Estimation de la contribution des émissions Îhiculaires à l'échappement et hors-échappement aux teneurs atmosphériques en PM10 par Positive Matrix Factorization (PMF)

The goal of this work is the development of a methodology allowing the assessment of road traffic exhaust and non-exhaust contributions (resuspension of road dusts, from brakes, tyres and road-surface-wear, from the corrosion of vehicle components...) to PM10 in an urban site. The approach used source apportionment modelling by PMF (Positive Matrix Factorization) with a chemical data set including chemical tracers. These data are obtained thanks to filter samples collected during short-time periods (4h temporal resolution). This study also includes the simultaneous sampling of chemical species on an urban background site (Grenoble-Les Frênes, France) and on a roadside site (Grenoble-Echirolles, France). This combination leads to accurate determination of traffic indicators sources. Finally, the source apportionment using PMF applied to this database gives possible contribution of sources to PM10. Results show that the road traffic source contribution to PM10 (exhaust + non-exhaust sources) was on average 34% and ranged from about 57% during the rush hours to 14% during less busy periods. Non-exhaust contribution is on average equivalent to the exhaust one.L'objectif de cette étude est de tester une méthodologie permettant de déterminer les contributions respectives aux teneurs atmosphériques en PM10 des émissions Îhiculaires à l'échappement et hors échappement (abrasion des freins, des pneus et de la route, remise en suspension des poussières de la chaussée...) dans un milieu urbain. La stratégie adoptée est d'appliquer une méthode de déconvolution des sources par un modèle statistique d'analyses multivariées (PMF, Positive Matrix Factorization) sur un jeu de données chimiques obtenues avec des filtres collectés sur des durées réduites (4h) et comprenant des traceurs spécifiques. Les prélèvements ont été réalisés simultanément sur un site de fond urbain (Grenoble-Les Frênes, France) et sur un site de proximité automobile (Grenoble-Échirolles, France). La discrimination des sources et la quantification de leur contribution par PMF sont ensuite obtenues sur la base de données établie. Les résultats montrent que les émissions Îhiculaires à l'échappement et hors échappement contribuent en moyenne à 34 % des PM10 et jusqu'à 57 % durant les heures de pointe, contre seulement 14 % durant les heures creuses. Sur la période de mesure, les émissions hors échappement sont en moyenne équivalentes aux émissions à l'échappement pour le site d'étude de proximité trafic

Global prevalence and genotype distribution of hepatitis C virus infection in 2015 : A modelling study

Publisher Copyright: © 2017 Elsevier LtdBackground The 69th World Health Assembly approved the Global Health Sector Strategy to eliminate hepatitis C virus (HCV) infection by 2030, which can become a reality with the recent launch of direct acting antiviral therapies. Reliable disease burden estimates are required for national strategies. This analysis estimates the global prevalence of viraemic HCV at the end of 2015, an update of—and expansion on—the 2014 analysis, which reported 80 million (95% CI 64–103) viraemic infections in 2013. Methods We developed country-level disease burden models following a systematic review of HCV prevalence (number of studies, n=6754) and genotype (n=11 342) studies published after 2013. A Delphi process was used to gain country expert consensus and validate inputs. Published estimates alone were used for countries where expert panel meetings could not be scheduled. Global prevalence was estimated using regional averages for countries without data. Findings Models were built for 100 countries, 59 of which were approved by country experts, with the remaining 41 estimated using published data alone. The remaining countries had insufficient data to create a model. The global prevalence of viraemic HCV is estimated to be 1·0% (95% uncertainty interval 0·8–1·1) in 2015, corresponding to 71·1 million (62·5–79·4) viraemic infections. Genotypes 1 and 3 were the most common cause of infections (44% and 25%, respectively). Interpretation The global estimate of viraemic infections is lower than previous estimates, largely due to more recent (lower) prevalence estimates in Africa. Additionally, increased mortality due to liver-related causes and an ageing population may have contributed to a reduction in infections. Funding John C Martin Foundation.publishersversionPeer reviewe

