The performance of different detrending methods in removing the low-frequencycontribution to the calculation of turbulent fluxes is investigated. The detrending methodsare applied to the calculation of turbulent fluxes of different scalars (temperature, ultrafineparticle number concentration, carbon dioxide and water vapour concentration), collectedat two different measurement sites: one urban and one suburban. We test and compare theperformance of filtering methodologies frequently used in real-time and automated procedures(mean removal, linear detrending, running mean, autoregressive filter) with the resultsobtained from a reference method, which is a spectral filter based on the Fourier decompositionof the time series. In general, the largest differences are found in the comparison betweenthe reference and the mean-removal procedures. The linear detrending and running-meanprocedures produce comparable results, and turbulent-flux estimations in better agreementwith the reference procedure than those obtained with the mean-removal procedure. Thebest agreement between the running mean and the spectral filter is achieved with a timewindow of 15min at both sites. For all the variables studied, average fluxes calculated usingthe autoregressive filter are increasingly overestimated for a time constant ? compared withthat obtained using the spectral filter. The minimization of the difference between the twodetrending methods is achieved with a time constant of 120 s, with similar behaviour observedat both sites.

The evaluation of the contribution of large coal-fired thermo-electrical power plant to atmospheric particulate matter (PM) concentrations is important for evaluation of risks to human health and potential influence on climate. The application of receptor models, based on chemical composition of PM, is not straightforward because the chemical profile of this kind of source is generally loaded with Si and Al and it is collinear with the profile of crustal particles (Bi et al, 2007).In this work a methodology, based on Positive Matrix Factorization (PMF) receptor model and Si/Al diagnostic ratio, has been developed to discriminate the coal-fired power plant contribution from the crustal contribution. Measurements were taken in six different campaigns from February 2010 to August 2014, collecting in total 347 PM10 daily samples at three sites having different characteristics: urban, urban background, and rural sites. These were located between 2.8 and 5.8 km from the Torrevaldaliga Nord power plant (indicated as TVN). The area studied was in the municipality of Civitavecchia in Central Italy. PM10 samples were collected simultaneously on quartz and polycarbonate substrates. Quartz filters were used for determination of OC/EC concentrations by thermo-optical method (Sunset instrument, NIOSH 5040 method). Polycarbonate filters were used for the determination of water soluble ions concentrations (NH4+, Ca2+, Mg2+, Na+, K+, Mg2+, SO42-, NO3-, Cl-), using high performances ion chromatography (HPIC), and of main metals concentrations (Si, Al, Ti, V, Mn, Fe, Ni, Cu, Zn, Br), using Energy Dispersive X-ray Fluorescence (ED-XRF).Nine sources were identified using PMF5.0 model and their contributions are shown in Figure 1. Results showed an average primary contribution of the power plant of 2% (±0.8%) in the studied area, with limited differences at the three sites analysed.The robustness of the methodology was tested inter-comparing the results obtained with two other independent evaluations of TVN power contribution: the first using the Chemical Mass Balance (CMB) receptor model and the second correlating the daily Si-Al factor/source contributions of PMF with wind directions and CALPUFF/CALMET dispersion model results. Results showed a good comparability within experimental uncertainties. The contribution of the power plant to secondary ammonium sulphate was investigated using an approach that integrates dispersion model and receptor models results (PMF and CMB). The contribution of the coal-fired power plant to secondary ammonium sulphate in PM10 were between 1.2% and 1.8% of PM10 at the three sites with an average of 1.5% of PM10 (±0.3%). The other sources apportioned were marine, nitrate, sulphate, crustal, road traffic, resuspended dust, biomass burning, and harbour-industrial. The comparison between the source contributions estimated with PMF and CMB showed a good agreement for all the source with the exclusion of traffic source that was overestima

The performance and the uncertainty of receptor models (RMs) were assessed in intercomparison exercises employing real-world and synthetic input datasets. To that end, the results obtained by different practitioners using ten different RMs were compared with a reference. In order to explain the differences in the performances and uncertainties of the different approaches, the apportioned mass, the number of sources, the chemical profiles, the contribution-to-species and the time trends of the sources were all evaluated using the methodology described in Belis et al. (2015). In this study, 87% of the 344 source contribution estimates (SCEs) reported by participants in 47 different source apportionment model results met the 50% standard uncertainty quality objective established for the performance test. In addition, 68% of the SCE uncertainties reported in the results were coherent with the analytical uncertainties in the input data. The most used models, EPA-PMF v.3, PMF2 and EPA-CMB 8.2, presented quite satisfactory performances in the estimation of SCEs while unconstrained models, that do not account for the uncertainty in the input data (e.g. APCS and FA-MLRA), showed below average performance. Sources with well-defined chemical profiles and seasonal time trends, that make appreciable contributions (>10%), were those better quantified by the models while those with contributions to the PM mass close to 1% represented a challenge. The results of the assessment indicate that RMs are capable of estimating the contribution of the major pollution source categories over a given time window with a level of accuracy that is in line with the needs of air quality management.

A measurement campaign was performed between 04/03/2013 and 17/07/2013 for simultaneous collection of PM2.5 samples in two nearby sites in southeastern Italy: an urban site and an urban background site. PM2.5 at the two sites were similar; however, the chemical composition and the contributions of the main sources were significantly different. The coefficients of divergence (CODs) showed spatial heterogeneity of EC (higher at the urban site because of traffic emissions) and of all metals. Major ions (NH4+, Na+, and SO42 -) and OC had low CODs, suggesting a homogeneous distribution of sea spray, secondary sulfate, and secondary organic matter (SOM = 1.6*OCsec, where OCsec is the secondary OC). The strong correlations between Na+ and Cl-, and the low Cl-/Na+ ratios, suggested the presence of aged sea spray with chloride depletion (about 79% of Cl-) and formation of sodium nitrate at both sites. In both sites, the non-sea-salt sulfate was about 97% of sulfate, and the strong correlation between SO42 - and NH4+ indicated that ammonium was present as ammonium sulfate. However, during advection of Saharan Dust, calcium sulfate was present rather than ammonium sulfate. The source apportionment was performed using the Positive Matrix Factorization comparing outputs of model EPA PMF 3.0 and 5.0 version. Six aerosol sources were identified at both sites: traffic, biomass burning, crustal-resuspended dust, secondary nitrate, marine aerosol, and secondary sulfate. The PMF3.0 model was not completely able, in these sites, to separate marine contribution from secondary nitrate and secondary sulfate from OC, underestimating the marine contribution and overestimating the secondary sulfate with respect to stoichiometric calculations. The application of specific constraints on PMF5.0 provided cleaner profiles, improving the comparison with stoichiometric calculations. The seasonal trends revealed larger biomass burning contributions during the cold period at both sites due to domestic heating emissions added to those of agricultural practices. Secondary aerosol represented about 50% of PM2.5 at both sites (about 1/3 due to SOM), with a slight increase during the cold season, probably due to the formation of secondary OC via gas-to-particle conversion. Secondary inorganic aerosol (nitrate plus sulfate) did not show seasonal trend because the reduction of nitrate due to thermal instability during the warm season was compensated by an almost equivalent increase of sulfate.

Source apportionment of aerosol is an important approach to investigate aerosol formation and transformation processes as well as to assess appropriate mitigation strategies and to investigate causes of non-compliance with air quality standards (Directive 2008/50/CE). Receptor models (RMs) based on chemical composition of aerosol measured at specific sites are a useful, and widely used, tool to perform source apportionment. However, an analysis of available studies in the scientific literature reveals heterogeneities in the approaches used, in terms of "working variables" such as the number of samples in the dataset and the number of chemical species used as well as in the modeling tools used. In this work, an inter-comparison of PM10 source apportionment results obtained at three European measurement sites is presented, using two receptor models: principal component analysis coupled with multi-linear regression analysis (PCA-MLRA) and positive matrix factorization (PMF). The inter-comparison focuses on source identification, quantification of source contribution to PM10, robustness of the results, and how these are influenced by the number of chemical species available in the datasets. Results show very similar component/factor profiles identified by PCA and PMF, with some discrepancies in the number of factors. The PMF model appears to be more suitable to separate secondary sulfate and secondary nitrate with respect to PCA at least in the datasets analyzed. Further, some difficulties have been observed with PCA in separating industrial and heavy oil combustion contributions. Commonly at all sites, the crustal contributions found with PCA were larger than those found with PMF, and the secondary inorganic aerosol contributions found by PCA were lower than those found by PMF. Site-dependent differences were also observed for traffic and marine contributions. The inter-comparison of source apportionment performed on complete datasets (using the full range of available chemical species) and incomplete datasets (with reduced number of chemical species) allowed to investigate the sensitivity of source apportionment (SA) results to the working variables used in the RMs. Results show that, at both sites, the profiles and the contributions of the different sources calculated with PMF are comparable within the estimated uncertainties indicating a good stability and robustness of PMF results. In contrast, PCA outputs are more sensitive to the chemical species present in the datasets. In PCA, the crustal contributions are higher in the incomplete datasets and the traffic contributions are significantly lower for incomplete datasets.

La relazione tra formazione di nuove particelle e parametri micrometeorologici e meteorologici è stata esaminata attraverso una campagna di misura nel Luglio 2010 in un sito di fondo urbano a Lecce. I dati mostrano frequenti eventi di picco nella concentrazione numerica di particelle che sono spesso associati ad eventi diurni (in condizione di intenso irraggiamento) di formazione e crescita di nanoparticelle. E' stato svolto uno studio per valutare l'influenza di tali eventi sulla distribuzione dimensionale delle particelle, sui diametri medi e mediani del particolato atmosferico, sul flusso turbolento verticale (che caratterizza lo scambio atmosfera-superficie) e sul gradiente verticale di concentrazione in prossimità del suolo.

In this work, the inorganic chemical profiles of soil samples collected at different sites in the Salentum peninsula (Italy, Apulia region) are discussed. The samples were re-suspended in the laboratory, for PM10 sampling, using a ventilated wooden chamber and were then chemically analysed measuring the abundances of 17 elements. Different land use categories of soils (olive grove, arable land, vineyards, sand, and urban dust) were included in the 50 samples analysed: 45 collected in background areas and five collected in the urban area of Lecce. The objectives were to compare the chemical profiles of raw soil and re-suspended PM10 for different crustal sources and to estimate the potential improvements in the calculation of the enrichment factors of atmospheric PM10. The variability of elemental abundances in samples of the same category of soil collected in different zones was of the same order of magnitude as the differences observed between the various categories of soil. This allows the calculation of a weighted average composition of soil and urban dust and the corresponding weighted average composition of re-suspended PM10. In re-suspended PM10 from average background soil, all of the elements except Ca, Na, K and V have larger abundances with respect to raw soil. In urban dust, this is limited to Ca, V and Mg. The crustal enrichment factors (EFs) of atmospheric PM10 were evaluated by considering different reference elements and different reference tables. Results indicated that it is possible to apply a two-threshold (S-1 and S-2) scheme for the interpretation of EF, with thresholds derived from uncertainty in soil categories and from the choice of the reference element. A specific element is likely of crustal origin if EF < S-1 and likely of anthropogenic origin if EF > S-2. Between the two thresholds, the element can be considered of mixed origin. The thresholds vary according to the geological composition used in the evaluation of EF. If the average composition of local re-suspended soils is used, the thresholds are S-1 = 2 and S-2 = 4. If raw soil is used, the thresholds become S-1 = 5 and S-2 = 10. If the average upper-crust composition from literature data is used, the thresholds further increase to S-1 = 10 and S-2 = 20. (C) 2012 Elsevier Ltd. All rights reserved.

