Characterization and preliminary risk assessment of road dust collected in Venice airport (Italy)

Road dust is a non-exhaust source that can significantly contribute to atmospheric particulate by resuspension. Beside the issue of the overcoming of guidelines limits for the air quality, the characterization of this matrix is of crucially high interest for the inherent toxicity of resuspended particles, that can act as carriers of heavy metals and toxic-carcinogenic components. In this paper, road dust collected in the Venice international airport is characterized with a multi-technique approach in order to identify the main pollutant sources and to highlight the differences between airside/landside places. The most polluted sites are identified and a preliminary risk assessment is performed taking into account ingestion, dermal intake and inhalation of fugitive particulate pathways. Specifically, the main sources are related to construction activities, anti-icing safety procedures, and brake, tire and road wear; streets are the most polluted landside places; PAHs, Na, Al, Cu, Zn, Ag, Cd are more concentrated in airside area; as regards the risk assessment As, BaP, Cr, Sb, BaA, and BbF are the most critical pollutants. Considering the high number of people passing or working in this airport and the ongoing works related to its enlargement which promotes the emission and the resuspension of fugitive dusts, this research addresses a fundamental step for the protection of potential receptors

Urban air quality in a mid-size city — PM2.5 composition, sources and identification of impact areas: From local to long range contributions

Urban air quality represents a major public health burden and is a long-standing concern to European citizens. Combustion processes and traffic-related emissions represent the main primary particulate matter (PM) sources in urban areas. Other sources can also affect air quality (e.g., secondary aerosol, industrial) depending on the characteristics of the study area. Thus, the identification and the apportionment of all sources is of crucial importance to make effective corrective decisions within environmental policies. The aim of this study is to evaluate the impacts of different emissions sources on PM2.5 concentrations and compositions in a mid-size city in the Po Valley (Treviso, Italy). Data have been analyzed to highlight compositional differences (elements and major inorganic ions), to determine PM2.5 sources and their contributions, and to evaluate the influence of air mass movements. Non-parametric tests, positive matrix factorization (PMF), conditional bivariate probability function (CBPF), and concentration weighted trajectory (CWT) have been used in a multi-chemometrics approach to understand the areal-scale (proximate, local, long-range) where different sources act on PM2.5 levels and composition. Results identified three levels of scale from which the pollution arose: (i) a proximate local scale (close to the sampling site) for traffic non-exhaust and resuspended dust sources; (ii) a local urban scale (including both sampling site and areas close to them) for combustion and industrial; and (iii) a regional scale characterized by ammonium nitrate and ammonium sulfate. This approach and results can help to develop and adopt better air quality policy action

Hybrid multiple-site mass closure and source apportionment of PM2.5 and aerosol acidity at major cities in the Po Valley

This study investigates the major chemical components, particle-bound water content, acidity (pH), and major potential sources of PM2.5 in major cities (Belluno, Conegliano, Vicenza, Mestre, Padua, and Rovigo) in the eastern end of the Po Valley. The measured PM2.5 mass was reconstructed using a multiple-site hybrid chemical mass closure approach that also accounts for aerosol inorganic water content (AWC) estimated by the ISORROPIA-II model. Annually, organic matter accounted for 31-45% of the PM2.5 at all sites, followed by nitrate (10-19%), crustal material (10-14%), sulfate (8-10%), ammonium (5-9%), elemental carbon (4-7%), other inorganic ions (3-4%), and trace elements (0.2-0.3%). Water represented 7-10% of measured PM2.5. The ambient aerosol pH varied from 1.5 to 4.5 with lower values in summer (average in all sites 2.2±0.3) and higher in winter (3.9±0.3). Six major PM2.5 sources were quantitatively identified with multiple-site positive matrix factorization: secondary sulfate (34% of PM2.5), secondary nitrate (30%), biomass burning (17%), traffic (11%), re-suspended dust (5%), and fossil fuel combustion (3%). Biomass burning accounted for ∼90% of total PAHs. Inorganic aerosol acidity was driven primarily by secondary sulfate, fossil fuel combustion (decreasing pH), secondary nitrate, and biomass burning (increasing pH). Secondary nitrate was the primary driver of the inorganic AWC variability. A concentration-weighted trajectory (multiple-site) analysis was used to identify potential source areas for the various factors and modeled aerosol acidity. Eastern and Central Europe were the main source areas of secondary species. Less acidic aerosol was associated with air masses originating from Northern Europe owing to the elevated presence of the nitrate factor. More acidic particles were observed for air masses traversing the Po Valley and the Mediterranean, possibly due to the higher contributions of fossil fuel combustion factor and the loss of nitric acid due to its interaction with coarse sea-salt particles

Sources and distribution of tracer elements in road dust: The Venice mainland case of study

Road 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

Characterization of road dust and resuspended particles close to a busy road of Venice mainland (Italy)

Road 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

On the estimation of precision in the measurement of elemental concentration in atmospheric particulate

The 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

Secondary inorganic aerosol evaluation: Application of a transport chemical model in the eastern part of the Po Valley

Secondary 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

The PM2.5chemical composition in an industrial zone included in a large urban settlement: main sources and local background

Chemical analyses, receptor modeling and meteorological data were combined to determine the composition and sources of PM2.5 sampled daily in a large area in Italy characterized by a high number of heterogeneous industrial emissions and contiguous to a major urban center. The PM2.5 local background in the area, i.e. the common basic composition and concentrations of PM2.5, was determined. Factor analysis-multiple linear regression analysis (FA-MLRA) was used to identify and quantify the main PM sources. Groups of samples with similar source contributions were then sorted using cluster analysis. The potential source location and the influence of long range transport were investigated by using the conditional probability function (CPF) and the potential source contribution function (PSCF) respectively. On an annual basis, five sources of PM were found relevant. Industrial emissions accounted for 3% of PM mass, whereas the main contribution to PM was related to a combination of ammonium nitrate, combustion (54%) and road traffic (36%), mainly related to urban emissions. The PM2.5 background was estimated to account for 20 mu g m(-3). It comprises contributions of 55% ammonium nitrate and combustion, 46% road traffic, 6% fossil fuel combustion and 3% industrial emissions. Source contributions are influenced by both local atmospheric circulation and regional transport

Environmental and traffic-related parameters affecting road dust composition: A multi-technique approach applied to Venice area (Italy)

Road dust is a non-exhaust source of atmospheric particulate by re-suspension. It is composed of particles originating from natural sources as well as other non-exhaust source such as tire, brake and asphalt wear. The discrimination between atmospheric particles directly emitted from abrasion process and those related to re-suspension is therefore an open issue, as far as the percentage contribution of non-exhaust emissions is becoming more considerable due also to the recent policy actions and the technological upgrades in the automotive field, focused on the reduction of exhaust emissions.In this paper, road dust collected along the bridge that connects Venice (Italy) to the mainland is characterized with a multi-technique approach in order to determine its composition depending on environmental as well as traffic-related conditions. Six pollutant sources of road dust particles were identified by cluster analysis: brake, railway, tire, asphalt, soil + marine, and mixed combustions.Considering the lack of information on this matrix in this area, this study is intended to provide useful information for future identification of road dust re-suspension source in atmospheric particulate. (C) 2015 Elsevier Ltd. All rights reserved