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International audience; The coming years are expected to bring rapid changes in the nanotechnology regulatory landscape, with the establishment of a new framework for nano-risk governance, in silico approaches for characterisation and risk assessment of nanomaterials, and novel procedures for the early identification and management of nanomaterial risks. In this context, Safe(r)-by-Design (SbD) emerges as a powerful preventive approach to support the development of safe and sustainable (SSbD) nanotechnology-based products and processes throughout the life cycle. This paper summarises the work undertaken to develop a blueprint for the deployment and operation of a permanent European Centre of collaborating laboratories and research organisations supporting safe innovation in nanotechnologies. The proposed entity, referred to as “the Centre”, will establish a ‘one-stop shop’ for nanosafety-related services and a central contact point for addressing stakeholder questions about nanosafety. Its operation will rely on significant business, legal and market knowledge, as well as other tools developed and acquired through the EU-funded EC4SafeNano project and subsequent ongoing activities. The proposed blueprint adopts a demand-driven service update scheme to allow the necessary vigilance and flexibility to identify opportunities and adjust its activities and services in the rapidly evolving regulatory and nano risk governance landscape. The proposed Centre will play a major role as a conduit to transfer scientific knowledge between the research and commercial laboratories or consultants able to provide high quality nanosafety services, and the end-users of such services (e.g., industry, SMEs, consultancy firms, and regulatory authorities). The Centre will harmonise service provision, and bring novel risk assessment and management approaches, e.g. in silico methodologies, closer to practice, notably through SbD/SSbD, and decisively support safe and sustainable innovation of industrial production in the nanotechnology industry according to the European Chemicals Strategy for Sustainability.

In vitro air–liquid interface (ALI) cell culture models can potentially be used to assess inhalation toxicology endpoints and are usually considered, in terms of relevancy, between classic (i.e., submerged) in vitro models and animal-based models. In some situations that need to be clearly defined, ALI methods may represent a complement or an alternative option to in vivo experimentations or classic in vitro methods. However, it is clear that many different approaches exist and that only very limited validation studies have been carried out to date. This means comparison of data from different methods is difficult and available methods are currently not suitable for use in regulatory assessments. This is despite inhalation toxicology being a priority area for many governmental organizations. In this setting, a 1-day workshop on ALI in vitro models for respiratory toxicology research was organized in Paris in March 2016 to assess the situation and to discuss what might be possible in terms of validation studies. The workshop was attended by major parties in Europe and brought together more than 60 representatives from various academic, commercial, and regulatory organizations. Following plenary, oral, and poster presentations, an expert panel was convened to lead a discussion on possible approaches to validation studies for ALI inhalation models. A series of recommendations were made and the outcomes of the workshop are reported.

EC4SafeNano is a 2016-2019 Coordination and Support Action, funded by the European Commission (Grant Agreement No 723623), coordinated by INERIS, and operated together by major European human health and environmental risk institutes with the support of associated partners, gathering stakeholders in the field of Nanotechnologies (regulators, industry, civil society, NGOs, service providers etc.). EC4SafeNano aims to bridge the gap between scientific knowledge on hazard and risk, and ‘fit-for-purpose’ risk management tools and strategies. The main objective of EC4SafeNano will be to develop and promote a harmonized vision of expertise and services in risk assessment and management, to enable the safe development and commercialization of nanotechnology and develop a sustainable structure to deliver these services. In this respect, two work packages were dedicated to gathering information on stakeholder needs and available services, by means of an online survey. Information was collected on the ability to provide technical services for testing and measuring, and/or to perform consultancy and desk top studies. For these services, detailed information on available technical equipment, software tools, methods used and application fields was requested. Alongside specific technical details, the service providers were asked to give a general overview of their current and future offers for nanosafety services by scoring a matrix table. The online survey resulted into 82 responses from 22 countries, including 2 non-European countries. An overview of current types of services demonstrated that testing and measuring and consultancy studies represented the majority of the offered services (each >20% of total), followed by training (12%). Across all the types of services, physicochemical characterization (12.5%), emission studies (6.8%), fate (5.1%), human health hazard studies (5.7%), occupational exposure assessment (8.8%), occupational risk assessment (5.2%), occupational risk management (5.5 %) and risk prevention (5.7%) were the main application fields for nanosafety. The information from service providers will be compared to the inventory of stakeholder needs, as part of a fit and gap analysis in another work package, and provide the basis for a catalogue of services to be offered by the EC4Safenano Centre. We will present the set-up of the survey to create an inventory of the competences and infrastructure of service suppliers, as well as the obtained results.

Nanotechnology is often said to be the industry of the 21st century. Nanostructured materials are expected to lead to the emergence of new products with enhanced features and functionalities. Their manufacturing often requires the use of nanoparticles (sizes below 100 nm) or larger particles (with a nanostructure) with varied sizes, shapes and chemical compositions. These nano-objects are the basic building blocks used to design nanostructured materials. The advent of these new objects raises the question of the development of an adapted metrology for their characterization in various contexts. Two examples of need may be underlined, nanosafety and process monitoring. First, little is known yet as to the risks related to nano objects in terms of impact on human health and the environment. There is therefore a need to detect and characterize these particles under various conditions. Second, production processes require tools for on line characterization of the final product. Thus, adapted instruments allowing, on site, on line and even real time characterization of these particles are to be designed. Laser-Induced Breakdown Spectroscopy (LIBS) is deemed as a technique of interest for the detection of nano-objects. Contrary to most particle counters, it allows determining the elemental composition of the particles and the mass concentrations of all the elements they are made of. LIBS tests have been carried out in the field of nanosafety. LIBS was demonstrated as a possible instrument for real-time detection and identification of Carbon Nano Tube (CNT) balls. So far, only random analysis in the particle flow was possible. A prototype allowing targeting particles (sizes > 500nm) prior to LIBS analysis is currently being designed to improve the hit rate. LIBS experiments applied to process monitoring have also been performed. It has been demonstrated that nanopowder stoichiometry could be monitored in real time. More recently, calibration free LIBS has been applied to stoichiometry determination of powders. Nanoparticle analysis using LIBS requires appropriate sampling. Demonstration has been made that nanoparticle analysis by LIBS could be enhanced using a radio frequency plasma as a trap. Applications in the field of nanosafety, process monitoring and life science are envisaged.

