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Synthèse bibliographie des valeurs repères et réglementaires dans l’air intérieur à l’échelle internationale en lien avec les sites et sols pollués
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Demystifying mist explosion hazards
No full textInternational audienceIt is essential that chemical and petrochemical industries take into account potential fire and explosion hazards as part of their risk assessments. Such hazards are sometimes related to flammable mists that can be generated by fluid releases from pressurized pipes or vessels, from condensation of hot vapours, or from splashing, etc. A recent study showed that around 10% of notified releases in the UK Offshore Hydrocarbon Release Database involved flammable mists. Analysis of the French and German ARIA and ZEMA databases also identified dozens of previous significant mist incidents. Despite this, there is limited guidance on hazardous area classification for flammable mists. Whilst classification of flammable gases and dusts is well established, there is a need for scientific evidence to support the classification of flammable mist hazards. To address this knowledge gap, this paper presents an extensive study of diesel, biodiesel, and light fuel oil mists. These high-flashpoint liquid fuels were chosen as they have a high industrial interest and were involved in many reported incidents. A Venturi-based mist generation system was used to ensure the control of the fuel concentration, the fuel/air ratio and a well-defined droplet size distribution. Mists with mean droplet diameters ranging from 5 to 100 μm were thus obtained. Experiments were carried out in a modified apparatus based on the standardized 20 L explosion sphere where the experimental conditions, including the air injection pressure to the ignition delay time, were varied. In the first set of tests, the minimum ignition energy, lower explosive limit and explosion severity of the fuels were determined at 40°C and atmospheric pressure. In order to examine the impact of the fuel vapour/liquid ratio on the explosion behaviour, tests were undertaken with an increasing sphere temperature from 30°C to 80°C. Results showed that the surrounding temperature had a significant effect on the thermo-kinetic explosion parameters Pex (explosion overpressure) and dP/dtex (rate of pressure rise). The value of dP/dtex increased markedly from approximately 24 bar.s-1 at T = 30°C to approximately 314 bar.s-1 at T = 80°C for a diesel mist concentration of 123 g.m-3. These findings were compared to numerical data calculated using combustion software. The influence of the temperature on the evolution of the droplet size distribution and the evaporation rate of droplets was also studied. In addition, a specifically designed metallic reservoir was used to pressurize and preheat the fluid before injection to mimic industrial leaks that could trigger hazardous explosions. The influence of such parameters on the mist explosion risk assessment was then assessed. The work presented in this paper improves our understanding of the physics behind mist explosions of high-flashpoint fuels. It also demonstrates the possibility of classifying hazardous mist areas using certain dimensionless numbers, such as the Ohnesorge and Reynolds numbers (which characterize droplet hydrodynamics) as well as the Spalding number (which characterizes droplet thermal behaviour)
Amélioration des prévisions de la qualité de l'air à haute résolution : focus sur les zones urbaines et périurbaines et les épisodes de pollution spécifiques en France
No full textNowadays, more than half of the world’s population lives in urban areas, air quality prediction in urban areas is therefore flagship topic. The improvement of mesoscale chemical transport models generally focused on the dynamics, physical parameterization processes, and chemical reaction mechanisms. In the first part of the study, three configurations of vertical diffusion coefficient (Kz) based on fisrt order closure K-theory are tested within CHIMERE model fed by IFS meteorology over one year. Although, all these Kz configurations are known to be efficient for mesoscale air quality simulations and the results show small differences between the three schemes, they all overestimated vertical mixing in urban areas. It is worth noting that the model used overestimates the ratio of PM2.5/PM10 by approximately 20% for all seasons. Discrepancies on emission inventories could be a relevant explanation. Many studies on the impact of physical parameterizations indicates the need of more accurate simulations of meteorological conditions for air quality modeling at urban scale. Also, for the second part of this work, the Weather Research and Forecast (WRF) model coupled with the chemistry transport model (CTM) CHIMERE has been used to understand the impact of physics parameterizations on air quality simulation during a short-term pollution episode on the Paris region. Large differences were found between different canopy schemes, showing an overall overestimation of concentrations during the pollution episode. The boundary layer schemes sensitivity tests display an underestimation of the boundary layer height which leads to a strong overestimations of pollutants concentration. The Boulac–BEP scheme had significantly better performances than the other schemes for the simulation of both the PBL height and the pollutants concentrations, indicating that both the canopy schemes and boundary layer schemes have a critical effect on air quality prediction in the urban region. The third part of this work focuses on the vertical resolution of the grid and the height of the first