The evaluation of the contribution of coal-fired thermo-electrical power plants to particulate matter (PM) is important for environmental management, for evaluation of health risks, and for its potential influence on climate. The application of receptor models, based on chemical composition of PM, is not straightforward because the chemical profile of this source is loaded with Si and Al and it is collinear with the profile of crustal particles. In this work, a new methodology, based on Positive Matrix Factorization (PMF) receptor model and Si/Al diagnostic ratio, specifically developed to discriminate the coal-fired power plant contribution from the crustal contribution is discussed. The methodology was applied to daily PM10 samples collected in central Italy in proximity of a large coal-fired power plant. Samples were simultaneously collected at three sites between 2.8 and 5.8 km from the power plant: an urban site, an urban background site, and a rural site. Chemical characterization included OC/EC concentrations, by thermo-optical method, ions concentrations (NH4+, Ca2+, Mg2+, Na+, K+, Mg2+, SO42-, NO3-, Cl-), by high performances ion chromatography, and metals concentrations (Si, Al, Ti, V, Mn, Fe, Ni, Cu, Zn, Br), by Energy dispersive X-ray Fluorescence (ED-XRF). Results showed an average primary contribution of the power plant of 2% (±1%) in the area studied, with limited differences between the sites. Robustness of the methodology was tested inter-comparing the results with two independent evaluations: the first obtained using the Chemical Mass Balance (CMB) receptor model and the second correlating the Si-Al factor/source contribution of PMF with wind directions and Calpuff/Calmet dispersion model results. The contribution of the power plant to secondary ammonium sulphate was investigated using an approach that integrates dispersion model results and the receptor models (PMF and CMB), a sulphate contribution of 1.5% of PM10 (±0.3%) as average of the three sites was observed.

Surface chemical composition of atmospheric particles plays an important role in determining reactivity and optical properties of aerosol than influencing its role in climate forcing (Ramanathan et al., 2001) and in the human health effects (Klejnowski et al. 2012, Kendall et al., 2001). In addition, surface composition is strongly depending on the sources/formation processes and on the size of particles. Particle modification in terms of composition and structure may also lead to multiple evolution pathways. There are many methods and instruments available for studying different properties of the surface of airborne Particulate Matter (PM), in terms of morphological and elemental composition (Coury and Dillner, 2008; Kirchner et al., 2003). X-ray photoelectron spectroscopy (XPS) could be a suitable technique to simultaneously investigate surface composition of particles and chemical speciation of the main elements like for example C, S, N, Na, Cl, Ca, Si, Mg and other minor hetero-elements. In this communication we present a systematic XPS surface study of different size fractions of PM. The samples analysed have been collected in a background site in Lecce inside the University Campus at about 4 km SW of the Lecce town (SE of Italy, coordinates 40°20'N, 18°06'E), in modality "size-segregated", using a 10-stage cascade impactor with rotating collection plates having an inlet with a nominal cut-off at 18 mm and 10 stages (MOUDI II, 120R). Flow-rate: 30 l/min and 10 stages (S1 - S10) nominal 50% efficiency cut-off at 10, 5.6, 3.2, 1.8, 1.0, 0.56, 0.32, Collection time was 48 h. Ten series of samples (100 sampling substrates in total) were collected between February and June 2011 on Al substrates (47 mm disks).The averaged mass size distribution showed a bimodal shape were the Accumulation mode was characterized with an of PM10) and the Coarse mode with an MMD=4.4 ± 0.4 44 ± 4.7% del PM10). XPS analysis has been focused first on the systematic evaluation of surface chemical composition of different size-segregated particles, to investigate the variability of the chemical surface composition comparing the accumulation and the coarse modes of atmospheric particles, and on the comparison between the chemical information (element quantitative distribution and speciation) of the surface with bulk chemical composition of collected particles when useful to investigate the generation processes and the sources of collected particles. The high resolution XPS spectra allowed to distinguish different organic functional groups (C-C/C=C, -C-O, -C=O/-C(O)N, -C(O)O, CO3=) and to speciate the detectable hetero-elements, sulphur (SO4=, sulphone and sulphide compounds), nitrogen (NH4+, NO3-, NO2- and organic-nitrogen compounds), sodium (Na+) and chlorine (Cl-) species. Significant differences in particles belonging to accumulation and coarse modes were observed and correlated with the formation processes and the sources from which particles originated. The oxygen co

The study and monitoring of absorbing aerosol and greenhouses gas variability due to natural andanthropic emissions capture great attention in the scientific community to study air quality and toinvestigate different climate scenarios, in particular in the Mediterranean Basin that is an hot spot forclimate change. In order to strengthen the environmental observation system in the Southern ItalianConvergence Regions I-AMICA (Infrastructure of High Technology for Environmental and ClimateMonitoring), a three year Italian National Operative Program (PON) project co-founded by the EuropeanRegional Development Fund, is being developed. The project also aim to strengthen the environmentalmonitoring in the South of Italy adopting both stationary and mobile in-situ stations for aerosols andgreenhouses gases and remote sensors, such as Raman lidars and wind lidars for atmospheric profiling.This work is based on the first observations performed at two stations: Lecce, a urban backgroundstation in the Apulia region and Lamezia Terme a background station in Calabria region. Differences inconcentration levels and in physical properties of aerosol at the two stations will be investigated. Threecase studies of long-range transport of natural aerosol creating exceedances of Air Quality Standard(AQS) daily threshold for PM10 will be investigated showing that the simultaneous analysis in the twosites helps in identifying these events and in evaluating their impact on atmospheric aerosol concentrations.

Shipping is a growing transport sector representing a relevant share of atmospheric pollutantemissions at global scale. In the Mediterranean Sea, shipping affects air quality ofcoastal urban areas with potential hazardous effects on both human health and climate.The high number of different approaches for investigating this aspect limits the comparabilityof results. Furthermore, limited information regarding the inter-annual trends ofshipping impacts is available. In this work, an approach integrating emission inventory,numerical modelling (WRF-CAMx modelling system), and experimental measurementsat high and low temporal resolution is used to investigate air quality shipping impact inthe Adriatic/Ionian area focusing on four port-cities: Brindisi and Venice (Italy), Patras(Greece), and Rijeka (Croatia). Results showed shipping emissions of particulate matter(PM) and NOx comparable to road traffic emissions at all port-cities, with larger contributionsto local SO2 emissions. Contributions to PM2.5 ranged between 0.5% (Rijeka) and 7.4%(Brindisi), those to PM10 were between 0.3% (Rijeka) and 5.8% (Brindisi). Contributions toparticle number concentration (PNC) showed an impact 2-4 times larger with respect tothat on mass concentrations. Shipping impact on gaseous pollutants are larger than thoseto PM. The contribution to total polycyclic aromatic hydrocarbon (PAHs) concentrationswas 82% in Venice and 56% in Brindisi, with a different partition gas-particle because of differentmeteorological conditions. The inter-annual trends analysis showed the primarycontribution to PM concentrations decreasing, due to the implementation of the European legislation on the use of low-sulphur content fuels. This effect was not present on other pollutants like PAHs.

Emissions of atmospheric pollutants from shipping and harbour activities are a growing concern at International level and, specifically, in the Mediterranean area. The continuous increase of global trade and of harbour services made maritime transport a key contributor to atmospheric pollution. The objective of this work is to give a comparable assessment of the impact of ship traffic and harbour activities to atmospheric PM2.5 and particle number concentrations (PNC) in two important port-cities of the Adriatic Sea: Venice and Brindisi. In Venice area, measurements were taken in 2007, 2009 and 2012 during summer, when the tourist ship traffic is at maximum. In Brindisi, measurements were performed in summer 2012 and in summer 2014. The two harbours have significant differences in the typology of ship traffic as well as in the volume of traffic and in the layout and logistic organization that could influence the impact of pollutant emissions on nearby urban areas. High temporal resolution measurements, both for particle number and mass concentrations, were used for identification of single ship plumes and for quantitative statistical evaluation of primary contribution of ship emissions to atmospheric aerosol concentrations. Results show that, in 2012, the contribution of ships emissions to PM2.5 was 7.4 (±0.5) for Brindisi harbour and 3.5 (±1) for Venice harbour. The contribution to particle number concentration was 26 (±1) and 6 (±1), respectively, for Brindisi and Venice harbour. Results show that the ship traffic contribution increases when particle size decreases and it is significantly larger on particle number concentration with respect to PM2.5. The inter-annual trends of the impact of shipping to atmospheric particles concentrations were investigated in the two areas showing a decrease in Venice correlated with the use of low-sulphur content fuel.

Concentrations, size distributions and particle number vertical turbulent fluxes were measured by the eddy-covariance method at an urban background site in southeastern Italy during the summer. CO2/H2O concentrations and fluxes were also determined together with meteorological parameters. Time series show that particles could be divided into two size classes with negatively-correlated temporal trends in diurnal hours: nanoparticles (diameter D-p < 50 nm) and larger particles (D-p > 50 nm). Larger particles include part of the Aitken mode and the accumulation mode. Nanoparticles peaked in diurnal hours due to the presence of several days with nucleation events when particles D-p > 50 nm were at minimum concentrations. Nucleation increased diurnal total particle concentration by a factor of 2.5, reducing mean and median diameters from D-mean = 62.3 +/- 1.2 nm and D-median = 29.1 +/- 1.3 nm on non-event days to D-mean = 35.4 +/- 0.6 nm and D-median = 15.5 +/- 0.3 nm on event days. During nucleation events, particle deposition increased markedly (i.e., downward fluxes), but no significant changes in CO2 concentrations and fluxes were observed. This is compatible with new particle formation above the measurement height and a consequent net transport towards the surface. Correlation with meteorology shows that the formation of new particles is correlated with solar radiation and favored at high wind velocity.

The analysis reported in thiswork has been performed to characterise PM10concentrationmeasuredin an urban background site in Lecce (Apulia region, Italy). PM10 concentration and its inorganicchemical composition have been studied using three procedures: a qualitative analysis of thecorrelation coefficients between the different species and of the crustal enrichment factor; the clusteranalysis (CA) and the principal component analysis (PCA). The results of the three procedures are ingood agreement. The five groups identified by the CA correspond to the five principal componentsobtained with the PCA and they reflect the results qualitatively inferred using the two-speciescorrelation coefficients. The CA results helped in putting in evidence a correlation between Ni, V andsulphate that was less evident in the PCA. The relative abundance of V is larger with wind fromtheNNWdirectionswherethemain industrial sites of the region are located. This suggests the presence ofanthropogenic inorganic secondary aerosol generated by a common source of V and SO2 that arelikely the industrial releases and the ship emissions. The absolute PCA (APCA) allowed thequantitative apportionment of the five components observed: crustal matter (49.5%), secondaryinorganic aerosol (24.1%), marine aerosol (6.3%), traffic (16.5%), and industrial (2.1%). ObservedPM10 concentration clearly shows a seasonal pattern, opposite to the one observed in the northernand central Italy, with average PM10 larger in the warm season (spring and summer) with respect tothe cold season as a consequence of the increase of crustal matter contribution likely due to theintrusion of African dust. These intrusions are more frequent in the warm season and have aninfluence on daily PM10 concentrations variable between 6% and 120% in this site. Correlation withmeteorological data indicates that the more intense cases of intrusions of African dust happen withwind blowing from the SW direction. Average PM10 concentration decreases of about 23% duringprecipitation. The decrease ismainly due to the decrease in crustal matter contribution and secondaryinorganic aerosol. The sum of the other three sources is almost not changing during precipitation.

