The role of outdoor and indoor air quality in the spread of SARS-CoV-2: Overview and recommendations by the research group on COVID-19 and particulate matter (RESCOP commission).

There are important questions surrounding the potential contribution of outdoor and indoor air quality in the transmission of SARS-CoV-2 and perpetuation of COVID-19 epidemic waves. Environmental health may be a critical component of COVID-19 prevention. The public health community and health agencies should consider the evolving evidence in their recommendations and statements, and work to issue occupational guidelines. Evidence coming from the current epidemiological and experimental research is expected to add knowledge about virus diffusion, COVID-19 severity in most polluted areas, inter-personal distance requirements and need for wearing face masks in indoor or outdoor environments. The COVID-19 pandemic has highlighted the need for maintaining particulate matter concentrations at low levels for multiple health-related reasons, which may also include the spread of SARS-CoV-2. Indoor environments represent even a more crucial challenge to cope with, as it is easier for the SARS-COV2 to spread, remain vital and infect other subjects in closed spaces in the presence of already infected asymptomatic or mildly symptomatic people. The potential merits of preventive measures, such as CO2 monitoring associated with natural or controlled mechanical ventilation and air purification, for schools, indoor public places (restaurants, offices, hotels, museums, theatres/cinemas etc.) and transportations need to be carefully considered. Hospital settings and nursing/retirement homes as well as emergency rooms, infectious diseases divisions and ambulances represent higher risk indoor environments and may require additional monitoring and specific decontamination strategies based on mechanical ventilation or air purification.

Molecular detection of SARS-CoV-2 from indoor air samples in environmental monitoring needs adequate temporal coverage and infectivity assessment.

The relevance of airborne exposure to SARS-CoV-2 in indoor environments is a matter of research and debate, with special importance for healthcare low-risk settings. Experimental approaches to the bioaerosol sampling are neither standardized nor optimized yet, leading in some cases to limited representativity of the temporal and spatial variability of viral presence in aerosols. Airborne viral viability moreover needs to be assessed. A study has been conducted collecting five 24-h PM10 samples in a COVID-19 geriatric ward in late June 2020, and detecting E and RdRp genes by RT-qPCR with a Ct between 36 and 39. The viral RNA detection at Ct = 36 was related to the maximal numerosity of infected patients hosted in the ward. Lacking a direct infectivity assessment for the collected samples an experimental model has been defined, by seeding twelve nasopharyngeal swab extracts from COVID-19 positive patients on Vero E6 cells; only the four extracts with a viral load above E+10 viral copies (approximately Ct<24) have been able to establish a persistent infection in vitro. Therefore, the cytopathic effect, a key feature of residual infectivity, could be considered unlikely for the environmental PM10 samples showing amplification of viral RNA at Ct = 36 or higher. A standardization of airborne SARS-CoV-2 long-term monitoring and of environmental infectivity assessment is urgently needed.

SARS-Cov-2RNA found on particulate matter of Bergamo in Northern Italy: First evidence.

BACKGROUND: The burden of COVID-19 was extremely severe in Northern Italy, an area characterized by high concentrations of particulate matter (PM), which is known to negatively affect human health. Consistently with evidence already available for other viruses, we initially hypothesized the possibility of SARS-CoV-2 presence on PM, and we performed a first experiment specifically aimed at confirming or excluding this research hyphotesys. METHODS: We have collected 34 PM10 samples in Bergamo area (the epicenter of the Italian COVID-19 epidemic) by using two air samplers over a continuous 3-weeks period. Filters were properly stored and underwent RNA extraction and amplification according to WHO protocols in two parallel blind analyses performed by two different authorized laboratories. Up to three highly specific molecular marker genes (E, N, and RdRP) were used to test the presence of SARS-CoV-2 RNA on particulate matter. RESULTS: The first test showed positive results for gene E in 15 out of 16 samples, simultaneously displaying positivity also for RdRP gene in 4 samples. The second blind test got 5 additional positive results for at least one of the three marker genes. Overall, we tested 34 RNA extractions for the E, N and RdRP genes, reporting 20 positive results for at least one of the three marker genes, with positivity separately confirmed for all the three markers. Control tests to exclude false positivities were successfully accomplished. CONCLUSION: This is the first evidence that SARS-CoV-2 RNA can be present on PM, thus suggesting a possible use as indicator of epidemic recurrence.

