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Le autrici sviluppano alcune riflessioni relative a una esperienza pluriennale di applicazione della metodologia di home visiting nella fascia 0-3 anni, sperimentata anche in casi per i quali si è verificato un intervento del tribunale per i minorenni. La cura nella costruzione dell'alleanza e nel potenziamento delle risorse presenti, l'interazione sistematica con tutte le figure professionali e i servizi coinvolti, l'attenzione alla delicatezza della fase di sviluppo, sono elementi importanti per il buon esito degli interventi sia nei contesti spontanei sia in quelli in tutela. Viene descritto il ruolo dell'operatrice di home visiting in funzione della collaborazione della famiglia e della possibilità di rendere più flessibili le rappresentazioni reciproche fra famiglie e servizi.

Chemical mass balance modeling (CMB) was applied to determine the PM10 sources and their contributions. PM10 samples were collected in Lecce (40.338N, 18.108E, a town of South Italy), during two monitoring campaigns performed on July 2005 and February 2006. Nine source profiles and average mass concentration of the following chemical parameters: elemental carbon (EC), organic carbon (OC), chlorine (Cl-), nitrate (NO3-), sulfate (SO42-), sodium (Na+), ammonium (NH4+), potassium (K+), magnesium (Mg2+), calcium (Ca2+), aluminum (Al), silicon (Si), titanium (Ti), vanadium (V), manganese (Mn), iron (Fe), copper (Cu), lead (Pb), and zinc (Zn) were used to run the CMB model. The results obtained by application of CMB8.2 are shown. The contributions to PM10 show that dominant contributor was traffic with 37% followed by petroleum industry with 19% and field burning with 16%. Minor source contributions were marine aerosol (1%), ammonium sulfate production (4%), ammonium nitrate production (11%), oil-fired power plant (0.1%), gypsum handling (10%) and crustal (2%). Moreover, the Absolute Principal Component Scores (APCS) model was applied to the PM10 samples collected in order to find a correlation between the two source profile sets. With APCS model five source profiles were found and a good correlation (correlation coefficient bigger than 0.8) between crustal, marine, industrial profiles of CMB model and the corresponding ones of APCS model was found.

From previous investigations a low antibody titre and a prolonged viremia in non-vaccinated compared to vaccinated gilts revealed to be the higher risk factor associated to fetus infection in conventional animals inseminated with PCV2 spiked semen. A trial was performed to compare antibody titres, viremia, fetuses and fetal membranes/fluids samples PCV2 positivity in four groups of conventional gilts: 6 vaccinated with a commercial inactivated PCV2 vaccine (VAI), 6 vaccinated with a commercial vaccine based on a ORF2 capsid protein expressed in a baculovirus system and licensed for use in piglets (VBI), 6 non vaccinated (NVI) and 3 non-vaccinated and non-infected controls (CTR). Both types of vaccines were administered in gilts at 120 and 150 days of life. All animals received Regumate® for 18 days followed by an estrus syncronization and superovulation protocol. VAI, VBI and NVI groups were inseminated with a double (24 hrs apart) dose of PCV2 negative semen spiked with a PCV2b strain isolated in a PMWS outbreak in Italy. CTR gilts were fecundated with a double dose of PCV2 free semen. PCV2 in tissues was assessed and quantified by real time PCR. In the VAI group 4 out of 6 gilts were pregnant, in VBI 3 out of 6, in NVI 3 out of 6 and in CTR 2 out of 3, from which were collected 25, 19, 33 and 20 fetuses, respectively and corresponding placenta membranes and amniotic fluid. No differences in antibody titres nor viremia were revealed among groups during the trial. CTR showed the significantly (P

