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Lifting the Fog Off Hydrocarbon Mist Explosions
No full textInternational audienceExplosion hazards do not only include gases, vapors and dusts, but also mists. Indeed, previous incident surveys identified dozens of accidents related to hydrocarbon mists generation and ignition. The ongoing occurrence of mist explosions demonstrates the need to assess the relevance of the current approaches for the evaluation of the mist ATEX risks and to determine reliable and standardized safety parameters for hydrocarbon mists. For this study, different fluids with a high industrial interest were selected (e.g. ethanol, kerosene, and diesel) to be tested in a new apparatus based on the standardized 20L explosion sphere. A new fluid injection system was deployed using siphon/gravity-fed spray nozzles comprising a Venturi junction and proposing a wide variety of dispersion performances. This system was controlled using a specifically dedicated program, which ensures the versatility of the apparatus and its adaptability to the different liquids tested. It allows a fine control of the gas carrier flow, the liquid flow and both the injection and ignition times, which makes it possible to change the dilution rate for a desired droplet size distribution. The droplet size distribution (DSD) was determined for the various fluids dispersed into the 20L sphere. Several tests were performed to determine the minimum ignition energy (MIE), the lower explosivity limit (LEL), the maximum explosion pressure (Pmax) and the maximum rate of pressure rise (dP/dt max) of hydrocarbon mists. For instance, for a DSD centered at 55μm, a maximum pressure of 9.2 bar and maximum rate of pressure rise up to 600 bar.s-1 were found for ethanol. As for kerosene, for a DSD centered at 80μm, 8.8 bar and 570 bar.s-1 were found respectively. Experimental results obtained between the LEL and the stoichiometric concentration were compared with numerical data obtained with Chemical Equilibrium with Applications and showed that they were coherent with the theoretical calculations and that tests were at least performed up to the stoichiometric concentration. A sensitivity analysis was conducted to stress the influence of parameters such as the chemical nature of the fuel, the DSD, the ignition energy or the mist temperature (gas/mist ratio). For instance, tests performed on kerosene showed that as the DSD increases, the mist cloud becomes harder to ignite and hence the LEL increases. These first results already allow to propose a new protocol to determine safety parameters for hydrocarbon mists and provide tools to support the evaluation of mist ATEX risks
Développement d'un protocole d'évaluation en chambre atmosphérique de préleveurs de particules employés dans le cadre d'études toxicologiques : (1) détermination des conditions de génération
No full textInternational audienceThere is a need to find new techniques for sampling atmospheric particles to carry out toxicological analyses (e.g. in vitro). Current techniques use unsuitable media (filters) for the analyses. A new approach would be to test new technologies used in the field of bioaerosols, with different sampling media (e.g. sampling directly in a liquid). Unfortunately, the collection efficiencies of these technologies remain poorly known. The present abstract is focused on the development of a protocol for the evaluation of such samplers in atmospheric chambers. The first generations tests (tests of different generation parameters, choice of instruments) are presented.Les dispositifs de prélèvement de particules atmosphériques actuels ne permettent pas d'effectuer de façon satisfaisante des analyses toxicologiques, en raison de l'utilisation d'un support (filtres) pouvant induire un impact sur la modification physico-chimique des particules ce qui est peu adapté pour les analyses toxicologiques (e.g. in vitro). C'est pourquoi un intérêt est porté sur de nouvelles technologies utilisées dans le domaine des bioaérosols permettant des prélèvements directement dans un milieu approprié pour exposer ultérieurement les cellules (e.g. prélèvement en milieu liquide) mais dont l'efficacité de collecte selon la taille des particules est inconnue. Le papier présenté ici s'intéresse au développement d'un protocole d'évaluation de tels préleveurs en chambre atmosphérique, pour lever ces inconnues. Les premiers essais de générations (tests de différents paramètres de génération, choix du matériel) y sont présentés. In fine, l'objectif est d'appréhender la méthode la plus adaptée permettant une collecte suffisante de particules pour une meilleure sensibilité et induisant l'impact le plus limité sur la modification physico-chimique des particules pour les analyses toxicologiques
Impacts of the COVID-19 lockdown on air pollution at regional and urban background sites in northern Italy
No full textInternational audienceThe COVID-19 lockdown measures gradually implemented in Lombardy (northern Italy) from 23 February 2020 led to a downturn in several economic sectors with possible impacts on air quality. Several communications claimed in the first weeks of March 2020 that the mitigation in air pollution observed at that time was actually related to these lockdown measures without considering that seasonal variations in emissions and meteorology also influence air quality. To determine the specific impact of lockdown measures on air quality in northern Italy, we compared observations from the European Commission Atmospheric Observatory of Ispra (regional background) and from the regional environmental protection agency (ARPA) air monitoring stations in the Milan conurbation (urban background) with expected values for these observations using two different approaches. On the one hand, intensive aerosol variables determined from specific aerosol characterisation observations performed in Ispra were compared to their 3-year averages. On the other hand, ground-level measured concentrations of atmospheric pollutants (NO2, PM10, O-3, NO, SO2) were compared to expected concentrations derived from the Copernicus Atmosphere Monitoring Service Regional (CAMS) ensemble model forecasts, which did not account for lockdown measures. From these comparisons, we show that NO2 concentrations decreased as a consequence of the lockdown by -30% and -40% on average at the urban and regional background sites, respectively. Unlike NO2, PM10 concentrations were not significantly affected by lockdown measures. This could be due to any decreases in PM10 and PM10 precursors) emissions from traffic being compensated for by increases in emissions from domestic heating and/or from changes in the secondary aerosol formation regime resulting from the lockdown measures. The implementation of the lockdown measures also led to an increase in the highest O-3 concentrations at both the urban and regional background sites resulting from reduced titration of O-3 by NO. The relaxation of the lockdown measures beginning in May resulted in close-to-expected NO2 concentrations in the urban background and to significant increases in PM10 in comparison to expected concentrations at both regional and urban background sites