Pattern Recognition and Anomaly Detection by Self-Organizing Maps in a Multi Month E-nose Survey at an Industrial Site.

Currently people are aware of the risk related to pollution exposure. Thus odor annoyances are considered a warning about the possible presence of toxic volatile compounds. Malodor often generates immediate alarm among citizens, and electronic noses are convenient instruments to detect mixture of odorant compounds with high monitoring frequency. In this paper we present a study on pattern recognition on ambient air composition in proximity of a gas and oil pretreatment plant by elaboration of data from an electronic nose implementing 10 metal-oxide-semiconductor (MOS) sensors and positioned outdoor continuously during three months. A total of 80,017 e-nose vectors have been elaborated applying the self-organizing map (SOM) algorithm and then k-means clustering on SOM outputs on the whole data set evidencing an anomalous data cluster. Retaining data characterized by dynamic responses of the multisensory system, a SOM with 264 recurrent sensor responses to air mixture sampled at the site and four main air type profiles (clusters) have been identified. One of this sensor profiles has been related to the odor fugitive emissions of the plant, by using ancillary data from a total volatile organic compound (VOC) detector and wind speed and direction data. The overall and daily cluster frequencies have been evaluated, allowing us to identify the daily duration of presence at the monitoring site of air related to industrial emissions. The refined model allowed us to confirm the anomaly detection of the sensor responses.

Breath Analysis: Comparison among Methodological Approaches for Breath Sampling.

Despite promising results obtained in the early diagnosis of several pathologies, breath analysis still remains an unused technique in clinical practice due to the lack of breath sampling standardized procedures able to guarantee a good repeatability and comparability of results. The most diffuse on an international scale breath sampling method uses polymeric bags, but, recently, devices named Mistral and ReCIVA, able to directly concentrate volatile organic compounds (VOCs) onto sorbent tubes, have been developed and launched on the market. In order to explore performances of these new automatic devices with respect to sampling in the polymeric bag and to study the differences in VOCs profile when whole or alveolar breath is collected and when pulmonary wash out with clean air is done, a tailored experimental design was developed. Three different breath sampling approaches were compared: (a) whole breath sampling by means of Tedlar bags, (b) the end-tidal breath collection using the Mistral sampler, and (c) the simultaneous collection of the whole and alveolar breath by using the ReCIVA. The obtained results showed that alveolar fraction of breath was relatively less affected by ambient air (AA) contaminants (p-values equal to 0.04 for Mistral and 0.002 for ReCIVA Low) with respect to whole breath (p-values equal to 0.97 for ReCIVA Whole). Compared to Tedlar bags, coherent results were obtained by using Mistral while lower VOCs levels were detected for samples (both breath and AA) collected by ReCIVA, likely due to uncorrected and fluctuating flow rates applied by this device. Finally, the analysis of all data also including data obtained by explorative analysis of the unique lung cancer (LC) breath sample showed that a clean air supply might determine a further confounding factor in breath analysis considering that lung wash-out is species-dependent.

Spermatic vein sclero-embolization through basilic vein access: A short communication.

Objectives: To depict the basics of percutaneous spermatic vein sclero-embolization through a right basilic vein access and to qualitatively assess the reduced discomfort and pain of this access compared to the femoral one through a VAS scale. Methods: From February 2019 to March 2020, 20 varicocele sclero-embolizations through a right basilic vein were performed and retrospectively evaluated. All patients were men with a median age of 24.5 years. Treatment technique is described, as well as mean radiation dose and procedural time, and complication rates. Results: Technical success was obtained in all patients. 1 access site complication requiring conversion to femoral access occurred. 100% of patients reported only a "mild" pain ranging from 1 to 3 on VAS scale, suggesting a comfortable access for this procedure. Conclusions: Basilic vein access determines easy left and right spermatic vein catheterization, rapid ambulation as well as easy monitoring of the access site for post-procedural evaluations.