layer which also plays a very important role in the transport modeling. The three configurations tested demonstrate the model's ability to simulate regular days without pollution episodes. However, during a pollution episode, the refinement of the vertical resolution and of the height of the first layer leads to a clear improvement of the modeling results compared to the initial configuration of the model. The air quality predictions in urban regions are mainly influenced by the urban canopy, the boundary layer and the diffusion conditions. The land surface model had a slight impact for both meteorological and air quality simulation. In the last part of this work, the eddy diffusion of WRF from a 1.5 order diffusivity closure scheme based on the kinetic energy of turbulence is directly integrated into CHIMERE in order to represent a more realistic vertical mixing near the surface for urban pollution applications. A two weeks high resolution simulation was performed in Paris, Lyon and Bordeaux with finest horizontal and vertical resolution of 1.67km and 12m respectively. The new eddy diffusion (NED) integrated in this research improves NO2 simulations at all urban site compared to the original Kz diffusion (IKD) on board CHIMERE. The average improvements in terms of RMSE are 18.77%, 24.51% and 9.52% in Paris, Lyon and Bordeaux, respectively. PM2.5 and PM10 simulation provided similar results with NO2, 13.47% and 19.08% improvements were found in the urban area of Paris. The simulation with more realistic eddy viscosities is better than initial Kz parameterization which has been widely used in CTM. This work illuminates the user to identify the best settings of atmospheric models for appropriate operational uses to simulate the air quality during pollution episodes or for long term analyses in urban areas.De nos jours, plus de la moitié de la population mondiale vit dans des zones urbaines. La prévision et l’analyse de la qualité de l'air dans les zones urbaines est un sujet d'actualité. L'amélioration des modèles de transport chimique à méso-échelle passe généralement par le développement de paramétrisations plus avancées en termes de dynamique et mécanismes chimiques. Dans la première partie de l'étude, trois configurations du coefficient de diffusion verticale (Kz) basées sur la théorie de fermeture de premier ordre (k-theory) sont testées avec le modèle CHIMERE alimenté par les données Européennes météorologiques IFS pendant une année. Ces configurations, bien que jugées efficaces pour les simulations de qualité de l'air à méso-échelle, montrent une surestimation significative du mélange vertical dans les zones urbaines avec des différences faibles entre les trois schémas. Il convient de noter que le modèle ainsi configuré a surestimé le rapport PM2.5/PM10 d'environ 20% quelle que soit la saison. L'étude de l'impact de la paramétrisation de la diffusion verticale confirme bien que la modélisation météorologique est d'une importance majeure pour la modélisation de la qualité de l'air. Par la suite, le modèle Weather Research and Forecast (WRF) couplé au modèle de transport de la chimie (CTM) CHIMERE a été utilisé pour comprendre l'impact des paramétrisations physiques sur la simulation de la qualité de l'air sur épisode de pollution en la région parisienne. Les différents schémas de canopée testés montrent des différences importantes avec une surestimation globale des concentrations pendant l'épisode de pollution. Les tests de sensibilité des schémas de la couche limite montrent une sous-estimation de la hauteur de la couche limite qui a pour conséquence une forte surestimation de la concentration des polluants pendant l'épisode de pollution. Le schéma de Boulac-BEP montre des performances significativement meilleures que les autres schémas pour la simulation de cette hauteur de couche limite ainsi que pour les concentrations en polluants, ce qui confirme bien que les schémas de canopée urbaine et de couche limite ont un effet critique sur la modélisation de la qualité de l'air dans la région urbaine. La troisième partie de ce travail porte sur l’impact de la résolution verticale de la grille et la hauteur de la première couche qui jouent également un rôle très important dans la modélisation du transport. Les trois configurations testées démontrent les capacités du modèle à simuler des journées normales hors épisodes de pollution. Cependant, lors d'un épisode de pollution, l'affinement de la résolution verticale et de la hauteur de la première couche entraîne une nette amélioration des résultats de modélisation en comparaison avec la configuration initiale du modèle. La simulation et la prévision de la qualité de l'air en région urbaine sont donc influencées par les caractéristiques de la canopée urbaine, la couche limite et les conditions de diffusion, le modèle de surface terrestre ayant un léger impact sur la simulation météorologique et la qualité de l'air. Dans la dernière partie de ce travail, la diffusivité turbulente de WRF issue d’un schéma de fermeture de la diffusivité d'ordre 1.5 basé sur l'énergie cinétique de la turbulence est intégrée dans CHIMERE afin de représenter un mélange vertical plus réaliste près de la surface pour les applications de pollution urbaine. Une simulation haute résolution de 15 jours en hiver a été réalisée sur Paris, Lyon et Bordeaux avec des résolutions horizontale et verticale fines de 1,67km et 12m respectivement. Il est à noter que la nouvelle diffusion verticale (NED) a amélioré la simulation du NO2 pour chaque site urbain par rapport à la diffusion Kz initiale (IKD). Les améliorations moyennes en termes de RMSE sont de 18,77%, 24,51% et 9,52% à Paris, Lyon et Bordeaux, respectivement [...
