Study of sources and atmospheric dynamics of particulate organic pollutants in Alpine valleys : contribution of new organic tracers for receptor modelling applications

Récemment, la qualité de l'air dans la région Rhône-Alpes est devenue un sujet sensible depuis sa mise en demeure par l'Union Européenne pour non respect des normes en vigueurs concernant les taux de particules fines (PM). Effectivement, certaines zones géographiques de la région connaissent de nombreux dépassements en PM10, particulièrement dans les vallées alpines durant la période hivernale. Ces dépassements en particules sont aussi accompagnés de fortes concentrations en composés organiques comme les hydrocarbures aromatiques polycycliques (HAP) constituants ces PM. Un accroissement des connaissances sur les sources de pollution atmosphérique particulaire et leurs dynamiques au sein des vallées alpines est alors nécessaire, ceci afin d'améliorer la mise en place des politiques de diminution des émissions grâce à une meilleure connaissance de l'influence des différentes sources au niveau régional. Ces travaux de thèse sont axés autour des émissions des sources industrielles encore mal connues et plus particulièrement l'industrie du carbone très présente dans les bassins industriels de ces fonds de vallées. Les approches classiques par les éléments métalliques n'étant pas spécifiques, l'exploration de la fraction organique a permis de proposer un profil chimique organique complet et d'avancer le benzo(b)naphtho(2,1-d)thiophène (BNT(2,1)), composé particulaire majoritaire de la famille des Hydrocarbures Aromatiques Polycycliques soufrés (HAPS) comme traceur de cette source. Ce composé a été détecté et quantifié sur plusieurs sites en proximité d'activités industrielles confirmant ainsi sa source potentielle. De plus le profil industriel a été introduit comme profil « source » afin d'évaluer sa robustesse dans les méthodologies de type modèle récepteur de bilan de masse comme le « Chemical Mass Balance » (CMB) et statistique comme la « Positive Matrix Factorization » (PMF). Les résultats ont confirmé l'intérêt de l'ajout des composés organiques à ces méthodologies. Ainsi, le profil industriel et les composés organiques HAPS ont permis de mieux tracer la source appelée génériquement « industrie du carbone » (combustions de charbon, de coke et de matériaux graphitiques) dans les vallées alpines mais aussi sur différents sites urbains français. En parallèle, un modèle de régression non linéaire multivarié (MRNL) a été développé pour la quantification des sources de HAP, basé sur l'utilisation de traceurs spécifiques de source (lévoglucosan, hopanes….) et de données météorologiques (gradient thermique). Son application a été validée sur un ensemble de sites alpins des vallées de l'Arve et de la Tarentaise. Un couplage entre ce modèle et les données de mesures optiques du carbone suie (BC) par aéthalomètre, a permis de proposer une solution aux mauvais résultats de corrélation entre les HAP mesurés et modélisés par le modèle MRNL sur le site de la vallée de la Maurienne. Ces faibles corrélations peuvent être liées à une mauvaise représentativité des composés organiques utilisés à tracer correctement les sources d'émission sur certains sites.Enfin, l'inter-comparaison de ces méthodologies pour la détermination des sources de HAP et plus particulièrement de la source industrielle permet de valider cette méthodologie dans une perspective opérationnelle de suivi des sources de HAP sur ces différents sites. Ces travaux réalisés au cours de cette thèse mettent en évidence l'intérêt de la caractérisation de la fraction organique des PM et les biais qui peuvent exister sur l'utilisation des composés organiques pour l'étude des sources d'émissions. Des alternatives y sont proposées afin de soulever ces ambiguïtés et d'améliorer l'étude des sources de HAP par les modèles récepteurs.Recently, Air quality has become a sensitive topic for Rhône-Alpes region due to the formal notice which was addressed by the European Commission for non-compliance with legislation in force. Indeed, certain geographic areas in the region present a lot of overruns in PM10, especially in Alpine valleys during winter. These overruns particles are also accompanied by high concentrations of organic compounds such as polycyclic aromatic hydrocarbons (PAHs), which constitute these PMs. An increase in khowledge about the sources of particulate air pollution and their dynamics in Alpine valleys is necessary, in order to improve the implementation of policies to reduce emissions through better knowledge of the influence of different sources at regional level. This thesis is focused around emissions from industrial sources still poorly known and particularly of the carbon industry highly present in these industrial areas of the valley bottoms. Traditional approaches by metallic elements being not specific, exploration of the organic fraction allowed to propose a complete organic chemical profile. In addition they led us to evidence the benzo(b)naphtho(2,1-d)thiophene (BNT(2,1)), the most abundant particulate compound of the family of sulfur-containing polycyclic aromatic hydrocarbons (PASHs), as a tracer of this source. This compound was detected and quantified on multiple sites in near industrial activities confirming its potential source. In addition the industrial profile was introduced as profile “source” in order to assess its robustness in methodologies of receptor model like the “Chemical Mass Balance “(CMB) and the “Positive Matrix Factorization” (PMF). The results confirmed the interest of the addition of organic compounds to these methodologies. Thus, the industrial profile and the PASHs compounds have allowed to better trace the source usually called “carbon industry” (coal, coke and graphite materials combustions) in the Alpine valleys but also in different French urban sites. In parallel, a non linear regression model (NLRM) was developed to PAH source apportionment, based on the use of specific molecular markers (levoglucosan, hopanes…) and of meteorological data (altitudinal temperature lapse rate). Its implementation has been validated on a set of sites of the Alpine valleys of Arve and Tarentaise. Coupling between this model and the optical measurements of black carbon (BC) by aethalometer, allowed to propose a solution to the poor performance of correlation between PAHs measured and modeled by NLRM model on this site of the Maurienne valley. These low correlations may be related to poor representativeness of organic compounds used to correctly trace the emission sources at some sites. Finally, the inter-comparison of these methodologies for the determination of PAH sources and especially of industrial source allows to validate this methodology in an operational perspective of monitoring of PAH levels on these sites. The work performed during this thesis highlights the interest of the characterizatin of the organic fraction of PM and the biases that may exist on the use of organic compounds for the study of the emission sources. Some alternatives are suggested to clarify ambiguities and improve the source apportionment of PAHs by receptor models