AI-Enhanced Tools and Strategies for Airborne Disease Prevention in Cultural Heritage Sites.

In the wake of the COVID-19 pandemic, the surveillance and safety measures of indoor Cultural Heritage sites have become a paramount concern due to the unique challenges posed by their enclosed environments and high visitor volumes. This communication explores the integration of Artificial Intelligence (AI) in enhancing epidemiological surveillance and health safety protocols in these culturally significant spaces. AI technologies, including machine learning algorithms and Internet of Things (IoT) sensors, have shown promising potential in monitoring air quality, detecting pathogens, and managing crowd dynamics to mitigate the spread of infectious diseases. We review various applications of AI that have been employed to address both direct health risks and indirect impacts such as visitor experience and preservation practices. Additionally, this paper discusses the challenges and limitations of AI deployment, such as ethical considerations, privacy issues, and financial constraints. By harnessing AI, Cultural Heritage sites can not only improve their resilience against future pandemics but also ensure the safety and well-being of visitors and staff, thus preserving these treasured sites for future generations. This exploration into AI's role in post-COVID surveillance at Cultural Heritage sites opens new frontiers in combining technology with traditional conservation and public health efforts, providing a blueprint for enhanced safety and operational efficiency in response to global health challenges.

Bioaerosol Sampling Devices and Pretreatment for Bacterial Characterization: Theoretical Differences and a Field Experience in a Wastewater Treatment Plant.

Studies on bioaerosol bacterial biodiversity have relevance in both ecological and health contexts, and molecular methods, such as 16S rRNA gene-based barcoded sequencing, provide efficient tools for the analysis of airborne bacterial communities. Standardized methods for sampling and analysis of bioaerosol DNA are lacking, thus hampering the comparison of results from studies implementing different devices and procedures. Three samplers that use gelatin filtration, swirling aerosol collection, and condensation growth tubes for collecting bioaerosol at an aeration tank of a wastewater treatment plant in Trieste (Italy) were used to determine the bacterial biodiversity. Wastewater samples were collected directly from the untreated sewage to obtain a true representation of the microbiological community present in the plant. Different samplers and collection media provide an indication of the different grades of biodiversity, with condensation growth tubes and DNA/RNA shieldTM capturing the richer bacterial genera. Overall, in terms of relative abundance, the air samples have a lower number of bacterial genera (64 OTUs) than the wastewater ones (75 OTUs). Using the metabarcoding approach to aerosol samples, we provide the first preliminary step toward the understanding of a significant diversity between different air sampling systems, enabling the scientific community to orient research towards the most informative sampling strategy.

Self-Organizing Maps: An AI Tool for Identifying Unexpected Source Signatures in Non-Target Screening Analysis of Urban Wastewater by HPLC-HRMS.

(1) Background: Monitoring effluent in water treatment plants has a key role in identifying potential pollutants that might be released into the environment. A non-target analysis approach can be used for identifying unknown substances and source-specific multipollutant signatures. (2) Methods: Urban and industrial wastewater effluent were analyzed by HPLC-HRMS for non-target analysis. The anomalous infiltration of industrial wastewater into urban wastewater was investigated by analyzing the mass spectra data of "unknown common" compounds using principal component analysis (PCA) and the Self-Organizing Map (SOM) AI tool. The outcomes of the models were compared. (3) Results: The outlier detection was more straightforward in the SOM model than in the PCA one. The differences among the samples could not be completely perceived in the PCA model. Moreover, since PCA involves the calculation of new variables based on the original experimental ones, it is not possible to reconstruct a chromatogram that displays the recurring patterns in the urban WTP samples. This can be achieved using the SOM outcomes. (4) Conclusions: When comparing a large number of samples, the SOM AI tool is highly efficient in terms of calculation, visualization, and identifying outliers. Interpreting PCA visualization and outlier detection becomes challenging when dealing with a large sample size.