Exposure to long-term nitrogen dioxide air pollution and breast cancer risk: A nested case-control within the French E3N cohort study
No full textInternational audienceBACKGROUND AND AIM: Nitrogen dioxide (NO2) is one of an important air pollutant due to its adverse effects on human health, however whether it is consistently associated with the risk of breast cancer (BC) is limited. In this study, we investigated the association between long term exposure to NO2 and risk of BC. METHODS: A total of 5,222 BC cases identified over the follow up period and 5,222 matched controls of a nested case-control study within a French E3N cohort study were examined. Mean exposure estimates to NO2 were estimated by CHIMERE and land use regression (LUR) models and assigned to the geocoded residential postal codes of participants for each year from recruitment 1990 through 2011. Multivariable conditional logistic regression models were used to compute odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Overall, in all women, for each 1 interquartile range (IQR) increase in NO2 levels (CHIMERE: 11.1 ug/m3, LUR: 17.8 ug/m3), the ORs of the model adjusted for confounders were 1.16(95% CI: 1.06-1.26) and 1.09(95% CI: 1.01-1.18) according to CHIMERE and LUR measures, respectively. The corresponding ORs in the fully model additionally adjusted for established BC risk factors = 1.13(95% CI: 1.03-1.24) for CHIMERE and 1.07(95% CI: 0.99-1.16) for LUR measures. Comparable results were found for postmenopausal women. Substantial heterogeneity in the ORs was observed by hormone receptor status, using NO2 measured by CHIMERE the ORs of the model 3 was 1.17 (95% CI: 1.04-1.31) for ER. With LUR NO2, the OR of ER+BC in the fully model = 1.08 (95% CI: 0.98-1.19). CONCLUSIONS: We provide an evidence of an increase BC risk in association with long term exposure to NO2 air pollution according to CHIMERE and LUR measures, with risks being higher for CHIMERE model. Subgroup analyses suggested stronger effects especially in postmenopausal women and for hormone dependent BC
A new model-based risk analysis approach that generate cyberattacks scenarios and combine them with safety risks
No full textInternational audienceFor many years, the introduction of connected systems and digital technology in critical industries worldwide makes them vulnerable to cyberattacks that can lead to undesirable safety accidents. Thus, analysing these attacks becomes an important matter during risk analysis. In most proposed risk analysis approaches applied in the industries, the safety subjects are taking into consideration without analysing the cyberattack that can lead to the same dangerous phenomenon as a safety incident, the safety and security subjects are treated separately, despite the common consequences and the interdependencies between them. Therefore, there is a strong interest in the development of risk analysis approaches combining safety and security, particularly in the process industry, which is a major potential hazard for local populations and the environment. In this article, a new model-based risk analysis approach is proposed, it presents a new way to generate the cyberattacks systematically based on the modelling system architecture and a list of generic vulnerabilities encountered on industrial systems. A likelihood evaluation for these attacks is presented with their combination with the safety risks
Chemoinformatics for the safety of energetic and reactive materials at Ineris
No full textInternational audienceThe characterization of physical hazards of substances is a key information to manage the risks associated to their use, storage and transport. With decades of work in this area, Ineris develops and implements cutting‐edge experimental facilities allowing such characterizations at different scales and under various conditions to study all of the dreaded accident scenarios. This review presents the efforts engaged by Ineris more recently in the field of chemoinformatics to develop and use new predictive methods for the anticipation and management of industrials risks associated to energetic and reactive materials as a complement to experiments.An overview of the methods used for the development of Quantitative Structure-Property Relationships for physical hazards are presented and discussed regarding the specificities associated to this class of properties. A review of models developed at Ineris is also provided from the first tentative models on the explosivity of nitro compounds to the successful application to the flammability of organic mixtures. Then, a discussion is proposed on the use of QSPR models. Good practices for robust use for QSPR models are recalled with specific comments related to physical hazards, notably for regulatory purpose. Dissemination and training efforts engaged by Ineris are also presented. The potential offered by these predictive methods in terms of in silico design and for the development of new intrinsically safer technologies in safety-by-design strategies is finally discussed. At last, challenges and perspectives to extend the application of chemoinformatics in the field of safety and in particular for the physical hazards of energetic and reactive substances are proposed