Etude des sources et de la dynamique atmosphérique de polluants organiques particulaires en vallées alpines : apport de nouveaux traceurs organiques aux modèles récepteurs

Recently, Air quality has become a sensitive topic for Rhône-Alpes region due to the formal notice which was addressed by the European Commission for non-compliance with legislation in force. Indeed, certain geographic areas in the region present a lot of overruns in PM10, especially in Alpine valleys during winter. These overruns particles are also accompanied by high concentrations of organic compounds such as polycyclic aromatic hydrocarbons (PAHs), which constitute these PMs. An increase in khowledge about the sources of particulate air pollution and their dynamics in Alpine valleys is necessary, in order to improve the implementation of policies to reduce emissions through better knowledge of the influence of different sources at regional level. This thesis is focused around emissions from industrial sources still poorly known and particularly of the carbon industry highly present in these industrial areas of the valley bottoms. Traditional approaches by metallic elements being not specific, exploration of the organic fraction allowed to propose a complete organic chemical profile. In addition they led us to evidence the benzo(b)naphtho(2,1-d)thiophene (BNT(2,1)), the most abundant particulate compound of the family of sulfur-containing polycyclic aromatic hydrocarbons (PASHs), as a tracer of this source. This compound was detected and quantified on multiple sites in near industrial activities confirming its potential source. In addition the industrial profile was introduced as profile “source” in order to assess its robustness in methodologies of receptor model like the “Chemical Mass Balance “(CMB) and the “Positive Matrix Factorization” (PMF). The results confirmed the interest of the addition of organic compounds to these methodologies. Thus, the industrial profile and the PASHs compounds have allowed to better trace the source usually called “carbon industry” (coal, coke and graphite materials combustions) in the Alpine valleys but also in different French urban sites. In parallel, a non linear regression model (NLRM) was developed to PAH source apportionment, based on the use of specific molecular markers (levoglucosan, hopanes…) and of meteorological data (altitudinal temperature lapse rate). Its implementation has been validated on a set of sites of the Alpine valleys of Arve and Tarentaise. Coupling between this model and the optical measurements of black carbon (BC) by aethalometer, allowed to propose a solution to the poor performance of correlation between PAHs measured and modeled by NLRM model on this site of the Maurienne valley. These low correlations may be related to poor representativeness of organic compounds used to correctly trace the emission sources at some sites. Finally, the inter-comparison of these methodologies for the determination of PAH sources and especially of industrial source allows to validate this methodology in an operational perspective of monitoring of PAH levels on these sites. The work performed during this thesis highlights the interest of the characterizatin of the organic fraction of PM and the biases that may exist on the use of organic compounds for the study of the emission sources. Some alternatives are suggested to clarify ambiguities and improve the source apportionment of PAHs by receptor models.Récemment, la qualité de l'air dans la région Rhône-Alpes est devenue un sujet sensible depuis sa mise en demeure par l'Union Européenne pour non respect des normes en vigueurs concernant les taux de particules fines (PM). Effectivement, certaines zones géographiques de la région connaissent de nombreux dépassements en PM10, particulièrement dans les vallées alpines durant la période hivernale. Ces dépassements en particules sont aussi accompagnés de fortes concentrations en composés organiques comme