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Featured Application: The results presented in this paper highlight the chemical nature of the deposits measured on high power line insulators in Italy; the results also underline the significant role of inorganic ions in forming a conductive layer on insulators when exposed to moisture, leading to the risk of flashover events. Applications are related to the prevention of such phenomena by identifying the phase transitions of atmospheric aerosols deposited on insulators and their associated conductive effect. This is achieved through the generation of synthetic aerosols and the study of their phase transitions and conductance in an aerosol exposure chamber (AEC). The reliability of the national power grid is a key issue in modern society. Atmospheric aerosols are the main cause of the reduction in the performance of insulators and the increase in the possibility of flashovers, resulting in power line failures. Under high ambient humidity, the water-soluble compounds of atmospheric aerosols collected on the insulators' surface can dissociate in ions and form a conductive layer, which may lead to flashover events. With a view to investigating the processes that drive these phenomena, the chemical composition of aerosol deposits on insulators in Italy was determined by ion chromatography analysis and thermos-optical and X-ray techniques. In addition, a synthetic aerosol with the same analyzed chemical composition was generated in a laboratory and deposited on PTFE filters and glass specimens allowing us to determine the deliquescence and crystallization relative humidity and the conductive effect in an aerosol exposure chamber. The results evidenced the presence of a hazardous inorganic ion layer, which generates a sharp phase transition of the aerosol deposit as a function of the ambient relative humidity; this layer poses a dangerous threat to the reliability of the power grid, increasing the probability of flashover events where the conductive layer facilitates the flow of electrical current across the insulator surface, potentially causing power outages or damage to the power lines. [ABSTRACT FROM AUTHOR]

Background: Bronchodilator delivery via a high-flow nasal cannula (HFNC) has generated interest in recent years. The efficacy of in-line vibrating mesh nebulizers with an HFNC during COPD exacerbation is limited. The aim of this study was to evaluate the clinical response of subjects with COPD exacerbation who require bronchodilator therapy (anticholinergic and β-agonist) by using a vibrating mesh nebulizer in line with an HFNC. Methods: This was a prospective single-center study performed in a respiratory intermediate care unit that enrolled patients with a diagnosis of COPD exacerbation who required noninvasive ventilation on admission. All the subjects underwent noninvasive ventilation breaks with an HFNC. After clinical stability, pulmonary function tests were performed to assess changes in FEV1 and clinical parameters before and after bronchodilation by using a vibrating mesh nebulizer in line with an HFNC. Results: Forty-six patients with COPD exacerbation were admitted. Five patients who did not use noninvasive ventilation and 10 patients who did not receive bronchodilator treatment with a vibrating mesh nebulizer were excluded. Thirty-one were selected, but 1 subject was secondarily excluded due to loss of data. Finally, 30 subjects were included. The primary outcome was spirometric changes in FEV1. The mean ± SD FEV1 before receiving bronchodilator treatment by using a vibrating mesh nebulizer in line with an HFNC was 0.74 ± 0.10 L, and, after receiving treatment, the mean ± SD FEV1 changed to 0.88 ± 0.12 L (P < .001). Similarly, the mean ± SD FVC increased from 1.75 ± 0.54 L to 2.13 ± 0.63 L (P < .001). Considerable differences were observed in breathing frequency and heart rate after receiving bronchodilator treatment. No relevant changes were observed in the Borg scale or SpO2 after treatment. The mean clinical stability recorded was 4 d. Conclusions: In subjects with COPD exacerbation, bronchodilator treatment by using a vibrating mesh nebulizer in line with an HFNC showed a mild but significant improvement in FEV1 and FVC. In addition, a decrease in breathing frequency was observed, suggesting a reduction in dynamic hyperinflation. [ABSTRACT FROM AUTHOR]