Number and mass particle concentrations and fluxes were measured, simultaneously with CO2 concentration and flux, in the urban area of Lecce (Italy). The measurements of the turbulent exchanges of atmospheric particles and gas were performed with an eddy-covariance station located near the busiest road of the town. For the smaller particles, the diurnal evolution of the particle number concentrations and fluxes shows a clear correlation with human activities, in particular vehicular traffic, which is the obvious candidate as the source of the two clear peaks in the CPC concentration in the morning and in the evening. The fluxes were upward for all the measurement period, even though small net deposition was observed for larger particles and during weekend. For the CPC, the correlation with the traffic daily pattern is extremely strong. The city is a continuous particle source. The data analysis seems also to suggest the presence of local urban nucleation events. CO2 and particle concentrations were larger at low wind velocity, instead, fluxes were larger at high wind velocity. This opposite behaviour suggests that the influence of local urban emissions is larger on fluxes with respect to concentrations. The average daily patterns of CO2 concentration show an overlap between biogenic cycle and urban emissions. Again, traffic appears to be the dominant source for fluxes and the urban area is a net source of CO2.

In this work the performances of three different tests widely used in scientific community for assessing turbulent flow stationarity have been tested and compared. The stationarity tests have been applied to turbulent fluxes of different scalars (temperature, carbon dioxide and water vapour concentration, ultrafine particle number concentration), collected over a wide range of surface roughness conditions, from almost smooth surfaces to surfaces with different degrees of complexity: suburban, urban and forested canopies. The application of the selected tests to the scalar and particle turbulent fluxes measured above the different experimental sites has frequently shown an ambiguous identification of non-stationarity in turbulent flux records, regardless of the surface conditions and of the transported quantity. The potential impact of surface characteristics, transported scalar, atmospheric stratification and micrometeorological conditions on test performances has been investigated. Finally a new operative stationarity index obtained by the combination of two tests has been proposed to assess the second-order stationarity of turbulence time series. (C) 2014 Elsevier B.V. All rights reserved.

Optical detectors for atmospheric aerosol concentration measurements are often used inair quality applications given their potentialities for online measurements of air qualityparameters at high temporal resolution. In this work the performances of different opticalaerosol detectors used in air quality applications have been tested and compared for urbanbackground aerosol conditions. Simultaneous measurements of aerosol number concentrations,size distributions and mass concentrations were taken in two different periods:November 2013 - February 2014 and May-June 2014 at an urban background site inLecce (Southeastern Italy). Measurements were carried out using an OPC Grimm (mod.1.109), an OPC FAI (Multichannel Monitor) and an optical photometer Mie pDR-1200.Good correlation, with determination coefficients R2 larger than 0.93 were found betweenparticle number concentrations measured by the two OPCs both in accumulation (0.28-0.90 lm for FAI and 0.29-0.90 lm for Grimm) and coarse modes (1.10-10 lm for FAIand 1.15-11.25 lm for Grimm). Absolute counting for the accumulation fraction showsthat Grimm OPC detects more particles (about 10%) than FAI OPC at concentration higherthan 200,000 particles/L in condition of high RH. This could be due to the changes of theoptical properties of particles in high RH conditions visible even if the inlets of the twoinstruments are conditioned for lowering RH in sampled air. The differences in the absolutecounting of the coarse fraction does not seems to be related to RH effects. The performancesin evaluating mass concentrations PM10, and PM2.5 were evaluated comparingOPCs and pDR-1200 outputs with reference gravimetric and b-ray methods (that appearedto be essentially equivalent). Good agreement between Grimm OPC and SWAM is foundboth in PM10 and PM2.5 fractions while FAI OPC revealed greater discrepancy and scatterwith respect to reference measurements. The performances of the pDR-1200 photometerwere lower with respect to the OPCs with a larger influence of RH and optical propertiesof particles. The analysis of diurnal average trends in number and mass concentrationsas well as the high temporal resolution responses of the instruments showed that opticaldetectors could be very useful to investigate atmospheric aerosol for air quality applicationsand to individuate and investigate specific pollution events. However, especially ifthey are used for evaluating mass concentrations (PM1, PM2.5 or PM10), it is necessary to take into account RH effects (even if the inlet are conditioned) and, possibly, use opticaldetectors together with reference gravimetric or b-ray methods to check their response inthe effective operative conditions.

Shipping is one of the transport sectors less regulated, although more than 80% of world trade is transported by ships [1] and its share of total anthropogenic emissions is significant, with effects on climate, human health and air quality, especially in coastal areas. Recent studies [2] demonstrated the effectiveness of implementation of the 2005/33/EC European Directive in reducing the impact of ship traffic on aerosol concentrations at local scale, however, the effect on climate is more uncertain. Detailed information regarding the size distribution of the impacts to particles and their correlation with gaseous emissions is needed to investigate the complex air quality-climate interaction of this source. Much of the literature studies focus on NOX, SO2, and particulate matter (PM) emissions while there is a gap of knowledge about the size distribution of emitted particles, especially in coarse fraction.This study was done in the framework of POSEIDON (POllution monitoring of Ship Emission: an IntegrateD approach fOr harbour of the Adriatic basiN) project (MED 2007-2013). The aim was to estimate the contribution of in-port ship emissions to gaseous atmospheric pollutants and to PM of different sizes in a port-city in South-Eastern Italy (Adriatic Sea), after the enforcement of the low-sulphur fuel EU-Directive. Measurements were taken at high temporal resolution at the Passenger Terminal site in the harbour area of Brindisi (40° 38? 43.32? N-17° 57? 36.39? E). Data collected by a Mobile Laboratory, were gaseous pollutants (NO2, NO, O3, SO2; 5 min resolution), particle number concentrations (PNC; 1 min resolution), particle size distribution in the range 0.25-32 ?m (1 min resolution) and NO2 and SO2 flow-rate emissions with a DOAS (Differential Optical Absorption Spectroscopy) remote-sensing system, called GASCOD (Gas Absorption Spectrometer Correlating Optical Differences). The Port Authority provided data of ship traffic and a video camera was used to synchronize all measurements and visually estimate number of vehicles (cars, trucks) during loading/unloading of ships at berth. Characterization of ship plumes in aspect of particle size, gaseous concentrations, duration, ratio NO/NO2, was performed. The impact analysis [3] was applied separating manoeuvring (arrival/departure of ships) and hotelling (loading/unloading activities) phases. Results showed that the primary contribution to PM1 and PM2.5 was significantly lower with respect to those to PNC for both phases, confirming that the majority of the particles emitted were in the ultrafine size range. Manoeuvring phase was characterized by higher impacts to SO2, NO, and NO2 than those to PNC, PM1 and PM2.5. Hotelling phase represented a significant share of the impact for NO, NO2, PNC but gave a low contribution to SO2 impact (due to low-sulphur fuel). Ultrafine particles (Dp<0.25 µm) represented 99% of the absolute contribution to PNC in number concentrations but only 18% of the contributi

Dry deposition of particles is an important way of aerosol removal from the atmosphere and a key process in surface-atmosphere exchanges. The deposition velocities, Vd, are often parameterised in air quality and climate modelling as function of the friction velocity, u*, atmospheric stability, and particle size (if size-segregated information is available). In this work, a study of the correlation between Vd and u* over different surfaces is presented for both PM2.5 and particle number fluxes. Results indicate an almost linear increase of Vd with u* with slopes similar for PM2.5 fluxes and particle number fluxes over the different surfaces analysed. This means that the ratios Vd/u* tend to collapse over similar values even if Vd and u* are significantly different because u* take into account most of the surface effects. There is a limited difference between stable cases and unstable/neutral cases with slightly lower deposition velocities in stable cases for fixed values of u*. The average value of Vd/u* is 0.010 ± 0.0017 (median 0.0062 ± 0.0015) (considering all stabilities) and 0.0097 ± 0.002 (median 0.005 ± 0.001) for stable cases. This could be the base for an empirical parameterisation of deposition velocities in air quality models. © 2014 Antonio Donateo and Daniele Contini.

This work reports an analysis of the concentration, size distribution, and depositionvelocity of atmospheric particles over snow and iced surfaces on the Nansen Ice Sheet(Antarctica). Measurements were performed using the eddy-correlation method at a remotesite during the XXII Italian expedition of the National Research Program in Antarctica(PNRA) in 2006. The measurement system was based on a condensation particle counter(CPC) able to measure particles down to 9 nm in diameter with a 50% efficiency and aDifferential Mobility Particle Sizer for evaluating particle size distributions from 11 to521 nm diameter in 39 channels. A method based on postprocessing with digital filterswas developed to take into account the effect of the slow time response of the CPC. Theaverage number concentration was 1338 cm-3 (median, 978 cm-3; interquartile range,435-1854 cm-3). Higher concentrations were observed at low wind velocities. Resultsgave an average deposition velocity of 0.47 mm/s (median, 0.19 mm/s; interquartile range,-0.21 -0.88 mm/s). Deposition increased with the friction velocity and was on average0.86 mm/s during katabatic wind characterized by velocities higher than 4 m/s. Observedsize distributions generally presented two distinct modes, the first at approximately15-20 nm and the second (representing on average 70% of the total particles) at 60-70 nm.Under strong-wind conditions, the second mode dominated the average size distribution.

Scaling laws for the diffusion generated by three different random walk models are reviewed. The random walks, defined on a one-dimensional lattice, are driven by renewal intermittent events with non-Poisson statistics and inverse power-law tail in the distribution of the inter-event or waiting times, so that the event sequences are characterized by self-similarity. Intermittency is a ubiquitous phenomenon in many complex systems and the power exponent of the waiting time distribution, denoted as complexity index, is a crucial parameter characterizing the system's complexity. It is shown that different scaling exponents emerge from the different random walks, even if the self-similarity, i.e. the complexity index, of the underlying event sequence remains the same. The direct evaluation of the complexity index from the time distribution is affected by the presence of added noise and secondary or spurious events. It is possible to minimize the effect of spurious events by exploiting the scaling relationships of the random walk models. This allows to get a reliable estimation of the complexity index and, at the same time, a confirmation of the renewal assumption. An application to turbulence data is shown to explain the basic ideas of this approach.

