13 research outputs found
Is the ozone climate penalty robust in Europe?
Ozone air pollution is identified as one of the main threats bearing upon human health and ecosystems, with 25 000 deaths in 2005 attributed to surface ozone in Europe (IIASA 2013 TSAP Report #10). In addition, there is a concern that climate change could negate ozone pollution mitigation strategies, making them insufficient over the long run and jeopardising chances to meet the long term objective set by the European Union Directive of 2008 (Directive 2008/50/EC of the European Parliament and of the Council of 21 May 2008) (60 ppbv, daily maximum). This effect has been termed the ozone climate penalty. One way of assessing this climate penalty is by driving chemistry-transport models with future climate projections while holding the ozone precursor emissions constant (although the climate penalty may also be influenced by changes in emission of precursors). Here we present an analysis of the robustness of the climate penalty in Europe across time periods and scenarios by analysing the databases underlying 11 articles published on the topic since 2007, i.e. a total of 25 model projections. This substantial body of literature has never been explored to assess the uncertainty and robustness of the climate ozone penalty because of the use of different scenarios, time periods and ozone metrics. Despite the variability of model design and setup in this database of 25 model projection, the present meta-analysis demonstrates the significance and robustness of the impact of climate change on European surface ozone with a latitudinal gradient from a penalty bearing upon large parts of continental Europe and a benefit over the North Atlantic region of the domain. Future climate scenarios present a penalty for summertime (JJA) surface ozone by the end of the century (2071-2100) of at most 5 ppbv. Over European land surfaces, the 95% confidence interval of JJA ozone change is [0.44; 0.64] and [0.99; 1.50] ppbv for the 2041-2070 and 2071-2100 time windows, respectively
Quels effets du confinement sur la qualitĂ© de lâair : retour sur le printemps 2020
International audienceThis article presents an analysis of the impact on air quality of lockdown measures implemented throughout Europe for nearly two months in spring 2020 to combat the Covid-19 health crisis. These measures have resulted in a drastic and unprecedented reduction in nitrogen dioxide emissions, mainly emitted by road traffic. Several European teams have conducted studies with the same objective, but with possibly different methods. Here, we applied two approaches based on the implementation of the CHIMERE chemistry-transport model to France and to Europe. One is based on the use of air quality simulations in which measurement data from in-situ monitoring networks are adjusted to correspond closely to observations. The other interprets emission reduction scenarios typical of lockdown measures. The advantages and disadvantages of each are discussed. However, they lead to conclusions that are consistent with each other, and with most of the studies identified on the subject: lockdown naturally decreased nitrogen dioxide concentrations by up to 60% in all large European cities. These studies make it possible to set an upper limit of these levels which will be difficult to lower. On the other hand, the levels of particulate matter, which is influenced by sources other than road traffic and by complex physicochemical phenomena, decreased less and followed a different curve, as the lockdown effect was felt a few days later. These results provide essential insights for decision-makers designing public policies for air quality.Cet article prĂ©sente une analyse de lâimpact sur la qualitĂ© de lâair des mesures de confinement gĂ©nĂ©ralisĂ©es Ă toute lâEurope pendant prĂšs de deux mois au printemps 2020, pour faire face Ă la crise sanitaire de la Covid-19. Ces mesures ont abouti Ă une rĂ©duction drastique et inĂ©dite des Ă©missions dâoxydes dâazote, principalement Ă©mis par le trafic routier. De nombreuses Ă©tudes ont Ă©tĂ© menĂ©es par plusieurs Ă©quipes europĂ©ennes avec le mĂȘme objectif, mais les mĂ©thodes dâanalyse peuvent diffĂ©rer. Dans le cas prĂ©sent, deux approches basĂ©es sur la mise en Ćuvre du modĂšle de chimie-Transport CHIMERE sont appliquĂ©es Ă lâĂ©chelle de la France et de lâEurope. Lâune repose sur lâexploitation de simulations de la qualitĂ© de lâair dans lesquelles les donnĂ©es de mesures des rĂ©seaux de surveillance in situ sont assimilĂ©es pour coller au mieux Ă lâobservation. Lâautre interprĂšte des scĂ©narios de rĂ©duction dâĂ©missions reprĂ©sentatifs des mesures de confinement. Les avantages et inconvĂ©nients de chacune sont commentĂ©s. Elles aboutissent cependant Ă des conclusions cohĂ©rentes entre elles, et avec la plupart des Ă©tudes recensĂ©es sur le sujet : le confinement fut logiquement Ă lâorigine dâune forte baisse des concentrations de dioxyde dâazote (jusquâĂ 60 %) dans toutes les grandes villes europĂ©ennes et ces travaux permettent dâapprĂ©hender une limite supĂ©rieure de ces niveaux quâil sera difficile dâabaisser. En revanche, les niveaux de particules influencĂ©s par dâautres sources que le trafic routier et par des phĂ©nomĂšnes physico-chimiques complexes ont diminuĂ© dans une moindre mesure et selon une dynamique diffĂ©rente, lâeffet du confinement ayant Ă©tĂ© ressenti avec quelques jours de dĂ©calage. Ces rĂ©sultats constituent une source de rĂ©flexion essentielle pour les dĂ©cideurs en charge de la dĂ©finition de politiques publiques pour la qualitĂ© de lâair