Caractérisation des aérosols organiques à Beyrouth, Liban

The chemical composition of PM2.5 includes both organic and inorganic compounds. Organic compounds, which constitute a significant fraction of the PM2.5 mass, can be emitted directly as primary aerosol from sources such as fossil-fuel combustion, biomass burning, and natural biogenic emissions, or formed in the atmosphere via chemical reactions leading to secondary organic aerosol (SOA) formation. SOA, which account for 20 – 80 % of total organic aerosol, are currently a major source of uncertainty in air quality modeling. The identification and quantification of the chemical composition of the organic fraction of PM2.5 and its source apportionment are of great interest, especially in the Middle East region where data on organic aerosols are currently lacking. Lebanon, a small developing country in the Middle East region located on the eastern shore of the Mediterranean basin represents a good example for characterizing organic aerosols in this region. To address this issue, the air quality in Beirut (the capital city of Lebanon) was investigated with a focus on organic aerosols. First, an air pollutant emission inventory was developed for Lebanon with a spatial resolution of 5 km x 5 km and for Beirut with a spatial resolution of 1 km x 1 km. The results obtained show that the road transport sector is the major contributor to carbon monoxide (CO), nitrogen oxides (NOx) and non-methane volatile organic compounds (VOC) emissions, whereas fossil fuel-fired power plants and large industrial plants are the major contributors to sulfur dioxide (SO2) and primary particulate matter (PM) emissions. Then, two intensive 15-day measurement campaigns were conducted at a semi-urban site located in a Beirut suburb to characterize air pollutant concentrations. The first measurement campaign took place in July 2011 and the second in February 2012. Measurements included PM2.5, organic carbon (OC) and elemental carbon (EC) mass concentrations as well as a molecular characterization of organic aerosols. Using these data, a source apportionment of organic aerosols was conducted for summer and winter. In summer, biogenic precursors such as monoterpenes and sesquiterpenes were the major source of OC due to intensive solar radiation and high ambient temperatures that promote biogenic VOC emissions and photo-oxidation reactions. In winter, biomass burning was the major source of organic aerosols because of the intensive use of wood burning for heating. Finally, air pollutant concentrations in Beirut were simulated for July 2011 with the Polyphemus/Polair3D chemical-transport model (CTM). The emission inventory mentioned above was used as input to the model. Meteorological simulations were conducted with the Weather Research and Forecasting model (WRF) using different configurations and the configuration leading to the best agreement with the observations was used to drive the air quality simulations. The simulated air pollutant concentrations were compared to the measured concentrations collected during the summer measurement campaign. The results show that the model reproduces satisfactorily the concentrations of ozone (O3), nitrogen dioxide (NO2), carbon monoxide (CO), and the major components of PM2.5. The differences obtained between the modeled and measured air pollutants concentrations are due in part to uncertainties in input data. Future studies should address the reduction of uncertainties such as those of the emission inventory. In addition, measurement campaigns involving several sites are needed to better characterize air pollution in Beirut and provide a more complete database to evaluate simulated air pollutant concentrationsLa