Introduction: In human medicine, chronic expanding hematoma (CEH) is a slow-growing reactive lesion, often associated with trauma or surgery that can mimic soft tissue sarcoma (STS). Canine CEH has been reported in puppies with history of injection or trauma at the site of the lesion. Materials and methods: hematoxylin ad eosin stained sections of canine subcutaneous CEH were examined and histological findings were compared with 3 cases of injection-type panniculitis. Anamnesis and follow up were collected. Results: 6 cases were collected. Lesions measured between 3 and 20 cm and were located on ischial tuberosity (2/6), flank (2/6), neck and shoulder. Histology evidenced a central cavity surrounded by a three-layered capsule including an internal layer of immature granulation tissue, an intermediate layer with perpendicularly oriented vessels, and an external fibrous layer infiltrating the adjacent tissues. After surgery 3 cases recurred and 3 had delayed healing. Three cases of injection-type panniculitis evidenced similar features with a thinner capsule and less evident layering. Conclusions: Based on these findings CEH seems to represent an unusual evolution of necrotizing panniculitis, that can undergo post-surgical complication, and have to be differentiated from STS. Introduction: Chronic expanding haematoma (CEH) is a slowgrowing reactive lesion that can mimic soft tissue sarcoma (STS) and that is associated with trauma or surgery in man. CEH has been reported in dogs following injection or trauma. Materials and Methods: Six cases of canine CEH were examined. Anamnesis and follow-up were collected. Tissues were processed routinely and stained. Microscopical findings in canine CEH were evaluated and compared with three cases of injection-type panniculitis (ITP). Results: CEHs were located on the ischial tuberosity (2/6), flank (2/ 6), neck and shoulder and ranged from 3 to 20 cm in diameter. Histology revealed a central cavity, containing fibrin and erythrocytes, surrounded by a multilayered capsule composed of an internal band of immature granulation tissue, an intermediate layer of perpendicularly oriented vessels and an external fibrous layer infiltrating adjacent tissues. After surgery, three cases recurred and three had delayed healing. Three cases of ITP lacked prominent layering, had a thinner capsule and mild inflammation. Conclusions: CEH may represent an uncommon evolution of necrotizing panniculitis that can undergo post-surgical complications and, because of the infiltrative growth, may need to be differentiated from STS.

Polycyclic aromatic hydrocarbons (PAHs) are known to exert mutagenic and carcinogenic effects. Research on extracted organic matter (EOM) from environmental mixtures has indicated several mechanisms of intracellular damage in living organisms. The toxic effect of environmental pollutants is usually assessed on cell systems or in single species. We used the model organism Caenorhabditis elegans to compare the effect of synthetic PAHs with that of the EOM from environmental mixtures. The biological effect was measured by monitoring the expression level of some crucial genes, sensitive parameters of the organism's response. The results indicate the ability of C. elegans to counteract damage by mounting a stress-response only in the presence of EOM. On the other hand the exposure of C. elegans to a mixture of synthetic PAHs determines the silencing of the transcriptional machinery, thus preventing the synthesis of proteins that are important for both the damage repair mechanism and survival itself. The results strongly indicate that the study of environmental toxicant effects at the molecular level may provide information on their mechanism of action. Copyright © 2011 John Wiley & Sons, Ltd.

Chemical composition data (ionic fraction, carbonaceous compounds and Polycyclic Aromatic Hydrocarbons) for PM2.5 were acquired during 2005–2007 years by seasonal sampling campaigns performed at six urban sites in Apulia Region. In addition, an industrial site was considered. Discriminant Function Analysis, Principal Component Analysis and Absolute Principal Component Scores were applied to dataset in order to identify PM2.5 sources and to estimate their contributions to samples mass. Three main sources were obtained for the urban sites: combustion processes, natural sources and secondary particulate. Moreover, the application of Principal Component Analysis on chemical and meteorological data highlighted the influence of temperature and relative humidity on natural sources, and the relevance of pressure on secondary particulate content. In PM2.5, secondary particulate contributed on average with 78% to total mass, while combustion processes and natural sources accounted, respectively, 15% and 6.5% of the fine fraction mass. For this reason the secondary background should be taken into account in order to suggest the efficient abatement strategies to improve local air quality in South of Italy.

The chemical composition of PM10 and PM2.5 samples collected during two seasonal monitoring campaigns at residential, urban and industrial Apulia Region- sites was investigated. Ionic fraction, carbonaceous compounds and Polycyclic Aromatic Hydrocarbons were determined for all samples. High correlations among PM data collected in the investigated sites suggested the regional character of particulate matter. It was also confirmed by five days back trajectories analysis. Moreover, no significant seasonal trend in PM mass concentration was observed in the investigated sites. These results, relevant for the area under investigations, were not observed in the North of Italy and Europe and allow to conclude that PM10 and PM2.5 cannot be considered ‘good’ indicators for the evaluation of local anthropic contributions to air quality. On the contrary, the high levels of Polycyclic Aromatic Hydrocarbons found in Taranto sampling sites suggested that PAHs can be a better indicator for this purpose. This result is also relevant in order to weigh the importance of industrial area and to suggest right policy control to decision makers.