Towards FAIR nanosafety data
No full textInternational audienceThe proposal of a FAIR-aligned Nanosafety Data Interface can advance findability, accessibility and interoperability across physicochemical, bio-nano interaction, human toxicity, omics, ecotoxicological and exposure data. Nanotechnology is a key enabling technology with billions of euros in global investment from public funding, which include large collaborative projects that have investigated environmental and health safety aspects of nanomaterials, but the reuse of accumulated data is clearly lagging behind. Here we summarize challenges and provide recommendations for the efficient reuse of nanosafety data, in line with the recently established FAIR (findable, accessible, interoperable and reusable) guiding principles. We describe the FAIR-aligned Nanosafety Data Interface, with an aggregated findability, accessibility and interoperability across physicochemical, bio-nano interaction, human toxicity, omics, ecotoxicological and exposure data. Overall, we illustrate a much-needed path towards standards for the optimized use of existing data, which avoids duplication of efforts, and provides a multitude of options to promote safe and sustainable nanotechnology
Emissions gazeuses et particulaires de véhicules légers : résultats du projet Rhapsodie.
No full textSummary of the reseach project RhapsodieThe Rhapsodie project, selected within the framework of the 2017 ADEME Cortea call for projects and conducted by IFPEN in partnership with INERIS, was completed in April 2020. The objective was to evaluate gas and particle emissions -regulated or otherwise -from passenger cars of the same model –1 diesel version equipped with an SCR on filter function and 1 gasoline version equipped with a particulate filter, both vehicles meeting Euro 6 d-TEMP standards, and 1 gasoline version without a filter, Euro 6b-accredited. The evaluations were conducted on an IFPEN rolling test bench over a cumulative distance of around 6,500 km. The impacts of different powertrains and associated exhaust gas after-treatments start conditions (ambient/hot) and particulate filter regeneration phases were quantified. Conversely, no significant effect of the Stop & Start function on emissions was observed
Enhancing the use of exposure science across EU chemical policies as part of the European Exposure Science Strategy 2020–2030
No full textInternational audienceBackground A scientific framework on exposure science will boost the multiuse of exposure knowledge across EU chemicals-related policies and improve risk assessment, risk management and communication across EU safety, security and sustainability domains. Objective To stimulate public and private actors to align and strengthen the cross-policy adoption of exposure assessment data, methods and tools across EU legislation. Methods By mapping and analysing the EU regulatory landscape making use of exposure information, policy and research challenges and key areas of action are identified and translated into opportunities enhancing policy and scientific efficiency. Results Identified key areas of actions are to develop a common scientific exposure assessment framework, supported by baseline acceptance criteria and a shared knowledge base enhancing exchangeability and acceptability of exposure knowledge within and across EU chemicals-related policies. Furthermore, such framework will improve communication and management across EU chemical safety, security and sustainability policies comprising sourcing, manufacturing and global trade of goods and waste management. In support of building such a common framework and its effective use in policy and industry, exposure science innovation needs to be better embedded along the whole policymaking cycle, and be integrated into companies’ safety and sustainability management systems. This will help to systemically improve regulatory risk management practices. Significance This paper constitutes an important step towards the implementation of the EU Green Deal and its underlying policy strategies, such as the Chemicals Strategy for Sustainability
Study of the day- and night-time SOA formation from the oxidation of furans and PAHs performed in an oxidation flow reactor
No full textInternational audienceBiomass burning significantly contributes to the concentration levels of ambient primary particulate matter (PM) especially in wintertime due to residential wood burning (Vicente et al., 2018). This source also emits large quantities of volatile and semi-volatile organic compounds leading to the formation, via (photo- ) chemical and condensation processes, of secondary organic aerosols (SOA) accounting for a significant part of fine PM concentrations. However, SOA physicochemical properties and formation yields from the corresponding precursors are still poorly documented in the literature particularly regarding nighttime chemistry (involving nitrate radical) (Bruns et al., 2016). The main aim of this work is to study the formation of biomass burning SOA from typical organic precursors namely PAHs and furans, under both daytime and nighttime chemistry
Assessment of advantages and limitations of installing PV on abandoned dumps
No full textInternational audienceThe feedback from international practice has shown that the installation of photovoltaic (PV) parks on abandoned dumps is one of the best environmental and economical solutions. This paper discusses the site selection criteria for the installation of PV systems on dumps. When installing the PV systems, different environmental, technical, and economic criteria should be respected. The ground movement and combustion hazards in the dumps appear to be the main constraints and limitations for the installation of photovoltaic panels. This paper presents several examples of the installation of photovoltaic panels on coal-lignite dumps in France. However, the number of projects is still very limited compared to the identified potential