Evaluation of the OECD QSAR toolbox automatic workflow for the prediction of the acute toxicity of organic chemicals to fathead minnow
No full textInternational audienceRegulatory frameworks require information on acute fish toxicity to ensure environmental protection. The experimental assessment of this property relies on a substantial number of fish to be tested and it is in conflict with the current drive to replace in vivo testing. For this reason, alternatives to in vivo testing have been proposed during the past years. Among these alternatives, there are Quantitative Structure-Activity Relationships (QSAR) that require the sole knowledge of chemical structure to yield predictions of toxicities. In this context, the OECD QSAR Toolbox is one of the leading QSAR tools for regulatory purposes that enables the prediction of fish toxicities. The aim of this work is to provide evidence about the predictive reliability of the automated workflow for predicting acute toxicity in fish which is embedded within this toolbox. The results herein presented show that the logic underpinning this automated workflow can predict with a reliability that, in the majority of cases, is comparable to inter-laboratory variability and, in a significant number of cases, is also comparable with intralaboratory variability. Moreover, considerations on the toxic mode of action provided by the OECD tool proved to be helpful in refining predictions and reducing the number of prediction outliers
An a Priori Index to Discriminate Contaminated Wasteland of Concern From the Ones Ready to Be Upgraded to an Ecological Usage
No full textInternational audienceThe future of urban and industrial wasteland is at the heart of environmental, social and economic issues. They have specific characteristics (structure, composition) which are constraints for biodiversity and the biological functioning of soils. However, an abandoned wasteland (whose soil functions were not altered beyond repair) ends up hosting transitional ecosystems with ecological value. Brownfield requalification operations most often come up against difficulties linked to the presence of pollutants (in most cases metallic) at the heart of the issues linked to degraded land. The French national methodology for the management of polluted sites and soils includes carrying out a study of health and environmental risks to assess whether a site is in a state compatible with its future use. When the health aspect is not a major issue (no housing project for example), the objectives of decontamination and / or restoration of soil quality must be based on an ecological risk assessment (ERA). These are generally not or not sufficiently applied, either for financial reasons or for lack of competence issues. The Tipomo project (transfer and index of concern: tools for valuing medium-contaminated wasteland) aims to construct an index of concern that allows the classification of polluted soils hosting transitional ecosystems. The question is to differentiate the soils which are candidates for immediate upgrading to an ecological usage (biodiversity reserve) from those which need an ERA. Applicable only on plots with significant vegetation, the index will be calculated by considering the levels of soil impregnation and its ability to trap polluting substances (characterization of bioavailability fraction). The method will be tested in a case study by comparing the interpretation of the index to the result of a bioassay battery (which take into account the mixture effect). This approach follows the general thinking behind the ERA Triad (ISO 19204) by using simultaneously chemical tools, ecotoxicological information and ecological observation. For the purpose of this work, the implementation of the TRIAD is simplified, leading to an index of “concern” rather than a risk index. The Tipomo field studies have started in June 2020. They will support the definition of the principles of the method and its use in applied regulatory context
Validation of the Hyalella azteca Bioconcentration Test (HYBIT)