L'intégration dès la conception des produits et en tenant compte de toute la vie du produit avec une vision d’économie circulaire est une approche prometteuse pour limiter l’impact des produits et des substances en termes de risques. Par exemple pour des nanomatériaux, il est notamment possible de travailler sur la taille et la structure. Cette approche, innovante et proactive, peut concerner bien d’autres substances. A une plus grande échelle, elle constitue aussi une des briques de réflexion sur l’usine du futur.

International audience; Aerosols released in the course of industrial processes may represent a threat for workers and the environment. Possible emission of micrometric / submicrometric particles such as CNT (carbon nanotube) powders at production sites or heavy metals at exhaust stacks of foundries and incinerators are two telling examples. The above considerations emphasize the need to develop an instrument allowing in-situ and real-time elemental identification and mass concentration determination of airborne particles. A LIBS-based (Laser Induced Breakdown Spectroscopy) system may be the appropriate tool to deal with such delicate issues. LIBS consists in focusing a powerful laser pulse on a material (solid, liquid, gas, aerosol, nanoparticle flow) whose elemental composition is to be determined. The strong heating of the sample at the focusing spot leads to the ignition of a hot and luminous transient ionized gas called plasma. Plasma light contains the signature of all the chemical elements the interrogated material is made of. This signature is read by sending the emitted light through a spectrometer equipped with a detector. The LIBS signal presents itself as an optical emission spectroscopy spectrum displaying lines corresponding to the detected elements...

In vitro air-liquid interface (ALI) cell culture models can potentially be used to assess inhalation toxicology endpoints and are usually considered, in terms of relevancy, between classic (i.e., submerged) in vitro models and animal-based models. In some situations that need to be clearly defined, ALI methods may represent a complement or an alternative option to in vivo experimentations or classic in vitro methods. However, it is clear that many different approaches exist and that only very limited validation studies have been carried out to date. This means comparison of data from different methods is difficult and available methods are currently not suitable for use in regulatory assessments. This is despite inhalation toxicology being a priority area for many governmental organizations. In this setting, a 1-day workshop on ALI in vitro models for respiratory toxicology research was organized in Paris in March 2016 to assess the situation and to discuss what might be possible in terms of validation studies. The workshop was attended by major parties in Europe and brought together more than 60 representatives from various academic, commercial, and regulatory organizations. Following plenary, oral, and poster presentations, an expert panel was convened to lead a discussion on possible approaches to validation studies for ALI inhalation models. A series of recommendations were made and the outcomes of the workshop are reported.

Les aérosols [1] peuvent être définis comme un ensemble de particules solides ou liquides en suspension dans un gaz. Certains aérosols émis par des procédés industriels peuvent présenter un danger pour les travailleurs et l’environnement. L’émission de particules de métaux lourds par des incinérateurs ou des fonderies en est un exemple. L’émission de nanoparticules dans les industries des nanotechnologies en est un autre. Dans ces deux cas, les techniques d’analyse courantes nécessitent plusieurs étapes. Tout d’abord il faut envoyer des personnels sur site pour faire des prélèvements. Les échantillons prélevés sont alors préparés puis seulement analysés. La procédure est longue et peut prendre quelques heures voire quelques jours. Ceci souligne l’importance de développer des techniques permettant des analyses en temps réel, sur le terrain, permettant l’identification chimique élémentaire immédiate de tous les éléments présents et la détermination de leurs concentrations en masse. La technique LIBS est jugée potentiellement prometteuse pour ces applications. Dans le domaine des métaux lourds [2], un prototype est développé à l’INERIS depuis plusieurs années. Il permet l’analyse des concentrations en masse d’aérosol avec des particules dans une gamme de taille variant de 0.5 à 10 μm avec des limites de détection de l’ordre du μg/m3. Ces analyses nécessitent un étalonnage préalable du système LIBS. Ce prototype est en phase d’amélioration pour abaisser les limites de détection. Dans le domaine des nanotechnologies, le suivi en temps réel sur un procédé de production de la stoechiométrie de nanopoudres peut être souhaitable. Un système LIBS permet de répondre à toutes les contraintes de ce genre d’opération visant une analyse semi quantitative pouvant être réalisée en recourant à un modèle de simulations de raie supposant l’équilibre thermodynamique local [3] et donc sans étalonnage. Cette présentation illustrera l’analyse d’aérosols dans une gamme de taille s’échelonnant du nanométrique au micrométrique avec et sans étalonnage.

International audience; The LIBS (Laser-Induced Breakdown Spectroscopy) technique has shown its potential in many fields of applications including that of aerosol analysis. The latter is usually carried out on the particle flow, thereby allowing quantitative detection in various experimental conditions such as ambient air analysis or exhaust stack monitoring, to name but a few. A possible alternative method for particle analysis has been experimented combining a low pressure RF (Radio-Frequency) plasma discharge with the LIBS technique. Such approach has two peculiar features in comparison to the usual LIBS analysis. First, the particles injected in the RF plasma discharge are trapped in levitation. Second, the analysis is performed at a reduced pressure of around 1 mbar. LIBS detection at such low pressure has this peculiarity that particle vaporization is assumed to be achieved through direct laser particle interaction whereas it is caused by laser-induced plasma ignited in the gas at atmospheric pressure. The use of such particle trap could allow improving particle sampling, making organic particle analysis possible (by using an inert gas for RF plasma ignition) and even (depending on the pressure) obtaining a better signal to noise ratio. Detection of the elements of nanoparticle agglomerates made following their injection in the RF discharge has demonstrated the feasibility of such approach. Future experiments are intended to explore its potentialities when tackling issues such as process control or ambient air monitoring.