Comparison of wood smoke PM2.5 obtained from the combustion of FIR and beech pellets on inflammation and DNA damage in A549 and THP-1 human cell lines.

The aim of this study was to investigate the effect on the induction of interleukin-8 of particulate matter (PM) from fir and beech pellets burnt in domestic appliances on two human cells lines, namely the lung epithelial cell line A549 and the promyelocytic cell line THP-1. The effects of PM2.5 obtained from combustion of beech and fir pellets were compared to reference diesel exhaust particulates (DEP). In parallel, wood smoke PM-induced genotoxicity and oxidative stress were also investigated in A549 cells. Cells were treated for different times (3-72 h) with increasing concentrations of PM2.5 obtained from sequential combustions of fir and beech pellets or reference DEP. Cell viability was assessed by lactate dehydrogenase leakage, and the release of interleukin-8 or CXCL8 (IL-8) was measured to evaluate the pro-inflammatory effect. Oxidative stress was evaluated by the 5(6)-carboxy-2',7'dichlorofluorescein diacetate (DCFH-DA) assay and DNA damage by the alkaline comet assay and micronucleus frequency by flow cytometry. Both A549 and THP-1 cells responded in a dose- and time-related manner to wood smoke PM2.5 with IL-8 release, particles obtained from late combustions being the most active. THP-1 cells were more sensitive than A549 cells. On a mass base, similar effects were observed for both fir and beech PM2.5. However, the combustion of beech pellets generated approximately three times more PM2.5 than fir pellets. Regarding the mechanism of PM2.5 uptake, in both THP-1 and A549 cells, cytochalasin D prevented PM2.5-induced IL-8 mRNA expression and cytokine release, indicating a key role for actin polymerization in particles uptake and that the production of IL-8 correlated with particle phagocytosis. As signal transduction pathway involvement, in both THP-1 and A549 cells, PM2.5-induced IL-8 release could be completely blocked by the selective inhibitor SB203580, indicating a role of p38 MAPK activation. PM2.5 from both fir and beech pellets also induced modest DNA lesions dose related, measured as strand breaks, whereas no increase in the number of micronucleus was observed. Similar effects were observed with DEP, arguing against less dangerous effects of wood smoke particles than other categories of combustion-derived particles in the same size range. Overall, results suggest that combustion conditions can significantly affect the characteristics of particles and the consequent toxicity, and that different woods can generate different amounts of PM2.5.

Non-invasive assessment of exhaled breath pattern in patients with multiple chemical sensibility disorder.

Multiple chemical sensitivity (MCS) is a complex disorder initiated by chemical exposure, particularly through the airways. MCS patients report sensitivity or intolerance to low levels of a wide spectrum of chemicals. Symptoms could include asthma-like signs, rhinitis, fatigue, cognitive dysfunction, psycho-physiological alteration, and other specific tissue reactions resembling hypoxic and oxidative stress effects. To recognize physiological signs that would allow the diagnosis of MCS in a non-invasive way we investigated the potential application of a new sensor system. In healthy volunteers, we measured exhaled breath content in the control condition and under exposure to olfactory stressors that mimic hypoxic or pollutant stressors playing a potential role in the generation of the MCS disorder. The recording system used is based on metal oxide semiconductor (MOS) sensor having a sensing range of 450-2,000 ppm CO(2) equivalents, which is able to detect a broad range of compounds playing a potential role in the generation of the MCS disorder, while correlating directly with the CO(2) levels. The results indicate that the recording system employed was suitable for the analysis of exhaled breath content in humans. Interestingly, the system was able to detect and discriminate between the exhaled breath content taken from the control condition and those from conditions under stress that mimicked exposures to pollutant or hypoxia. The results suggest that chronic hypoxia could be involved in the MCS disorder.

The Role of the Transjugular Intrahepatic Porto-Systemic Shunt in an Emergency Setting.

