1,720,982 research outputs found
Sources and distribution of tracer elements in road dust: The Venice mainland case of study
No full textRoad dust is an important non-exhaust traffic source of atmospheric particulate matter, from re-suspension of finer particles carried out by wind and traffic flow. Particles of road dust have both natural and anthropogenic origin; the latter is characterized by higher concentrations of several pollutants and are significantly emitted by other non-exhaust traffic source such as the brake and road wear process. Therefore the discrimination between atmospheric particles directly emitted from abrasion process and those related to re-suspension is currently an open issue.
Unlike the exhaust sources related to the fuel combustion, the non-exhaust emissions are not regulated by Communitarian Directives, although their percentage contribution is becoming more relevant due to the recent technological upgrades in the automotive field, focused on the reduction of exhaust emissions.
In this work we studied the morphology and the chemical composition of road dust particles collected on urban, sub-urban and rural roads of Venice mainland (Northern Italy) in August 2013. Results of SEM-EDS and ICP-OES were processed with statistical tools (i.e., enrichment factors and principal components analysis) in order to identify the main pollutant sources affecting the monitored areas. Peculiar associations among Cr, Mn, Zn, Cu, Fe suggested brake pads and tires wear as the dominant source of these elements, whereas the presence of Pb, Co, Ba, Ti was attributed to the tear of the painted horizontal signals. Moreover, the presence of particles originated from the latter source was also confirmed by the presence of glass beads with diameters ranging from 20 μm to 250 μm
Secondary inorganic aerosol evaluation: Application of a transport chemical model in the eastern part of the Po Valley
No full textSecondary inorganic aerosol (SIA) represents an important component of fine particulate matter in Europe. A photochemical model has been used to assess the distribution of secondary inorganic ions (sulfate, nitrate and ammonium) in the eastern part of the Po Valley, close to Venice. Specific meteorological and environmental conditions and very highly urbanized and industrialized areas make this domain one of the most polluted in Europe. Several studies have been conducted to assess particulate matter (PM10 and PM2.5) areal distribution. However, SIA formation dynamics are still a research subject especially in the transition environments, where the changes in the orography and in the land-use can affect air mass movements and atmospheric composition. This paper is a first attempt to simulate SIA distribution by using a photochemical model in the sea/land Venice transition area. Moreover, a modeling approach with clean boundary conditions has been used to check local and regional influence on SIA levels in the domain. Results reveal that, despite the importance of regional influences, local formation processes are important in SIA distribution especially during warm periods. SO42- and NH4+ are more linked to emission sources distribution than NOT that tends to be more diffused in the study area. The use of a photochemical model, suitably tested in a such complex area, can improve air pollution knowledge and can help in air quality decision making
Gaseous and PM10-Bound Pollutants Monitored in Three Sites with Differing Environmental Conditions in the Venice Area (Italy)
No full textUnderstanding and controlling air pollution in highly populated areas is very important, although interpreting the levels of gaseous pollutants and airborne particulate matter is complicated by dominant natural and anthropogenic emissions, micro-meteorological processes, and chemical reactions which take place directly in the atmosphere. For this reason, it is very difficult to relate the characteristics of air pollution to one or more specific emission sources. The aim of this paper is to detect associations among elements and organic compounds emitted from specific sources by means of chemical analyses, statistical processing of data, seasonal evolution study, and geochemical considerations to trace their origin. A detailed characterization of air quality during the period September 2000–September 2001 was carried out in three locations of the Venice region: A heavy traffic urban site, a public park, and the island centre of the city of Venice. Twenty-eight inorganic elements, four polycyclic aromatic hydrocarbons, CO and benzene were quantified and processed by a statistical procedure based on factor analysis considering variations on a seasonal basis. Results show the presence of associations between elements and compounds with the same behaviour in all sampling points. This indicates that several pollutants originate from a common source, and are then “diluted” throughout the study area, maintaining the imprint of their origin. Pt, polycyclic aromatic hydrocarbons, CO and benzene originating from the exhaust gas of vehicles are all linked in the traffic factor, whereas Cd is associated with Se, having a common source in industrial processes
On the estimation of precision in the measurement of elemental concentration in atmospheric particulate
No full textThe measurement of elemental concentration of atmospheric particulate involves collection, preparation
and processing protocols that contribute to the result uncertainty, which is often attributed to the sole error
given by the final used analytical technique. In this work, a detailed estimation of precision to associate to the
characterization of PM1 collected near the airstrip of Venice airport is presented. This evaluation is particularly
critical for example in the analyses performed by Positive Matrix Factorization receptor model, that allows to
identify and to estimate the emission contribution of the sources affecting the atmosphere of a monitored area.
PM1 air concentration was determined gravimetrically after appropriate stabilization of the samples, that were
subsequently digested with a mixture of acids. The digested samples were then twice diluted, and analyzed by
Inductively Coupled Plasma – Optical Emission Spectroscopy. The processing steps that give the higher contribution
to the result uncertainty are pointed out
Elemental characterization of PM2.5 in different environmental condition in the Venice area
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Characterization of road dust and resuspended particles close to a busy road of Venice mainland (Italy)
No full textRoad trafc contributes to atmospheric particulate matter with exhaust (fuel combustion) and non-exhaust (wear of vehicle
parts such as brake, tires and abrasion of the road surface) emissions. Road dust is composed of particles belonging to natural
and anthropogenic sources related in large part to road trafc. To date, understanding the relative contribution of road dust
resuspension and particles directly emitted by abrasion to particulate matter is still a matter of debate. In this work, road dust
and resuspended particles samples are collected at diferent heights and with increasing sampling time near a busy road of
Venice mainland. Elemental composition and morphology of particles were investigated with a combination of techniques:
inductively coupled plasma optical emission spectroscopy (ICP-OES), inductively coupled plasma mass spectrometry (ICPMS), laser difraction analysis and scanning electron microscopy–energy-dispersive X-ray spectrometry (SEM–EDX). The
diferences between deposited and resuspended particles were highlighted and the main pollutant sources were identifed
to study the resuspension process related to the trafc fow. Resuspended particles were divided into six groups related to
the presence of anti-ice material, to soil resuspension and to the road surface and vehicle parts wear. The contributions of
clustered particles vary with the height from the road level. This study, the frst one focusing on the road trafc particles
resuspension in Veneto region, will provide topical information for the identifcation of this source in atmospheric particulate
samples
Geochemical characterization of PM10 emitted by glass factories in Murano, Venice (Italy)
No full textTrace metals, Polycyclic aromatic hydrocarbons, Lagoon of Venice, Glass manufacturin
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