Particular Matter (PM) data are the most used for the assessment of air quality, but it is also useful to monitor VOC and CO. The health impact of PM increases with decreasing aerodynamic dimensions, therefore most of the monitoring is aimed at PM10 (fraction of PM with aerodynamic dimensions smaller than 10 µm) and PM2.5 (fraction with aerodynamic dimensions lower than 2.5 µm). Generally, anthropogenic emissions contribute mainly to PM2.5 levels, whereas natural sources can largely affect PM10 concentrations. PM2.5/PM10 ratio can be used as a proxy of the origin (anthropogenic vs natural) of the PM, providing a useful indication about the main sources of PM that characterizes a specific geographical or urban setting. This paper presents the results of the analysis of continuous measurements of PM10 and PM2.5 concentrations at eight stations of the regional air quality monitoring network in Abruzzo (Central Italy), in the period 2017–2018. The application of models based on machine learning technique shows that PM2.5/PM10 ratio can be used to classify PM emissions and to know the nature of the emission source (natural and anthropogenic), under determinate conditions, and properly taking into account the meteorological parameters. [ABSTRACT FROM AUTHOR]

Various mitigation measures have been implemented to fight the coronavirus disease 2019 (COVID-19) pandemic, including widely adopted social distancing and mandated face covering. However, assessing the effectiveness of those intervention practices hinges on the understanding of virus transmission, which remains uncertain. Here we show that airborne transmission is highly virulent and represents the dominant route to spread the disease. By analyzing the trend and mitigation measures in Wuhan, China, Italy, and New York City, from January 23 to May 9, 2020, we illustrate that the impacts of mitigation measures are discernable from the trends of the pandemic. Our analysis reveals that the difference with and without mandated face covering represents the determinant in shaping the pandemic trends in the three epicenters. This protective measure alone significantly reduced the number of infections, that is, by over 78,000 in Italy from April 6 to May 9 and over 66,000 in New York City from April 17 to May 9. Other mitigation measures, such as social distancing implemented in the United States, are insufficient by themselves in protecting the public. We conclude that wearing of face masks in public corresponds to the most effective means to prevent interhuman transmission, and this inexpensive practice, in conjunction with simultaneous social distancing, quarantine, and contact tracing, represents the most likely fighting opportunity to stop the COVID-19 pandemic. Our work also highlights the fact that sound science is essential in decision-making for the current and future public health pandemics. [ABSTRACT FROM AUTHOR]

The air quality monitoring is based on the determination of some gaseous pollutants and PM10 and PM2.5. Recent studies have reported the importance of the determination aerosol fraction below 1 µm both for the dynamic of the airborne and for the public health issue. This paper would like to investigate the importance of this fraction in the air quality monitoring. Further, a particular focus will be devoted the role of the Ultrafine Particles, i.e. particles below 100 nm, in the aerosol formation and in the human exposure. Two case studies will be presented and discussed on how the submicron particles can be determined and interpreted their role. In the first case, the measurements will be performed in downtown Rieti, city located in central Italy, 100 km North from Rome, with the scope to draw the behavior in relationship to the emission flexes. In the second scenario, the personal exposure of pedestrians will be investigated in Venafro, a small city located 150 km South-East Rome, by means of measuring PMx, total submicron fraction, different aerosol dimensional sizes in the range 5-360 nm along with the total Volatile Compounds. The different sources and contributions affecting the aerosol levels in the two areas will be investigated and extensively discussed as well as the role of the such particles in the aerosols science. [ABSTRACT FROM AUTHOR]

Abstract: PIXE and ICP-AES techniques are largely used in atmospheric aerosol studies. Since PIXE is able to provide the total elemental concentrations, while ICP-AES results depend on the extraction conditions, parallel PIXE and ICP-AES measurements of Fe, Al, Cu, Pb, Mn, Cr, Ni, V, As on PM10 and PM2.5 samples were compared. Two extraction procedures were applied to samples from 5 sites at different anthropization level in Italy: a “weak” extraction (HNO3 at pH=1.5) and a “strong” extraction (micro-wave oven in HNO3 and H2O2 – following EU rules). The amount of the metal extracted in the different conditions resulted to be strongly dependent on the sampling site, on the main sources of the particle (crustal or anthropic) containing the metal and on the sampled size class. [Copyright &y& Elsevier]