Transjugular intrahepatic porto-systemic shunt (TIPSS) is an interventional radiology procedure whose aim is to create artificial communication between the portal and the hepatic blood flow in order to reduce the pressure gradient in portal hypertension. The indications to perform a TIPSS procedure can be framed in an elective or emergency setting: refractory ascites to diuretic therapy and secondary prophylaxis of variceal hemorrhage are the most frequent reasons for executing a TIPSS in an election context, while acute uncontrolled variceal bleeding is the principal indication that a TIPSS needs to be performed in an emergency setting. In recent years, the role of the TIPSS has been redefined for several conditions, such as ectopic varices, portal vein thrombosis, Budd-Chiari syndrome, hepatic veno-occlusive disease, and many others. This review aims to perform a deep analysis of when and why a TIPSS procedure should be carried out in an emergency, pointing out the related most common technical difficulties and complications.

Technological Advancements in Interventional Oncology.

Interventional radiology, and particularly interventional oncology, represents one of the medical subspecialties in which technological advancements and innovations play an utterly fundamental role. Artificial intelligence, consisting of big data analysis and feature extrapolation through computational algorithms for disease diagnosis and treatment response evaluation, is nowadays playing an increasingly important role in various healthcare fields and applications, from diagnosis to treatment response prediction. One of the fields which greatly benefits from artificial intelligence is interventional oncology. In addition, digital health, consisting of practical technological applications, can assist healthcare practitioners in their daily activities. This review aims to cover the most useful, established, and interesting artificial intelligence and digital health innovations and updates, to help physicians become more and more involved in their use in clinical practice, particularly in the field of interventional oncology.

Interventional Radiology in the Treatment of Pancreatic Adenocarcinoma: Present and Future Perspectives.

Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease; patients' long-term survival is strictly linked to the surgical resection of the tumor but only a minority of patients (2-3%) have a resectable disease at diagnosis. In patients with surgically unresectable disease, interventional radiology is taking on an increasing role in treatment with the application of loco-regional percutaneous therapies. The primary purposes of this narrative review are to analyze the safety and efficacy of ablative techniques in the management of borderline resectable and locally advanced diseases and to underline the role of the interventional radiologist in the management of patients with distant metastases. The secondary purpose is to focus on the synergy between immunotherapy and ablative therapies.

Identification of a characteristic VOCs pattern in the exhaled breath of post-COVID subjects: are metabolic alterations induced by the infection still detectable?

SARS-CoV-2 is expected to cause metabolic alterations due to viral replication and the host immune response resulting in increase of cytokine secretion and cytolytic activity. The present prospective observational study is addressed at exploring the potentialities of breath analysis in discrimination between patients with a documented previous history of symptomatic SARS-CoV-2 infection and, at the moment of the enrollment, exhibiting a negative nasopharyngeal swab and acquired immunity (post-COVID) and healthy subjects with no evidence of previous SARS-CoV-2 infection (no-COVID). The main purpose is to understand if traces of metabolic alterations induced during the acute phase of the infection are still detectable after negativization, in the form of a characteristic volatile organic compound (VOC) pattern. An overall number of 60 volunteers aged between 25 and 70 years were enrolled in the study (post-COVID: n.30; no-COVID: n. 30), according to well-determined criteria. Breath and ambient air samples were collected by means of an automated sampling system (Mistral) and analyzed by thermal desorption-gas chromatography-mass spectrometry (TD-GC/MS). Statistical tests (Wilcoxon/Kruskal-Wallis test) and multivariate data analysis (principal component analysis (PCA), linear discriminant analysis) were performed on data sets. Among all compounds detected (76 VOCs in 90% of breath samples), 5 VOCs (1-propanol, isopropanol, 2-(2-butoxyethoxy)ethanol, propanal and 4-(1,1-dimethylpropyl)phenol) showed abundances in breath samples collected from post-COVID subjects significantly different with respect to those collected from no-COVID group (Wilcoxon/Kruskal-Wallis test,p-values <0.05). Although not completely satisfactory separation between the groups was obtained, variables showing significant differences between the two groups and higher loadings for PCA are recognized biomarkers of COVID-19, according to previous studies in literature. Therefore, based on the outcomes obtained, traces of metabolic alterations induced by SARS-CoV-2 infection are still detectable after negativization. This evidence raises questions about the eligibility of post-COVID subjects in observational studies addressed at the detection of COVID-19. (Ethical Committee Registration number: 120/AG/11).