A central challenge to ensure the sustainable production and use of nanotechnologies is to understand the risks for environment, health and safety associated with this technology and resulting materials and products (engineered nanomaterials), and how to identify and implement practical strategies to minimise these risks. Knowledge about nanotechnology processes is growing rapidly, achieved through numerous European or national programs launched over the last decade, but effective use of this knowledge for risk management by market actors is lagging behind. The H2020 project EC4SafeNano starting on 01/11/2016 for 3 years will define and design a sustainable European structure for European expertise on nanosafety in order to Bridge the gap between research and application for public and private actors, between knowledge on risks and risk management, and to bring a Balance between Science and Appliance, The proposed partnership will set up a structure to integrate expertise activities across the member states, and provide the interface between the scientific community and these other parties to develop and supply knowledge and technical services appropriate to each community. EC4SafeNano aims to build an open collaborative network gathering expertise in risk management of nanotechnologies. All interested organization are invited to take part in the initiative as an Associated Partner helping to design the future European Centre and establish harmonized approaches for the proposed solutions and services. The Associated Partners will be active at the European level through their participation in the Focus Networks and will act in an ‘ambassador’ role for the member states where they are based. National centers are foreseen to mirror the European center. EC4SafeNano seeks to establish a record of accomplishment in developing ‘fit-for-purpose’ solutions and providing access to reliable data and experience to help solve the range of environment, health and safety challenges that will be required to develop safe and sustainable innovation for nanotechnology. EC4SafeNano also seeks to establish principles for safe management of nanotechnology, and to assist public and private organizations and industry in the application of these principles. European joint calls for expertise will help demonstrate the concept of establishing and providing this collective expertise to answer demands. The core group and associates are experienced in providing expert advice to industry and other private actors, to public authorities and regulatory bodies and in communicating evidence based expertise to these different target audiences.

Currently, there is an explosion of consumer products containing nanoparticles. On the one hand, the presence of nanomaterials in these products is considered to be innovative but, on the other hand, it also raises controversies about their potential effects on human health and environment. In order to reduce uncertainties and get a first insight on the nanomaterials available on the market, several countries decided to implement institutional inventories: Consumer Products Inventory (USA), Nanodatabase (Denmark), ANEC/BEUC (Europe), RIVM (Netherlands), R-Nano (France) and new ones are in development (Belgium and Sweden). However, as underlined by different stakeholders, the current registries only offer a partial view of the current uses of nanomaterials on the European market. In order to support the development of an adapted regulation, which reflects the market reality, it becomes then urgent to develop new tools that can provide a relevant sight of this reality. In this study, we present a simple approach using qualitative research tools that we believe will help the Authorities to adapt and priorize coming regulatory works. This approach is illustrated through a case study on silver nanoparticles. Based on a study of available inventories and of the registrations of European patents, an analysis of the distribution of categories of consumer products containing silver nanoparticles was carried out. Furthermore, we undertook two kinds of analyses to map the uses of silver nanoparticles. First, a bibliometric survey of the 10 000 most recent publications in peer-review journals on Web of Science was performed. Secondly, we used the textual analysis of contents of 2438 headlines in international press to highlight the key issues in the public sphere. From this study, several kinds of category uses were highlighted. Current and prospective uses of silver nanoparticles can be outlined from figure 1. This study allowed the identification of new profiles of industries beyond inventories and gives new point of view of suspected gaps between the number of registered end-products and the consumer products on the market, nowadays and in the future.

International audience; Carbon Nanotubes (CNTs) are deemed as revolutionary materials very likely to be utilized in numerous fields such as electronics, energy, and medicine, to name but a few. The emergence of this new fiber-shaped material with remarkable properties and dimensions of a few micrometers in length and a few tens of nanometers in diameter raises concerns about potential exposure of workers involved in the whole production cycle. These risks emphasize the need to develop tools allowing identifying such objects, either as isolated fibers or entangled in bundles, in situ and if possible in real time. In this context, experiments aiming at detecting potential particle release while manipulating raw CNT powders were performed at ARKEMA research center in a high safety cell dedicated to scientific experiments. Two techniques were employed. First, particle collection on TEM grids was achieved using two samplers, the first based on aspiration and the second on diffusion assisted with thermophoretic repulsion. These allowed differed analysis of single particle morphology, size and chemical composition. Second, real time multi-elemental composition of particle emission was monitored using LIBS. Eventually, though not quantitative, the coupling of TEM grid analysis with LIBS data demonstrated the possibility of real time detection of CNTs entangled in bundles.

New issues related to process control and workplace surveillance accompany the emergence of nanotechnology industry. The quality control of nanoparticles in industrial production and their monitoring for workplace surveillance purposes require on-line determination of concentration and chemical composition. This involves the development of new real-time and in-situ characterization techniques. In this context, laser-induced breakdown spectroscopy (LIBS) is a promising technique in both process control and workplace surveillance. Thus, experiments with two different approaches of the LIBS technique have been carried out. The first approach used a flow cell to determine the elemental composition of an aerosol with a calibration-free (CF) procedure. The second one used a low-pressure radio-frequency (RF) cell as a particle trap to analyze aerosols containing nanoparticles. The experimental setup consists of the aforementioned analysis cells coupled to a LIBS optical setup. In both cases, studied particles were injected using an inert gas (argon/helium). The flow cell setup used an aerosol flow of alumina (Al2O3) micrometric particles for the analysis. The LIBS-RF setup used RF plasma generated with the inert gas (argon) at a low- pressure (2 mbar) to concentrate and trap particles in levitation inside the RF plasma. In both cases, the optical setup consists of focusing laser pulses of 5 ns duration originating from a Q- switched Nd:YAG laser (1064 nm) on the aerosol inside each analysis cell where the plasma was generated. When resorting to CF-LIBS, the recorded spectra were compared to theoretical spectra calculated for a plasma in the Local Thermodynamic Equilibrium1. We found that the stoichiometric composition of the alumina particles can be deduced from the best agreement between measured and computed spectra if the experimental conditions are properly chosen without any requirement of calibration with standards. The use of the low-pressure RF plasma cell as a particle trap improved the sampling by concentrating particles. The LIBS-RF signal was enhanced by eliminating the plasma continuum thanks to the low-pressure. Elements difficult to analyze in conventional conditions such as C,H,O,N were detected with a very good signal-to-noise ratio. New studies aiming to validate the CF-LIBS with other powders (CaTiO3 and MnTiO3) are currently underway and new experiments with the LIBS-RF aiming to determine the particle density and the elemental concentration in an aerosol are scheduled.

