1,720,986 research outputs found
Caratterizzazione chimica del particolato atmosferico in Veneto: Dieci anni di studi
No full textLo studio della composizione del particolato atmosferico (PM) nel Veneto, accoppiato all'acquisizione dei dati meteorologici, ha offerto molte opportunità per comprendere gli andamenti stagionali e le sorgenti del particolato atmosferico. Un risultato ormai consolidato offerto da queste analisi mostra che durante il periodo invernale, così come gran parte della pianura padana, vi è una forte associazione tra le concentrazioni di PM con le sostanze strettamente legate alla combustione della biomassa legnosa. Inoltre risulta non trascurabile il contributo dell'aerosol secondario che è legato alle emissioni di precursori gassosi da traffico, combustioni per il riscaldamento residenziale. Al contrario durante il periodo estivo risulta molto più importante il contributo dovuto alla risospensione di materiale crostale e del "road dust". Gli interventi per la riduzione dell'inquinamento atmosferico nel corso degli anni si sono dimostrati spesso inefficaci perché non hanno inciso in modo drastico sulla riduzione delle sorgenti e non hanno modificato i comportamenti sociali su larga scala
Long-term impact of agricultural practices on the diversity of small mammal communities: a case study based on owl pellets
No full textSmall mammals have been seldom used as indicators of biodiversity responses to environmental changes, probably because their long-term population trend in a given area is not easy to monitor. To assess the impact of agricultural intensification in a protected area of northern Italy, we compared the composition of its small mammal communities, as assessed in 1994–1995 and 2015–2016 by the analysis of owl pellets (N = 265 and 302, respectively), which provides an effective and affordable method for assessing changes in the diversity and structure of small mammal assemblages over time. We recorded a sharp reduction in the frequency of occurrence of shrews (Sorex spp. and Crocidura spp.), which were replaced by generalist/anthropophilic rats (Rattus norvegicus) and house mice (Mus domesticus). Overall richness and diversity of the community varied only slightly, while trophic level and functional diversity indices clearly reflected the decline of the predator-level fraction of the community. We could reliably exclude both broad-scale land use- and climate changes as drivers of variation in the composition of small mammal communities and ascribe the decline of insectivores to changes in agricultural practices, namely the increase in cover of maize fields and spread of both herbicides and insecticides. Our results are consistent with the general opinion that crop specialization and increasing chemical inputs reduce the diversity and abundance of invertebrate prey, with bottom-up effects on higher trophic levels
Thirteen years of air pollution hourly monitoring in a large city: Potential sources, trends, cycles and effects of car-free days
No full textThirteen air pollutant concentrations were measured hourly for 13 years (2000-2013) at an urban background site of a large city in the eastern Po Valley (Italy) and results were chemometrically analysed. The pollutant list includes CO, NO, NO2, NOx, O-3, SO2, benzene, toluene, ethylbenzene, o-, m- and p-xylenes and PM10, all known or suspected of having adverse effects on human health. The hourly data were statistically processed to detect the long-term trends in relation to the changes in the emission scenarios occurred in the last decade. The most probable emission sources and atmospheric photochemical processes were investigated by analyzing the seasonal, weekly, diurnal cycles of pollutants and the lagged correlations amongst pollutants. The role of micrometeorological factors upon the air quality was assessed by analyzing the relationships with key weather parameters, while the location of the potential sources was studied by matching atmospheric circulation and pollution data through bivariate polar plots and conditional probability functions. In addition, a new statistical procedure is presented and tested to analyze the periods when common mitigation measures were adopted in the city (e.g., the total stop of traffic and car-free days) and to evaluate their real effect upon the air quality. By providing direct information on the levels and trends of key pollutants, this study finally enables some general considerations about air pollution in an important hotspot of Southern Europe, the eastern Po Valley, where the levels of some key pollutants are still far from meeting the EC limit and target values. It may help policy-makers to take successful mitigation measures
Seasonal trends and spatial variations of PM10-bounded polycyclic aromatic hydrocarbons in Veneto Region, Northeast Italy
Full text linkThe Veneto Region extends for w18.4$103 km2 in the northeastern part of the Po Valley and includes
mountains, hills, plain and coastal environments with very different and discontinuous anthropogenic
pressures. Although many efforts have been made to mitigate air pollution, the European air quality
standards for atmospheric pollutants are frequently breached. This study investigates the levels of eight
PM10-bound PAHs collected in 21 stations categorized as rural background, urban and suburban backgrounds,
traffic and industrial hot-spots during one year (2011). Data were statistically processed to