The Mediterranean Basin is considered a hot-spot region in term of air-quality and climate change due to the impact of anthropogenic and natural processes. Nevertheless, permanent infrastructures for the observations and the recognition of the atmospheric composition variability changes are still too sparse in this region. To contribute to a more accurate and wide-spread observation system, in the framework of the Project "I-AMICA" - Advanced Infrastructure for the Environmental-Climatic Monitoring (a three years Italian National Operative Program - PON, co-founded by the European Regional Development Fund ), four permanent Climatic- Environmental Observatories have been set up in the southern Italy: Lecce (Apulia Region, 4020' 8" N, 18 07' 28" E, 37 m a.s.l.), Lamezia Terme (Calabria Region, 38 52' 34" N, 16 13' 56" E, 6 m a.s.l.), Capo Granitola (Sicily, 3734' N, 12 39' E, 5 m a.s.l.) and Mt. Curcio (Calabria, 39 31' N, 16 42' E, 1796 m a.s.l). These Observatories were equipped with homogeneous and standardized experimental set-up for measurements of aerosol properties (number size distribution, absorption and scattering coefficient, mass, equivalent black carbon), reactive and greenhouse gases (O3, NO, NO2, SO2, CO, CO2, CH4). The I-AMICA Observatories represent different conditions of the Mediterranean region, from suburban conditions at Lecce to costal background conditions at Lamezia Terme and Capo Granitola and high-mountain remote conditions at Mt. Curcio. The integration of the information from this high-quality observation network can be used for studies of aerosol transport from marine environment and Sahara desert, as well as for investigation of secondary pollutants formation in the gaseous and aerosol phase, investigation of continental outflow to Mediterranean Sea, impacts of vessel emissions on regional air quality and trans-boundary pollution.In this work, we provide a preliminary overview of gas and aerosol variability, together with the description of selected special events registered in the first year of activity at these four regional GAW-WMO stations. A general characterization of these observatories in terms of location, meteorology and atmospheric transport patterns will be also provided. We also present and discuss the experimental set-up (sampling systems, calibration strategies, standards) used to implement WMO/GAW guidelines at each of these stations and methodologies to identify measurement period characterized by background conditions.

Air samples were collected in Venice during summer 2009 and 2012 to measure gas and particulate concentrations of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and polychlorinated naphthalenes (PCNs). PCB-11, considered a marker for non-Aroclor contamination of the environment, was found for the first time in the Venetian lagoon and in Europe. An investigation on sources has been conducted, evidencing traffic as the major source of PAHs, whereas PCBs have a similar composition to Aroclor 1248 and 1254; in 2009 a release of PCN-42 has been hypothesized. Toxicological evaluation by TCA and TEQ methods, conducted for the first time in Venice air samples, identified BaP, PCB-126 and PCB-169 as the most important contributors to the total carcinogenic activity of PAHs and the total dioxin-like activity of PCBs and PCNs. (C) 2014 Elsevier B.V. All rights reserved.

I-AMICA (Infrastruttura di Alta tecnologia per il Monitoraggio Climatico Ambientale - Infrastructure of High Technology forEnvironmental and Climate Monitoring) is a three years challenging project, co-funded by Italian National Operative Program (PON)and European Regional Development Fund. A lot of effort distinguish the project to strengthen the environmental monitoring inItalian South Mediterranean with the aim to support the integration among research, high training, and innovation. A special issue isalso to be proactive in synergies among public and private research organizations. The activities are focused on actions addressed tostrengthen the observational infrastructures for atmosphere, forest and coastal areas in the regions of Southern Italy, whose economicgrowth and social well-being are strongly related to the environment quality. In such Convergence Regions (Campania, Apulia,Calabria and Sicily), instrumental networks (e.g. advanced sensors, software tools, integrated platforms and mobile laboratory andstations) dedicated to the environmental and climatic monitoring in the Mediterranean area, in terms of air quality, forest andagriculture, coastal marine ecosystems will be promoted and developed. In order to raise the national and international competitive capacity, four "pillar" activities are aimed to (1) strengthen observing infrastructures for climate and environment and data processing systems, (2) promote innovation, technological development and industrial transfer, (3) integrate these observational activities into international programs (i.e. GAW-WMO, ACTRIS, EARLINET, GMOS, ICOS, FLUXNET, SHARE, NEXT DATA) that will allow I-AMICA to effectively be integrated with important networks.Finally, (4) through the implementation of observations, networking, technological applications and territorial services in the Convergence Regions, I-AMICA provides an important support to the local and regional communities.

Aerosol and gaseous pollution measurements were carried out at an urban background site in thesouth of Italy located near an industrial complex. Collection of 24 h samples of PM10 and PM2.5and successive chemical quantification of metals were performed. Data were compared withmeasurements taken at a suburban background site, located at 25 km distance. The comparisonshowed the presence of an industrial contribution with a well defined chemical emission profile,similar, in terms of metals content, to urban emissions. As this made difficult the quantitativecharacterisation of the contribution of the two sources to atmospheric PM, a statistical method basedon the treatment of data arising from high temporal resolution measurements was developed. Datawere taken with a micrometeorological station based on an integrating nephelometer (Mie pDR-1200) for optical detection of PM2.5 concentration, with successive evaluation of vertical turbulentfluxes using the eddy-correlation method. Results show that the contribution from the two sources(urban emissions and industrial releases) have a very different behaviour, with the industrialcontribution being present at high wind velocity with short concentration peaks (average duration4 min) associated to strong positive and negative vertical fluxes. The estimated contribution to PM2.5is 2.3% over long-term averages. The urban emissions are mainly present at low wind velocity, withlonger concentration peaks in the morning and late evening hours, generally associated to smallpositive vertical fluxes. The characterisation of the contribution was performed using depositionvelocity Vd that is on average 3.5 mm s1 and has a diurnal pattern, with negligible values during thenight and a minimum value of around 9 mms1 late in the afternoon. Results show a correlationbetween Vd, friction velocity and wind velocity that could be the basis for a parameterisation of Vd to beused in dispersion codes.

Il particolato atmosferico (PM) è un inquinante noto per i suoi effetti negativi sia sull'ambiente che sulla salute umana a causa di esposizione in ambienti indoor e di esposizione outdoor, ed è pertanto oggetto di numerosi studi scientifici. Seppure gli effetti tossici del PM siano stati correlati ad alcune sue proprietà chimico-fisiche, i meccanismi di tossicità non sono ancora del tutto noti. Numerosi studi hanno suggerito che alcuni effetti negativi sulla salute sono riconducibili al potenziale ossidativo (OP) del particolato, che porta ad elevate concentrazioni di Reactive Oxygen Species (ROS), specie chimiche in grado di provocare danni a livello cellulare. Per questo motivo, nella comunità scientifica internazionale, il potenziale ossidativo (OP) del particolato atmosferico è considerato come un potenziale indicatore di rischio per la salute umana. Il contributo al potenziale ossidativo di sorgenti antropogeniche specifiche, come il traffico stradale, la combustione di biomasse e le emissioni industriali, è stato studiato in diversi siti di misura. Tuttavia, le informazioni relative al OP di sorgenti naturali sono scarse e non sono, ad esempio, disponibili dati relativi all'influenza del trasporto transfrontaliero di polveri del Sahara (Saharan Dust Outbreak, SDO) al potenziale ossidativo. Pertanto, è stato condotto uno studio sul potenziale ossidativo di due frazioni dimensionali (PM2.5 e PM10) del particolato atmosferico raccolto presso l'Osservatorio Climatico-Ambientale di ISAC-CNR di Lecce, stazione regionale della Global Atmosphere Watch (GAW).

Emissions of atmospheric pollutants from ships andharbour activities are a growing concern at international level giventheir potential impacts on air quality and climate. These close-to-landemissions have potential impact on local communities in terms of airquality and health. Recent studies show that the impact of maritimetraffic to atmospheric particulate matter concentrations in severalcoastal urban areas is comparable with the impact of road traffic of amedium size town. However, several different approaches have beenused for these estimates making difficult a direct comparison ofresults. In this work, an integrated approach based on emissioninventories and dedicated measurement campaigns has been appliedto give a comparable estimate of the impact of maritime traffic toPM2.5 and particle number concentrations in three major harbours ofthe Adriatic/Ionian Seas. The influences of local meteorology and ofthe logistic layout of the harbours are discussed.

In this work an integrated methodology (emission inventories, modelling and experimental approach) was applied to investigate impact of shipping to atmospheric pollutants in four Adriatic/Ionian port-cities (Brindisi, Venice, Patras and Rijeka).

Harbours are important hubs for social and economic development of coastal Mediterranean areas. However, ship emissions are also a significant source of atmospheric pollution in port-cities with potential effects on both human health and climate. At European level (Viana et al., 2014), the impact of shipping to particulate matter (PM) concentrations is larger in Mediterranean area with respect to Northern Europe. Further, information on impact on ultrafine and nanoparticles is still fragmentary and not sufficient to have a global picture on this metric. International legislations to reduce ship emissions, both at Worldwide and European levels, are mainly based on the use of low-sulphur content fuel that is effective also in reducing primary impact of shipping to atmospheric aerosol (Contini et al., 2015).In the framework of POSEIDON project, a measurement campaign was performed between 27th June and 15th October 2014, in the harbour area of Brindisi (SE Italy, 40° 38? 43.32? N - 17° 57? 36.39? E). A mobile laboratory was used to investigate the contribution of ship traffic and harbour activities (hotelling, loading and unloading of ships) to gaseous pollutants and to concentrations of atmospheric particles of different sizes.The mobile laboratory was equipped to measure, at high temporal resolution, gaseous pollutants (NO2, NO, O3, SO2 at 5 minutes resolution), total particle number concentrations (Grimm CPC 5.403 at 1 minute resolution), particle size distribution in the range 0.25-34 µm using a Grimm OPC 1.109 (1 minute resolution) and further, a DOAS (Differential Optical Absorption Spectroscopy) remote-sensing system was employed for detection of NO2 and SO2 fluxes from ships in harbour (Premuda et al., 2011). Ship traffic details were collected from Brindisi Port Authority and arrival and departure times were synchronised with concentration measurements using a night & day video camera. A low-volume PM2.5 sequential sampler was used to collect 24-hour samples using the gravimetric method to calibrate optical measurements.Collected data allowed to individuate short-term concentration peaks associated with ship traffic and concentration increases associated with correlated harbour activities. An example is reported in Figure 1. Measurements show that SO2 presents brief concentration peaks associated with the manoeuvring phase and lower concentrations during the hotelling phase. This is compatible with the use of low-sulphur content fuel in European harbours (European Directive 2012/33/EC). Nitrogen oxides concentrations show a significant contribution, especially for NO, for both manoeuvring and hotelling, loading/unloading phases. Simultaneously, a depletion of O3 (not shown) was observed. Particle concentrations show a dynamics that is strongly depending on particle size. Ultrafine particles (diameter Dp<0.25 µm) show peaks well correlated with nitrogen oxides peaks. Instead, accumulation mode particles (0.25 µm<Dp<1 µm) show concen

