1,720,983 research outputs found
Assessment of air pollutants contribution of harbour activities in Venice and Brindisi areas
Full text linkThe influence of in-port ships emissions to atmospheric pollutants concentration was investigated in the two Adriatic port-cities of Brindisi and Venice, integrating experimental data, modeling and emission inventories. In Brindisi, the contribution to concentration of gaseous pollutants (NO, NO2, SO2 and O3) and of particulate matter (in number and mass) of different sizes (range 0.009-32 μm) was estimated differentiating hotelling (including loading/unloading activities) and manoeuvring (ship arrival/departure) phases. Harbour logistics impact was substantial on concentrations of NO, NO2 and particles number (increased in 2014 compared to 2012) especially in the ultrafine fraction. In Venice multi-year data allowed evaluate the effectiveness of the European legislation (2005/33/EC) and of local mitigation strategies in lowering the primary contribution to PM2.5 although an increased ship traffic
Inter-annual trend of the primary contribution of ship emissions to PM2.5 concentrations in Venice (Italy): Efficiency of emissions mitigation strategies
Full text linkShips and harbour emissions are currently increasing, due to the increase of tourism and trade, with potential impact on global air pollution and climate. At local scale, in-port ship emissions influence air quality in coastal areas impacting on health of coastal communities. International legislations to reduce ship emissions, both at Worldwide and European levels, are mainly based on the use of low-sulphur content fuel. In this work an analysis of the inter-annual trends of primary contribution, ε, of tourist shipping to the atmospheric PM2.5 concentrations in the urban area of Venice has been performed.\ud
Measurements have been taken in the summer periods of 2007, 2009 and 2012. Results show a decrease of ε from 7% (±1%) in 2007 to 5% (±1%) in 2009 and to 3.5% (±1%) in 2012. The meteorological and icrometeorological conditions of the campaigns were similar. Tourist ship traffic during measurement campaigns increased, in terms of gross tonnage, of about 25.4% from 2007 to 2009 and of 17.6% from 2009 to 2012. The decrease of ε was associated to the effect of a voluntary agreement (Venice Blue Flag) for the use of low-sulphur content fuel enforced in the area between 2007 and 2009 and to the implementation of the 2005/33/CE Directive in 2010. Results show that the use of low-sulphur fuel could effectively reduce the impact of shipping to atmospheric primary particles at local scale. Further, voluntary agreement could also be effective in reducing the impact of shipping on local air quality in coastal areas
Concentration and size distribution of atmospheric particles in southern Italy during COVID-19 lockdown period
No full textMany countries imposed lockdown (LD) to limit the spread of COVID-19, which led to a reduction in the emission of anthropogenic atmospheric pollutants. Several studies have investigated the effects of LD on air quality, mostly in urban settings and criteria pollutants. However, less information is available on background sites, and virtually no information is available on particle number size distribution (PNSD). This study investigated the effect of LD on air quality at an urban background site representing a near coast area in the central Mediterranean. The analysis focused on equivalent black carbon (eBC), particle mass concentrations in different size fractions: PM(2.5) (aerodynamic diameter D(a) < 2.5 μm), PM(10) (D(a) < 10 μm), PM(10-2.5) (2.5 < D(a) < 10 μm); and PNSD in a wide range of diameters (0.01–10 μm). Measurements in 2020 during the national LD in Italy and period immediately after LD (POST-LD period) were compared with those in the corresponding periods from 2015 to 2019. The results showed that LD reduced the frequency and intensity of high-pollution events. Reductions were more relevant during POST-LD than during LD period for all variables, except quasi-ultrafine particles and PM(10-2.5). Two events of long-range transport of dust were observed, which need to be identified and removed to determine the effect of LD. The decreases in the quasi-ultrafine particles and eBC concentrations were 20%, and 15–22%, respectively. PM(2.5) concentration was reduced by 13–44% whereas PM(10-2.5) concentration was unaffected. The concentration of accumulation mode particles followed the behaviour of PM(2.5), with reductions of 19–57%. The results obtained could be relevant for future strategies aimed at improving air quality and understanding the processes that influence the number and mass particle size distributions
An inter-comparison of PM2.5 at urban and urban background sites: Chemical characterization and source apportionment
No full textA 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 (NH+4,Na+, and SO2-4) 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 lowCl-/Na+ ratios, suggested the presence of aged sea spraywith chloride depletion (about 79% of Cl-) and for-mation of sodium nitrate at both sites. In both sites, the non-sea-salt sulfate was about 97% of sulfate, and the strong correlation between SO2-4 and NH+4 indicated that ammonium was present as ammonium sulfate. How-ever, 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 fromOC, underestimating themarine contribution and overestimating the secondary sulfatewith respect to stoi- chiometric calculations. The application of speci?c constraints on PMF5.0 provided cleaner profiles, improving the comparison with stoichiometric calculations. The seasonal trends revealed larger biomass burning contribu- tions during the cold period at both sites due to domestic heating emissions added to those of agricultural prac-tices. 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 thewarmseason was compensated by an almost equivalent increase of sulfate
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Analysis of source chemical profiles, planning of the measurement campaign and of the chemical characterisation of aerosol
No full text
Stima del contributo al particolato ed agli IPA delle emissioni da traffico navale e da attività portuali nell’area di Brindisi
No full textObiettivo del lavoro è fornire una stima dell’impatto del traffico navale e delle relative attività portuali (arrivo/partenza/movimentazione e stazionamento di navi) sulla concentrazione di PM2.5, sulla concentrazione numerica
di particelle (PNC) e di idrocarburi policiclici aromatici (IPA), nella città portuale di Brindisi. Le attività sono state
condotte nell’ambito del progetto CESAPO da giugno a ottobre 2012. I contributi al PM2.5 ed al PNC sono stati ricavati
con una metodologia basata sull’accoppiamento di misure ad alta risoluzione temporale, direzione del vento e database dei
transiti delle navi. Sono state calcolate le medie a breve periodo (1 min) dei dati di concentrazione di PM2.5 e PNC per
mettere in evidenza i picchi di breve durata nelle serie temporali associate alle attività portuali, alle navi ed al traffico
veicolare connesso con le operazioni di carico e scarico. Le emissioni delle navi durante le fasi di manovra e stazionamento mostrano un chiaro pattern giornaliero, con due picchi distinti, specialmente per PNC, alle 7:00 e alle 18:00, da specifici settori di direzione del vento. Secondo l’approccio sviluppato da Contini et al. (2011, Journal of Environmental Management 92, 2119-2129), il contributo dovuto al traffico navale è pari al 7.4% (± 0.5%) per il PM2.5 ed al 26% (± 1%) per il PNC. Considerando anche il contributo delle attività portuali connesse, tali valori passano al 9.3% (± 0.5%) e al 39% (± 1%), rispettivamente. La concentrazione di IPA risulta maggiore nei campioni del settore portuale/industriale (5.34 ng/m3) rispetto all’intera area di Brindisi (3.89 ng/m3), soprattutto per il fenantrene e il fluorene. Il contributo locale dell’area portuale/industriale alla concentrazione di IPA nella fase gassosa è pari al 24%, mentre nella fase particolato è del 35%. Il contributo generale della stessa area agli IPA è del 54% e del 62%, rispettivamente in fase gassosa e particolato
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