Insights on the way uncertainties are taken into account in risks maps - Some recommendations in the case air pollution risk prevention
Le prĂ©sent article vise Ă fournir une analyse de lâĂ©tat de lâart des pratiques en matiĂšre de cartographie des risques et Ă rendre compte de lâanalyse de la prise en compte des incertitudes et de la dimension temporelle dans les cartographies des risques. AprĂšs avoir analysĂ© les effets de la cartographie des risques et des incertitudes sur la gestion des risques ainsi que la perception du public au sens large, nous proposerons des pistes de solutions en termes de cartographie dans le cas de la prĂ©vention des pollutions atmosphĂ©riques.This paper will provide a critical analysis of the state of the art of practices in risk mapping and the way uncertainties and the temporal dimension are taken into account in risks maps. After analyzing the effects risks and uncertainties mapping on risk management and on the perception of the public at large, we will propose possible solutions in terms of risk mapping in the case of the prevention risks due to atmospheric pollutions
Impact des émissions naturelles sur les épisodes de pollution photochimique (application à la région du Fossé Rhénan)
Les Composés Organiques Volatils (COV) biotiques jouent un rÎle significatif dans la formation et le développement d'épisodes de pollution photochimique. Leur forte réactivité et leur abondance dans la troposphÚre, en font des précurseurs significatifs de l'ozone, des PANs et du formaldéhyde. La prise en compte de ces COV par les modÚles de prévision de la qualité de l'air se heurte aux incertitudes relatives à la quantification de leurs émissions et aux mécanismes chimiques de la troposphÚre dans lesquels ils sont impliqués. Dans ce contexte, la prise en compte des COV biotiques dans le modÚle de chimie-transport CHIMERE a été améliorée en intégrant une double approche, numérique et expérimentale. Concernant les émissions biotiques, des mesures de terrain réalisées lors d'une campagne européenne, ont permis la détermination sur site de taux et flux d'émission de COV biotiques de trois espÚces forestiÚres trÚs abondantes en France : Abies alba, Fagus sylvatica et Pseudotsuga menziesii, à partir de la méthode des cuvettes instrumentées. Ces résultats, complétés par une étude bibliographique, ont permis de mettre à jour la base de données des facteurs d'émission spécifique de la zone d'étude et de la France. Cette base de données a été utilisée pour estimer les émissions annuelles de COV par l'écosystÚme forestier français. Concernant la réactivité des COV biotiques, une synthÚse critique de la bibliographie a conduit à l'élaboration d'un nouveau mécanisme chimique permettant de mieux modéliser leur réactivité. Les développements effectués ont abouti à une nouvelle version du modÚle CHIMERE dont les résultats ont été évalués par rapport aux observation disponibles dans la région du Fossé Rhénan, région fortement émettrice de COV biotiques. Si la modélisation des concentrations d'ozone est peu affectée par les modifications apportées, la modélisation des concentrations de PANs et de formaldéhyde y est nettement sensible. Une importante étude de sensibilité relative à la prise en compte des COV biotiques dans les modÚles, a permis de mettre en évidence la nécessité et la pertinence de réaliser des compromis et des simplifications pour modéliser la contribution des COV biotiques dans la formation d'épisode photochimique à l'ozone. Des mesures de terrain et des travaux pour affiner la connaissance des processus réactionnels seront néanmoins toujours nécessaires pour simuler correctement les autres polluants secondaires ainsi que les aérosols organiques.TOULOUSE-ENSIACET (315552325) / SudocSudocFranceF
New SHS' challenges in risk governance and management for safety, security and health and environment issues