Abstract: Surface measurements of multi-channel aerosol mass concentration are analyzed together with LIDAR observations at L''Aquila, a central Italy site part of the EARLINET network (http://www.earlinet.org/), with the main purpose of discriminating aerosol particles originated from in-situ sources and those transported from remote sites, and their effects on local aerosol load and on the aerosol optical depth. Four major episodes of both Saharan desert and forest fire aerosol transport were observed during spring–summer months of 2007. The analysis of these events shows that at the ground surface the aerosol mass concentration increase due to desert dust particles is about 160% of the PMcoarse, whereas forest fires increase the PM1 by about 150%, with respect to typical reference unperturbed conditions during the same time period. Calculation of the aerosol optical depth (AOD) from the LIDAR retrieved aerosol extinction at 351nm shows that the corresponding increases in AOD are 95% for Saharan dust and 220% in case of forest fires. These results show that in a site impacted by aerosol transport from the desert and frequent forest fires, the first has the bigger effect in terms of local aerosol load in the coarse mode, whereas the latter impacts more the PM1 and the UV aerosol extinction and optical depth. A well tested radiative transfer model (TUV, Madronich and Floke, 1998), extended to the solar near infrared spectrum, has been used to calculate the top-of-atmosphere radiative change due to these transported aerosols: the calculated change is of the order of 0.5–1W/m2 for forest fire events end 1–2W/m2 for Saharan dust. The larger impact of desert aerosols is due to their much larger effective radius with respect to forest fire aerosols, whose scattering efficiency rapidly declines for solar wavelengths in the visible and near infrared range. [Copyright &y& Elsevier]

Abstract: Vertically resolved observations of dust optical properties were carried out at the EARLINET station of Naples (southern Italy, 40.838° N, 14.183° E, 118m above sea level) from May 2000 to August 2003. 45 outbreaks with a mean temporal length of about 4days were observed, 40% of which were characterized by dust plume intrusion into the Planetary Boundary Layer. The mean values of the altitude of base, top and of the thickness of the dust plume were derived. Dust optical properties were studied along the vertical profile in terms of statistical and climatological analysis of aerosol backscatter, extinction and lidar ratio measured inside the dust layer. Mean values of backscattering and extinction coefficients of (1.2±0.1)10−6 m−1 sr−1 and (0.61±0.06)10−4 m−1, respectively, were obtained in the whole observation period, while the mean value of LR at 351nm resulted to be 47±3sr. Mean values of dust concentration and dust fluxes were also estimated. The highest values of concentration have been observed on spring and summer months resulting of (150±60)μg·m−3 and (80±30)μg·m-3, and mean dust fluxes were (0.8±0.4)·10−3 gm−2 s−1 and (1.6±0.7)·10−3 gm−2 s−1, respectively. Finally, aerosol optical properties retrieved from lidar vertical profiles and sun-photometer measurement, in-situ sampling and models outcomes were used to fully examine the most intense dust outbreak observed during the whole study period. [Copyright &y& Elsevier]

Abstract: The concentrations of free amino acids were determined in atmospheric particulate matter from the city of Venice (Italy) in order to better understand their origin. The analysis of aerosol samples was carried out via high-performance liquid chromatography coupled to a triple quadrupole tandem mass spectrometric detector (HPLC/ESI-MS/MS). The internal standard method was used and the analytical procedure was validated by evaluating the trueness, the precision, the recovery, the detection and the quantification limits. The particulate matter was collected using quartz fiber filters and extracted in methanol; after filtration the extract was directly analyzed. Forty samples were collected from April to October 2007 and the average concentrations of free amino acids in the aerosol were: alanine 35.6pmolm−3, aspartic acid 31.1pmolm−3, glycine 30.1pmolm−3, glutamic acid 32.5pmolm−3, isoleucine 2.4pmolm−3, leucine 2.7pmolm−3, methionine, cystine and 3-hydroxy-proline below the limit of detection, phenylalanine 2.8pmolm−3, proline 43.3pmolm−3, serine 8.6pmolm−3, threonine 2.8pmolm−3, tyrosine 1.7pmolm−3, valine 3.8pmolm−3, asparagine 70.2pmolm−3, glutamine 38.0pmolm−3, 4-hydroxy-proline 2.5pmolm−3, methionine sulfoxide 1.1pmolm−3, and methionine sulfone 0.1pmolm−3. The total average concentration of these free amino acids in aerosol samples of Venice Lagoon was 334pmolm−3. The temporal evolution and multivariate analysis indicated the photochemical origin of 4-hydroxy-proline and methionine sulfoxide and for other compounds an origin further away from the site of sampling, presumably reflecting transport from terrestrial sources. [Copyright &y& Elsevier]