Ports have always had a dual nature: on the one hand they are hubs for tourism and commercial activities, providingwealth and prosperity of the neighbouring towns; on the other hand they are source of atmospheric pollution,creating great concern, since they are often located near city centres. Great attention has been paid to minimizepollution from road traffic, while that produced by ship traffic was considered only in recent years, despite contributingnearly 50% of total atmospheric particulate in several medium-size port-cities.This work was conducted in the framework of the POSEIDON (POllution monitoring of Ship Emission: an IntegrateDapproach fOr harbor of the Adriatic basiN) project (MED programme 2007-2013). The objective of POSEIDONactivities is to quantify the relative contribution of maritime traffic to atmospheric pollutants concentration infour port-cities of the Adriatic Sea (Brindisi, Venice, Patras and Rijeka). At the same time POSEIDON proposes toidentify policy gaps and to support the proposal of integrated common strategies and future actions for sustainabledevelopment of coastal area in the Adriatic Sea.This study focuses on the port-city of Venice. The ship traffic impact was quantified using different methodologiesand referring to various pollutants that are not yet included in the current legislation on ship emissions:1. PM2.5 and particle number concentration (PNC), using data at high temporal resolution [1];2. PM10 and PM2.5 at low resolution, using atmospheric vanadium data [2];3. Metals in PM10, conducting a source apportionment (Positive Matrix Factorization technique) [2];4. Gaseous and particulate PAHs, adopting a double sampling method [2, 3].With the exception of PNC, data were collected from 2007 (or 2009) to 2013, permitting the evaluation of the effectof the European Directive 2005/33/EC (which was enforced on 1st January 2010) on the air quality of Venice.The outcomes showed a decrease in the contribution of ship traffic to particulate matter, both from measurementsat high and low resolution. On the contrary, the contribution to metals and PAHs seems to be stable or even increased,over the years.From this work it is clear the need to add other pollutants in the legislation which regulates shipping emissions:i) ultrafine particles, since a stronger shipping contribution was observed to PNC respect to PM2.5; ii) metals andparticulate-PAHs, since no decrement was observed after the introduction of the 2005/33/EC Directive.[1] Contini D., Gambaro A., Donateo A., Cescon P., Cesari D., Merico E., Belosi F., Citron M. (2015). Inter-annual trend of the primary contributionof ship emissions to PM2.5 concentrations in Venice (Italy): Efficiency of emissions mitigation strategies. Atmospheric Environment102, 183-190.[2] Gregoris E., Barbaro E., Morabito E., Toscano G., Donateo A., Cesari D., Contini D., Gambaro A. (2015). Impact of maritime traffic onpolycyclic aromatic hydrocarbons, metals an

Pollutant emissions from ships and harbour activities constitute an important source of pollution of coastalareas with potential influences on the climate and the health of their inhabitants. A recent review (Viana etal., 2014) shows that these emissions could have an important impact on the Mediterranean and that there is alack of data for the Eastern and South-Eastern part of this area. This work presents an analysis of the impactof ship emissions to atmospheric particle concentrations (PM) in four important port-cities (Patras Greece,Brindisi and Venice Italy, and Rijeka Croatia) of the Adriatic/Ionian area. The study was performed within thePOSEIDON project (Pollution monitoring of ship emissions: an integrated approach for harbours of the Adriaticbasin, funded within the MED Programme 2007-2013). The study uses an integrated approach using emissioninventories, dispersion modelling and measurements taken at high temporal resolution (1 min) and low temporalresolution for chemical characterization of PM. The emission inventories of the four port-cities show that shipscontribute between 11.7% and 31.0% of the total PM emissions being a source locally comparable with roadtraffic (ranging between 11.8% and 26.6%). The source apportionment using the receptor model PMF showed anoil combustion source (that includes ship emissions), characterized by V and Ni, in Brindisi, Venice and Rijekawith V/Ni ratio ranging between 1.4 and 4.2 indicating local differences in chemical profiles of the emissions.The V concentrations were used to evaluate the contributions of primary ship emissions to PM (Agrawal etal., 2009) that resulted between 1.3% and 2.8%. The contribution to secondary sulphate was 11% of PM2.5 inBrindisi (Cesari et al., 2014). The analysis of high-temporal resolution measurements taken near the harbourareas of Venice, Patras and Brindisi showed a contribution of ship emissions to PM2.5 varying between 3.5%and 7.4%. The relative contribution to particle number concentrations (PNC) was larger at all sites (between6% and 26%). This demonstrates that ship particulate emissions include mainly small and ultrafine particles.The trend of the impact of passenger ships primary emissions to PM2.5 concentrations in Venice between2007 and 2012 showed a decrease from 7% (1%) to 3.5% (1%) even if the gross tonnage of ship trafficincreased in the same period by 47% (Contini et al., 2015). This was a consequence of the use of low-sulphurcontent fuels due to the application of local mitigation strategies and of the European Directive 2005/33/EC.The WRF-CAMx modeling system was applied over the Central and Eastern Mediterranean so as to identifythe air quality impact of ship emissions. The zero-out modelling method was implemented involving modelsimulations performed while including and omitting the ship emissions. The results for both gaseous and particulatepollutant concentrations generally show a fairly

The improvement of the Solar and Wind short-term forecasting represents a critical goal for the weather prediction community and is of great importance for a better estimation of power production from solar and wind farms. In this work we analyze the performance of two deterministic models operational at ISAC-CNR for the prediction of short-wave irradiance and wind speed, at two experimental sites in southern Italy. A post-processing technique, i.e the multi-model, is adopted to improve the performance of the two mesoscale models. The results show that the multi-model approach produces a significant error reduction with respect to the forecast of each model. The error is reduced up to 20 % of the model errors, depending on the parameter and forecasting time.

Ship emissions are a growing concern, especially in coastal areas, for potential impacts on human healthand climate. International mitigation strategies to curb these emission, based on low-sulphur contentfuels, have proven useful to improve local air quality. However, the effect on climate forcing is lessobvious. Detailed information on the influence of shipping to particles of different sizes is needed toinvestigate air quality and climate interaction. In this work, the contributions of maritime emissions toatmospheric concentrations of gaseous pollutants (NO, NO2, SO2, and O3) and of particles (sizes from0.009 mm to 30 mm) were investigated considering manoeuvring (arrival and departure of ships) andhotelling phases (including loading/unloading activities). Results showed that the size distributions ofshipping contributions were different for the two phases and could be efficiently described, usingmeasured data, considering four size-ranges. The largest contribution to particles concentration wasobserved for Dp < 0.25 mm, however, a secondary maximum was observed at Dp ¼ 0.35 mm. The minimumcontribution was observed at Dp around 0.8e0.9 mm with a negligible contribution from hotellingfor size range 0.4e1 mm. The comparison of 2012 and 2014 datasets showed no significant changes ofgaseous and particulate pollutant emissions and of the contribution to particle mass concentration.However, an increase of the contribution to particle number concentration (PNC) was observed. Resultssuggested that harbour logistic has a relevant role in determining the total impact of shipping on airquality of the nearby coastal areas. Additionally, future policies should focus on PNC that represents animportant fraction of emissions also for low-sulphur fuels. DOAS remote sensing proved a useful tool todirectly measure NO2 and SO2 ship emissions giving estimates comparable with those of emission inventoryapproach.

High number concentrations of particles in atmosphere could be due to nucleation events and successive growth phenomena (Kulmala et al., 2004). These events have been recorded in different environments including remote areas, forests, coastal and urban sites (Hamed et al., 2007). The aim of this work is to investigate the effects of nucleation events on particle number turbulent vertical fluxes, characterising surface-atmosphere exchange of aerosol, and on size distributions in an urban background area in summer conditions. The influence of meteorological and micrometeorological parameters as well as CO2/H2O concentrations and fluxes on nucleation events will be investigated.Site description, set-up and data post-processingThe measurement campaign was performed between 13th and 31st July 2010 using the mobile laboratory of the Lecce Section of ISAC-CNR placed at the University Campus (40°20'10.8''N, 18°07'21.0''E) at about 3.5 km SW of the town of Lecce. Equipment includes an eddy-correlation (EC) station using a condensation particle counter (CPC, Grimm 5.403), an ultrasonic anemometer (Gill R3), and a IR gas analyser (Li-7500, LICOR Environmental) for CO2 and H2O vapour concentrations and fluxes measurements. A scanner mobility particle sizer (SMPS, Grimm 5.500) was used to measure size distributions in the size range between 11 nm and 1083 nm. Measured time series were post-processed to evaluate the fluxes of particles (FN), CO2 (FC), sensible and latent heat, and the corresponding scalar concentrations over 30 minutes averaging periods using the methodology and corrections described in Contini et al. (2012).ResultsTwo classes of particles could be put in evidence: nanoparticles (NP, diameter Dp<50 nm) and coarse particles (NC, Dp>50 nm, including Aitken and accumulation mode) that have a completely uncorrelated dynamics. Nanoparticles show maximum concentrations, on averages, in diurnal hours around midday when coarse particles present minimum average concentrations. This behaviour is due to the presence of days with nucleation events, like that shown in Fig. 1. During event days, on average, it has been observed an increase of downward fluxes (i.e. deposition) compatible with the hypothesis of aerosol formation above the measurement height (10 m). The measurement period has been divided in two categories: event (E) and nonevent (NE) days. Measured parameters have been averaged separately for the two categories in the time period between 9:00 and 16:00. Results are reported in Table 1 with their standard errors. Event days are characterised by concentrations about 3 times larger than non-event days, an average diameter reduced to about 1/2 and significantly larger deposition. Instead, CO2 concentrations and fluxes are similar for E and NE days, whereas E days are characterised by higher temperature and wind speed.

Exposure to atmospheric particulate matter (PM) leads to adverse health effects although the exact mechanisms of toxicity are still poorly understood. Several studies suggested that a large number of PM health effects could be due to the oxidative potential (OP) of ambient particles leading to high concentrations of reactive oxygen species (ROS). The contribution to OP of specific anthropogenic sources like road traffic, biomass burning, and industrial emissions has been investigated in several sites. However, information about the OP of natural sources are scarce and no data is available regarding the OP during Saharan dust outbreaks (SDO) in Mediterranean regions. This work uses the a-cellular DTT (dithiothreitol) assay to evaluate OP of the water-soluble fraction of PM2.5 and PM10 collected at an urban background site in Southern Italy. OP values in three groups of samples were compared: standard characterised by concentrations similar to the yearly averages; high carbon samples associated to combustion sources (mainly road traffic and biomass burning) and SDO events. DTT activity normalised by sampled air volume (DTTv), representative of personal exposure, and normalised by collected aerosol mass (DTTM), representing source-specific characteristics, were investigated. The DTTv is larger for high PM concentrations. DTTv is well correlated with secondary organic carbon concentration. An increased DTTv response was found for PM2.5 compared to the coarse fraction PM2.5-10. DTTv is larger for high carbon content samples but during SDO events is statistically comparable with that of standard samples. DTTM is larger for PM2,5 compared to PM10 and the relative difference between the two size fractions is maximised during SDO events. This indicates that Saharan dust advection is a natural source of particles having a lower specific OP with respect to the other sources acting on the area (for water-soluble fraction). OP should be taken into account in epidemiological studies to evaluate the potential health risks associated to ROS in regions affected by high pollution events due to Saharan dust advection. (C) 2017 Elsevier Ltd. All rights reserved.

Receptor models (RMs), based on chemical composition of particulate matter (PM), such as Chemical MassBalance (CMB) and Positive Matrix Factorization (PMF), represent useful tools for determining the impact ofPM sources to air quality. This information is useful, especially in areas influenced by anthropogenic activities,to plan mitigation strategies for environmental management. Recent inter-comparison of source apportionment(SA) results showed that one of the difficulties in the comparison of estimated source contributions is the compatibilityof the sources, i.e. the chemical profiles of factor/sources used in receptor models. This suggests that SAbased on integration of several RMs could give more stable and reliable solutions with respect to a single model.The aim of this work was to perform inter-comparison of PMF (using PMF3.0 and PMF5.0 codes) and CMB outputs,focusing on both source chemical profiles and estimates of source contributions. The dataset included347 daily PM10 samples collected in three sites in central Italy located near industrial emissions. Samples werechemically analysed for the concentrations of 21 chemical species (NH4+, Ca2+, Mg2+, Na+, K+, Mg2+, SO4 2-,NO3-, Cl-, Si, Al, Ti, V, Mn, Fe, Ni, Cu, Zn, Br, EC, and OC) used as input of RMs. The approach identified 9 factor/sources: marine, traffic, resuspended dust, biomass burning, secondary sulphate, secondary nitrate, crustal,coal combustion power plant and harbour-industrial. Results showed that the application of constraints inPMF5.0 improved interpretability of profiles and comparability of estimated source contributions with stoichiometriccalculations. The inter-comparison of PMF and CMBgave significant differences for secondary nitrate, biomassburning, and harbour-industrial sources, due to non-compatibility of these source profiles that have localspecificities. When these site-dependent specificities were taken into account, optimising the input source profilesof CMB, a significant improvement in the comparison of the estimated source contributions with PMF wasobtained.

