A. Donateo

The direct influence of ship traffic on atmospheric PM2.5, PM10 and PAH in Venice.

The direct influence of ship traffic on atmospheric levels of coarse and fine particulate matter (PM(2.5), PM(10)) 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(®) and Mie pDR-1200) operating at a high temporal resolution (20s and 1s respectively) for PM(2.5) and PM(10). 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 PM(2.5) and to PM(10) is from 1% up to 8%.

Gas-particle distributions, sources and health effects of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and polychlorinated naphthalenes (PCNs) in Venice aerosols.

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.

Application of PMF and CMB receptor models for the evaluation of the contribution of a large coal-fired power plant to PM10 concentrations

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 5.8km 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(+), Ca(2+), Mg(2+), Na(+), K(+), Mg(2+), SO4(2-), 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.

Impact of maritime traffic on polycyclic aromatic hydrocarbons, metals and particulate matter in Venice air.

AbstractHarbours are important hubs for economic growth in both tourism and commercial activities. They are also an environmental burden being a source of atmospheric pollution often localized near cities and industrial complexes. The aim of this study is to quantify the relative contribution of maritime traffic and harbour activities to atmospheric pollutant concentration in the Venice lagoon. The impact of ship traffic was quantified on various pollutants that are not directly included in the current European legislation for shipping emission reduction: (i) gaseous and particulate PAHs; (ii) metals in PM10; and (iii) PM10 and PM2.5. All contributions were correlated with the tonnage of ships during the sampling periods and results were used to evaluate the impact of the European Directive 2005/33/EC on air quality in Venice comparing measurements taken before and after the application of the Directive (year 2010). The outcomes suggest that legislation on ship traffic, which focused on the issue of the emissions of sulphur oxides, could be an efficient method also to reduce the impact of shipping on primary particulate matter concentration; on the other hand, we did not observe a significant reduction in the contribution of ship traffic and harbour activities to particulate PAHs and metals. Graphical abstractImpact of maritime traffic on polycyclic aromatic hydrocarbons, metals and particulate matter and evaluation of the effect of an European Directive on air quality in Venice

Correlation of Dry Deposition Velocity and Friction Velocity over Different Surfaces for PM2.5 and Particle Number Concentrations

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, , atmospheric stability, and particle size (if size-segregated information is available). In this work, a study of the correlation between Vd and over different surfaces is presented for both PM2.5 and particle number fluxes. Results indicate an almost linear increase of Vd with with slopes similar for PM2.5 fluxes and particle number fluxes over the different surfaces analysed. This means that the ratios Vd/ tend to collapse over similar values even if Vd and are significantly different because 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 . The average value of Vd/ 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.

Characterisation of PM2,5 concentrations and turbulent fluxes on a island of the Venice Lagoon using high temporal resolution measurements

This work presents an analysis of PM2.5 concentrations and vertical turbulent fluxes on an island of the Venice lagoon. Data were collected during three measurement campaigns in spring, summer and winter periods. Measurements were taken with a high-resolution optical PM2.5 detector, coupled with a micrometeorological station that allowed the evaluation of the vertical turbulent fluxes of PM2.5 using the eddy-correlation technique. The main objective of this paper is to analyse the daily and seasonal pattern in PM2.5 concentrations and fluxes and to discuss their correlation with the main meteorological and micrometeorological parameters using high temporal resolution measurements. Observed data showed a seasonal pattern in turbulent fluxes with daytime average positive value during winter and negative during summer. Deposition velocities, ranged from –60 to 20 mm/s, appeared to be mainly influenced by atmospheric stability. There were larger emissions in cases of high wind velocities blowing from water sector indicating a significant potential contribution of sea spray to PM2.5 fluxes. The local atmospheric circulation, due to the orography of the area, was characterised by diurnal winds coming from the Adriatic Sea and nocturnal wind coming from the Alps. This circulation influenced deposition velocity creating an increase of negative fluxes in the morning at the starting of the sea breeze. A diurnal pattern in concentration has been observed and it is similar for all three measurement campaigns, with higher concentrations in nocturnal periods. The daily pattern was investigated in terms of its correlation with meteorological and micro-meteorological parameters, and was found highly correlated with the diurnal pattern of boundary layer height (BLH) and with relative humidity.

Comparison of indirect methods for the estimation of Boundary Layer height over flat-terrain in a coastal site

In this paper an analysis of different indirect methods for the calculation of the boundary layer height (BLH) using sodar, ultrasonic anemometer and a prognostic model based on single point surface measurements is presented. In particular the automatic spectral routine developed for Remtech sodar is compared with the results obtained with the parameterization of the vertical velocity variance of a minisodar, with the calculation of a prognostic model, with a parameterization based on horizontal velocity spectra and with the BLH evaluated from the intensity of minisodar echoes in stable conditions. The data of a radiosonde system taken in a nearby site was also analysed to get an independent evaluation of BLH for comparison. There is a significant scatter in the data for both the evaluation through the variance of vertical wind speed and the spectral analysis of the horizontal wind velocity although created by different effects. In unstable conditions the different methods give a similar pattern even if the prognostic model in some days predicts a significantly higher BLH with respect to the other methods. In stable nocturnal conditions the performances of the Remtech routine are worse than those in unstable conditions with an evident overestimation of the BLH that it is likely related to the overestimation of vertical turbulence and to the use of multiple range gates in the algorithm. Taking as reference the evaluation of BLH of the sodar, the spectral method applied to ultrasonic anemometer data seems to be affected by the lowest biases and it is a possible candidate, for the development of automatic routines for operational evaluation of BLH possibly with a different parameterisation for stable and unstable cases.

Characterisation of particle size distributions and corresponding size-segregated turbulent fluxes simultaneously with CO 2 exchange in an urban area

Number and mass particle concentrations and fluxes were measured, simultaneously with CO2 concentration and flux, in the urban area of Lecce (Italy). The measurements of the turbulent exchanges of atmospheric particles and gas were performed with an eddy-covariance station located near the busiest road of the town. For the smaller particles, the diurnal evolution of the particle number concentrations and fluxes shows a clear correlation with human activities, in particular vehicular traffic, which is the obvious candidate as the source of the two clear peaks in the CPC concentration in the morning and in the evening. The fluxes were upward for all the measurement period, even though small net deposition was observed for larger particles and during weekend. For the CPC, the correlation with the traffic daily pattern is extremely strong. The city is a continuous particle source. The data analysis seems also to suggest the presence of local urban nucleation events. CO2 and particle concentrations were larger at low wind velocity, instead, fluxes were larger at high wind velocity. This opposite behaviour suggests that the influence of local urban emissions is larger on fluxes with respect to concentrations. The average daily patterns of CO2 concentration show an overlap between biogenic cycle and urban emissions. Again, traffic appears to be the dominant source for fluxes and the urban area is a net source of CO2.

A Case Study of Municipal Solid Waste Landfills Impact on Air Pollution in South Areas of Italy

The average PM10 concentrations observed at Burgesi and Nardò landfills were comparable with the average of the territory while PM10 at Cavallino landfill was higher than the typical average. The VOC concentrations showed the predominant occurrence of the limonene and alfa-pynene compounds at all sites. Maximum concentrations of limonene and alfa-pynene were observed at Cavallino landfill. The PCDD/F and PCB concentrations showed significant variabilities among the different sites. It was noted that the average concentrations of the PCDD/F were higher at Nardò landfill. No particular correlations were observed between PCDD/F and PAH concentrations and between PCB and PAH concentrations.