Abstract: In the frame of the MIUR-AEROCLOUDS project (Study of Direct and Indirect Aerosol Effects on Climate), night-time and daytime size-segregated aerosol samples were collected concurrently at five different sites (near-city, urban, rural, marine and mountain background sites). The paper reports on the daily evolution of the main aerosol chemical characteristics as a function of particle size in different environments over the Italian Peninsula, spanning from the Po Valley to the south Tyrrhenian coast. Two 4-day intensive observation periods (IOPs) were undertaken in July 2007 and February 2008, under meteorological conditions typical of the summer and winter climate for Italy. In the summer IOP, under stable atmospheric conditions, at the low-altitude continental sites the diurnal evolution of the planetary boundary layer (PBL), induces an atmospheric dilution effect driving the particulate matter (PM) concentrations, while, at the mountain site, it determines the upward motion of polluted air masses from the Po Valley PBL in daytime. The fine fraction was dominated by ammonium salts and carbonaceous matter (water-soluble organic matter, WSOM, and water-insoluble carbonaceous matter, WINCM). High concentrations of ammonium sulphate and WSOM due to enhanced photochemical activity constituted the background aerosol composition over the whole country, whereas, ammonium nitrate and WINCM were more associated to local emissions (e.g. urban site with concentrations peaking in the finest size range due to strong local traffic-related sources of ultrafine particles). During the winter IOP in the Po Valley, the shallow PBL depths and low wind velocity, especially at night, favoured the condensation of semi-volatile species (i.e. organic matter and ammonium nitrate), causing the high fine PM concentration observed at ground level. [ABSTRACT FROM AUTHOR]

Particle size distribution in the range 0.3< D p ≤20 μm, has been analysed from August 2002 to July 2006 at the GAW Station of Mt. Cimone (44.10 N, 10.42 E; 2165 m asl) in the northern Italian Apennines. The seasonal aerosol number size distribution, characterized by a bimodal shape, showed a behaviour typical for background conditions, characterized by highest values in summer and lowest in winter. The seasonal and diurnal variations of the larger accumulation mode (0.3< D p ≤1 μm average values: 26.15 cm−3) and the coarse mode (1< D p ≤20 μm, average value: 0.17 cm−3) particle number concentrations (N 0.3–1 and N 1–20, respectively) exhibited a seasonal cycle with the highest values in spring–summer and the lowest value in autumn–winter. Except in winter, N 0.3–1 showed a clear diurnal variation with high values during day-time. N 1–20 showed a less marked diurnal variation (but with higher variability), suggesting the influence of non-continuous sources of coarse particle (i.e. Saharan dust events). Since July 2005, continuous measurement of black carbon (BC) concentrations was also available at the measurement site. On average low BC concentrations were recorded (average value: 0.28 μg m−3) even if a few events of high concentrations were recorded both in warm and cold season. Apart from wet scavenging processes which strongly affected aerosol concentrations, combined analysis of N 0.3–1, BC, meteorological parameters and air mass back-trajectories, suggests that the transport of polluted air masses from the lower troposphere (by local, regional or long-range transport) represents an important mechanism favouring N 0.3–1 and BC increases at Mt. Cimone. In particular, a trajectory statistical analysis for the period July 2005–July 2006 allowed the identification of the main source regions of BC and N 0.3–1 for Mt. Cimone: north Italy, west Europe and east Europe. [Copyright &y& Elsevier]

Abstract: A project is in progress to study the environmental problems of Taranto, an industrial town in the South of Italy. Within this framework we studied the atmospheric aerosol composition by means of continuous sampling and PIXE measurements. Particulate matter (PM) was collected simultaneously in two sampling sites during winter and summer 2004 by two streaker samplers, which separate the fine and coarse aerosol modes. Hourly concentrations of elements from Na to Pb were measured at the new 3MV Tandetron accelerator of the LABEC laboratory of INFN in Florence. [Copyright &y& Elsevier]