A field campaign was performed simultaneously at five measurement sites, having different characteristics, to characterize the spatial distribution of the carbonaceous content in atmospheric aerosol in Southern Italy during the winter season. Organic carbon (OC) and elemental carbon (EC) were measured at urban (Naples), suburban (Lecce), coastal/marine (Lamezia Terme and Capo Granitola), and remote (Monte Curcio) locations. OC and EC mass concentrations were quantified by the thermal-optical transmission (TOT) method, in 24-h PM10 and PM2.5 samples collected on quartz fiber filters, from 25 November 2015 to 1 January 2016. The different sites showed marked differences in the average concentrations of both carbonaceous species. Typically, OC average levels (?standard deviation) were higher at the sites of Naples (12.8 ? 5.1 and 11.8 ? 4.6 ?g/m3) and Lecce (10.7 ? 5.8 and 9.0 ? 4.7 ?g/m3), followed by Lamezia Terme (4.3 ? 2.0 and 4.0 ? 1.9 ?g/m3), Capo Granitola (2.3 ? 1.2 and 1.7 ? 1.1 ?g/m3), and Monte Curcio (0.9 ? 0.3 and 0.9 ? 0.3 ?g/m3) in PM10 and PM2.5, respectively. Similarly, EC average levels (?standard deviation) were higher at the urban sites of Naples (2.3 ? 1.1 and 1.8 ? 0.5 ?g/m3) and Lecce (1.5 ? 0.8 and 1.4 ? 0.7 ?g/m3), followed by Lamezia Terme (0.6 ? 0.3 and 0.6 ? 0.3 ?g/m3), Capo Granitola (0.3 ? 0.3 and 0.3 ? 0.2 ?g/m3), and Monte Curcio (0.06 ? 0.04 and 0.05 ? 0.03 ?g/m3) in PM10 and PM2.5, respectively. An opposite trend was observed for the OC/EC ratios ranging from 6.4 to 15.9 in PM10 and from 6.4 to 15.5 in PM2.5 with lower values in urban sites compared to remote sites. Different OC-EC correlations, 0.36 &lt; R2 &lt; 0.90, were found in four observation sites. This behavior suggests the contributions of similar sources and common atmospheric processes in both fractions. No correlations were observed between OC and EC at the site of Naples. The average secondary organic carbon (SOC) concentrations, quantified using the minimum OC/EC ratio method, ranged from 0.4 to 7.6 ?g/m3 in PM10 and from 0.4 to 7.2 ?g/m3 in PM2.5, accounting from 37 to 59% of total OC in PM10 and from 40 to 57% in PM2.5 with higher percentages in the urban and suburban sites of Naples and Lecce.

We present a characterization of reactive gases (RG: O3, NO, NO2, SO2, CO) and methane (CH4) variability in the central Mediterranean basin, analyzing in situ measurements at three new permanent WMO/GAW Observatories in Southern Italy: Capo Granitola - CGR (Sicily), Lamezia Terme - LMT (Calabria) and Lecce - ECO (Apulia). At all the measurement sites, a combination of the breeze wind system (especially at CGR and LMT), PBL dynamics, anthropogenic/natural emissions, and photochemistry lead the appearance of well-defined diurnal cycles for the observed RG. According to O3/NOx variability, local emissions appeared to influence CGR and LMT (no NOx data were available for ECO during the period of study) in 4% and 20% of the hourly data, nearby sources in 39% and 40%, remote sources in 31% and 14%, while background O3/NOx were observed in 26% of cases for both the stations. Most of the background O3/NOx were observed during daytime, when offshore air masses usually affected the measurement sites. Local sources of CH4 at CGR can be related to biogenic (oxic) emissions from biomasses along the coastline, while emissions from live stocks can represent a local source of CH4 at LMT. Finally, we provide first hints about the export of O3 from Sicily/Southern Italy to the Mediterranean Sea by comparing simultaneous observations at CGR and Lampedusa (LMP), a small island in the middle of the Strait of Sicily where a WMO/GAW Regional Station is located. In summer, O3 increased by some 7 ppb for transport times lower than 48 h, while no statistical significant differences were observed for travel time longer than 48. This would suggest that photochemical O3 production occurred within air-mass travelling from CGR to LMP, but also that the central Mediterranean MBL represents a O3 sink for relatively aged air-masses.

La campagna di misura AFIRE (Aerosol Fluxes in uRban Environment), condotta nell'area urbana di Lecce dal 10 Marzo al 24 Aprile 2015, ha permesso misure di concentrazione e di flussi verticali turbolenti di particelle in modalità size-segregated, mediante eddy-covariance [1], insieme ai flussi di CO2/H2O. La base sperimentale, installata a 11.5 m di altezza dal suolo, è stata equipaggiata con un sistema ottimizzato composto da un Condensation Particle Counter (CPC) e da un Optical Particle Counter (OPC), per la distribuzione in numero di particelle (PNSD) comprese in un intervallo dimensionale tra 0.09 e 3 micron, da un anemometro ultrasonico e da un rilevatore veloce ad infrarossi di CO2/H2O. Dopo una fase preliminare di post-processing dei dati grezzi con relative correzioni di tipo strumentale e fisico, i dati elaborati sono stati selezionati con un'angolazione favorevole ad impedire possibili influenze di edifici adiacenti.Obiettivo principale dello studio è la caratterizzazione della dinamica del particolato e della CO2 attraverso un'analisi dei pattern della concentrazione numerica e della distribuzione dimensionale nell'area urbana. Il maggior contributo (dell'ordine di 104 /cm3) è sulle particelle appartenenti ai diametri più piccoli e nei giorni feriali. I pattern giornalieri delle particelle mostrano picchi nella loro concentrazione collegati ad intense attività di traffico veicolare o a possibili eventi di nucleazione, mentre le concentrazioni di CO2 evidenziano un comportamento diverso per l'influenza del background e del ciclo biogenico con un decremento nelle ore diurne. I flussi di CO2 presentano un ciclo giornaliero e settimanale con due picchi distinti, mattino e sera.

The Mediterranean, populated by over 500 million people in about 30 countries facing the basin, is one of the main worldwide hotspot for climate change and air quality. The conditions that favor this situation are related with presence of anthropic (i.e. urban and marine) and natural (i.e. mineral dust and wildfires) pollutants. In the framework of the I-AMICA PON project (Infrastruttura di Alta tecnologia per il. Monitoraggio Integrato Climatico-Ambientale, http://www.i-amica.it/i-amica/?lang=en), in the Southern area of Italy, three Climatic Environmental Observatories have been activated at the end of 2014 at the sea coastal sites of: Lamezia Terme (Calabria Region, 38° 52' N 16° 13' E ), Lecce (Apulia, 40° 20' N 18° 7' E) and Capo Granitola (Sicily, 37°34' N 12° 39' E). Data are near real time transmitted to a common server, allowing to a fast common overview of the atmospheric composition over the Central Mediterranean Sea.To provide near-real-time (NRT) information on natural pollutantscontribution to the aerosol load, and in particular Saharan dust, three Climatic Environmental Observatories have been activated at the end of 2014 at the sea coastal sites of: Lamezia Terme (Calabria Region, 38° 52' N 16° 13' E), Lecce (Apulia, 40° 20' N 18° 7' E) and Capo Granitola (Sicily, 37°34' N 12° 39' E). In the framework of the I-AMICA PON project (Infrastruttura di Alta tecnologia per il. Monitoraggio Integrato Climatico-Ambientale, http://www.i-amica.it/i-amica/?lang=en), an algorithm able to capture in near real time the dust outbreak events over the sampling sites was developed. It is based on simultaneous real time analysis of optical aerosol properties, in particular, analysis ofthe scattering angstrom exponent (SAE) and single scattering albedo (SSA) while 3D air-mass back-trajectories (96 hour long) are used to corroborate the origin of air masses from North Africa. In this wayThis methodology allow to , a period of observation is flagged as "dust event" when a period of observation with a minimal duration for a fixed amount of time appropriately defined, when SSAE reports values less than 0.5 and SSAE is in the range 0.8-0.95 (Costabile at al., 2013), together with air-masses traced back to a defined northern Africa box. The simultaneity simultaneousof these occurrences of these aerosol properties at the three Observatories, flagged by the web-central-server, permits to identify and define the incidences of the transport in NRT on synoptic scale.All the Observatories are equipped with a TSI 3563 nephelometer (450, 550 and 700nm) and a MultiAngle Absorption Photometer, allowing to calculate SSA at 635 nm and SAE. These parameters are calculated on STD and truncation corrected measurements. By using measurement of absorption and scattering coefficients carried out by photometer and 3? nephelometer, the SSA and SAE characterization of the aerosol optical properties is carried out for all the sites. These parametersaerosol propertie

The Mediterranean Basin is considered a hot-spot region in term of air-quality and climate change due to the impact of anthropogenic and natural processes, however permanent experimental infrastructures for the observations and the recognition of the atmospheric composition variability changes are still too sparse in this region. To contribute to a more accurate and wide-spread collection of data, in the framework of the Project "I-AMICA" (Advanced Infrastructure for the Environmental-Climatic Monitoring), sponsored by the Italian Ministry for University, Research and Education and by the European Regional Development Founds, three Climatic-Environmental Observatories have been set up in the southern Italy: Lecce (40° 20' 8" N, 18° 07' 28" E, 37 m a.s.l.), Lamezia Terme (38° 52' 34" N, 16° 13' 56" E, 6 m a.s.l.) and Capo Granitola (37° 34' N, 12° 39' E, 5 m a.s.l.).These observatories represent different conditions: from suburban rural conditions at Lecce to costal background conditions at Lamezia Terme and Capo Granitola. Lecce and Lamezia Terme observations can be used for studies of air-mass transport from marine environment and the northern Africa dust as well as for investigation of secondary pollutants formation in the gaseous and aerosol phase. The Capo Granitola is situated at the south coast of Sicily: this station is perfectly located for studies of marine environment, impacts of vessel emissions on regional air quality and for studies of processes of aerosol formation, transformation and transport. These observatories were equipped with homogeneous and standardized experimental set-up for measurements of aerosol properties (number size distribution, absorption and scattering coefficient, mass, equivalent black carbon), reactive gases (O3, NO, NO2, SO2, CO) and greenhouse gases (CO2, CO). In particular, the continuous investigation of CO, CO2 and CH4 variability is based on the use of CRDS systems (Picarro G2401). In this work, we provide a characterization of the three observatories in terms of location, meteorology and transport patterns. We also present and discuss the experimental set-up (sampling systems, calibration strategies, gas standards) used to implement the CO, CO2 and CH4 measurement programmes at each of these stations. Moreover, the first 6 months (January - June 2015) of continuous observations will be presented, thus providing a preliminary assessment of winter-spring variability and background levels at the measurement sites.