detect the PAH seasonal trends, their relationship with other air pollutants and micro-meteorological
parameters and the space variations at a regional scale. Results show that PAHs levels are relatively
high in the largest part of the region, with 10 sites exceeding the levels of BaP targeted by the European
legislation. Two sites exhibited anomalously high PAHs concentrations and this anomaly became even
more evident when considering the population density as a surrogate for the potential anthropogenic
pressure. The PAHs levels were found directly proportional to other gaseous pollutants (CO, NO, NOx,
SO2) suggesting common polluting sources. The analysis of time trends of PAH concentrations reveals
significant coincidences throughout the region, i.e. simultaneous changes are observed in most sites as a
consequence of similar emission sources and accumulation/removal processes. In this scenario, the
control strategies currently imposed at local level (e.g. traffic limitations) have proven scarcely effective
in mitigating air pollution and a real coordination at regional or even interregional level cannot be
further postponed. Peculiar features of the PAHs pollution in the Veneto were also identified and some
measures for protecting the human health were suggested
The dark side of the tradition: The polluting effect of Epiphany folk fires in the eastern Po Valley (Italy)
Full text linkIn the Veneto Region (Po Valley, Northeastern Italy) on the eve of Epiphany, an important religious celebration, during the night between January 5th and 6th thousands of folk fires traditionally burn wooden material. The object of this study is to characterize the 2013 episode, by monitoring the effects on the air quality in the region's lowlands. The daily concentrations of PM2.5 and PM10 exceeded 250 and 300 μg m− 3, respectively and the PM10 hourly values were above 600 μg m− 3 in many sites. The levels of total carbon, major inorganic ions, polycyclic aromatic hydrocarbons and biomass burning tracers (levoglucosan and K+) were measured in 84 samples of PM10 and 38 of PM2.5 collected at 32 sites between January 4th and 7th. Total carbon ranged from 11 μg m− 3 before the pollution episode to 131 μg m− 3 a day afterwards, K+ from 0.6 to 5.1 μg m− 3, benzo(a)pyrene from 2 to 23 ng m− 3, and levoglucosan from 0.5 to 8.3 μg m− 3. The dispersion of the particulate matter was traced by analyzing the levels of PM10 and PM2.5 in 133 and 51 sites, respectively, in the Veneto and neighboring regions. In addition to biomass burning the formation of secondary inorganic aerosol was revealed to be a key factor on a multivariate statistical data processing. By providing direct information on the effects of an intense and widespread biomass burning episode in the Po Valley, this study also enables some general considerations on biomass burning practices
Air quality across a European hotspot: Spatial gradients, seasonality, diurnal cycles and trends in the Veneto region, NE Italy
Full text linkThe Veneto region (NE Italy) lies in the eastern part of the Po Valley, a European hotspot for air pollution. Data for key air pollutants (CO, NO, NO2, O3, SO2, PM10 and PM2.5) measured over 7 years (2008/2014) across 43 sites in Veneto were processed to characterise their spatial and temporal patterns and assess the air quality. Nitrogen oxides, PM and ozone are critical pollutants frequently breaching the EC limit and target values. Intersite analysis demonstrates a widespread pollution across the region and shows that primary pollutants (nitrogen oxides, CO, PM) are significantly higher in cities and over the flat lands due to higher anthropogenic pressures. The spatial variation of air pollutants at rural sites was then mapped to depict the gradient of background pollution: nitrogen oxides are higher in the plain area due to the presence of strong diffuse anthropogenic sources, while ozone increases toward the mountains probably due to the higher levels of biogenic ozone-precursors and low NO emissions which are not sufficient to titrate out the photochemical O3. Data-depth classification analysis revealed a poor categorization among urban, traffic and industrial sites: weather and urban planning factors may cause a general homogeneity of air pollution within cities driving this poor classification. Seasonal and diurnal cycles were investigated: the effect of primary sources in populated areas is evident throughout the region and drives similar patterns for most pollutants: road traffic appears the predominant potential source shaping the daily cycles. Trend analysis of experimental data reveals a general decrease of air pollution across the region, which agrees well with changes assessed by emission inventories. This study provides key information on air quality across NE Italy and highlights future research needs and possible developments of the regional monitoring network
Long-term trends of PM10-bound arsenic, cadmium, nickel, and lead across the Veneto region (NE Italy)
Full text linkSince the mid-90s, the European Community has
adopted increasingly stringent air quality standards.
Consequently, air quality has generally improved across
Europe. However, current EU standards are still breached
in some European hotspots.
The Veneto region (NE Italy) lies in the eastern
part of the Po Valley, a major European hotspot for air
pollution, where EU standards for particulate matter,
nitrogen oxides and ozone are still breached at some
sites.