Some peak PM10 episodes, occurred during PM monitoring campaigns performed on October 2005 and February and June 2006 in Bari town, have been characterized. Moreover back trajectories of air masses and Principal Component Analyses were applied. Three of the peak PM10 episodes investigated were related to local emissions of primary pollutants during poor atmospheric dispersion conditions. The other two peak PM10 episodes considered are related with long range transport air masses toward Apulia region: in one case the chemical characterization and the back trajectories analysis indicate that high PM10 value detected is due to the Saharan dust advection in the Apulia region; in the other case air masses with different origin give rise to high PM10 value. Moreover PM10 daily mean concentrations, presented in this paper collected from January 2005 to August 2007 and obtained by automatic device in six stations of air quality monitoring networks in Bari territory, do not show a seasonal trend for PM10 concentrations, contrary to the PM10 trend shown in the towns of North Italy. This can be explained mostly considering that our region presents generally meteo-climatic conditions that favour pollutants dispersion.

The human activities in their various aspects cause a change in the natural air quality. This change results more marked in very populated and in high industrialized areas. Some pollutants emitted are typical of a particular activity. Each source of pollution is identified by its profile in the composition of the emissions in the environment. Multivariate receptor models can be used in order to apportion pollutants to the different sources assessing the contribution of each source to the total pollution. This paper deals with the application of Absolute Principal Component Scores (APCS) receptor model to data obtained from the automatic network of air quality monitoring in the city of Bari (South Italy). The parameters monitored by automatic networks, as bihourly values, are PM10, NOx, CO, Benzene, Toluene, Xilene. The data shown in this paper concerning 1 month almost of sampling in different monitoring stations of Bari Municipality during the period of time from January 2005 to April 2006. Moreover preliminary results obtained applying the APCS model to daily PM2.5 samples collected during SITECOS PRIN project are shown. The results concerning data collected in corso Cavour (Bari) during the month of October 2005. The results obtained by APCS receptor model seem to suggest a poor contribution of the “vehicular traffic source” and a relevant contribution of the “secondary particulate source” to particulate matter concentrations.

A method for the determination of Cu(II), Ni(II), Zn(II), Co(II), Fe(II), and Pd(II) at ppb/subppb levels by ion chromatography was developed, improving a previous work of the same authors. In order to lower the detection limits, the direct injection of a large sample volume (5 mL) and 4‐(2‐pyridylazo) resorcinol solution at pH 6, with hexadecylpyridinium chloride as the post‐column reagent were used. The obtained calibration curves were linear (for each metal R2≥0.99) with good reproducibility; the detection limits for Cu(II), Ni(II), Zn(II), Co(II), Fe(II), and Pd(II) were 1.1, 0.46, 39, 0.18, 4.5, and 1.7 ppb, respectively.

L’ematoma cronico espansivo (ECE) è una lesione reattiva descritta nell’uomo e caratterizzata da crescita lenta e progressiva, che può mimare il sarcoma dei tessuti molli, e talvolta secondaria a trauma o chirurgia. L’ECE è stato segnalato anche nel cane, in soggetti giovani, a seguito di iniezione o trauma. In questo studio sono stati esaminati 6 casi di ECE in cani adulti. I tessuti sono stati processati e colorati secondo le tecniche di routine e sono stati raccolti i dati anamnestici e di follow-up. Le caratteristiche istologiche delle lesioni sono state comparate con 3 casi di pannicolite secondaria ad inoculo o sospetta tale. Gli ECE erano localizzati sulla tuberosità ischiatica (2/6), fianco (2/6), collo e spalla, con diametro variabile da 3 a 20 cm. All’istologia si evidenziava una cavità centrale, contenente fibrina ed eritrociti, circondata da una capsula pluristratificata composta da uno strato interno costituito da tessuto di granulazione immaturo, uno strato intermedio composto da vasi orientati perpendicolarmente alla cavità centrale, ed uno strato fibroso esterno che infiltrava i tessuti adiacenti. Dopo la chirurgia, 3 casi hanno presentato recidiva e in 3 casi si è avuta guarigione rallentata. Nei 3 casi di pannicolite secondaria ad inoculo la capsula era più sottile, la stratificazione meno evidente, ed era infiltrata da una lieve infiammazione. Sulla base dei dati raccolti, l’ECE potrebbe rappresentare un’evoluzione non comune della pannicolite necrotizzante che può andare incontro a complicazioni post-chirurgiche e, dato il suo carattere infiltrante, deve essere differenziata da un sarcoma dei tessuti molli.