La prĂ©vention des risques a connu de nombreuses Ă©volutions, avancĂ©es mais aussi des moments de stagnation et des Ă©checs patents lors dâaccidents industriels majeurs, de catastrophe sanitaires et environnementales et de pollutions de lâenvironnement. Cet article propose des nouveaux dĂ©fis en matiĂšre de prĂ©vention des risques issus dâune analyse diachroniques des Ă©volutions de la discipline et de ses dĂ©clinaisons pratiques en France. Pour y parvenir, nous avons dans un premier temps Ă©tabli une mise en perspective historique des Ă©volutions thĂ©oriques, pratiques et rĂ©glementaires en matiĂšre de prĂ©vention des risques. Dans un second temps, nous avons proposĂ© des Ă©lĂ©ments de discussion sur les postures dâĂ©valuation diachronique en matiĂšre de gestion et de gouvernance des risques. Dans un troisiĂšme temps, nous avons souhaitĂ© illustrer nos propos par un domaine dâapplication concret en analysant les trajectoires des problĂ©matiques en gestion des risques sur le cas de la prĂ©vention des pollutions atmosphĂ©riques.Risk practices have significantly evolved these years. In 2004, invited to the SRA Europe conference to talk about the advances in the field of risks prevention, Claude Frantzen called it a Tango on the asymptote. In this article, we wanted to discuss the difficulty of establishing a framework of diachronic assessment of developments in risks prevention in the field of safety, security and environment - health (SSEH). Defining an assessment framework of the strategies and the policies in risks governance and management helps to identify challenges based on an embedded analysis of the contributions and the limits of regulation, research and practices in these areas. This article will share new challenges for risks prevention based on a diachronic analysis of the evolutions of the discipline and its practical variations in France
Air Control Toolbox (ACT_v1.0): a flexible surrogate model to explore mitigation scenarios in air quality forecasts
International audienceWe introduce the first toolbox that allows exploring the benefit of air pollution mitigation scenarios in the every-day air quality forecasts through a web interface. Chemistry-transport models (CTMs) are required to forecast air pollution episodes and assess the benefit that shall be expected from mitigation strategies. However, their complexity prohibits offering a high level of flexibility in the tested emission reductions. The Air Control Toolbox (ACT) introduces an innovative automated calibration method to cope with this limitation. It consists of a surrogate model trained on a limited set of sensitivity scenarios to allow exploring any combination of mitigation measures. As such, we take the best of the physical and chemical complexity of CTMs, operated on high-performance computers for the every-day forecast, but we approximate a simplified response function that can be operated through a website to emulate the sensitivity of the atmospheric system to anthropogenic emission changes for a given day and location. The numerical experimental plan to design the structure of the surrogate model is detailed by increasing level of complexity. The structure of the surrogate model ultimately selected is a quadrivariate polynomial of first order for residential heating emissions and second order for agriculture, industry and traffic emissions with three interaction terms. It is calibrated against 12 sensitivity CTM simulations, at each grid point and every day for PM10, PM2.5, O3 (both as daily mean and daily maximum) and NO2. The validation study demonstrates that we can keep relative errors below 2â% at 95â% of the grid points and days for all pollutants. The selected approach makes ACT the first air quality surrogate model capable to capture non-linearities in atmospheric chemistry response. Existing air quality surrogate models generally rely on a linearity assumption over a given range of emission reductions, which often limits their applicability to annual indicators. Such a structure makes ACT especially relevant to understand the main drivers of air pollution episode analysis. This feature is a strong asset of this innovative tool which makes it also relevant for source apportionment and chemical regime analysis. This breakthrough was only possible by assuming uniform and constant emission reductions for the four targeted activity sectors. This version of the tool is therefore not suited to investigate short-term mitigation measures or spatially varying emission reductions
Dispersion et impact des panaches de fumĂ©es dâincendies industriels : le cas de Lubrizol