International audience; Carbon aerosol is now recognized as a major uncertainty on climate change and public health, and specific instruments are required to address the time and space evolution of this aerosol, which efficiently absorbs light. In this paper, we report an experiment, based on coupling lidar remote sensing with Laser-Induced-Incandescence (LII), which allows, in agreement with Planck's law, to retrieve the vertical profile of very low thermal radiation emitted by light-absorbing particles in an urban atmosphere over several hundred meters altitude. Accordingly, we set the LII-lidar formalism and equation and addressed the main features of LII-lidar in the atmosphere by numerically simulating the LII-lidar signal. We believe atmospheric LII-lidar to be a promising tool for radiative transfer, especially when combined with elastic backscattering lidar, as it may then allow a remote partitioning between strong/less light absorbing carbon aerosols.

Les nouvelles substances et technologies, les nouveaux usages ou les préoccupations sociétales font apparaître des risques que l’on qualifie d’émergents.

Large-scale industrial production of nanoparticles requires quality control through measurements of the size distribution and chemical composition. For this purpose, new on-line monitoring techniques allowing real-time and in-situ characterization have to be developed. Producing composite nanoparticles elaborated from several chemical elements requires an instantaneous and in-situ stoichiometry control. In this context, laser-induced breakdown spectroscopy (LIBS) is a promising technique. LIBS consists in focusing a powerful laser pulse on a material (solid, liquid, gas, nanoparticle flow) whose elemental composition is to be determined. The strong heating of the sample at the focusing spot leads to the ignition of a plasma. Simultaneous detection of all the elements is then achieved through optical emission spectroscopy. The LIBS technique has already been tested at INERIS for on-line monitoring, monitoring of heavy metal particle emission in the exhaust duct of a foundry and for controlling work environment. Thus, experiments aiming at determining the stoichiometry of aerosols using a calibration-free LIBS technique have been carried out. The experimental setup consists of an analysis cell coupled to a LIBS optical setup. A vortex mixer has been used to suspend alumina Al2O3 micrometric particles. The suspended particles are then flowed through the cell using an inert gas (argon/helium). Laser pulses of 5 ns duration originating from a Q-switched Nd:Yag laser (1064nm) were focused inside the analysis cell on the aerosol flux where the plasma was generated. The LIBS signal was collected from the plasma using a telescope and spectra containing lines of aluminium Al and oxygen O were recorded using an echelle spectrometer coupled with an intensified charge-coupled device detector. The recorded spectra were then compared to theoretical spectra calculated for a plasma in the Local Thermodynamic Equilibrium . We demonstrate that the stoichiometric composition of the alumina particles can be deduced from the best agreement between measured and computed spectra if the experimental conditions were properly chosen. These preliminary experiments show that stoichiometry of alumina particles may be determined on-line without resorting to calibration with standards.

The quality control of nanoparticles in industrial production requires on-line measurements of the size distribution and chemical composition. This involves the development of new real-time and in-situ characterization techniques. Producing composite nanoparticles elaborated from several chemical elements requires an instantaneous and in-situ stoichiometry control. In this context, laser-induced breakdown spectroscopy (LIBS) is a promising technique. Thus, experiments aiming to determine the elemental composition of aerosols using a calibration-free LIBS technique have been carried out. The experimental setup consists of an analysis cell coupled to a LIBS optical setup. A vortex mixer has been used to suspend alumina Al2O3 micrometric particles. The suspended particles are then flowed through the cell using an inert gas (argon/helium). Laser pulses of 5 ns duration originating from a Q-switched Nd:YAG laser (1064? nm) were focused inside the analysis cell on the aerosol flux where the plasma was generated. The LIBS signal was collected from the plasma using a telescope and spectra containing lines of aluminium and oxygen were recorded using an echelle spectrometer coupled to an intensified charge-coupled device detector. The recorded spectra were then compared to theoretical spectra calculated for a plasma in the Local Thermodynamic Equilibrium [1]. We found that the stoichiometric composition of the alumina particles can be deduced from the best agreement between measured and computed spectra if the experimental conditions are properly chosen. In particular, the background gas and the gate delay have to be optimized to perform precise measurements. These preliminary experiments show that the elemental composition of alumina particles can be measured via LIBS without any requirement of calibration with standards.

Heavy metals have long been known to be detrimental to human health and the environment. Their emission is mainly considered to occur via the atmospheric route. Most of airborne heavy metals are of anthropogenic origin and produced through combustion processes at industrial sites such as incinerators and foundries. Current regulations impose threshold limits on heavy metal emissions. The reference method currently implemented for quantitative measurements at exhaust stacks consists of on-site sampling of heavy metals on filters for the particulate phase (the most prominent and only fraction considered in this study) prior to subsequent laboratory analysis. Results are therefore known only a few days after sampling. Stiffer regulations require the development of adapted tools allowing automatic, on-site or even in-situ measurements with temporal resolutions. The Laser-Induced Breakdown Spectroscopy (LIBS) technique was deemed as a potential candidate to meet these requirements. On site experiments were run by melting copper bars and monitoring emission of this element in an exhaust duct at a pilot-scale furnace in a French research center dedicated to metal casting. Two approaches designated as indirect and direct analysis were broached in these experiments. The former corresponds to filter enrichment prior to subsequent LIBS interrogation whereas the latter entails laser focusing right through the aerosol for detection. On-site calibration curves were built and compared with those obtained at laboratory scale in order to investigate possible matrix and analyte effects. Eventually, the obtained results in terms of detection limits and quantitative temporal monitoring of copper emission clearly emphasize the potentialities of the direct LIBS measurements.

