and supported by the European Commission-Joint Research Centre in Ispra, Italy. The sunspot number (SN) data were downloaded from SILSO (Royal Observatory of Belgium, Brussels, Belgium), while the NAO records were retrieved from the Climate Prediction Centre of the National Oceanic and Atmospheric Administration, USA. Since the temporal resolution of the Be-7 measurements varied between six and eight days, they were first linearly interpolated into an array of weekly data, and then, the daily SN and NAO data were averaged into weekly records to match the Be-7 data. Next, Pearson’s correlation analysis and wavelet transform were used to analyse the time series. The low Pearson’s correlation coefficients between the Be-7 specific activity in the surface air and SN (-0.15207) on one hand, and the NAO index and SN (0.13512) on the other hand, imply a lack of direct linear interrelations between these variables. The Pearson’s correlation coefficient between the Be-7 specific activity in the surface air and NAO index is even lower (-0.05904). However, the Be-7 specific activity wavelet spectrum shows a pronounced annual period, and looking further into the link between the Be-7 specific activity and NAO index at this characteristic periodicity, reveals a prominent pattern. Specifically, the wavelet coherence levels between these two parameters show variations that seem to be in agreement with the 11-year solar cycle: the coherence increases as the sunspot number transitions between its extremes, and it decreases around the maxima and minima in sunspot number. Further, phase difference shows that at the one-year periodicity, the Be-7 specific activity always lags behind the NAO index. The phase difference ranges between 2 and 6 months; it reaches the minimum around the solar activity extremes, and the maximum in-between. These findings imply that, although weak, the signature of sunspot number can be seen in the wavelet coherence level between the Be-7 specific activity and NAO index.

Cooling towers (CTs) are used to dissipate excess heat from water by evaporation, common in large facilities as hospital, companies, and hotels. The main risk attributed to CTs is represented by Legionella, a Gram-negative bacterium associated with a severe form of pneumonia known as Legionnaires' disease (LD). The infection route is by inhalation of aerosols reaching the lower respiratory tract. Despite several events associated with CTs, the knowledge in this field is still limited. The aim of this study was to develop a predictive model of bioaerosol dispersion using PM10 particles as a proxy, to generate risk maps of Legionella spread in the surrounding area in several weather and microbiological conditions. The Legionella contamination in the CT basin was 40938 ± 24523 cfu/L, with four peaks independent of the season, associated with an increase in air minimum temperature values (+1–2 °C) and a high relative humidity (66–100%) preceded by rainfall (0.2–30.6 mm/day). The model revealed that the most extensive bioaerosol spread is predicted in winter and summer, with an increase in Legionella risk at a distance of up to 1.5 km from the CT. This method represents a novel integrated approach for the prevention and management of LD risk in CTs.

In this study, a new chemiluminescent method based on the dependence of luminol light emission induced by free radicals in airborne particulate matter (PM) is proposed as a screening assay for the rapid characterization of samples from different sources based on their redox properties. This parameter is considered critical for assessing particulate matter toxicity and its impacts on human health. We propose a cell-free, luminescent assay to evaluate the redox potential of particulate matter directly on the filters employed to collect it. A joint chemometric approach based on Principal Component Analysis and Hotelling Analysis was applied to quickly sort out ambient particulate samples with a significantly different light emission profile caused by Luminol reaction. Based on Spearman correlation analysis, the association of the samples light emission intensity with their chemical composition and emission sources was attempted. The overall methodology was tested with certified reference materials and applied to two series of particulate matter samples previously subjected to thorough chemical speciation and subsequent source apportionment. The results show the effectiveness of the luminescent method, allowing the quick assessment of particulate matter oxidative potential, but providing further evidence on the complexity of the oxidative potential determination in this kind of samples. The chemometric processing of the whole dataset clearly highlights the distinct behavior among the two series of samples, the certificate standard reference materials, and the blank controls, supporting the suitability of the approach.

Mentre il degrado attuale delle risorse naturali del pianeta comporta una minaccia sempre più grande per la biodiversità e il benessere umano, le soluzioni basate sulla natura (NBS) rappresentano un mezzo all'avanguardia e collaborativo per affrontare una varietà di sfide ambientali, sociali ed economiche, prediligendo un approccio naturale e sostenibile. Le NBS trovano diverse applicazioni, tra le quali spiccano le sfide legate all’urbanizzazione. Il seguente articolo ne presenta una panoramica basata sui risultati del progetto H2020 iSCAPE, in cui la presenza di alberi in contesto urbano è studiata come valida risorsa per mitigare l’effetto isola di calore urbana, per migliorare la qualità dell’aria e per supportare l’adattamento agli effetti avversi del cambiamento climatico.

Mineral dust represents one of the main components of particulate matter (PM) in the Mediterranean area. The rapid identification of Saharan dust events in PM samples is desirable and required for several reasons, including their role in direct effect on climate by radiative forcing as well as their adverse effects on human health. For this purpose, the feasibility of UV–Vis Diffuse Reflectance Spectroscopy (UV–Vis DRS) is described as a rapid, inexpensive and non-destructive method of analysis of PM filters. The method developed allows to parameterize the PM filter colors and to obtain semiquantitative data related to iron oxide minerals, mainly hematite and goethite, two of the most representative minerals of Saharan dust in the Mediterranean area. The obtained results were validated based on the correlation between the spectrophotometric data of iron oxides from the membranes with the quantitative assessment of the concentration of iron by Particle Induced X-ray Emission (PIXE). Moreover, colorimetric parameterization allows setting up a classification approach for filters with potential for a posteriori use of this data in the study of the optical behavior of aerosol particles in the air. In this work, it is demonstrated how, as the concentration of iron mineral oxides and especially of hematite increases, the extent of redness color in PM filters grows up. Therefore, this technique can be extremely useful for a rapid, cheap and unambiguous identification of Saharan dust events in PM filters. The diagnosis of Saharan dust events was performed on PM10 filters with a strong mineral dust component and demonstrated with the residence time analysis of back-trajectory ensembles, proving the reliability of this non-destructive methodology. This method has the potential to be adopted by the Environmental Protection Agencies, although further evaluations are necessary and currently underway to assess their applicability not only for PM filters sampled in remote stations but also in urban stations affected by both anthropogenic pollution and Saharan dust events.