Osservatorio Climatico-Ambientale di I-AMICA a Lecce: attività e prospettive di un centro d'eccellenza al servizio del territorio

The eddy covariance is the most direct, efficient and reliable method to measure the turbulent flux of a scalar (Baldocchi, 2003). Required conditions for high-quality eddy covariance measurements are amongst others stationarity of the measured data and a fully developed turbulence. The simplest method for obtaining the fluctuating components for covariance calculation according to Reynolds averaging rules under ideal stationary conditions is the so called mean removal method. However steady state conditions rarely exist in the atmosphere, because of the diurnal cycle, changes in meteorological conditions, or sensor drift. All these phenomena produce trends or low-frequency changes superimposed to the turbulent signal. Different methods for trend removal have been proposed in literature; however a general agreement on how separate low frequency perturbations from turbulence has not yet been reached. The most commonly applied methods are the linear detrending (Gash and Culf, 1996) and the high-pass filter, namely the moving average (Moncrieff et al., 2004). Moreover Vickers and Mahrt (2003) proposed a multi resolution decomposition method in order to select an appropriate time scale for mean removal as a function of atmospheric stability conditions. The present work investigates the performance of these different detrending methods in removing the low frequency contribution to the turbulent fluxes calculation, including also a spectral filter by a Fourier decomposition of the time series. The different methods have been applied to the calculation of the turbulent fluxes for different scalars (temperature, ultrafine particles number concentration, carbon dioxide and water vapour concentration). A comparison of the detrending methods will be performed also for different measurement site, namely a urban site, a suburban area, and a remote area in Antarctica. Moreover the performance of the moving average in detrending time series has been analyzed as a function of the averaging windows for different scalars in different measurement campaigns.

We investigate the time intermittency of turbulent transport associated with the birth-death of self-organized coherent structures in the atmospheric boundary layer. We apply a threshold analysis on the increments of turbulent fluctuations to extract sequences of rapid acceleration events, which is a marker of the transition between self-organized structures. The inter-event time distributions show a power-law decay psi(t) proportional to  1/?, with a strong dependence of the power-law index ? on the threshold. A recently developed method based on the application of event-driven walking rules to generate different diffusion processes is applied to the experimental event sequences. At variance with the power-law index ? estimated from the inter-event time distributions, the diffusion scaling H, defined by hX2it2H , is independent from the threshold. From the analysis of the diffusion scaling it can also be inferred the presence of different kind of events, i.e. genuinely transition events and spurious events, which all contribute to the diffusion process but over different time scales. The great advantage of event-driven diffusion lies in the ability of separating different regimes of the scaling H. In fact, the greatest H, corresponding to the most anomalous diffusion process, emerges in the long time range, whereas the smallest H can be seen in the short time range if the time resolution of the data is sufficiently accurate. The estimated diffusion scaling is also robust under the change of the definition of turbulent fluctuations and, under the assumption of statistically independent events, it corresponds to a self-similar point process with a well-defined power-law index ?_D= 2.1, where D denotes that ?_D is derived from the diffusion scaling. We argue that this renewal point process can be associated to birth and death of coherent structures and to turbulent transport near the ground, where the contribution of turbulent coherent structures becomes dominant.

Organic (OC) and Elemental Carbon (EC) are important components of atmospheric aerosol particles, playing a key role in climate system and potentially affecting human health. There is a lack of data reported for Southern Italy and this work aims to fill this gap, focusing the attention on the long-term trends of OC and EC concentrations in PM2.5 and PM10, and on atmospheric processes and sources influencing seasonal variability. Measurements were taken at the Environmental-Climate Observatory of Lecce (SE Italy, 40°20'8''N-18°07'28''E, 37 m a.s.l.), regional station of the Global Atmosphere Watch program (GAW-WMO). Daily PM10 and PM2.5 samples were collected between July 2013 and July 2016. In addition, starting in December 2014, simultaneous equivalent Black Carbon (eBC) concentrations in PM10 were measured using a Multi Angle Absorption Photometer. A subset of 722 PM samples (361 for each size fraction) was analysed by using a thermo-optical method with a Sunset Laboratory OC/EC analyser, to determine elemental and organic carbon concentrations. The average PM10 and PM2.5 concentrations were 28.8 µg/m3 and 17.5 µg/m3. The average OC and EC concentrations in PM10 were 5.4 µg/m3 and 0.8 µg/m3, in PM2.5 these were 4.7 µg/m3 and 0.6 µg/m3. Carbonaceous content was larger during cold season with respect to warm season as well as secondary organic carbon (SOC) that was evaluated using the OC/EC minimum ratio method. SOC was mainly segregated in PM2.5 and represented 53% - 75% of the total OC. A subset of EC data was compared with eBC measurements, showing a good correlation (R2=0.80), however, eBC concentrations were higher than EC concentrations of an average factor of 1.95 (+/- 0.55 standard deviation). This could be explained by the presence of a contribution of Brown Carbon (BrC), for example from biomass burning, in eBC measurements. Weekly patterns showed a slight decrease of carbon content during weekends with respect to weekdays especially visible on eBC concentration due to the decrease of road traffic emissions. The daily patterns of hourly eBC concentrations showed a decrease in central diurnal hours, due to the cycle of planetary boundary-layer height, and concentrations peaks during rush hours due to road traffic emissions.

A one-year (July 2013-July 2014) dataset of PM2.5 and PM10 was collected at the Environmental-Climate Observatory (regional station of the Global Atmosphere watch - GAW-WMO), recently built in an urban background area in Lecce (SE Italy, 40°20'8''N-18°07'28''E, 37 m asl) within the I-AMICA project (PON R&C 2007-2013). Roughly, one sample every three days was chemically analysed for a total of 226 simultaneous samples (113 for each size fraction). Elemental and organic carbon were determined via thermo-optical method (Sunset OC/EC analyser, NIOSH5040 protocol), major ions Cl-, NO3-, SO42-, C2O42-, Ca2+, Na+, K+, Mg2+ via IC and 23 metals via ICP-MS (Li, Al, Ti, V, Mn, Fe, Co, Cu, Zn, As, Se, Rb, Sr, Nb, Cd, Sb, Ba, La, Ce, Nd, Dy, Pb, Th). The dataset was analysed using mass closure stoichiometric calculations for sea-spray, secondary inorganic aerosol (SIA) and crustal matter and using Positive Matrix factorization model (PMF5) to investigate the seasonal trends of eight particle sources (sea-spray, nitrate, sulphate, biomass burning, crustal, crustal carbonates, traffic, and industrial). Several cases of sea-spray events were observed with an average contribution of 16% to the coarse fraction (PM10-2.5) and 3% to PM2.5. Larger contributions were observed in autumn and winter and in high winds periods. Sea-spray interacted with nitric acid with a consequent chloride depletion, 60% on average for both PM2.5 and PM10. The Cl- depletion was significantly larger at high temperature during spring and summer with a trend opposite to that of secondary nitrate that was lower during spring and summer due to its thermal instability. Secondary nitrate had larger concentration in the coarse fraction at high temperature, instead at lower temperature the fine fraction of nitrate dominated. Organic matter was evaluated as OM=1.6xOC and represented 31% (PM10) and 43% (PM2.5), EC represented 2.7% (PM10) and 3.1% (PM2.5). Carbonaceous species were higher during autumn and winter with OC well correlated with K+ supporting the relevant contribution of biomass burning found with PMF5. Secondary organic carbon, evaluated with the minimum OC/EC ratio, was entirely segregated in PM2.5 accounting for 80% of total OC. Two crustal contributions were found, one characterised by metal oxides representing long-range transport of dust including Saharan dust advection, and the other characterised by crustal carbonates (mainly calcium carbonates) compatible with the local soil composition (limestone). Secondary sulphate was mainly ammonium sulphate/bisulphate entirely segregated in PM2.5, however, during intense cases of Saharan dust advection, a coarse component of CaSO4 was observed.

Particulate matters and ozone are often neglected as pollutant elements when people deal with widespread pollution. Particulate matters PM 10 , PM 2.5 , are produced by human activities namely industries and car traffic but also by natural activities like blowing wind from desert, volcanoes, etc... Ozone, instead, has a double consideration: it is beneficial as ozone layer in the upper atmosphere because it serves as natural filter to reduce UV rays that arrive at earth surface. But at ground level, high amounts of ozone, in terms of concentration are harmful for human health. The research presents the effect of wind in a transitional and seasonal period on particulate matters and ozone. The paper also illustrates the application of retarded differential functional equations or delayed differential functional equations for studying the effect of wind in pollution distribution.

Measurements of vertical turbulent fluxes of particles in urban areas are a powerful tool to characterise road traffic pollution and the dynamics of particles in the urban surface layer (Deventer et al., 2015). This information allow characterising the exchange of particles between a city and the atmosphere. In this work, size-segregated fluxes of particles (size range 0.009-3 µm) and CO2 were investigated in the urban area of Lecce (South Italy) together with fluxes of sensible and latent heat. Measurements were taken at 14 m above the ground on the roof of a building in using the eddy covariance (EC) approach (Contini et al, 2012).Measurements were carried out from 10th March to 24th April 2015 during the experimental campaign AFIRE (Aerosol Fluxes in uRban Environment) using an optimized setup that comprised a Condensation Particle Counter (CPC, Grimm 5.403) and an Optical Particle Counter (OPC, Grimm 1.109), coupled with an ultrasonic anemometer and an IR gas analyzer (Licor LI-7500) for CO2 and H2O vapour concentration measurements. The synchronized application of CPC and OPC allowed the direct calculation of particle number concentration and fluxes, for diameters from 0.009 to 0.25 µm by the CPC and from 0.25 to 3 µm in the 16 individual size bins provided by the OPC. The data sets needed an accurate verification and a consistent post processing (de-spiking of time series, detrending, removal of non-stationary periods) to reduce the effects of meteorological parameters on the calculations of fluxes. Furthermore, because the measurement site was located near various buildings, the subset of data corresponding to wind direction from SW to NNE were selected (leaving 59% of the data) to minimize flow distortions. Fluxes were corrected for high frequency losses due to the limited time response of the CPC (1.3s) and of the OPC (0.5s) and for the effect of density fluctuations. The aim of this work was to characterize the dynamics of atmospheric aerosol and CO2 through an analysis of number concentrations and fluxes patterns and their correlation with energy fluxes, meteorological parameters, and vehicular traffic rate. Concentrations and fluxes footprints were also evaluated and analyzed to interpret concentration and fluxes daily patters and their correlation with the local micrometeorology. The average particle daily concentration patterns show that the major contribution (~104 /cm3) comes from particles corresponding to smaller diameters and during weekdays. During daytime, the data show two large concentration peaks in morning and evening and a midday peaks indicating a correlation with intense vehicular traffic but also a possible influence of nucleation events. A similar analysis was done for CO2/H2O concentration showing that the average CO2 concentration had a different behavior, with a decrease in diurnal hours, due to the influence of background transport and of the biogenic cycle.The correlation analysis of the concentration time

Atmospheric aerosols have potential effects on human health, on the radiation balance, on climate, and on visibility.The understanding of these effects requires detailed knowledge of aerosol composition and size distributionsand of how the different sources contribute to particles of different sizes. In this work, aerosol sampleswere collected using a 10-stage Micro-Orifice Uniform Deposit Impactor (MOUDI). Measurements were takenbetween February and October 2011 in an urban background site near Lecce (Apulia region, southeast of Italy).Samples were analysed to evaluate the concentrations of water-soluble ions (SO4 2-, NO3-, NH4+, Cl-, Na+, K+,Mg2+ and Ca2+) and of water-soluble organic and inorganic carbon. The aerosols were characterised by twomodes, an accumulation mode having a mass median diameter (MMD) of 0.35 ± 0.02 ?m, representing51 ± 4% of the aerosols and a coarse mode (MMD = 4.5 ± 0.4 ?m), representing 49 ± 4% of the aerosols.The data were used to estimate the losses in the impactor by comparison with a low-volume sampler. The averageloss in the MOUDI-collected aerosol was 19 ± 2%, and the largest loss was observed for NO3- (35 ± 10%).Significant losses were observed for Ca2+ (16 ± 5%), SO4 2 - (19 ± 5%) and K+ (10 ± 4%), whereas the lossesfor Na+ and Mg2+ were negligible. Size-segregated source apportionment was performed using Positive MatrixFactorization (PMF), which was applied separately to the coarse (size interval 1-18 ?m) and accumulation (sizeinterval 0.056-1 ?m) modes. The PMF model was able to reasonably reconstruct the concentration in each sizerange.The uncertainties in the source apportionment due to impactor losseswere evaluated. In the accumulationmode, it was not possible to distinguish the traffic contribution from other combustion sources. In the coarsemode, it was not possible to efficiently separate nitrate from the contribution of crustal/resuspension origin.