The wall paintings of the Michelozzo’s Courtyard (XVI century) at the main entrance of Palazzo Vecchio in Florence are in an advanced state of degradation. With the aim of understanding the environmental conditions in the Courtyard a wide research project has been instigated. In this study, the fine and coarse fractions of the PM10 have been collected by a ‘streaker’ sampler with an hourly resolution and then analysed by PIXE at the 3MV tandetron accelerator in Florence; the first results will be presented here. [Copyright &y& Elsevier]

The composition of particulate matter in the atmosphere of four major Italian towns (Florence, Genoa, Milan and Naples) has been studied with the extensive application of IBA techniques. The aerosol has been collected simultaneously in the four towns during the first weeks of year 2001, by two-stage continuous streaker samplers, which provide the separation of the particulate matter in two fractions. The concentrations in air of about 20 elements, and the total particulate mass, have been extracted in the PM2.5 and PM10 fractions with hourly resolution by PIXE, PIGE and optical analyses of about 2700 samples. IBA analyses have been performed at the 3 MeV external proton beam of the INFN accelerator facility at the University of Florence. [Copyright &y& Elsevier]

This study tests the release of SARS-CoV-2 RNA into the air during normal breathing, without any sign of possible risk of contagion such as coughing, sneezing or talking. Five patients underwent oropharyngeal, nasopharyngeal and salivary swabs for real-time reverse transcriptase PCR (RT-PCR) detection of SARS-CoV-2 RNA. Direct SARS-CoV-2 release during normal breathing was also investigated by RT-PCR in air samples collected using a microbiological sampler. Viral RNA was detected in air at 1 cm from the mouth of patients whose oropharyngeal, nasopharyngeal and salivary swabs tested positive for SARS-CoV-2 RNA. In contrast, the viral RNA was not identified in the exhaled air from patients with oropharyngeal, nasopharyngeal and salivary swabs that tested negative. Contagion of SARS-CoV-2 is possible by being very close to the mouth of someone who is infected, asymptomatic and simply breathing.

The spread of SARS-CoV-2 by contact (direct or indirect) is widely accepted, but the relative importance of airborne transmission is still controversial. Probability of outdoor airborne transmission depends on several parameters, still rather uncertain: virus-laden aerosol concentrations, viability and lifetime, minimum dose necessary to transmit the disease. In this work, an estimate of outdoor concentrations in northern Italy (region Lombardia) was performed using a simple box model approach, based on an estimate of respiratory emissions, with a specific focus for the cities of Milan and Bergamo (Italy). In addition, the probability of interaction of virus-laden aerosol with pre-existing particles of different sizes was investigated. Results indicate very low (<1 RNA copy/m 3 ) average outdoor concentrations in public area, excluding crowded zones, even in the worst case scenario and assuming a number of infects up to 25% of population. On average, assuming a number of infects equal to 10% of the population, the time necessary to inspire a quantum (i.e. the dose of airborne droplet nuclei required to cause infection in 63% of susceptible persons) would be 31.5 days in Milan (range 2.7-91 days) and 51.2 days in Bergamo (range 4.4-149 days). Therefore, the probability of airborne transmission due to respiratory aerosol is very low in outdoor conditions, even if it could be more relevant for community indoor environments, in which further studies are necessary to investigate the potential risks. We theoretically examined if atmospheric particles can scavenge virus aerosol, through inertial impact, interception, and Brownian diffusion. The probability was very low. In addition, the probability of coagulation of virus-laden aerosol with pre-existing atmospheric particles resulted negligible for accumulation and coarse mode particles, but virus-laden aerosol could act as sink of ultrafine particles (around 0.01 μm in diameter). However, this will not change significantly the dynamics behaviour of the virus particle or its permanence time in atmosphere., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Hand hygiene is a fundamental component of infection prevention, but few studies have examined whether hand-drying method affects the risk of dissemination of potential pathogens., Aim: To perform a multi-centre, internal-crossover study comparing bacterial contamination levels in washrooms with hand-drying by either paper towels (PT) or jet air dryer (JAD; Dyson)., Methods: A total of 120 sampling sessions occurred over 12 weeks in each of three hospitals (UK, France, Italy). Bacteria were cultured from air, multiple surfaces, and dust. Washroom footfall (patients/visitors/staff) was monitored externally., Findings: Footfall was nine times higher in UK washrooms. Bacterial contamination was lower in PT versus JAD washrooms; contamination was similar in France and the UK, but markedly lower in Italian washrooms. Total bacterial recovery was significantly greater from JAD versus PT dispenser surfaces at all sites (median: 100-300 vs 0-10 cfu; all P < 0.0001). In the UK and France, significantly more bacteria were recovered from JAD washroom floors (median: 24 vs 191 cfu, P < 0.00001). UK meticillin-susceptible Staphylococcus aureus recovery was three times more frequent and six-fold higher for JAD vs PT surfaces (both P < 0.0001). UK meticillin-resistant S. aureus recovery was three times more frequent (21 vs 7 cfu) from JAD versus PT surfaces or floors. Significantly more enterococci and extended-spectrum β-lactamase (ESBL)-producing bacteria were recovered from UK JAD versus PT washroom floors (P < 0.0001). In France, ESBL-producing bacteria were recovered from dust twice as often during JAD versus PT use., Conclusion: Multiple examples of significant differences in surface bacterial contamination, including by faecal and antibiotic-resistant bacteria, were observed, with higher levels in JAD versus PT washrooms. Hand-drying method affects the risk of (airborne) dissemination of bacteria in real-world settings., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)