Aim of the present study is to explore how the chemical composition of particulate matter (PM) and meteorological conditions combine in shaping the air microbiome in Savona (Italy), a medium-size, heavily inhabited urban settlement, hosting a wide range of industrial activities. In particular, the air microbiome and PM10 were monitored over six months in 2012. During that time, the air microbiome was highly dynamic, fluctuating between different compositional states, likely resulting from the aerosolization of different microbiomes emission sources. According to our findings, this dynamic process depends on the combination of local meteorological parameters and particle emission sources, which may affect the prevalent aerosolized microbiomes, thus representing further fundamental tools for source apportionment in a holistic approach encompassing chemical as well as microbiological pollution. In particular, we showed that, in the investigated area, industrial emissions and winds blowing from the inlands combine with an airborne microbiome which include faecal microbiomes components, suggesting multiple citizens’ exposure to both chemicals and microorganisms of faecal origin, as related to landscape exploitation and population density. In conclusion, our findings support the need to include monitoring of the air microbiome compositional structure as a relevant factor for the final assessment of local air quality.

The present paper describes the assessment of the atmospheric deposition processes in a basin valley through a multidisciplinary approach based on the data collected within an extensive physico-chemical characterization of the soils, combined with the local meteorology. Surface soil cores were collected on a NNW-SSE transect across the Terni basin (Central Italy), between the Monti Martani and the Monti Sabini chains (956 m a.s.l.), featuring the heavily polluted urban and industrial enclave of Terni on its bottom. Airborne radiotracers, namely 210Pb and 137Cs, have been used to highlight atmospheric deposition. We observed an increased deposition flux of 210Pb and 137Cs at sites located at the highest altitudes, and the associated concentration profiles in soil allowed to evaluate the role of atmospheric deposition. We also obtained a comprehensive dataset of stable anthropogenic pollutants of atmospheric origin that showed heterogeneity along the transect. The behavior has been explained by the local characteristic of the soil, by seeder-feeder processes promoted by the atmospheric circulation, and was reconciled with the concentration profile of radiotracers by factor analysis. Finally, the substantial impact of the local industrial activities on soil profiles and the role of the planetary boundary layer has been discussed and supported by simulations employing a Lagrangian dispersion model.

In this work, the climatic impacts of modifying urban surface characteristics are examined for the medium-sized city of Vantaa, Finland, in the current climate and in a projected future climate of 2040–2069. In simulations with the SURFEX air-surface interaction model with a horizontal resolution of 500 m, the fraction of green spaces and relatively sparsely built suburban-type land use was increased at the expense of more densely built commercial and industrial areas. The influence of this land use intervention was found to be rather modest but comparable to the effects of the expected climate change under the RCP8.5 greenhouse gas scenario. For temperature, the climate change is the dominating effect, while wind speed is mainly controlled by surface characteristics. For relative humidity, climate change and the imposed intervention are of comparable importance. The results of this sensitivity study are intended to support policy makers by assessing the potential impact of altering the urban layout in order to improve thermal comfort or as a countermeasure to climate warming in a high-latitude city.

Events of very high concentrations of 7Be cosmogenic radionuclide have been recorded in the subpolar regions of Europe during the cold season. With an aim to investigate the mechanisms responsible for those peak 7Be events, and in particular to verify if they are associated with the fast descent of stratospheric air masses occurring during sudden stratospheric warming (SSWs), we analyse 7Be observations at six sampling sites in Scandinavia during January–March 2003 when very high 7Be concentrations were observed and the Arctic vortex was relatively unstable as a consequence of several SSWs. We use the GEOS-Chem chemistry and transport model driven by the MERRA-2 meteorological reanalysis to simulate tropospheric 7Be over Northern Europe. We show that the model reasonably reproduces the temporal evolution of surface 7Be concentrations observed at the six sampling sites. Our analysis of model simulations, surface 7Be observations, as well as atmospheric soundings of ozone and temperature indicates that the 7Be peak observed in late February 2003 (between 20 and 28 February 2003) at the six sampling sites in Scandinavia was associated with downward transport of stratospheric vortex air originated during SSW that occurred a few days before the peak (18–21 February 2003).