International audienceCet article expose, Ă travers lâexemple des travaux scientifiques menĂ©s dans le cadre de la gestion de lâincendie de lâusine Lubrizol (Rouen) en septembre 2019, les enjeux associĂ©s Ă la modĂ©lisation de la dispersion des panaches de fumĂ©es gĂ©nĂ©rĂ©s par les accidents industriels de grande ampleur. Selon la nature des composĂ©s chimiques transportĂ©s par ces panaches, les consĂ©quences en termes dâimpacts environnementaux et sanitaires sont plus ou moins importantes et diffĂšrent dans lâespace et dans le temps. Nous proposons une classification des questionnements suscitĂ©s par la gestion dâune situation dâurgence environnementale (phases accidentelle et post-accidentelle) et une revue des outils de simulation numĂ©riques mobilisables pour y rĂ©pondre. La valeur ajoutĂ©e de ces modĂšles et leurs limites sont discutĂ©es. Le cas de lâincendie de Rouen en septembre 2019 est particuliĂšrement instructif Ă ce titre puisque les diffĂ©rentes approches ont Ă©tĂ© mises en Ćuvre et questionnĂ©es par lâInstitut national de lâenvironnement industriel et des risques (Ineris), qui fut mobilisĂ© auprĂšs des pouvoirs publics pendant toute la crise. Il a permis de mettre en exergue la maturitĂ© des modĂšles et leurs incertitudes pour simuler des conditions rĂ©elles, en particulier celles liĂ©es au terme source. De fait, leur mise en Ćuvre en situation dâurgence se justifie avant tout par une logique de surveillance des impacts plutĂŽt que dâĂ©valuation de risques
14 th Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes -2-6
Abstract: Dispersion modelling is often used to estimate potentially contaminated areas in case of accidental release of microorganisms in the atmosphere. In the specific case of Legionella, accidental spread in the atmosphere due to contaminated cooling towers system may occur over distance larger than 10km. In addition, most cooling towers are located in urban areas where dispersion due to obstacles is complex. In this case, dispersion models have to take into account complex flows and microphysical processes that occur within the plume and may have an impact on the survival of the microorganisms. To estimate the concentration of microorganisms in these areas, a specific module has been developed within the lagrangian dispersion model Micro Swift Spray (MSS, Aria technologies). This module takes into account microorganisms outside or inside water liquid droplets and microphysical interaction inside the plume. A simple biological module governing the survival of airborne microorganisms has also been implemented in the dispersion model. In order to evaluate this model, a field campaign of biological aerosols dispersion was performed by CSTB (Champs-sur-Marne, France) on June 23 rd , 2009. Spores of bacillus atrophaeus (usually referred to as BG) initially contained in a water tank were disseminated in a suburban area from a source at 3 meters above ground level. Air was sampled by DGA MNRBC (Vert-Le-Petit, France) at 4 various locations from 50 to 300 meters from the source to monitor NG concentration. Direct impaction onto Petri dishes was performed with slit-samplers and sixstage Andersen impactors. Wetted-wall cyclones and SKC Biosamplers were also implemented in order to sample air and generate liquid samples. Dispersion modelling for this campaign has been carried out by INERIS using the microorganism module developed in MSS. The results show that predicted concentrations and in situ measurements are in agreement. MSS Model was implemented to simulate legionella airborne dispersion from a virtual cooling tower at the same location. The biological model has been activated. Results show that the impact of biological model on airborne concentration is significant
An Evaluation of the CHIMERE Chemistry Transport Model to Simulate Dust Outbreaks across the Northern Hemisphere in March 2014
Mineral dust is one of the most important aerosols over the world, affecting health and climate. These mineral particles are mainly emitted over arid areas but may be long-range transported, impacting the local budget of air quality in urban areas. While models were extensively used to study a single specific event, or make a global analysis at coarse resolution, the goal of our study is to simultaneously focus on several affected areasâEurope, North America, Central Asia, east China and the Caribbean areaâfor a one-month period, March 2014, avoiding any parameter fitting to better simulate a single dust outbreak. The simulation is performed for the first time with the hemispheric version of the CHIMERE model, with a high horizontal resolution (about 10 km). In this study, an overview of several simultaneous dust outbreaks over the Northern Hemisphere is proposed to assess the capability of such modeling tools to predict dust pollution events. A quantitative and qualitative evaluation of the most striking episodes is presented with comparisons to satellite data, ground based particulate matter and calcium measurements. Despite some overestimation of dust concentrations far from emission source areas, the model can simulate the timing of the arrival of dust outbreaks on observational sites. For instance, several spectacular dust storms in the US and China are rather well captured by the models. The high resolution provides a better description and understanding of the orographic effects and the long-range transport of dust plumes