This paper analyses elemental (EC), organic (OC) and total carbon (TC) concentration in PM2.5 and PM10 samples collected over the last few years within several national and European projects at 37 remote, rural, urban, and traffic sites across the Italian peninsula.The purpose of the study is to obtain a picture of the spatial and seasonal variability of these aerosol species in Italy, and an insight into sources, processes and effects of meteorological conditions.OC and EC showed winter maxima and summer minima at urban and rural locations and an opposite behaviour at remote high altitude sites, where they increase during the warm period due to the rising of the Planetary Boundary Layer (PBL). The seasonal averages of OC are higher during winter compared to summer at the rural sites in the Po Valley (from 1.4 to 3.5 times), opposite to what usually occurs at rural locations, where OC increases during the warm period. This denotes the marked influence of urban areas on the surrounding rural environment in this densely populated region.The different types of sites exhibit marked differences in the average concentrations of carbonaceous aerosol and OC/EC ratio. This ratio is less sensitive to atmospheric processing than OC and EC concentrations, and hence more representative of different source types. Remote locations are characterised by the lowest levels of OC and especially EC, with OC/EC ratios ranging from 13 to 20, while the maximum OC and EC concentrations are observed at road-traffic influenced urban sites, where the OC/EC ratio ranges between 1 and 3. The highest urban impacts of OC and EC relative to remote and rural background sites occur in the Po Valley, especially in the city of Milan, which has the highest concentrations of PM and TC and low values of the OC/EC ratio.

The statistics of the fluctuating concentration field within a plume is important in the analysis of atmospheric dispersion of toxic, inflammable and odorous gases. Previous work has tended to focus on concentration fluctuations in single plumes released in the surface layer or at ground level and there is a general lack of information about the mixing of two adjacent plumes and how the statistical properties of the concentration fluctuations are modified in these circumstances. In this work, data from wind tunnel experiments are used to analyse the variance, skewness, kurtosis, intermittency, probability density function and power spectrum of the concentration field during the mixing of two identical plumes and results are compared with those obtained for an equivalent single plume. The normalised variance, skewness and kurtosis on the centre-lines of the combined plume increase with distance downwind of the stack and, in the two-source configuration, takes lower values than those found in the single plumes. The results reflect the merging process at short range, which is least protracted for cases in which the sources are in-line or up to 30° and more, the plumes are effectively side-by-side during the merging process and the interaction between the vortex pairs in each plume is strong. Vertical asymmetry is observed between the upper and the lower parts of the plumes, with the upper part having greater intermittency (i.e. the probability that no plume material is present) and a more pronounced tail to the concentration probability distribution. This asymmetry tends to diminish at greater distances from the source but occurs in both buoyant and neutral plumes and is believed to be associated with the 'bending-over' of the emission in the cross-flow and the vortex pair that this generates. The results allowed us to identify three phases in plume development. The first, very near the stack, is dominated by turbulence generated within the plume and characterised by concentration spectra with distinct peaks corresponding to scales comparable with those of the counter-rotating vortex pair. A second phase follows at somewhat greater distances downwind, in which there are significant contributions to the concentration fluctuations from both the turbulence internal to the plume and the external turbulence. The third phase is one in which the concentration fluctuations appear to be controlled by the external turbulence present in the ambient flow. © 2013 Springer Science+Business Media Dordrecht.

The direct influence of ship traffic on atmospheric levels of coarse and fine particulate matter (PM2.5, PM10) and fifteen polycyclic aromatic hydrocarbons (PAHs) has been estimated in the urban area of Venice. Data analysis has been performed on results collected at three sites over the summer, when ship traffic is at a maximum. Results indicate that monitoring of the PM daily concentrations is not sufficiently detailed for the evaluation of this contribution, even though it could be useful for specific markers such as PAHs. Therefore a new methodology, based on high temporal resolution measurements coupled with wind direction information and the database of ship passages of the Harbour Authority of Venice has been developed. The sampling sites were monitored with optical detectors (DustTrack (R) and Mie pDR-1200) operating at a high temporal resolution (20s and Is respectively) for PM2.5 and PM10. PAH in the particulate and gas phases were recovered from quartz fibre filters and polyurethane foam plugs using pressurised solvent extraction, the extracts were then analysed by gas chromatography-high-resolution mass spectrometry. Our results shows that the direct contribution of ships traffic to PAHs in the gas phase is 10% while the contribution to PM2.5 and to PM10 is from 1% up to 8%. (C) 2011 Elsevier Ltd. All rights reserved.

The Fourier transform infrared (FTIR) spectroscopy allows the measurement of absorption peaks, due to vibrational transitions of individual chemical bonds, leading to the identification and quantification of main functional groups in a complex system. A number of investigations reporting the FTIR spectra of airborne aerosol samples have appeared in the last years (Coury and Dillner, 2009).In the attenuated total reflectance (ATR) mode, the sample is placed directly on a transparent crystal with a high refractive index, through which the IR beam is passed. The spectrum is then measured detecting the attenuation of the light reflected within the crystal and delivered to the detector. The path length depends solely on the penetration depth of the evanescent wave beyond the interface; therefore, the technique is suitable for analysing thin solid films with high sensitivity and repeatability.In this work, we have employed the ATR-FTIR technique for analysing thin solid films of particulate matter (PM) components, extracted from filter-deposited aerosol material, by solubilisation in deionized water. The goal was the identification of functional groups, soluble in aqueous biological fluids, able to influence the toxicological potential of airborne particles, in order to elucidate the relationships between PM chemical characteristics and human health effects.

Nell'ambito del progetto PON I-AMICA (www.i-amica.it), è stato raccolto un dataset annuale (Luglio 2013-Luglio 2014) di PM2.5 e PM10 presso l'Osservatorio Climatico-Ambientale di Lecce (40°20'8''N-18°07'28''E, 37 m asl), stazione regionale della rete GAW-WMO (Global Atmosphere Watch), con lo scopo di analizzare i trends stagionali dei contributi delle diverse sorgenti antropiche e naturali alla frazione fine e coarse del particolato. Campioni giornalieri sono stati raccolti su filtri in quarzo utilizzando un campionatore automatico a raggi ? (Swam5A Dual Channel Monitor, FAI Instruments, 2.3 m3/h). La caratterizzazione chimica è stata eseguita su 226 campioni (113 per ogni frazione dimensionale) per la determinazione dei principali metalli via ICP-MS (Li, Al, Ti, V, Mn, Fe, Co, Cu, Zn, As, Se, Rb, Sr, Nb, Cd, Sb, Ba, La, Ce, Nd, Dy, Pb, Th), dei principali ioni solubili via IC (Cl-, NO3-, SO42-, C2O42-, Ca2+, Na+, NH4+, K+, Mg2+) e della componente carboniosa (EC e OC) mediante il metodo termo-ottico (rilevatore Sunset, protocollo NIOSH5040).

La valutazione dell'impatto delle centrali termoelettriche a carbone alle concentrazioni di particolato atmosferico è importante per la valutazione dei rischi per la salute umana e dei potenziali effetti sui cambiamenti climatici. L'applicazione di modelli a recettore non è semplice perché il profilo chimico delle emissioni di tali centrali è caratterizzato da Si e Al ed è collineare al profilo del materiale terrigeno [1]. In questo lavoro è stata sviluppata una metodologia, basata sul modello Positive Matrix Factorization (PMF) e sul rapporto diagnostico Si/Al, per discriminare il contributo della centrale a carbone dal contributo della crosta terrestre. La metodologia è stata applicata a 347 campioni giornalieri di PM10 raccolti in tre siti (urbano, di fondo urbano e rurale) in prossimità della centrale di Torrevaldaliga Nord (Civitavecchia), localizzati tra 2.8 e 5.8 km dalla centrale stessa. I risultati hanno mostrato un contributo primario medio della centrale pari al 2% (± 0.8%) nell'area in esame, con lievi differenze nei tre siti analizzati .La validità della metodologia è stata analizzata confrontando i risultati ottenuti con due approcci indipendenti: il modello a recettore Chemical Mass Balance (CMB) e la correlazione del contributo del fattore Si-Al del PMF con le direzioni del vento e con i risultati del sistema modellistico a dispersione Calpuff/Calmet per stimare il contributo della centrale. Inoltre, è stato sviluppato un approccio che integra i risultati del modello a dispersione ed i risultati dei modelli a recettore (PMF e CMB) per stimare il contributo della centrale al solfato di ammonio secondario Tale contributo è risultato, in media, pari a 1.5% del PM10 (± 0.3%) con limitata variabilità tra i tre siti di misura.

Surface chemical composition of particles has a key role in determining the reactivity and optical properties of atmospheric aerosol. This composition depend on the particles sources and formation processes and it influences human health and climate. In this work, the X-ray photoelectron spectroscopy (XPS) has been used for the systematic surface characterization of atmospheric particles of different sizes, collected using a 10-stage MOUDI-II rotating cascade impactor in an urban background site. The high resolution XPS spectra allowed to distinguish different organic functional groups (C-C/CC, -C-O, -CO/-C(O)N, -C(O)O, C-O3=) and to speciate the detectable hetero-elements, sulphur (S-O42-, sulphone and sulphide compounds), nitrogen (N-H4+, N-O3-, N-O2- and organic-nitrogen compounds), sodium (Na⁺) and chlorine (Cl^-) species. Significant differences in particles belonging to accumulation (small particles) and coarse (large particles) modes were observed being due to the formation processes and sources from which particles originated. The oxygen concentrations is inversely correlated with carbon concentrations, however, the content of oxidized organic carbon is not correlated with oxygen content confirming that the oxygen increment observed in large particles can likely be attributed to the contribution of inorganic species (crustal origin). The speciation of nitrogen showed ammonium only in the accumulation mode and nitrate only in coarse mode excluding the presence of ammonium nitrate of secondary origin in the area studied. A correlation of Na and Cl was attributed to the marine contribution with an excess of Cl on the surface correlated with the depletion of Cl observed in the bulk of particles.