In the volcanic area of the Euganean Hills district (100 km2), the indoor radon often exceeds the threshold level of 300 Bq/m3 stipulated by the Council Directive 2013/59/Euratom, thus suggesting the need to investigate the possible link between observed radon concentrations and the local geology (Trotti et al., 1998,1999; Strati et al., 2014). More recently, statistical and geostatistical analysis on rock samples identified high U, Th and K concentrations associated with areas characterised by trachyte and rhyolite lithologies (Tositti et al., 2017). With this contribution, we completed our investigation on the natural radioactivity in the Euganean Hills district extending the rocks dataset, performing on-site soil gas survey, and considering other important factors which can locally increase the radon occurrence, such as hydrothermal alterations, types of soils (e.g., geochemistry or presence of organic matters), and faults. Furthermore, we elaborated a Geogenic Radon Potential map to assess the local spatial relationships between the measured soil gas radon concentrations and seven proxy-variables: fault density (FD), total gamma radiation dose (TGDR), 220Rn (Tn), digital terrain mode (SLOPE), moisture index (MI), heat load index (HLI) and soil permeability (PERM). Empirical Bayesian Regression Kriging (EBRK) was used to develop the most accurate hazard map of the considered area, thus, providing the local administration an up-to-date decisional tool for the land use planning. For the high radon emission measured, the high density of dwelling, and its geomorphological features, the Euganean Hills district represented a very meaningful case of study. Trotti, F., Tanferi, A., Lanciai, M., Mozzo, P., Panepinto, V., Poli, S., Predicatori, F., Righetti, F., Tacconi, A., Zorzine, R., 1998. Mapping of areas with elevated indoor radon levels in Veneto. Radiat. Prot. Dosim. 78 (1), 11–14.Trotti, F., Tanferi, A., Bissolo, F., Fustegato, R., Lanciai, M., Mozzo, P., Predicatori, F., Querini, P., Righetti, F., Tacconi, A., 1999. A Survey to Map Areas with Elevated Indoor Radon Levels in Veneto, Radon in the Living Environment, 19-23 April 1999, Athens, Greece, 859–868.Strati V., Baldoncini M., Bezzon G.P, Broggini C., Buso G.P., Caciolli A., Callegari I., Carmignani L, Colonna T, Fiorentini G., Guastaldi E., Kaçeli Xhixhaf M., Mantovani F, Menegazzo R., Moub L., Rossi Alvarez C., Xhixha G., Zanon A., 2014. Total natural radioactivity, Veneto (Italy). Journal of Maps, Vol. 11, Issue 4, 545–551. http://doi.org/10.1080/17445647.2014.923348.Tositti L., Cinelli G., Brattich E., Galgaro A., Mostacci D., Mazzoli C., Massironi M., Sassi R., 2017. Assessment of lithogenic radioactivity in the Euganean Hills magmatic district (NE Italy). J. Environ. Radioact. 166, 259–269. https://doi.org/10.1016/j.jenvrad.2016.07.011

The Euganean Hills of North East Italy have long been recognised as an area characterized by a higher than average natural radiation background. This is due to two main reasons: a) primary lithogenic radiation due to rhyolitic and trachytic outcrops, which are “acidic alkaline” magmatic rocks potentially enriched in uranium and thorium; b) secondary sources related to a geothermal field – widely exploited for spa tourism in the area since the Roman age – producing surface release of radon-enriched fluids. Though radioactivity levels in the Euganean district have been often investigated in the past – including recent works aimed at assessing the radiation doses from radon and/or total gamma radiation – no effort has been put so far into producing a thorough assessment linking radiation protection data to geological-structural features (lithology, faults, water, organic matter content, etc.). This work represents the first part of the interdisciplinary project “Geological and geochemical control on Radon occurrence and natural radioactivity in the Euganean Hills district (North-Eastern Italy)”, aimed at producing detailed results of the actual radiation levels in connection mainly with lithological parameters. A detailed sampling strategy, based on lithostratigraphy, petrology and mineralogy, has been adopted. The 151 rock samples collected were analyzed by high resolution γ-ray spectrometry with ex situ HPGe detectors. Statistical and geostatistical analyses were performed, and outlier values of U and Th – possibly associated with anomalies in the geological formation – were identified. U, Th and K concentration maps were developed using both the entire database and then again after expunging the outliers; the two were then compared. In all maps the highest values can be associated to trachyte and rhyolite lithologies, and the lowest ones to sedimentary formations. The external dose due to natural radionuclides in the soil – the so called terrestrial gamma dose rate – has been calculated using the U, Th and K distribution measured in the bedrock samples.

Green infrastructure (GI) in urban areas may be adopted as a passive control system to reduce airpollutant concentrations. However, current dispersion models offer limited modelling options to evaluate its impact on ambient pollutant concentrations. The scope of this review revolves around the following question: how can GI be considered in readily available dispersion models to allow evaluation of its impacts on pollutant concentrations and health risk assessment? We examined the published literature on the parameterisation ofdeposition velocitiesand datasets for bothparticulate matterandgaseous pollutantsthat are required for deposition schemes. We evaluated the limitations of different air pollution dispersion models at two spatial scales –microscale(i.e. 10–500 m) and macroscale (i.e. 5–100 km) - in considering the effects of GI onair pollutantconcentrations and exposure alteration. We conclude that the deposition schemes that represent GI impacts in detail are complex, resource-intensive, and involve an abundant volume of input data. An appropriate handling of GI characteristics (such as aerodynamic effect, deposition of air pollutants and surface roughness) in dispersion models is necessary for understanding the mechanism of air pollutant concentrations simulation in presence of GI at different spatial scales. The impacts of GI on air pollutant concentrations and health risk assessment (e.g., mortality, morbidity) are partly explored. The i-Tree tool with the BenMap model has been used to estimate the health outcomes of annually-averaged air pollutant removed by deposition over GI canopies at the macroscale. However, studies relating air pollution health risk assessments due to GI-related changes in short-term exposure, via pollutant concentrations redistribution at the microscale and enhanced atmospheric pollutant dilution by increasedsurface roughnessat the macroscale, along with deposition, are rare. Suitable treatments of all physical and chemical processes in coupled dispersion-deposition models and assessments against real-world scenarios are vital for health risk assessments.