connaissance des sources primaires (combustion des énergies fossiles, combustion de la biomasse, éruptions des volcans, etc.) et secondaires (oxydation des composés organiques volatils (COV) suivie de la condensation formant des composés organiques particulaires) de l'aérosol organique ainsi que la caractérisation et la quantification de sa composition chimique restent un défit majeur, en particulier dans la région du Moyen Orient où les études de caractérisation de l'aérosol organique n'existent pas jusqu'à présent. Le Liban, un pays du Moyen Orient qui se situe au bord du bassin méditerranéen, représente un bon exemple pour la caractérisation des aérosols organiques dans cette région. Les travaux menés durant cette thèse s'inscrivent dans un objectif de l'étude de la qualité de l'air à Beyrouth (la capitale du Liban) en se concentrant plus spécifiquement sur les aérosols organiques. Tout d'abord, cette thèse a permis le développement d'un inventaire des émissions pour les gaz et les particules pour le Liban avec une résolution spatiale de 5 km x 5 km et pour la capitale Beyrouth avec une résolution spatiale de 1 km x 1 km. Les résultats obtenus indiquent que le transport routier est la source majoritaire responsable des émissions de monoxyde de carbone (CO), d'oxydes d'azote (NOX) et de composés organiques volatils non méthaniques (COVNM), tandis que les industries et les centrales électriques sont les principaux émetteurs des émissions de dioxyde de souffre (SO2) et des particules primaires. Ensuite, afin de caractériser les concentrations des polluants et plus spécialement la fraction organique des particules, deux campagnes de mesures intensives de 15 jours chacune ont été menées sur un site semi-urbain situé dans la banlieue de Beyrouth. Une première campagne estivale s'est déroulée en juillet 2011 et une deuxième campagne hivernale en février 2012. Ces campagnes, qui s'inscrivent dans le cadre du projet ECOCEM (Emission and Chemistry of Organic Carbon in East Mediterranean Beirut) ont permis une spéciation moléculaire et une catégorisation des sources en été et en hiver de l'aérosol organique au site de mesures où les campagnes ont été menées. En été, les précurseurs biogéniques tels que les monoterpènes et les sesquiterpènes qui aboutissent à la formation des aérosols organiques secondaires biogéniques sont la principale source à cause de l'insolation intensive et les températures élevées qui favorisent les émissions et les réactions de photo-oxydations. En hiver, la combustion de la biomasse est la principale source en raison de la combustion du bois dans le secteur résidentiel pour le chauffage. Enfin, les concentrations ambiantes des polluants à Beyrouth ont été simulées durant le mois de juillet 2011 à partir de données de l'inventaire des émissions développé dans le cadre de cette thèse en utilisant le modèle de chimie-transport Polyphemus/Polair3D. Les concentrations de polluants simulées avec le modèle ont été comparées aux concentrations mesurées durant la campagne estivale afin d'évaluer le modèle. Les résultats obtenus révèlent que le modèle est capable de simuler de manière satisfaisante les concentrations d'ozone (O3), de NOX et la plupart des composés présents dans les particules fines. Les différences entre le modèle et les mesures peuvent résulter des incertitudes dans les données d'entrée qui ont une très grande influence sur les sorties du modèle. Pour cela, une réduction des incertitudes engendrées par les données d'entrée et plus spécifiquement celles liées à l'inventaire des émissions est nécessaire. Par ailleurs, des mesures chimiques sur plusieurs sites sont aussi nécessaires dans le futur afin de mieux évaluer les simulations des concentrations de polluant