In order to promote sustainable development of nanotechnologies, standardisation has to be considered as a pillar for success. Indeed, the current lack of standardisation allowed tensions to increase between the various stakeholders (researchers, industry, public authorities and consumers) as it entails the jeopardization of both commercial and regulatory perspectives. Thus, when considering standardization, safety appears very quickly as an outstanding and essential requirement. New powders containing nano-objects imply new risks that have to be evaluated and managed to enable their sustainable and efficient development. This growing-fast technology and the recent results published in the literature put into evidence that a major effort is now required to assess the safety parameters of powders containing nano-objects, especially their propensity to burn, explode and disperse in case of a loss of containment, in order to manage industrial risks. The explosivity and flammability properties have to be given in the safety data sheet for a safe storage, handling and transport of any powder and are key safety parameters to ensure proper industrial safety management. In this perspective, the European Committee for Standardization (CEN) set up the Technical Committee 352 (CEN/TC 352) in 2006 to develop and maintain up to date standards in the field of nanotechnologies. Part of the work group (WG 3) dedicated to Health, Safety and Environment, the CEN/TC 352/WG3/PG3 led by INERIS was constituted to develop a Technical Specification (TS) for the determination of explosivity and flammability properties of manufactured nano-objects in powder form.

Bon nombre de polluants sont présents sous forme particulaire dans l’environnement ou en milieu industriel. Dans l’air comme dans les eaux, des particules micrométriques ou sub-micrométriques jouent un rôle dans leur transport, qu’il s’agisse par exemple de métaux lourds ou d’objets nanostructurés tels les nanoparticules, leurs agrégats et leurs agglomérats. Pour doser les concentrations de ces pollluants, les techniques de mesure chimique élémentaire couramment utilisées nécessitent le déplacement de personnels sur site, des prélèvements, une préparation en laboratoire puis enfin l’analyse. Il existe à l’heure actuelle peu d’instruments permettant de détecter, sur site, in-situ et en temps réel, l’émission de particules et de mesurer les concentrations émises selon leur nature chimique élémentaire. La technique LIBS (Laser-Induced Breakdown Spectroscopy) ou spectroscopie de plasma induit par laser semble adaptée à une telle problématique. A l’INERIS, elle a été ainsi appliquée à l’analyse des particules dans l’air pour le contrôle de procédés, la surveillance des ambiances de travail et le suivi de l’émission de métaux lourds sous forme particulaire en fonderie. Dans tous ces cas, les particules ont été introduite dans une cellule d’analyse dans laquelle des impulsions laser de longueur d’onde 1064 nm de durée 5 ns ont été focalisées. Le plasma formé vaporise les particules et permet des mesures semi quantitative et quantitative sur les particules. Ainsi, il est possible de détecter en temps réel des pelotes de nanotubes de carbone et de suivre la concentration en masse de cuivre dans les conduits d’évacuation d’une fonderie. Des expériences préliminaires utilisant une cellule plasma radiofréquence permettant de piéger les particules en lévitation a été utilisé dans le but d’améliorer les limites de détection. Enfin, plus récemment, nos efforts se sont portés sur la détermination de la stoechiométrie de particules composites sans étalonnage en ajustant des spectres simulés sur des spectres expérimentaux en faisant l’hypothèse de l’équilibre thermodynamique local. La technique LIBS a également été appliquée à l’analyse des particules dans les liquides. Tout d’abord, un montage LIBS a été couplé avec un jet liquide. Les travaux réalisés ont consisté à étudier l’optimisation du rapport signal sur bruit et du volume liquide évaporé en fonction de la longueur d’onde laser et de la fluence utilisée. Les résultats ont montré que l’utilisation du rayonnement UV permettait d’obtenir les meilleurs résultats. En plus de l’analyse par jet liquide, un autre mode d’échantillonnage des particules, consistant à les aérosoliser, a été testé et les deux modes comparés. Cette comparaison a mis en évidence les potentialités respectives de ces deux modes.

Nous avons utilise des cristaux de KTP et de KNbO 3 comme oscillateurs parametriques optique (OPO) pompes par un laser Titane:Saphir accordable. Pour l'OPO base sur un KTP «monolithique» en configuration d'accord de phase non critique de type II (θ=90° et Φ=0°), on obtient un seuil de 0,2 MW/cm 2 et une efficacite de conversion totale de 37%. L'OPO base sur le KNbO3 permet d'obtenir un signal et une complementaire variant de 0,95 a 3,8 μm lorsque l'on balaie la pompe entre 740 et 860 nm. Implemente dans notre systeme Lidar, ce cristal nous a permis de mesurer a 3,5 μm la taille et la concentration des gouttelettes d'eau lors d'un episode de brouillard, sur une distance de 1500 m. Le rayon moyen des gouttelettes d'eau est de 8,7 μm et la concentration est de 10 mg/m 3 .

La detection optique a distance de type Lidar (Light Detection and Ranging) pourrait etre appliquee pertinemment pour diagnostiquer la presence dans l'atmosphere d'agents biologiques. R. Chang et al [1] ont recemment demontre qu'il est possible de detecter des bacteries par fluorescence induite par laser (LIF). Toutefois, en milieu reel, il faut eviter toute interference avec d'autres sources d'emission: les hydrocarbures et leurs residus de combustion. Nous presentons ici les spectres LIF comparatifs de plusieurs aerosols candidats a la detection.

We present the results of an extensive study on urban aerosols performed in the summer of 1996 in Lyon. Non-volatile urban particles have been sampled using filters. Size distribution and composition, determined by scanning electronic microscopy (SEM) and X-Ray microanalysis, reveal two main modes at 0.1 and 0.9 μm, the composition of which is soot for the first and 60% in number soot — 40% silica for the second. Mie calculations have been performed using the actual size distribution and composition to determine the optical backscattering and extinction coefficients. The optical characteristics were then used for Lidar measurements. The combined SEM and Lidar techniques allowed to obtain the first quantitative 3D-profiles of urban aerosols concentrations. Potential and limitations of the method are critically discussed.