The increasing frequency and intensity of extremeheat waves are currently causes of concern worldwide for their effects on several aspects of the natural ecosystems as well as on human health and comfort. These phenomena can be further exacerbated in urban areas in combination with the Urban Heat Island (UHI) effect that enhances the thermal discomfort. While such phenomena have been analyzed with regional models at local scales and with different urban canopy models, very few studies have been conducted on the evolution of the UHI in a climate change scenario. To this aim, a new dataset including global bias-corrected climate model output data suitable for WRF can be used. The new dataset deriving from version 1 of NCAR's Community Earth System Model allows us to estimate the potential effects of climate changes on the UHI phenomena under different future scenarios. This stud y will be conducted by means of WRF model simulating the UHI in a medium size city of the Po Valley, namely Bologna, spanning different seasons in the Mid Future (2045-2050) and in the far future (2075-2080) under the Representative Concentration Pathways 8.5 scenario (RCP8.5). The WRF model is driven by the Global 6-Hourly Bias-corrected Coupled Model Intercomparison Project, Phase 5 (CMIP5),Community Earth System Model (CESM) dataset over Europewith different resolution nested domains centered over the city of Bologna. In order to evaluate the performance of the model setup, it was also verified using reanalysis (ERA5) and CESM driven historical simulations. An analysisof the mean temperature and wind intensity in the inner domain of the city will be conducted together with a climatic analysis of the Emilia -Romagna region. This study mayassist to develop UHI mitigation strategies, mainly but not only restricted to the cities in the whole Po valley region, as well as to develop new policies aimed at improving the urban thermal comfort.

Extreme heat events and urban heat island effect are among the major problems the humanity is currently facing in association with the increasing urbanization. Both these problems, besides being related to bad life quality of urban citizens, also determine a large energy consumption leading to increased emissions of air quality pollutants within a context already stressed by various sources of pollutants (Salamanca et al., 2014). Urban heat island and the various problems related to the thermal conditions of the urban environment are frequently observed in highly urbanized areas (Hunt et al., 2017). Several studies have been conducted on the Urban Heat Island (UHI) using both experimental and modeling techniques. The spatial and temporal distribution of air temperature within a city is strongly depend on meteorological factors and on various parameters of the city texture such as its density, morphology and material of buildings, as well as thermal emissions associated to human activities (Yang et al., 2010). In this work, we will present an analysis of numerical simulations of Urban Heat Island effect in a medium-size city of the Po Valley (Bologna, Italy) conducted with two different models, i.e. one temperature perturbation type namely the ADMS-Temperature and Humidity Model (ADMS-TH) and one mesoscale numerical weather prediction model, namely the WRF model. The temperature perturbation-type is able to resolve local temperature variations at street scale, taking into account both meteorological variables and all the parameters related to the use of soil and the objects such as buildings and other anthropogenic sources and trees that are included in the domain. This model was previously validated against meteorological observations with good accuracy in Lecce, where it was demonstrated that it is capable to predict correctly temperature and humidity daily trends, with higher accuracy than simplified computational fluid dynamics simulations (Maggiotto et al., 2014) The WRF mesoscale meteorological model is capable to simulate the 2m-temperature in the inner city with a resolution of hundreds of meters by the means of different urban parameterizations. Moreover, the effect of the buildings and of the canopies on the energy balance of the city can be taken into account by means of the Building Effect Parameterization (BEP) and Building Energy (BEM) parameterizations, both implemented in WRF. The performance of the two models is verified comparing with the meteorological observations conducted in the urban area of Bologna by the Emilia Romagna Environmental Protection Agency (ARPAE) network. Specifically, we will highlight advantages and disadvantages of each model type, focusing on a case study in summer 2017. Conclusions will be derived for adoption of the two models in the setting up of heat mitigation strategies in Italian cities.

Air pollution continues to pose significant threats in many regions of the world, including Europe where exceedances of limit values are still frequent in urban areas for most pollutants (nitrogen oxides NOx, particulate matter in form of PM10 and PM2.5, and ozone O3). The control and prevention of episodes of severe air quality is very important both for the management of traffic in urban areas and for citizens’ health and life quality. In fact, the availability of accurate forecasts for air pollution episodes could further support decisions related to traffic closures and make also a significant impact on lifestyles especially for citizens suffering from respiratory problems. In this study, the Atmospheric Dispersion Modelling System (ADMS) is used in combination with the mesoscale Weather Research and Forecasting (WRF) for making good accurate predictions of spatial variations in the concentrations of the main air pollutants in the urban area of Bologna, Italy. The study area includes all emitting sources of air quality pollutants, as well as meteorological and air quality monitoring stations from the reference network, over a domain of 20 x 30 km with a resolution of 200x200 m. The WRF model was used to simulate hourly forecasts of the meteorological variables necessary for the initialization of the ADMS dispersion model. The output parameters obtained from WRF such as simulated air temperature, wind intensity and wind direction were also compared with the data observed in the meteorological station of the Marconi airport in Bologna. The suggested integrated strategy and the performance of the model is verified comparing with the observations of air quality pollutants from the Emilia Romagna Environmental Protection Agency (ARPAE) network in the urban area of Bologna. The ADMS model shows good agreement with observed concentrations over the whole considered reference year (2017). The results of different case studies will be presented and discussed. In particular, we will present the first results obtained spanning different weather conditions both in the summer and in winter seasons. The aims of this work are: test the WRF-ADMS Urban coupling, automate the steps of the methodology and verify the reliability of air quality forecasts. Possible developments of this work will be the use of machine learning techniques to improve local air quality forecasts which is current under study.