Characterization of organic aerosols in Beirut, Lebanon

La connaissance des sources primaires (combustion des énergies fossiles, combustion de la biomasse, éruptions des volcans, etc.) et secondaires (oxydation des composés organiques volatils (COV) suivie de la condensation formant des composés organiques particulaires) de l'aérosol organique ainsi que la caractérisation et la quantification de sa composition chimique restent un défit majeur, en particulier dans la région du Moyen Orient où les études de caractérisation de l'aérosol organique n'existent pas jusqu'à présent. Le Liban, un pays du Moyen Orient qui se situe au bord du bassin méditerranéen, représente un bon exemple pour la caractérisation des aérosols organiques dans cette région. Les travaux menés durant cette thèse s'inscrivent dans un objectif de l'étude de la qualité de l'air à Beyrouth (la capitale du Liban) en se concentrant plus spécifiquement sur les aérosols organiques. Tout d'abord, cette thèse a permis le développement d'un inventaire des émissions pour les gaz et les particules pour le Liban avec une résolution spatiale de 5 km x 5 km et pour la capitale Beyrouth avec une résolution spatiale de 1 km x 1 km. Les résultats obtenus indiquent que le transport routier est la source majoritaire responsable des émissions de monoxyde de carbone (CO), d'oxydes d'azote (NOX) et de composés organiques volatils non méthaniques (COVNM), tandis que les industries et les centrales électriques sont les principaux émetteurs des émissions de dioxyde de souffre (SO2) et des particules primaires. Ensuite, afin de caractériser les concentrations des polluants et plus spécialement la fraction organique des particules, deux campagnes de mesures intensives de 15 jours chacune ont été menées sur un site semi-urbain situé dans la banlieue de Beyrouth. Une première campagne estivale s'est déroulée en juillet 2011 et une deuxième campagne hivernale en février 2012. Ces campagnes, qui s'inscrivent dans le cadre du projet ECOCEM (Emission and Chemistry of Organic Carbon in East Mediterranean Beirut) ont permis une spéciation moléculaire et une catégorisation des sources en été et en hiver de l'aérosol organique au site de mesures où les campagnes ont été menées. En été, les précurseurs biogéniques tels que les monoterpènes et les sesquiterpènes qui aboutissent à la formation des aérosols organiques secondaires biogéniques sont la principale source à cause de l'insolation intensive et les températures élevées qui favorisent les émissions et les réactions de photo-oxydations. En hiver, la combustion de la biomasse est la principale source en raison de la combustion du bois dans le secteur résidentiel pour le chauffage. Enfin, les concentrations ambiantes des polluants à Beyrouth ont été simulées durant le mois de juillet 2011 à partir de données de l'inventaire des émissions développé dans le cadre de cette thèse en utilisant le modèle de chimie-transport Polyphemus/Polair3D. Les concentrations de polluants simulées avec le modèle ont été comparées aux concentrations mesurées durant la campagne estivale afin d'évaluer le modèle. Les résultats obtenus révèlent que le modèle est capable de simuler de manière satisfaisante les concentrations d'ozone (O3), de NOX et la plupart des composés présents dans les particules fines. Les différences entre le modèle et les mesures peuvent résulter des incertitudes dans les données d'entrée qui ont une très grande influence sur les sorties du modèle. Pour cela, une réduction des incertitudes engendrées par les données d'entrée et plus spécifiquement celles liées à l'inventaire des émissions est nécessaire. Par ailleurs, des mesures chimiques sur plusieurs sites sont aussi nécessaires dans le futur afin de mieux évaluer les simulations des concentrations de polluantsThe chemical composition of PM2.5 includes both organic and inorganic compounds. Organic compounds, which constitute a significant fraction of the PM2.5 mass, can be emitted directly as primary aerosol from sources such as fossil-fuel combustion, biomass burning, and natural biogenic emissions, or formed in the atmosphere via chemical reactions leading to secondary organic aerosol (SOA) formation. SOA, which account for 20 – 80 % of total organic aerosol, are currently a major source of uncertainty in air quality modeling. The identification and quantification of the chemical composition of the organic fraction of PM2.5 and its source apportionment are of great interest, especially in the Middle East region where data on organic aerosols are currently lacking. Lebanon, a small developing country in the Middle East region located on the eastern shore of the Mediterranean basin represents a good example for characterizing organic aerosols in this region. To address this issue, the air quality in Beirut (the capital city of Lebanon) was investigated with a focus on organic aerosols. First, an air pollutant emission inventory was developed for Lebanon with a spatial resolution of 5 km x 5 km and for Beirut with a spatial resolution of 1 km x 1 km. The results obtained show that the road transport sector is the major contributor to carbon monoxide (CO), nitrogen oxides (NOx) and non-methane volatile organic compounds (VOC) emissions, whereas fossil fuel-fired power plants and large industrial plants are the major contributors to sulfur dioxide (SO2) and primary particulate matter (PM) emissions. Then, two intensive 15-day measurement campaigns were conducted at a semi-urban site located in a Beirut suburb to characterize air pollutant concentrations. The first measurement campaign took place in July 2011 and the second in February 2012. Measurements included PM2.5, organic carbon (OC) and elemental carbon (EC) mass concentrations as well as a molecular characterization of organic aerosols. Using these data, a source apportionment of organic aerosols was conducted for summer and winter. In summer, biogenic precursors such as monoterpenes and sesquiterpenes were the major source of OC due to intensive solar radiation and high ambient temperatures that promote biogenic VOC emissions and photo-oxidation reactions. In winter, biomass burning was the major source of organic aerosols because of the intensive use of wood burning for heating. Finally, air pollutant concentrations in Beirut were simulated for July 2011 with the Polyphemus/Polair3D chemical-transport model (CTM). The emission inventory mentioned above was used as input to the model. Meteorological simulations were conducted with the Weather Research and Forecasting model (WRF) using different configurations and the configuration leading to the best agreement with the observations was used to drive the air quality simulations. The simulated air pollutant concentrations were compared to the measured concentrations collected during the summer measurement campaign. The results show that the model reproduces satisfactorily the concentrations of ozone (O3), nitrogen dioxide (NO2), carbon monoxide (CO), and the major components of PM2.5. The differences obtained between the modeled and measured air pollutants concentrations are due in part to uncertainties in input data. Future studies should address the reduction of uncertainties such as those of the emission inventory. In addition, measurement campaigns involving several sites are needed to better characterize air pollution in Beirut and provide a more complete database to evaluate simulated air pollutant concentration