Nanotechnology is often said to be the industry of the 21st century. With the advent of nanostructured materials has emerged a new kind of nanostructured particles with different sizes, shapes and chemical compositions referred to as NOAA (Nano Object, their Aggregates and their Agglomerates). Either when being synthesized or accidentally released in the course of the manufacturing process, adapted metrology tools allowing their detection / characterization in situ and in real time (if possible) are to be developed for applications such as process control and workplace surveillance. LIBS was deemed as a promising technique to deal with such issue [1-3]. With the final aim in view to enhance detection of these objects, preliminary experiments were carried out coupling a LIBS analyzer with a low pressure RF (Radio Frequency) plasma discharge (instead of the usual flow cell) acting as a particle trap [4]. Agglomerates of composite nanoparticles of SiC and Al2O3 were injected into the RF plasma discharge where they were trapped and remained in levitation. Nanosecond laser pulses were then focused on the trapped particles, thereby producing the LIBS signal. LIBS detection was therefore achieved with a satisfying signal to noise ratio at a reduced pressure of 0.25 mBar instead of the atmospheric pressure. Thus, this coupling presents several advantages. All injected particles are trapped and can potentially be analyzed, thereby improving sampling. Organic particle analysis is made possible without interferences with the C, H, N, O, elements already present in the air when using an inert gas such as argon or helium for RF plasma generation. In addition, the signal-to-noise ratio may be higher at reduced pressure than at atmospheric pressure. The obtained results, though qualitative so far, have demonstrated the potentialities of such coupling for elemental identification of the elements composite nanoparticle agglomerates are made of. Future experiments are intended to optimize the LIBS detection, to assess the detection limits and to obtain quantitative results when tackling issues such as process control or ambient air monitoring. The use of other laser diagnostics could be envisaged as well for size and morphology measurements.

Risks associated with the end-of-life of nanomaterials are an issue that needs to be addressed so that the public perception and opinion, with regard to these emerging technological products, can effectively be supported by experimental evidences. In order to find new ecological ways to treat nanoproducts at their end-of-life, a new home-made demonstrator system was setup at INERIS, specifically designed to perform burning tests, coupled to a differential thermal analyzer to monitor the combustion kinetics. To assess nanoobject release during combustion, a high-performance nanocomposite polymer commonly used in the automotive industry, namely the polymeric compound acrylonitrile butadiene styrene matrix mixed with 3 wt% of multiwalled carbon nanotubes (MWCNTs) was tested. To assess the potential release of carbon nanotubes (CNTs) during the combustion with this tool, the particle size distribution in the fumes was measured using an electrical low pressure impactor, and CNTs were collected using an aspiration-based transmission electron microscopy grid sampler. One of primary objective of these preliminary tests described in this study consisted in validating whether CNT fibers can be released in the gas phase during the combustion of a polymeric matrix filled with CNTs. It was found indeed that MWCNT of about 12-nm diameter and 600-nm length can be released in the ambient environment during combustion of 3 % MWCNT ABS. Such information is critical to assess whether a nanoproduct can be deemed to be considered as 'nanosafe by design' in its risk assessment.

Nanotechnology is often said to be the industry of the 21st century. In most cases, the designing of nanostructured materials implies utilizing engineered nanoparticles as basic building blocks. Such materials often have new functionalities and enhanced properties which make them of great interest for many industrial applications. The apparent limitless possibilities offered by nanotechnologies in terms of applications and economic gain are to lead to a dramatic increase of engineered nanoparticle production. The need for nanoparticle-based materials is therefore expected to grow along with that for nanometrology allowing characterization of nanoparticles in-situ and in real time if possible. Workplace surveillance and process control are among many others issues where such instrumental development is required.

Transmission electron microscopy (TEM) coupled with energy-dispersive X-ray (EDX) offers a very comprehensive tool for individual particle analysis allowing the determination of size, morphology, specific surface, and elemental composition. This information is needed in aerosol studies, especially in the field of nanomaterials. However, observations with TEM require a controlled sampling on an adapted analysis support, namely TEM grid. Techniques allowing sampling on TEM grids are of great interest to aerosol analysis. Indeed, sample preparation is not required, thereby gaining time and avoiding a risk for the sample to be altered. The present study evaluates the efficiency of a new particle collection technique based on filtration through one class of TEM-dedicated supports, namely TEM porous grids. Two types of porous grids, considered as the best on the market for this application, have been put to the test: the 'Quantifoil' type porous grid, which has a regular structure, and the 'Holey' type (Agar Scientific, Stansted, Essex, England). A filter holder has been developed specifically for this application, the MPS (Mini-Particle Sampler , Ecomesure, Janvry, France). Experimental tests have been carried out with a flow rate of 0.3 L min-1. They show that the collection is operational in the 5-nm to 150-nm size range, with a minimum efficiency of 15-18% around 30 nm. Simulation confirms these results and shows an increased efficiency even below 5 nm and beyond 150 nm. The filter holder MPS designed in this study is a low-cost, portable, versatile, and easy-to-use tool.

International audience; Pollution of air and water are major concerns both at domestic and European Union level. With the aim in view to preserve and improve water quality, the European Community has adopted a water framework directive (WFD). Its objective is to achieve a good ecological and chemical status of waters by 2015. In this context, research in metrology has been engaged at INERIS in order to detect pollutants such as heavy metals {both in ionic or particulate forms}. Though they were not cited in the directive since they are considered as emerging pollutants, nanoparticles are an object of concern whose detection should be made possible as well. The constraints imposed by regulations and the emergence of new pollutants, emphasize the need to develop an instrument allowing in-situ and real-time elemental identification and mass concentration determination of particles suspended in water. Environmental monitoring and surveillance of pollutants in particulate form possibly released in waste waters by industries involved in nanoparticle manufacturing and processing are two telling examples of applications of such instrumental development. The LIBS (Laser-Induced Breakdown Spectroscopy) technique was retained to tackle such issue.