Here we explore how the chemical composition of particulate matter (PM) and meteorological conditions combine in shaping the air microbiome in a heavily inhabited industrial urban settlement. During the observation time, the air microbiome was highly dynamic, fluctuating between different compositional states, likely resulting from the aerosolization of different microbiomes emission sources. This dynamic process depends on the combination of local meteorological parameters and particle emission sources, which may affect the prevalent aerosolized microbiomes. In particular, we showed that, in the investigated area, industrial emissions and winds blowing from the inlands combine with an airborne microbiome that includes faecal microbiomes components, suggesting multiple citizens’ exposure to both chemicals and microorganisms of faecal origin, as related to landscape exploitation and population density. In conclusion, our findings support the need to include monitoring of the air microbiome compositional structure as a relevant factor for the final assessment of local air quality.

Low-cost sensors based on the optical particle counter (OPC) are increasingly being used to collect particulate matter (PM) data at high space and time resolution. In spite of their huge explorative potential, practical guidelines and recommendations for their use are still limited. In this work, we outline a few best practices for the optimal use of PM low-cost sensors based on the results of an intensive field campaign performed in Bologna (44&deg, 30&prime, N, 11&deg, 21&prime, E, Italy) under different weather conditions. Briefly, the performances of a series of sensors were evaluated against a calibrated mainstream OPC with a heated inlet, using a robust approach based on a suite of statistical indexes capable of evaluating both correlations and biases in respect to the reference sensor. Our results show that the sensor performance is sensibly affected by both time resolution and weather with biases maximized at high time resolution and high relative humidity. Optimization of PM data obtained is therefore achievable by lowering time resolution and applying suitable correction factors for hygroscopic growth based on the inherent particle size distribution.

Travel demand management measures/policies are important to sustain positive changes among individuals' travel behaviour. An integrated agent-based microsimulation platform provides a rich framework for examining such interventions to assess their impacts using indicators about demand as well as supply side. This paper presents an approach, where individual schedules, derived from a lighter version of an activity-based model, are fed into a MATSIM simulation framework. Simulations are performed for two European cities i.e. Hasselt (Belgium), Bologna (Italy). After calibrating the modelling framework against aggregate traffic counts for the base case, the impacts of a few traffic management policies (restricting car access, increase in bus frequency) are examined. The results indicate that restricting car access is more effective in terms of reducing traffic from the network and also shifting car drivers/passengers to other modes of travel. The enhancement of bus infrastructure in relation to increase in frequency caused shifting of bicyclist towards public transport, which is an undesirable result of the policy if the objective is to improve sustainability and environment. In future research, the framework will be enhanced to integrate emission and air dispersion models to ascertain effects on air quality as a result of such interventions., Comment: Post-print

Many industrial by-products contain Naturally Occurring Radioactive Materials (NORM) that normally represent a cost in terms of monitoring, risk management and storage. When included in new mix designs of bricks, these materials may become a valuable sustainable resource. Before marketing, companies involved in development and commercialization of these new building materials ensure safety related to radiation, usually by assessing radon-related risk. According to the Council Directive 2013/59/Euratom, both raw materials and final products used in building constructions need to be tested for activity concentration. The present work explores the radionuclide concentration and the radon exhalation of bricks obtained recycling different types of potentially radioactive wastes: i) trachyte as by-product resulting from quarrying operations, and ii) two different types of industrial sludge derived from ceramic tiles industry. Raw materials were studied to foresee any potential radioactive risk derived from their use as secondary raw materials, while bricks were investigated to assess the influence of mineralogy and texture on their radioactive properties and their effective radon-risk. The results obtained here show that, although radon emanation in bricks is primarily determined by radionuclide concentration in the raw materials, textural features significantly affect radon mobility and exhalation.

The abatement performance of photocatalytic coatings on NOx concentrations in real-world street canyons remains an open question considering the very different conclusions reached by the few previous field studies. To fill this gap, an intensive experimental campaign was carried out in summer 2018 in the outskirts of Bologna in Italy. The experimental design involved two parallel street canyons in an open-air controlled environment fully instrumented for measuring air pollutant concentrations, meteorological and turbulence variables in presence of a photocatalytic coating. Specifically, the coating utilized TiO2 photocatalysts. Several controlled pollutant release experiments with a known pollutant source were conducted within the two canyons, of which one coated with TiO2 and the other free (reference canyon). The comparison of observations in the two canyons indicated a distinct behavior of airflows, leading to higher concentrations in the coated canyon. Three independent methods were developed to demonstrate the abatement performance of the coatings in an open-air controlled environment. The first method involved the comparison of the two canyons before and after the application of the coating; the second one regarded the derivation of normalized concentrations to remove the effect of the different geometry and dilution volume of the canyons; the third method involved dispersion modeling simulations conducted during the controlled pollutant release experiments. All the three methods demonstrated a photocatalytic reduction of NOx in the range of 14–21%, suggesting the potential effect of photocatalysis under real weather conditions.

The complex interaction between the Urban Heat Island (UHI), local circulation, and air quality requires new methods of analysis. To this end, this study investigates the multiple scale nature of the UHI and its relationship with flow and pollutant dispersion in urban street canyons with and without the presence of vegetation. Two field experimental campaigns, one in summer and one in winter, were carefully designed in two parallel urban street canyons in the city of Bologna (44&deg, 29&prime, N, 11&deg, 20&prime, E, Italy) characterized by a similar orientation with respect to the impinging background flow but with a different aspect ratio and a different presence of vegetation. In addition to standard meteorological variables, the dataset collected included high-resolution flow data at three levels and concentration data of several pollutants. The UHI has been evaluated by combining surface temperature of building facades and ground surfaces acquired during two intensive thermographic campaigns with air temperature from several stations in order to verify the presence of intra-city neighborhood scale UHIs additional to the more classical urban&ndash, rural temperature differences. The presence of trees together with the different morphologies was shown to mitigate the UHI intensity of around 40% by comparing its value in the center of the city free of vegetation and the residential area. To capture the multiple-scale nature of UHI development, a simple relationship for the UHI convergence velocity, used as a surrogate for UHI strength, is proposed and used to establish the relationship with pollutant concentrations. The reliability of the proposed relationship has been verified using a Computational Fluid Dynamics (CFD) approach. The existence of a robust relationship between UHI strength and pollutant concentration may indicate that the positive effect of mitigation solutions in improving urban thermal comfort likely will also positively impact on air pollution. These results may be useful for a quick assessment of the pollutant accumulation potential in urban street canyons.