This study shows for the first time a chemical and morphological characterization of agricultural aerosols released during three important agricultural operations: threshing, plowing and sowing. The field campaigns were carried out in the eastern part of the Po Valley, Italy, in summer and autumn 2009. The aerosol particles were sampled on quartz fiber filters and polytetrafluoroethylene membranes in order to allow Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analysis and Scanning Electron Microscopy equipped with an Energy Dispersive X-ray Spectrometer (SEM-EDS) investigations, respectively. The organic carbon mass concentrations were measured with a Sunset Laboratory Dual-Optical Organic Carbone/Elemental Carbon (OCEC) Aerosol analyzer. The morphological and chemical analyses by SEM-EDS allowed recognizing four main particle classes: organic, silica, calcite and clay minerals. The organic particles contribute to both fine and coarse aerosol fractions up to ca. 50% for all three agricultural activities. This was also confirmed by OCEC analysis for fine fraction. Most of the agricultural aerosols, about 60%, were single particles and the remaining 40% were agglomerations of particles. The ICP-MS results showed that threshing and plowing produce more aerosol particles than sowing, which was characterized by important amounts of clay minerals produced from land soils., (Copyright © 2014. Published by Elsevier B.V.)

Previous studies reported significant variability of air pollutants across Europe with the lowest concentrations generally found in Northern Europe and the highest in Southern European countries. Within the MED-PARTICLES project the spatial and temporal variations of long-term PM and gaseous pollutants data were investigated in traffic and urban background sites across Southern Europe. The highest PM levels were observed in Greece and Italy (Athens, Thessaloniki, Turin and Rome) while all traffic sites showed high NO2 levels, frequently exceeding the established limit value. High PM2.5/PM10 ratios were calculated indicating that fine particles comprise a large fraction of PM10, with the highest values found in the urban background sites. It seems that although in traffic sites the concentrations of both PM2.5 and PM10 are significantly higher than those registered in urban background sites, the coarse fraction PM2.5-10 is more important at the traffic sites. This fact is probably due to the high levels of resuspended road dust in sites highly affected by traffic, a phenomenon particularly relevant for Mediterranean countries. The long-term trends of air pollutants revealed a significant decrease of the concentration levels for PM, SO2 and CO while for NO2 no clear trend or slightly increasing trends were observed. This reduction could be attributed to the effectiveness of abatement measures and strategies and also to meteorological conditions and to the economic crisis that affected Southern Europe., (Copyright © 2014 Elsevier B.V. All rights reserved.)