International audience; Les aérosols peuvent être définis comme des particules solides ou liquides en suspension dans un gaz avec des diamètres s'échelonnant du nanomètre jusqu'à plusieurs micromètres. La génération d'aérosols dans les procédés industriels peut représenter une menace pour les travailleurs comme pour l'environnement. La possible émission, sous forme de particules de tailles micrométriques/submicroniques, de métaux lourds issus des rejets canalisés d'industries (telles que les fonderies ou les incinérateurs) ou bien encore de pelotes de nanotubes de carbone sur leur lieu de production, en sont deux exemples. Les rejets de métaux lourds dans l'atmosphère sont essentiellement d'origine anthropique et produits par des industries impliquant notamment des procédés de combustion comme les incinérateurs et les fonderies. Compte tenu des effets nocifs avérés des métaux lourds sur l'homme et l'environnement, les rejets sont encadrés par des réglementations (arrêtés du 02 février 1998 et du 20 septembre 2002). L'évolution de celles-ci, toujours plus stricte, nécessite le développement d'outils adaptés et notamment, d'une instrumentation de terrain permettant l'analyse in-situ en automatique avec une résolution temporelle adéquate. Les travaux présentés ici sont focalisés sur la quantification en temps réel de la fraction particulaire dans une gamme de tailles s'échelonnant de 1 à 10 µm. Depuis leur découverte, les nanotubes de carbone (NTC) suscitent un intérêt croissant eu égard aux très nombreuses applications possibles dans de nombreux domaines industriels. Les nombreuses applications potentielles des NTC soulèvent l'enthousiasme mais également des inquiétudes. Les possible effets que pourraient avoir les NTC sur la santé humaine sont très mal connus et les recherches sur ces sujets toujours en cours. Leur morphologie en forme de fibre est inquiétante car elle rappelle celle de l'amiante. Au risque lié à la morphologie des NTC s'ajoute celui de la toxicité chimique des éléments contenus dans les nanotubes de carbone, souvent des éléments de catalyse. Sur les lieux de production, la voie aérienne est la source la plus probable de contamination. Bien que les procédés de production soient sécurisés, une possible fuite n'est jamais à écarter. De plus, le risque d'exposition existe à plusieurs étapes de production, tels que le conditionnement du produit final par exemple. Il est donc nécessaire de disposer d'outils de terrain permettant d'accéder à la taille et à la morphologie mais aussi à la composition chimique des particules émises. Il existe à l'heure actuelle peu d'instruments permettant, in-situ et en temps réel, de détecter l'émission de particules et de mesurer les concentrations émises selon leur nature chimique élémentaire. La technique LIBS (Laser-Induced Breakdown Spectroscopy) ou spectroscopie de plasma induit par laser semble adaptée à une telle problématique. C'est pourquoi elle a été appliquée dans les deux cas susmentionnés

NANOPARTICLES ; TEM SAMPLER EFFICIENCY

Today, nanotechnology is a growing field of research and nanoparticle-based material production is expected to soar in years to come. The development of robust and reliable technologies for detection and measurement of airborne nanoparticles is a key point for the protection of workers health in the research and industry. Today, commercially available instruments provide global measurements of the particles concentration in the air. Selective monitoring will strongly improve the security level by giving the concentration of each element present in the air. To achieve this goal, the LIBS (Laser-Induced breakdown Spectroscopy) technique was deemed as a potential candidate. LIBS measurements consist in focusing a laser pulse on a material which elemental composition is to be determined. At the focus spot, plasma is generated and analysed by optical emission spectroscopy. This method provides the concentration of each element in the aerosol, in real time, and does not require sample preparation. These qualities are advantages over the other techniques

International audience; Vertical profiles of particle mass concentration in the urban canopy above the city of Lyon have been obtained from Lidar measurements of atmospheric backscattering, over a period of three days. The concentrations measured at 50 m above the ground have been compared with the mass concentration of PM10 measured by a ground-based sampler located near the Lidar site. At certain times during the measurement campaign, the Lidar concentration measurements at 50 m agree reasonably well with the concentrations at ground level but at other times the differences between the two sets of measurements are so great that they cannot be explained by possible uncertainties in the data processing. Even when the Lidar and ground-based measurements coincide, there are significant differences between the two signals. To explain these differences we have computed the trajectories of the air parcels that pass over the Lidar, using a numerical model for the wind field that takes into account surface features such as relief and changes in roughness. This analysis showed that the differences can be explained by the meteorological conditions (wind speed and direction, vertical profiles of temperature) and the positions of the different sources of particulate matter relative to the measurement site. The combination of Lidar, ground-based sampler and air mass trajectory calculations is shown to be a powerful tool for discriminating between different sources of pollution, which could be useful in enforcing an urban air quality policy.