In this work we address the linkage between urban heat island (UHI) and air quality in the metropolitan area of Bologna (Italy), which is one of the pilot cities in H2020-iSCAPE (www.iscapeproject.eu). Occurrence of heat waves in the region is projected to increase in the future and superimposition with the UHI phenomenon is expected to have strong impacts on local circulation and pollutant dispersion patterns. Dynamic features of the UHI formation and evolution is examined by a combination of data analyses from two intensive field campaigns carried out in August 2017 and February 2018 integrated with high-resolution numerical modelling using an urbanized version of the model WRF. The experimental campaigns included a suite of instruments deployed in two neighbourhoods of Bologna city to evaluate profiles of turbulent fluxes of momentum and sensible heat, air temperature via distributed low-cost sensors, surface temperature using infra-red camera, particulate matter, ozone and traffic-related compounds concentrations. Data are also integrated with boundary-layer height measurements obtained by a Vaisala ceilometer (CL31) and radiosonde soundings available from a nearby station. Stand-alone preliminary model runs using WRF-3.8 and validated with several weather stations show that in presence of a heat-wave (the worst condition for the urban environment in south European cities, such as the one that occurred in July 2015 and in 2017), the UHI contribution exceeds rural temperatures of 4-6 °C during the night. It is shown that air quality in street canyons worsen under UHI phenomenon for which a simple physics-based relationship is proposed.

The simultaneous aerosol sampling at two heights in southern Spain may provide valuable information on the vertical structure of the dust transport from North Africa to the Iberian Peninsula. It also allows the characterization of the ambient air at two sites with distinct anthropogenic impact. This work presents the results obtained from the first field campaign of the FRESA project (Impact of dust-laden African air masses and of stratospheric air masses in the Iberian Peninsula. Role of the Atlas Mountains), performed in the period July-November 2017 at El Albergue Universitario in Sierra Nevada (2550 m a.s.l.) and the city of Granada (650 m a.s.l.). The two sites were instrumented with a low-volume sampler with PM10 inlet for daily sampling and mass and chemical composition characterization, a high-volume sampler for total suspended particles (TSP) for weekly sampling and radionuclide activity determination, and with a GRIMM 365 optical particle counter that provides continuously the aerosol size distribution. In Sierra Nevada, daily PM10 concentrations range from 0 to 100 μg m-3 depending mainly on the origin and features of the air masses that reach this high-elevation site. Levels overpassed 50 μg m-3 on 5 days and were lower than 20 μg m-3 on 90 days. The impact of dust-laden African airflows is particularly intense as dust is transported in most of the cases within well-defined low mid-tropospheric layers. The associated episodic concentrations largely exceed 40 μg m-3. In turn, clean subsiding airflows associated to the polar jet strongly reduce concentrations. In Granada, daily PM10 concentrations are moderately high with values generally between 20 and 40 μg m-3 before the first snows fall over Sierra Nevada. Levels were over 50 μg m-3 on 2 days while they were lower than 20 μg m-3 on 32 days. The highest concentrations do not reach the peaks found at Sierra Nevada. The impact of anthropogenic aerosols of local origin, which are accumulated on high-stability conditions, and also of regional origin (both from the Mediterranean and from the SW Iberian Peninsula) is significant. The contribution of African dust outbreaks superimposes to concentrations in the ambient air and in some events the increase is observed one day after African dust impacts Sierra Nevada. After the first snows over Sierra Nevada, PM10 levels drop and only accumulation periods or African dust events increase concentrations to those before the first snows. Back-trajectories (96-hour, calculated with HYSPLIT using ERA-Interim data of 0.5 degree resolution) show that air flows are quite often decoupled at the two altitudes. Dust-laden African flows reached Sierra Nevada on 33 days; of these, dust was advected poleward over the Atlas near the Algerian-Moroccan border on 19 days and on the remaining 14 it followed a pathway over the Atlantic close to the Moroccan coast. However, only on 3 days air masses of African origin reached Granada. In turn, airflows reaching Granada passed previously over the western Mediterranean Sea on 32 days while only on 3 days Mediterranean flows reached Sierra Nevada. Moreover, the residence time over northern Africa of the air parcels reaching Sierra Nevada while at the same time parcels reaching Granada resided over the Mediterranean is 11,338 hours during the study period. In contrast, the residence time when those reaching Granada resided over Africa is only of 56 hours. This implies that during African dust outbreaks the air masses reaching the study area at the lowest levels do not have African origin but have resided over the Mediterranean. Chemical analysis of the PM10 samples (in progress) while provide the first direct experimental evidence of this fact. The diurnal pattern of both PM10 and particle number concentrations at Granada presents the two typical peaks. Particle concentrations are smaller in winter than in summer, even though in winter the atmospheric boundary layer is shallower and domestic heating is used. Much higher concentrations of coarse (supermicronic) particles are found in summertime during the course of the day. Finer (submicronic) particles present a stronger morning peak (centered about 10 LT) in winter and also concentrations are slightly higher at about 20-21 LT, being quite similar the rest of the day in winter and summer. A number of distinct episodes can be identified: strong African dust impact at Sierra Nevada while Granada is heavily polluted by anthropogenic aerosols (1 August 2017); strong African dust impact at Sierra Nevada which is observed the following day in Granada (15-16 August 2017); African dust outbreaks impacting simultaneously both sites (25 November 2017); episode of accumulation of pollutants at Granada whilst very low concentrations are registered at Sierra Nevada (19-24 November 2017); and fair air quality at both sites (16 September 2017).