Urban particulate matter (PM) can affect green plants either via deposition on the above-ground biomass, where the contaminants can penetrate the leaf surface, or indirectly via soil-root interaction. In our investigation, a model experiment was carried out to demonstrate the direct effect of PM on tomato (Solanum lycopersicum L.) plant growth. A monitoring campaign of PM10 was conducted at an urban background site of Canosa (Apulia, Southern Italy) in four different days (1, 2, 3, 4). PM10 samples were collected for 24 hours on quartz fiber filter. The filters were then cut into two parts, one of which was used for the chemical characterization of the PM10 and one for the growth of tomato. Organic and elemental carbon and polycyclic aromatic hydrocarbons (PAHs) content were analysed for all the tested filters. Tomato plants were grown for 18 days directly on filters absorbed with PM10. The germination rate of tomato seeds and some parameters of seedlings primary growth of this plant species (length of root and shoot, their fresh weight and content of photosynthetic pigments in shoot) were used as laboratory indicators of phytotoxicity. Substantial differences were found in the growth of root apparatus respect to that of control plants. A significant decrease of primary root elongation, a large amount of secondary roots and a decrease in plant and root weights were found. To assess if the direct exposition of roots to PM10 induced an oxidative stress, reactive oxygen species (ROS) concentration was evaluated by measuring the fluorescence arising from oxidation of DCFH-DA in both control and treated roots. Quantitative analysis of ROS indicated that an oxidative burst in response to abiotic stress occurred in roots directly grown on PM10, whose detrimental effect was also confirmed by the findings on chlorophyll content and chlorophyll-to-carotenoid ratio.

This study shows the direct effect of atmospheric particulate matter on plant growth. Tomato ( Solanum lycopersicum L.) plants were grown for 18 d directly on PM10 collected on quartz fiber filters. Organic and elemental carbon and polycyclic aromatic hydrocarbons (PAHs) contents were analyzed on all the tested filters. The toxicity indicators (i.e., seed germination, root elongation, shoot and/or fresh root weight, chlorophyll and carotenoids content) were quantified to study the negative and/or positive effects in the plants via root uptake. Substantial differences were found in the growth of the root apparatus with respect to that of the control plants. A 17–58% decrease of primary root elongation, a large amount of secondary roots and a decrease in shoot (32%) and root (53–70%) weights were found. Quantitative analysis of the reactive oxygen species (ROS) indicated that an oxidative burst in response to abiotic stress occurred in roots directly grown on PM10, and this detrimental effect was also confirmed by the findings on the chlorophyll content and chlorophyll-to-carotenoid ratio.

PM concentrations are measured in three sites of the North of Italy: an urban (Milan-MI; 45°31’19”N, 9°12’46”E), rural (Oasi Bine-OB; 45°13’33’’N, 10°45’00’’E) and high altitude remote site (Alpe San Colombano-ASC, m.2280 asl; 46°46’11’’N 10°30’19’’E). Daily PM2.5 samples are collected by using a low volume gravimetric sampler (38,33 l/min). Samples are chemical characterised for the main inorganic ions (Na+, K+, Ca++, Mg++ NH4+ , F-, Cl-, NO3-, SO42= ,by IC) and carbonaceus fraction (EC and OC, by TOT). Chemical speciation of the organic carbon is focuesed on certain compound classes. Low-molecular weight (C2-C7) carboxylic acids (mono and dicarboxylic acid) are analysed by IC; n-alkanes (C20-C32) and polycyclic aromatic hydrocarbons (PAHs) are analysed by GC-MS;. Carboxylic acids are associated to atmospheric oxidation and they are known to be an important contribution to secondary organic aersol (SOA). The n-alkane pattern is investigated through the carbon precerence index (CPI) and % Cwax to evaluate the contribution of vegetation during different seasons. PAHs concentrations and relative mass contribution to fine PM are a tracer for contribution of combustion source in the three sites. During winter, when high altitude sites are above the mixing boundary layer of the polluted plan, PAHs mass contribution to PM2.5 at ASC site is up to 10 time lower compared with MI site