National audience; Laser-Induced Breakdown Spectroscopy (LIBS) has been employed to detect sodium chloride and metallic particles with sizes ranging from 40 nm up to 1 um produced by two different particle generators. The LIBS technique combined with a Scanning Mobility Particle Sizer (SMPS) was evaluated as a potential candidate for workplace surveillance in industries producing nanoparticle-based materials. Though research is still currently underway to secure nanoparticle production processes, the risk of accidental release is not to be neglected. Consequently, there is an urgent need for the manufacturers to have at their command a tool enabling leak detection in-situ and in real time so as to protect workers from potential exposure. In this context, experiments dedicated to laser-induced plasma particle interaction were performed. To begin with, spectral images of the laser-induced plasma vaporizing particles were recorded to visualize the spatio-temporal evolution of the atomized matter and to infer the best configuration for plasma light collection, taking into account our experimental set-up specificity. Then, on this basis, time-resolved spectroscopic measurements were performed to make a first assumption of the LIBS potentialities. The influence on the LIBS signal of parameters such as chemical nature of particles, their concentration, laser wavelength, laser energy, kind of background gas was investigated and temporal optimization of the LIBS signal recording settings was achieved. Eventually, repeatability and limits of detection were assessed and discussed; La technique LIBS (Laser-Induced Breakdown Spectroscopy) a été employée pour détecter des particules métalliques ou de chlorure de sodium dont les tailles s'échelonnent de 40 nm à 1 um et ce avec deux générateurs de particules différents. La technique LIBS couplée à un SMPS (Scanning Mobility Particle Sizer, détection en taille et en nombre) a été évaluée comme technique potentiellement utilisable pour la surveillance des lieux de production de nanoparticules. Bien que la sécurisation des procédés fasse l'objet de recherches actives, le risque de fuite sur une unité de production n'est pas à écarter. En conséquence, il est urgent pour les fabricants de disposer d'un outil permettant la détection d'une fuite, in-situ et en temps réel afin de protéger les travailleurs d'une possible exposition à des nanoparticules. C'est dans ce contexte que des expériences dédiées à l'interaction laser / plasma / particules ont été menées. Pour commencer, des expériences d'imagerie spectrale ont été réalisées afin de visualiser la répartition de la matière vaporisée dans le plasma et d'optimiser au mieux la collection de la lumière du plasma pour les analyses LIBS, en tenant compte des spécificités de notre montage. A partir de ces résultats, des expériences de spectroscopie d'émission résolue en temps ont été conduites afin d'évaluer les potentialités de la technique LIBS. La dépendance du signal LIBS a été évaluée en fonction de paramètres tels que la nature chimique des particules, leur concentration, la longueur d'onde et l'énergie du laser, le type de gaz ambiant et les paramètres temporels optimaux pour l'optimisation du signal LIBS ont été déterminés. Finalement, répétabilité et limites de détection ont été évaluées et discutées.

International audience; Laser-Induced Breakdown Spectroscopy has been employed to detect sodium chloride and metallic particles with sizes ranging from 40 nm up to 1 µm produced by two different particle generators. The Laser-Induced Breakdown Spectroscopy technique combined with a Scanning Mobility Particle Sizer was evaluated as a potential candidate for workplace surveillance in industries producing nanoparticle-based materials. Though research is still currently under way to secure nanoparticle production processes, the risk of accidental release is not to be neglected. Consequently, there is an urgent need for the manufacturers to have at their command a tool enabling leak detection in-situ and in real time so as to protect workers from potential exposure. In this context, experiments dedicated to laser-induced plasma particle interaction were performed. To begin with, spectral images of the laser-induced plasma vaporizing particles were recorded to visualize the spatio-temporal evolution of the atomized matter and to infer the best recording parameters for Laser-Induced Breakdown Spectroscopy analytical purposes, taking into account our experimental set-up specificity. Then, on this basis, time-resolved spectroscopic measurements were performed to make a first assumption of the Laser-Induced Breakdown Spectroscopy potentialities. Particle size dependency on the LIBS signal was examined. Repeatability and limits of detection were assessed and discussed. All the experiments carried out with low particle concentrations point out the high time delays corresponding to the Laser-Induced Breakdown Spectroscopy signal emergence. Plasma temperature temporal evolution was found to be a key parameter to explain this peculiarity inherent to laser / plasma / particle interaction.

International audience; In the context of the air quality improvement, there is an increasing need to monitor gas and particle emissions originating from exhaust stacks (incinerators, foundries, etc.) for regulation enforcement purposes. Lots of pollutants are targeted; among them, heavy metals are mostly found in particulate forms. Hence, there is a need to promote the development of suitable on line analytical techniques. To that end, laser-induced breakdown spectroscopy (LIBS) appears to be a good technique. Indeed, it is quantitative, fast (

International audience; Laser-induced Breakdown Spectroscopy (LIBS) was employed for on-line and real time process monitoring during nanoparticle production by laser pyrolysis. Laser pyrolysis has proved to be a reliable and versatile method for nanoparticle production. However, an on-line and real time monitoring system could greatly enhance the process optimization and accordingly improve its performances. For this purpose, experiments aiming at demonstrating the feasibility of an on-line monitoring system for silicon carbide nanoparticle production using the LIBS technique were carried out. Nanosecond laser pulses were focused into a cell through which part of the nanoparticle flux diverted from the production process was flowed for LIBS analysis purposes. The nanoparticles were vaporized within the laser-induced plasma created in argon used as background gas in the process. Temporally-resolved emission spectroscopy measurements were performed in order to monitor nanoparticle stoichiometry. Promising results were obtained and on-line Si/C-x stoichiometry was successfully observed. These results put forward the possibility of real time correction of the nanoparticle stoichiometry during the production process.

Today, nanotechnology is a growing field of research and nanoparticlebased material production is expected to soar in years to come. Though research is still currently under way to secure nanoparticle production processes, the risk of accidental release is not to be neglected. Consequently, there is an urgent need for the manufacturers to have at their command a tool enabling leak detection in-situ and in real time so as to protect workers from potential exposure. In this context, the LIBS technique was evaluated as a potential candidate for workplace surveillance in industries producing nanoparticle-based materials. This work was focused on the comprehension of the mechanisms taking place during laser / plasma / particle interaction in order to further achieve LIBS measurements with optimum efficiency. Though the present study was devoted to nanoparticle analysis, particle size was extended up to 1 m to facilitate the comprehension of the mechanisms involved when vaporizing particles within a laser-induced plasma. Polydisperse and monodisperse flows of sodium and metallic particles with sizes ranging from 40 nm up to 1 m produced by two different particle generators were introduced in a cell dedicated to LIBS analysis. To begin with, time-resolved spectral imagery was employed to visualize the spatialtemporal evolution of the vaporized matter within the expanding plasma plume induced in air containing particles and flowing through the cell. Then, time-resolved emission spectroscopy measurements were carried out for LIBS purposes. The influence on the LIBS measurements of parameters such as chemical nature of particles, their concentration, laser wavelength, laser energy, kind of background gas have been investigated. The results obtained combining spectral imagery and emission spectroscopy fuel the debate on the mechanisms involved during particle vaporization within the laser induced plasma and highlight the importance of studying the analytical signal temporal evolution when analyzing particles using LIBS.