An atmospheric emission inventory of anthropogenic and biogenic sources for Lebanon

International audienceA temporally-resolved and spatially-distributed emission inventory was developed for Lebanon to provide quantitative information for air pollution studies as well as for use as input to air quality models. This inventory covers major anthropogenic and biogenic sources in the region with 5 km spatial resolution for Lebanon and 1 km spatial resolution for its capital city Beirut and its suburbs. The results obtained for CO, NOx, SO2, NMVOC, NH3, PM10 and PM2.5 for the year 2010 were 563, 75, 62, 115, 4,12, and 9 Gg, respectively. About 93% of CO emissions, 67% of NMVOC emissions and 52% of NOx emissions are calculated to originate from the on-road transport sector while 73% of SO2 emissions, 62% of PM10 emissions and 59% of PM2.5 emissions are calculated to originate from power plants and industrial sources. The spatial allocation of emissions shows that the city of Beirut and its suburbs encounter a large fraction of the emissions from the on-road transport sector while urban areas such as Zouk Mikael, Jieh, Chekka and Selaata are mostly affected by emissions originating from the industrial and energy production sectors. Temporal profiles were developed for several emission sectors. (C) 2012 Elsevier Ltd. All rights reserved

Perturbed Information Processing Complexity in Experimental Epilepsy

International audienceComorbidities, such as cognitive deficits, which often accompany epilepsies, constitute a basal state, while seizures are rare and transient events. This suggests that neural dynamics, in particular those supporting cognitive function, are altered in a permanent manner in epilepsy. Here, we test the hypothesis that primitive processes of information processing at the core of cognitive function (i.e., storage and sharing of information) are altered in the hippocampus and the entorhinal cortex in experimental epilepsy in adult, male Wistar rats. We find that information storage and sharing are organized into substates across the stereotypic states of slow and theta oscillations in both epilepsy and control conditions. However, their internal composition and organization through time are disrupted in epilepsy, partially losing brain state selectivity compared with controls, and shifting toward a regimen of disorder. We propose that the alteration of information processing at this algorithmic level of computation, the theoretical intermediate level between structure and function, may be a mechanism behind the emergent and widespread comorbidities associated with epilepsy, and perhaps other disorders. SIGNIFICANCE STATEMENT Comorbidities, such as cognitive deficits, which often accompany epilepsies, constitute a basal state, while seizures are rare and transient events. This suggests that neural dynamics, in particular those supporting cognitive function, are altered in a permanent manner in epilepsy. Here, we show that basic processes of information processing at the core of cognitive function (i.e., storage and sharing of information) are altered in the hippocampus and the entorhinal cortex (two regions involved in memory processes) in experimental epilepsy. Such disruption of information processing at the algorithmic level itself could underlie the general performance impairments in epilepsy

Exploring the seasonal NMHC distribution in an urban area of the Middle East during ECOCEM campaigns: very high loadings dominated by local emissions and dynamics