Progress in interventional radiology treatment of pulmonary embolism: A brief review.

Pulmonary embolism represents a common life-threatening condition. Prompt identification and treatment of this pathological condition are mandatory. In cases of massive pulmonary embolism and hemodynamic instability or right heart failure, interventional radiology treatment for pulmonary embolism is emerging as an alternative to medical treatment (systemic thrombolysis) and surgical treatment. Interventional radiology techniques include percutaneous endovascular catheter directed therapies as selective thrombolysis and thrombus aspiration, which can prove useful in cases of failure or infeasibility of medical and surgical approaches.

Optimizing the Angiography Protocol to Reduce Radiation Dose in Uterine Artery Embolization: The Impact of Digital Subtraction Angiographies on Radiation Exposure.

PURPOSE: The aim was to compare a protocol of uterine artery embolization (UAE) consisting in three digital subtraction angiographies (DSAs)-Group A, with a protocol based on a single DSA-Group B. MATERIALS AND METHODS: This is a single-center prospective randomized study enrolling 20 women (mean age 41 years, range 22-55 years) with uterine fibroids treated with UAE, from January 2015 to February 2016. All UAEs were performed by two interventional radiologists using the same angiography machine. Protocol of Group A consisted in three DSA runs (non-selective pelvic view and selective uterine views before and after embolization). Protocol of Group B consisted in 1 DSA run: selective UA angiography before embolization. (Fluoroscopic roadmap was used for UA catheterization; fluoroscopy storage was used as control after embolization.) Each patient was randomized to receive Protocol A in one pelvic side and Protocol B on the other. RESULTS: All patients received bilateral UAE. Mean fluoroscopy time for UA catheterization was 11.3 ± 3.7 s. (Protocol A) and 9.93 ± 2.99 s. (Protocol B) (p = 0.19). Fluoroscopy dose for catheterization and embolization was not different between both protocols (p = 0.14). Identification of the UA origin score was similar in both protocols (median error = 0, p = 0.79). Mean dose area product (DAP) was 40859 mGy/cm2 (Protocol A) and 28839 mGy/cm2 (Protocol B) (p = 0.003). Mean effective dose (ED) decreased from Protocol A (14.6 mSv) to Protocol B (9.2 mSv; - 37%). Mean absorbed dose (AD) to ovaries and uterus, respectively, decreased of 53% and 55% from Protocol A to Protocol B. CONCLUSION: Reducing the number of DSA runs from 3 to 1 during UAE allows at least a 30% reduction on radiation exposure, without compromising technical outcomes.

Operative Protocol for Testing the Efficacy of Nasal Filters in Preventing Airborne Transmission of SARS-CoV-2.

BACKGROUND: Standardized methods for testing Viral Filtration Efficiency (VFE) of tissues and devices are lacking and few studies are available on aerosolizing, sampling and assessing infectivity of SARS-CoV-2 in controlled laboratory settings. NanoAg-coated endonasal filters appear a promising aid for lowering viable virus inhalation in both adult and younger populations (e.g., adolescents). OBJECTIVE: to provide an adequate method for testing SARS-CoV-2 bioaerosol VFE of bio-gel Ag nanoparticles endonasal filters, by a model system, assessing residual infectivity as cytopathic effect and viral proliferation on in vitro cell cultures. METHODS: A SARS-CoV-2 aerosol transmission chamber fed by a BLAM aerosol generator produces challenges (from very high viral loads (105 PFU/mL) to lower ones) for endonasal filters positioned in a Y shape sampling port connected to a Biosampler. An aerosol generator, chamber and sampler are contained in a class II cabinet in a BSL3 facility. Residual infectivity is assessed from aliquots of liquid collecting bioaerosol, sampled without and with endonasal filters. Cytopathic effect as plaque formation and viral proliferation assessed by qRT-PCR on Vero E6 cells are determined up to 7 days post inoculum. RESULTS: Each experimental setting is replicated three times and basic statistics are calculated. Efficiency of aerosolization is determined as difference between viral load in the nebulizer and in the Biosampler at the first day of experiment. Efficiency of virus filtration is calculated as RNA viral load ratio in collected bioaerosol with and without endonasal filters at the day of the experiment. Presence of infectious virus is assessed by plaque forming unit assay and RNA viral load variations. CONCLUSIONS: A procedure and apparatus for assessing SARS-CoV-2 VFE for endonasal filters is proposed. The apparatus can be implemented for more sophisticated studies on contaminated aerosols.