Il particolato atmosferico (PM) è costituito da una miscela di particelle solide e liquide aventi origine primaria e secondaria. La composizione chimica del PM varia notevolmente e dipende da fattori quali le fonti di combustione, il clima, la stagione e il tipo di inquinamento. Il PM è costituito da particelle di materiale carbonioso, da composti organici volatili o semi-volatili adsorbiti sulle particelle carboniose, da ioni, metalli di transizione, materiali di origine biologica e minerali. Se classificato in base alla sua granulometria, il PM è distinto in "coarse" e "fine" e le due frazioni comprendono le particelle aventi rispettivamente diametro aerodinamico superiore e inferiore ai 2.5 µm (PM2.5). Il particolato fine ed ultrafine è quello maggiormente associato agli effetti negativi sulla salute umana perché può raggiungere le vie respiratorie più profonde fino ad arrivare agli alveoli polmonari, tuttavia non si può escludere la pericolosità delle particelle, caratterizzate da diametro aerodinamico inferiore ai 10 µm (PM10). In generale gli effetti del PM sui diversi organismi variano a seconda della concentrazione in atmosfera, delle loro caratteristiche fisicochimiche e dal tempo di esposizione degli organismi a tale inquinante. In questo lavoro è stata studiata l'interazione del PM10 con tre differenti organismi. Estratti organici di PM10 (EOM) e soluzioni standard di Idrocarburi Policiclici Aromatici (IPA) sono stati testati sugli organismi modello Rhodobacter (R.) sphaeroides 2.4.1 e Caenorhabditis elegans. Campioni di PM10 raccolti su filtri in fibra di quarzo sono stati utilizzati come supporto per la crescita di piantine di pomodoro (Solanum lycopersicon). I risultati ottenuti indicano che gli effetti degli estratti organici di particolato atmosferico sono fortemente dipendenti dal tipo di organismo che ad essi viene esposto. Mentre il C. elegans subisce un effetto negativo, con una mortalità fino al 50% a partire dal secondo stadio larvale (Liuzzi et al, 2012), l'esposizione di R. sphaeroides agli EOM non mostra effetti dannosi, eccettuata una contenuta diminuzione della velocità di crescita. Le piante esposte al particolato mostrano un evidente cambiamento nella morfologia dell'apparato radicale e stress ossidativo rappresentato da un aumento del contenuto di radicali dell'ossigeno (ROS).

Particulate matter (PM) is a very complex mixture of many inorganic and organic compounds of primary and secondary origin and this is the main reason why the desired reduction of its concentration and the identification of its many sources constitute a very difficult task. It is widely recognised that atmospheric particles are responsible for adverse effects on the ecosystem, the climate and the health of human beings (Pope & Dockery, 2006). Epidemiological studies have shown a consistent association of the mass concentration of urban air thoracic particles (PM10 particles with an aerodynamic diameter smaller than 10 μm), and its sub-fraction fine particles (PM2.5 particles with an aerodynamic diameter smaller than 2.5 μm), with mortality and morbidity among cardio-respiratory patients (WHO, 2005). Recent studies indicate that PM10 is associated to respiratory responses while PM2.5 may contribute to cardiovascular diseases (Wyzga, 2002). The chemical characteristics of the particulate fractions and biological mechanisms responsible for these adverse health effects are still unknown as well as the aerosol parameters (mass, particle size, surface area, etc) involved in the health impacts (Hauck et al., 2004). In addition, there is an indication that the increase in the atmospheric aerosol burden delays the global warming attributed to the increase in greenhouse gasses (GHG: CO2, CH4, N2O, halocarbons). Whether the increase in GHGs since preindustrial times is producing a warming of 2.3 Wm,anthropogenic contributions to aerosols (primarily sulphate, organic carbon, black carbon, nitrate and dust) together produce a cooling effect, with a total direct radiative forcing of -0.5 Wm2 and an indirect cloud albedo forcing of -0.7 Wm (IPCC, 2007). In recent years many studies have been carried out to determine the chemical composition of atmospheric particulate matter (Vecchi et al., 2007). Most of these studies were devoted to the identification of the main particle sources, with the purpose to identify viable strategies for their reduction. In this chapter we focus the attention mostly on the ionic component of