Non-methane hydrocarbons play an important role in the formation of photochemical oxidants such as ozone. We investigate factors controlling the distribution of non-methane hydrocarbons in an urban area of the Middle East. The study highlights the importance of local emissions and atmospheric dynamics, and the limited effect of photochemistry at the measurement site. Abstract Measurements of over 70 C2-C16 non-methane hydrocarbons (NMHCs) were conducted in suburban Beirut (1.3 million inhabitants) in summer 2011 and winter 2012 during the Emission and Chemistry of Organic Carbon in the East Mediterranean (ECOCEM) field campaign. The levels of NMHCs observed exceeded by a factor of two in total volume the levels found in northern mid-latitude megacities (Paris and Los Angeles), especially for the unburned fossil fuel fraction. Regardless of the season, the major compounds, explaining 50% of the concentrations, were toluene, isopentane, butane, m,p-xylenes, propane and ethylene, emitted by mobile traffic and gasoline evaporation sources. Most NMHCs show a distinct seasonal cycle, with a summer maximum and a winter minimum, unlike seasonal cycles usually observed in the northern mid-latitude urban areas. We show that NMHC distribution is mainly driven by strong local emissions and local atmospheric dynamics, with no clear evidence of photochemical removal in summer or influence from long-range transport

Multi-year levels and trends of non-methane hydrocarbon concentrations observed in ambient air in France

International audienceMeasurements of 31 non-methane hydrocarbons (NMHCs) were carried out at three urban (Paris, 2003-2014, Strasbourg, 2002-2014 and Lyon, 2007-2014) sites in France over the period of a decade. A trend analysis was applied by means of the Mann-Kendall non-parametric test to annual and seasonal mean concentrations in order to point out changes in specific emission sources and to assess the impact of emission controls and reduction strategies. The trends were compared to those from three rural sites (Peyrusse-Vieille, 2002-2013, Tardière, 2003-2013 and Donon, 1997-2007). The results obtained showed a significant yearly decrease in pollutant concentrations over the study period and for the majority of species in the range of -1 to -7% in accordance with the decrease of NMHC emissions in France (-5 to -9%). Concentrations of long-lived species such as ethane and propane which are recognized as tracers of distant sources and natural gas remained constant. Compounds associated with combustion processes such as acetylene, propene, ethylene and benzene showed a significant decline in the range of -2% to -5% yr-1. These trends are consistent with those recently described at urban and background sites in the northern mid-latitudes and with emission inventories. C7-C9 aromatics such as toluene and xylenes as well as C4-C5 alkanes such as isopentane and isobutane also showed a significant decrease in the range of -3% to -7% yr-1. The decreasing trends in terms of % yr-1 observed at these French urban sites were typically higher for acetylene, ethylene and benzene than those reported for French rural sites of the national observatory of Measurement and Evaluation in Rural areas of trans-boundary Air pollution (MERA). The study also highlighted the difficult choice of a long term sampling site representative of the general trends of pollutant concentrations

Characterization of organic tracer compounds in PM2.5 at a semi-urban site in Beirut, Lebanon

International audienceA measurement campaign was conducted at a semi-urban site located in the suburbs of the city of Beirut (Lebanon) during summertime (2–18 July 2011). The molecular composition of organic PM2.5 was investigated following a chemical derivatization gas chromatography/mass spectrometry technique. Accordingly, several classes of compounds represented by 18 individual organic tracers were determined. These tracers include levoglucosan, a tracer for biomass combustion, dicarboxylic acids, and several tracers for the photo-oxidation of isoprene, α-pinene and β-caryophyllene. The sum of the mean concentrations of the isoprene oxidation products was 4 ng/m3, that of α-pinene was 124 ng/m3 and that of β-caryophyllene was 11 ng/m3. For other tracers of organic aerosols, the highest concentrations were obtained for carboxylic acids with an average value of 939 ng/m3. An average value of 49 ng/m3 was obtained for levoglucosan. Organic and elemental carbon concentrations were measured by a thermo-optical analyzer. Average values were 5.6 and 1.8 μg/m3, respectively. A reconstruction of organic PM2.5 composition suggests that cooking, fossil-fuel combustion, biomass burning, sesquiterpenes, monoterpenes, and isoprene contribute on average about 27 ± 13, 16 ± 7, 5 ± 3, 26 ± 5, 26 ± 13 and < 1 ± 0.3% of PM2.5 organic carbon, respectively

Potential sources of PM10 impacting the Hauts-de-France region over a 5-year period (2009-2013) identified by receptor modeling: Influence of precipitation, air mass altitude, length of backward trajectories and the use of a weighting function

International audienc