The presence of variable heat fluxes between building walls and air within a street canyon, due to the non-uniform sun-light radiation at the street level, poses a key challenge for modeling the heat exchanges with local three-dimensional numerical approaches. In absence of trees, regions with temperature distribution much higher than air temperature, and therefore significant temperature gradients, might arise, while the trees shadowing effects on the walls mitigate these temperature peaks. Heat exchange processes between building walls and external air within the canyon is an important topic in air quality modeling, considering that the thermal structure largely affects the dynamics and pollutant concentration. The influence of trees is analyzed by considering different shadowing characteristics and crown shapes. The study is approached via the computational fluid dynamics finite-volume method, with large eddy simulations (LES) to model turbulence within the canyon and Boussinesq approach to model heat transfer [1]. Consequences on pollutant concentrations are analyzed. The thermal boundary conditions on the building surfaces are set by analyses on the basis of previous experimental results obtained from infrared camera during a UHI experiment [2], for the latitude and longitude of the case study, the orientation, the time of the day. A map with the maximum temperatures reached within the urban area analyzed as a function of the time instant is obtained. We propose a new formulation for the exchanges as a way to link thermal features in street canyons to pollutant concentrations [3]. Model simulations have been validated by previous studies done under the EU funded project iSCAPE (www.iscapeproject.eu). Temperature measured by distributed sensors, surface temperature using infra-red camera, together with measurements of particulate matter, ozone and traffic-related compounds concentrations will be used for the validation of the model. The model will give a tool to design and optimize the key characteristics within the city district (vegetation, geometry of buildings, etc.) in order to minimize the effects of pollutant concentration hotspots within an urban heat island.

Radon-222 and its progenies in the atmosphere have been widely utilized as powerful tracers to quantify atmospheric processes that include: i) source tracking and transport (within and between troposphere and stratosphere) time scales of air masses, including the stability and vertical movement of air masses; ii) removal rate constants and residence times of aerosols; iii) deposition velocities and washout ratios of aerosols; iv) sources of continental dust in an air mass; v) flux to and exchange between environmental systems of other gaseous species (e.g., CH4, Hg0); and vi) processes of attachment of metal ions to atmospheric aerosols. In addition, radon is increasingly being used as a tool for quantifying stability influences on urban pollutant concentrations. As a rule, radon is especially useful wherever a concentration gradient of this radiotracer is observed, providing a uniquely efficient tool for atmospheric circulation in complex topography conditions. The polar plots methodology is increasingly being used for exploring the sources of atmospheric pollutants. In fact, the use of smart use of wind speed and directionanemological parameters may lead to can be informative because it often leads to the suggestion of source locations and source characteristicszation , such as height of emission above the surfaceon the basis of radon whose behavior is statially and temporally well recognizable. In this work, radon, whose source term is well known, was has been used as a tracer to constrain atmospheric transport of particulate matter and its chemical constituents, together with atmospheric gaseous pollutants, in a coastal site located in north-eastern Italy. Results suggest that under the development of sea-breeze conditions, typical of the warm season, typical of coastal locations such as the measurement sitelike in the present case study, may successfully benefit of this approach in efficiently reconstructing pollutant dynamicsespecially during the summer season, the use of polar plots can be misleading in the absence of independent and well-known tracers.

This study provides an analysis of a five-year time series chemical composition of the bulk deposition (2009–2013), collected within a farm surrounded by industrial and urban settlements in a semi-rural area of the Po Valley, with the aim of characterizing potential emission sources affecting precipitation composition at the site. Most monitoring efforts in this region, recognized as one of the most polluted in the world both due to the intense industrialisation and urbanisation as well as to frequent air stagnation conditions, are presently devoted more to gaseous and particulate pollutants than to precipitation chemistry. The bulk deposition samples were very concentrated in chemical species, both acidic and alkaline, high compared to other polluted sites in the world and to locations in the same district. The mean ions concentrations (in μeq l−1) are: NO3 − (243) > SO4 2− (220) > PO4 3− (176) > Cl− (153) > NO2 − (29) > F− (2.6); NH4 + (504) > Ca2+ (489) > K+ (151) > Na+ (127) > Mg2+ (127). pH data shows a trend toward slightly alkaline conditions attributed to the large presence of ammonium and crustal elements, in spite of high concentrations of nitrates and sulphates. The relevant concentrations of Ca2+ and Mg2+ further suggests that these alkaline conditions might be due to the correspondingly significant concentrations of carbonates/bicarbonates in our dataset. While back-trajectories analysis suggests the stronger importance of local resuspension over long-range transport, statistical analyses on ion composition highlight the key role exerted by agricultural activity, especially in the case of NH4 +, K+, Ca2+ and PO4 3− (especially linked to fertilisation practices and soil resuspension due to mechanical operations). Apart from Na+ and Cl− ions which correlate well as expected, indicating their likely common origin from marine salt, the identification of the origin of the other ions is very complex due to the contribution of diverse local sources, such as industrial and residential settlements.