[Particulate matter and atmospheric pollutants exposure for outdoor workers in the Muggia area (Trieste, Italy)]. / Indagine sull'esposizione a polveri ed inquinanti atmosferici di lavoratori outdoor nell'area di Muggia (Trieste).

UNLABELLED: Urban air pollution originates from traffic, heating and industrial activities and it exposes several categories of workers to noxious chemicals; in recent years various surveys have been carried on taxi drivers, bus drivers, policemen, newspaper kiosks, fuel station workers and general population, for assessing exposure to main contaminants, benzene and PAHs in particular. AIM: defining a specific sampling strategy for collecting an experimental data base for the assessment of potential population exposure to atmospheric particulate matter in the Muggia area (Trieste, North-East Italy). MATERIALS AND METHODS: A sample of 14 urban police officers working mainly on the roads and potentially subject to occupational exposure has been analyzed, as well as a sample of the municipal administrative personnel (13 people) working in indoor environments during the same sampling periods. Exposure has been monitored by personal samplers and high volume environmental samples; urinary levels of 1 OH-pyrene and creatinine were collected for each participant at the end of each sampling period. RESULTS: PAHs analyses provided diagnostic ratios for identification of the sources of pollution. In general experimental BaP values stay below the environmental target value, with satisfactory agreement between environmental and personal monitoring. Levels of urinary 1 OH-pyrene for administrative personnel was detected always below the background value (0.089 micromoles/mole creatinine), while they are above the background and below the attention value for most of urban police officers. CONCLUSIONS: Municipal police officers participating to the present study, while belonging to one of the categories of people most exposed to outdoor PM, do not show any worrying exposure to the considered chemicals associated to their occupational activity, in comparison to other factors, possibly associated to personal lifestyles.

Evaluation of Residual Infectivity after SARS-CoV-2 Aerosol Transmission in a Controlled Laboratory Setting.

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) is mainly transmitted through respiratory droplets, aerosols, or direct contact with fomites from an infected subject. It has been reported that SARS-CoV-2 is stable and viable in aerosol up to 16 h in controlled laboratory conditions. However, the aerosolization conditions varied a lot between the studies. In this work, an experimental laboratory model of SARS-CoV-2 aerosolization was established, employing an impinger nebulizer, a cylindrical chamber for aerosol travel, and a SKC biosampler for the collection of particles. The efficiency of the system was assessed based on the molecular determination of the viral load in the nebulizer after the aerosolization and in the aerosol collected at the end of the travel. Moreover, the residual infectivity was tested in vitro on the Vero E6 cell line, through the observation of the cytopathic effect (CPE), and the quantification of the viral load in the supernatants at 7 days post inoculation (dpi). A high RNA viral load was found in the SKC biosampler after aerosolization, indicating that it was possible to transport a high virus titer through the 30-cm chamber with all the dilutions (initial 105, 104, 103 plaque forming unit-PFU/mL). At the 7 dpi, an increment of the RNA viral load was determined for the dilutions 105 and 104 PFU/mL tested, while only the initial 105 PFU/mL resulted in visible CPE. Our findings allowed us to achieve the resilience of SARS-CoV-2 in aerosol form, at a concentration comparable to those reported for clinical samples. This mode of transmission should be considered for the mitigation and preventive measures to counteract SARS-CoV-2 spreading.