This study aims to analyse the PM10-bound
arsenic, cadmium, nickel, and lead concentrations over a
10 years-long period (2010-2020) in the Veneto Region
by using data collected by the local environmental
protection agency (ARPAV) in 20 sampling stations
mostly distributed across the plain areas of the region
and categorized as rural (RUR), urban (URB), and
suburban (SUB) background, industrial (IND) and traffic
(TRA) hotspots (Figure 1). The comprehensive dataset
discussed in this study was statistically investigated to
detect the seasonal trends, their relationship with other
air pollutants and meteorological parameters and their
spatial variations at a regional scale. This study
completes previous air quality studies over the Veneto
region for gaseous pollutants and bulk PM10 (Masiol et al.
2017).
Samplings were carried out according to CEN EN
12341:1998 standard on quartz fibre filters and were
continuous for 24 h, starting at midnight. The gravimetric
determination of PM10 mass was measured following
the CEN EN 12341:2014 standard. The elemental analysis
was performed using an ICP-MS (Agilent 7700) after acid
digestion (EN 14902:2005).
The trends were analysed using different
approaches on the monthly-averaged data. The shape of
trends and their seasonal variations were assessed
through the seasonal-trend decomposition time series
procedure based on “Loess” (STL). The linear trends were
computed by the Mann-Kendall trend test (p < 0.05) and
the Theil-Sen nonparametric estimator of slope (MK-TS).
Since this latter analysis assumes monotonic linear
trends and does not consider the shape of trends, the
presence of possible breakpoints was investigated using
the piecewise regression.
Generally, monthly patterns of all analysed
elements show higher concentrations during winter,
following PM10 concentrations. Some exceptions were
detected and discussed. Results of trend analysis indicate
statistically significant negative (decreasing) or null linear
trends in almost all stations. A few positive (increasing)
but not statistically significant trends were also detected.
Some sites showed rapid decreases occurred in
short periods and linked to peculiar events or local
causes. Among others, several sites across the Venice
area showed significant drops of arsenic concentrations
after the REACH (Registration Evaluation Authorisation
of Chemicals) implementation (Formenton et al., 2021).
Data used in this study are provided by ARPAV (Agenzia
Regionale per la Prevenzione e Protezione Ambientale
del Veneto, https://www.arpa.veneto.it/)
A procedure to evaluate the factors determining the elemental composition of PM2.5. Case study: the Veneto region (northeastern Italy)
No full textThe Po Valley is one of the most important hot spots in Europe for air pollution. Morphological features and anthropogenic pressures lead to frequent breaching of air quality standards and to high-pollution episodes in an ~46 Ã 103-km2-wide alluvial lowland. Therefore, it is increasingly important to study the air quality in a wide geographical scale to better implement possible and successful mitigation measures. The Veneto region lies in the eastern part of the Po Valley and the elemental composition of PM has been mainly studied in the Venice area, whereas scarce data are available for the remaining territory of the region. In this study, the elemental composition of PM2.5was investigated over 1 year (2012â2013) at six major cities of the Veneto region. Samples were analyzed for 16 elements (Ca, Al, Fe, S, K, Mg, Ti, Mn, Zn, Ba, As, Ni, Pb, Sb, V, and Cu), and results were processed to investigate spatial and seasonal variations, the influence of meteorological factors, and the most probable sources by using a procedure based on (i) elemental ratios (Cu/Sb, Cu/Zn, Cu/Pb, Mn/V, V/Ni, and Zn/Pb), (ii) cluster analysis on wind data, and (iii) conditional probability function (CPF). The percentage of elements in PM2.5ranged between 11 and 20%, and Ca and S were the most abundant elements in the region. Typical seasonal variations and similar trends were exhibited by each element, especially in the lowland. Some elements such as Zn, K, Mn, Pb, and Sb were found at high concentrations during the cold period. However, no similar dispersion processes were observed throughout the region, and their concentrations were mostly depending on individual local sources. In the alpine and foothill parts of the region, lower concentrations were recorded with respect to the Po Valley cities, which resulted enriched of most of the elements considered in this study. The cluster analysis on wind data and the CPF of the ratio-related sources demonstrated that a widespread pollution condition exists in the region, apart from the coastal area. However, specific directions (e.g., a link with high-traffic roads, industrial areas, and airports) resulted the most probable explanation for each ratio-related source. In addition, the Veneto region hosts one of the most important Mediterranean ports for the cruise sector (Venice harbor), and its impact was previously demonstrated in the historical city center. In this study, the impact of Venice shipping emissions was estimated to be 3.5% of PM2.5in some particular days
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
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