Le recenti politiche europee sono rivolte alla valutazione dei possibili effetti nocivi di miscele complesse di sostanze chimiche (REACH) utilizzando metodi che escludano l'impiego di vertebrati. In questa relazione vengono illustrati gli effetti di tossicità di particolato atmosferico su due organismi modello: Caenorhabditis elegans e Rhodobacter sphaeroides. I campioni di particolato sono stati raccolti in due siti della città di Bari e da questi sono stati estratti i composti organici solubili in acetone ed esano. I risultati ottenuti da tali test hanno mostrato un effetto tossico sul nematode C. elegans, mentre nel caso del batterio fotosintetico gli effetti sono limitati ad una leggera diminuzione della velocità di crescita. Gli sviluppi futuri di questo studio saranno orientati verso frazioni granulometriche quali PM1 e nano particolato e verso altri sistemi modello.

A

Polycyclic aromatic hydrocarbons (PAHs) are known to exert mutagenic and carcinogenic effects. Research on extracted organic matter (EOM) from environmental mixtures has indicated several mechanisms of intracellular damage in living organisms. The toxic effect of environmental pollutants is usually assessed on cell systems or in single species. We used the model organism Caenorhabditis elegans to compare the effect of synthetic PAHs with that of the EOM from environmental mixtures. The biological effect was measured by monitoring the expression level of some crucial genes, sensitive parameters of the organism's response. The results indicate the ability of C. elegans to counteract damage by mounting a stress-response only in the presence of EOM. On the other hand the exposure of C. elegans to a mixture of synthetic PAHs determines the silencing of the transcriptional machinery, thus preventing the synthesis of proteins that are important for both the damage repair mechanism and survival itself. The results strongly indicate that the study of environmental toxicant effects at the molecular level may provide information on their mechanism of action.

The PM2.5 and PM10 fractions were simultaneously collected in three sites of the Bari territory (South-East Italy) during winter and summer sampling campaigns. The ionic components and the carbon fractions of the PM samples were determined. The Principal Component Analysis and Absolute Principal Component Scores of the dataset allowed to identify similar PM sources in the two PM fractions: organic and inorganic secondary compounds, local and diffuse combustion processes, calcium carbonate, sea salt. While secondary and combustion compounds were mainly in PM2.5, primary and natural species were prevalent in coarse PM. Seasonal and site-specific differences were investigated.

In this preliminary work the toxic activity of Polycyclic Aromatic Hydrocarbons (PAHs) mix standard solutions was studied using "Caenorhabditis elegans" (C. eleguns) as system for biological studies.The nematode cultures were exposed for 3 days to 0.01, 0.1 and 1 ppb (nglml) of PAH Mix and even if no morphological alterations were observed on the C. elegans populations, the lethality was about 50% when the PAHs concentrations were equal to 0.1 and 1 ppb. Moreover, the lethality test was performed using an organic extract from a PM10 sample.When the gene expression pattern was analyzed a down regulation of the expression on all the genes considered was observed, indicating that the genotoxic effect was scattered on the entire transcription mechanism.These results indicate that "C, elegans" is an effective model for the study of PAHs toxicity; future studies will be oriented to the toxicity evaluation of extracts from PM2.5 and PM10 samples collected in Apulia cities.

Some peak PM10 episodes, occurred during PM monitoring campaigns performed on October 2005 and February and June 2006 in Bari town, have been characterized. Moreover back trajectories of air masses and Principal Component Analyses were applied. Three of the peak PM10 episodes investigated were related to local emissions of primary pollutants during poor atmospheric dispersion conditions. The other two peak PM10 episodes considered are related with long range transport air masses toward Apulia region: in one case the chemical characterization and the back trajectories analysis indicate that high PM10 value detected is due to the Saharan dust advection in the Apulia region; in the other case air masses with different origin give rise to high PM10 value. Moreover PM10 daily mean concentrations, presented in this paper collected from January 2005 to August 2007 and obtained by automatic device in six stations of air quality monitoring networks in Bari territory, do not show a seasonal trend for PM10 concentrations, contrary to the PM10 trend shown in the towns of North Italy. This can be explained mostly considering that our region presents generally meteo-climatic conditions that favour pollutants dispersion.

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