No full textInternational audienceBioconcentration factors (BCF) for regulatory purposes are conventionally determined experimentally by aqueous exposure bioconcentration fish tests according to OECD test guideline (TG) 305. Fish bioconcentration studies are time consuming, expensive, and use vertebrate organisms in the range of 100-200 organisms per study. The availability of alternative methods may help to reduce the use of fish for BCF testing. The Hyalella azteca Bioconcentration Test (HYBIT) provides a non-vertebrate alternative for fish bioconcentration studies. The suitability of H. azteca as an alternative test organism for bioconcentration studies was recently investigated. Eighteen substances of different hydrophobicity (log KOW 0.7 - 7.8) were tested under flow-through or semi-static conditions to determine steady-state and kinetic bioconcentration factors (BCFSS and BCFK). It has been shown that the BCFs obtained from bioconcentration studies with the freshwater amphipod H. azteca correlate significantly (r²=0.69) with fish BCF values described in the literature. Thus, H. azteca BCF values can be assessed in accordance with the standard B criteria, e.g. BCF > 2000 (REACH), and thereby enable the prediction of B or non-B classification in the standard fish test. Generally, technical (smaller-scale test systems) and economic reasons (less time-consuming, more cost-efficient) favour the use of H. azteca over fish in bioconcentration studies. In addition, significantly smaller amounts of test substance are required compared to the flow-through test with fish. A protocol for carrying out bioconcentration tests with the aquatic invertebrate species H. azteca under standardized conditions has been developed as part of the project CEFIC-LRI ECO40. This protocol includes both, the flow-through and semi-static test design. Validation was needed to confirm the transferability of the test protocols and to prove the reproducibility of the results obtained in order to support the development of a new OECD TG. For this purpose, a multi-laboratory ring trial involving the HYBIT was carried out in 2020. The ring test has confirmed the high potential of the Hyalella azteca Bioconcentration Test (HYBIT) to be used as a non-vertebrate alternative for bioconcentration studies. The transferability of the test protocols (semi-static and flow-through approach) as well as the reproducibility of the results obtained was proven supporting the development of a new OECD TG
La spectrométrie de masse haute résolution pour la recherche de micropolluants organiques dans l’environnement
No full textNational audienceNon-targeted analysis is currently experiencing significant developments in the field of environmental analysis since it opens up investigations of environmental quality to a very large number of compounds. This article consists of feedback from 12 French laboratories on the practices and cautions to be considered when carrying out non-targeted analyses, in particular for the detection of suspect compounds in samples from aquatic environments. Although this analytical approach provides new and very promising information, it is still a complex technique that must be used with many precautions to ensure high-quality results. The joint discussions carried out within the group of laboratories make it possible to synthesise technical information in order to present the challenges of this methodology of major interest in environmental analysis. These issues are presented in a simple and accessible way to laboratories, to those requesting analysis or anyone interested in this new analytical approach. We also address locks related to the specificity of non-targeted analyses, the development of methods and the reporting of results, in order to provide keys of understanding for the laboratories and the end-users of the results. This work is thus intended to be a technical guide to discover the benefits and opportunities of non-targeted analysis, and also a set of good practices for those who collect or analyse data obtained with such analytical technologies.L’analyse non ciblée connaît une forte période de croissance dans le domaine de l’analyse environnementale, car elle ouvre le champ des investigations de la qualité des milieux à un très grand nombre de composés. Cet article consiste en un retour d’expérience de 12 laboratoires français sur les pratiques et les précautions à considérer lors de la réalisation d’analyses non ciblées, en particulier pour la recherche de composés suspects dans les échantillons issus des milieux aquatiques. En effet, si cette technique apporte des informations nouvelles et très prometteuses, elle n’en reste pas moins une technique complexe qu’il convient d’utiliser avec de nombreuses précautions pour assurer des résultats de qualité. La réflexion commune entreprise dans le groupe de laboratoires, a permis de synthétiser des informations techniques afin de présenter les enjeux de cette méthodologie d’intérêt majeur en analyse environnementale de façon simple et accessible aux laboratoires, demandeurs d’analyse ou toute personne intéressée par ce type d’approche. Les verrous liés à la spécificité des analyses non ciblées, au développement de méthodes et au rendu de résultats ont été développés pour fournir des clés de compréhension pour les laboratoires et les utilisateurs de résultats. Ce travail s’attache ainsi à être un guide de découverte de la technique pour les personnes désireuses de voir ce que peut apporter l’analyse non ciblée, mais également un guide de bonnes pratiques pour celles et ceux qui acquièrent ou qui analysent des données issues de ces techniques