Il progetto Horizon H2020 iSCAPE (“Improving the Smart Control of Air Pollution in Europe”, GA No. 689954) si propone di acquisire conoscenze sulle interazioni tra clima urbano e inquinamento atmosferico in alcune città europee. Nell’ambito di questo progetto, la città metropolitana di Bologna è stata selezionata come città pilota in quanto sita all’interno della Pianura Padana, ben noto hot-spot in termini di qualità dell’aria e cambiamento climatico. In aggiunta, essa è caratterizzata dalla presenza di aree densamente edificate e trafficate, come i canyon urbani, dove la caratterizzazione di qualità dell’aria, dinamica atmosferica e turbolenza, nonché della loro interazione, è particolarmente interessante caratterizzare la qualità dell'aria, la dinamica atmosferica e la turbolenza. Con questo scopo, durante l’estate 2017 e l’inverno 2018, sono state effettuate due campagne di monitoraggio intensivo in due differenti street-canyon (via Marconi e via Laura Bassi) situati all’interno della città, caratterizzati dal medesimo orientamento Nord-Sud e simile volume di traffico, ma da diversa struttura geometrica e presenza di alberazione (presente solamente in via Laura Bassi). Le misurazioni di qualità dell’aria (PM10, PM2.5, NOx, CO, O3, BTEX) si sono avvalse di due laboratori mobili di ARPAE Emilia-Romagna. In aggiunta, sono stati installati anemometri sonici e termoigrometri a diversi livelli all'interno e al di sopra dei canyons (Laura Bassi/Marconi: 3/4m – 9/8m – 15/25m) per la caratterizzazione della turbolenza atmosferica. Fin dalla campagna estiva è apparso evidente l’effetto di amplificazione dello street canyon sulle concentrazioni di inquinanti: in particolare gli NOx presentano concentrazioni medie orarie doppie rispetto al resto della città e medie al minuto che raggiungono valori prossimi al fondoscala strumentale. Il confronto evidenzia quindi il ruolo della turbolenza atmosferica e delle forzanti termiche interne al canyon sul trasporto degli inquinanti negli urban street canyon.

In this work, PM10 samples previously subjected to thorough chemical speciation and receptor modelling, have been investigated for their bio-toxicity using an inhibition test based on bacterial luminescence modulation when in contact with airborne particulate samples. The variation of light emission intensity from a luminescent bacteria strain, the Photobacterium phosphoreum, is proposed as an efficient proxy for the quantification of bio-toxic effects induced by airborne particulate matter. PM10 samples characterized by definite levels of pollutants from the pertaining air shed were found to induce a decrease in the bacterial bioluminescence intensity, expressed as percentage of Inhibition Ratio (IR%). This behaviour suggests the decay of this energy-consuming activity because of a toxic effect. Cluster analysis on chemical composition and IR% data provides evidence of a statistically significant association between the adverse effects on living cells and the range of specific chemical species in PM10.

Traffic induced emissions have been commonly addressed as one of the major sources of air pollution in cities. The typical structures of European historical city centres, such as street canyons where the presence of densely built up areas limits the efficacy of atmospheric winds to disperse pollutants, enhance near ground concentrations. It is known that tree planting in urban street canyons influences pollutants dispersion and exchange with the free atmosphere by affecting wind ventilation at street and neighbourhood levels. Nevertheless, the actual quantification of tree influence depends on different and mutual interacting factors: synoptic meteorological conditions, wind stress at the top of the canyon, geometry of the street canyon, morphology of the neighbourhood and vegetation type. Within the recently EU-funded H2020 project iSCAPE (www.iscapeproject.eu), two intensive experimental campaigns (summer 2017 and winter 2018) have been conducted in two different urban street canyons in the city of Bologna (IT) with the aim of quantifying the impact of vegetation (two lines of trees at the edge of both sides of the road) on the street canyon in mitigating pollutant concentrations within the urban environment. Specifically, multi-levels sonic anemometers coupled with thermo-hygrometer data, as well as high resolution pollutant concentrations of several compounds (e.g. NOx, CO, PMx), have been used to quantify near surface pollutant dispersion using ventilation mechanisms in both vegetated and non-vegetated street canyons. New ventilation parameters, based on turbulent fluxes and evaluated during non-synoptic conditions, have been developed to explain the pollutant distribution under different wind directions and tree crown characteristics (i.e. porosity). Results are sought for extension to other European cities that are characterized by low synoptic conditions and similar morphological structures.

The Horizon H2020 iSCAPE (“Improving the Smart Control of Air Pollution in Europe”, GA No. 689954; www.iscapeproject.eu) project aims to study the interactions between urban climate and atmospheric pollution in some European cities. The city of Bologna was selected as pilot city due to its strategical location within the Po Valley, a recognized hot-spot in terms of air quality and climate change. The whole Po Valley is also characterized by high population density and heavily busy areas. During wintertime, poor ventilation conditions, strong thermal inversions and atmospheric pollution build-up frequently favors the formation of fogs in this region, even though fog events in the city of Bologna fog events are not as frequent as elsewhere in this region, where however they tend to occur less and less frequently. Two Optical Particle Counters were deployed within the winter 2018 intensive experimental campaign carried out in two different street canyons (Marconi and Laura Bassi Veratti Sts.) located in the city of Bologna, characterized by the same North-South geographical orientation and similar traffic volumes, but different geometric structures and presence of vegetation: in fact, while Laura Bassi Veratti St. presents a tree line along both sides of the street, vegetation is almost absent in Marconi St. This work presents the comparison between particle size distributions collected at the two experimental sites, as well as the influence of different synoptic meteorological conditions (clear sky, rain, snow) on particles number densities.