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

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.

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.

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.

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.

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.

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

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.

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.

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.

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.

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

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.

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.