les hydrocarbures aromatiques polycycliques (HAP) constituants ces PM. Un accroissement des connaissances sur les sources de pollution atmosphérique particulaire et leurs dynamiques au sein des vallées alpines est alors nécessaire, ceci afin d'améliorer la mise en place des politiques de diminution des émissions grâce à une meilleure connaissance de l'influence des différentes sources au niveau régional. Ces travaux de thèse sont axés autour des émissions des sources industrielles encore mal connues et plus particulièrement l'industrie du carbone très présente dans les bassins industriels de ces fonds de vallées. Les approches classiques par les éléments métalliques n'étant pas spécifiques, l'exploration de la fraction organique a permis de proposer un profil chimique organique complet et d'avancer le benzo(b)naphtho(2,1-d)thiophène (BNT(2,1)), composé particulaire majoritaire de la famille des Hydrocarbures Aromatiques Polycycliques soufrés (HAPS) comme traceur de cette source. Ce composé a été détecté et quantifié sur plusieurs sites en proximité d'activités industrielles confirmant ainsi sa source potentielle. De plus le profil industriel a été introduit comme profil « source » afin d'évaluer sa robustesse dans les méthodologies de type modèle récepteur de bilan de masse comme le « Chemical Mass Balance » (CMB) et statistique comme la « Positive Matrix Factorization » (PMF). Les résultats ont confirmé l'intérêt de l'ajout des composés organiques à ces méthodologies. Ainsi, le profil industriel et les composés organiques HAPS ont permis de mieux tracer la source appelée génériquement « industrie du carbone » (combustions de charbon, de coke et de matériaux graphitiques) dans les vallées alpines mais aussi sur différents sites urbains français. En parallèle, un modèle de régression non linéaire multivarié (MRNL) a été développé pour la quantification des sources de HAP, basé sur l'utilisation de traceurs spécifiques de source (lévoglucosan, hopanes….) et de données météorologiques (gradient thermique). Son application a été validée sur un ensemble de sites alpins des vallées de l'Arve et de la Tarentaise. Un couplage entre ce modèle et les données de mesures optiques du carbone suie (BC) par aéthalomètre, a permis de proposer une solution aux mauvais résultats de corrélation entre les HAP mesurés et modélisés par le modèle MRNL sur le site de la vallée de la Maurienne. Ces faibles corrélations peuvent être liées à une mauvaise représentativité des composés organiques utilisés à tracer correctement les sources d'émission sur certains sites.Enfin, l'inter-comparaison de ces méthodologies pour la détermination des sources de HAP et plus particulièrement de la source industrielle permet de valider cette méthodologie dans une perspective opérationnelle de suivi des sources de HAP sur ces différents sites. Ces travaux réalisés au cours de cette thèse mettent en évidence l'intérêt de la caractérisation de la fraction organique des PM et les biais qui peuvent exister sur l'utilisation des composés organiques pour l'étude des sources d'émissions. Des alternatives y sont proposées afin de soulever ces ambiguïtés et d'améliorer l'étude des sources de HAP par les modèles récepteurs

Effect of energy renovation on indoor air quality and thermal environment in winter of a primary school in a highly polluted French alpine valley

International audienc

Nickel-Manganese Catalysts as Biomimics of the active site of NiFe hydrogenases: a Combined Electrocatalytical and DFT Mechanistic Study

International audienc

The N stable isotopes from particulate ammonium nitrate: understanding of the atmospheric processes and the sources of PM10 in France

Aerosol nitrate is an important fraction of the mass of the fine particles (PM) in atmosphere. Moreover, aerosol nitrogen species are predominantly anthropogenic over Europe (traffic, industry and farming). In the view of the increasingly drastic constraints of the European air quality standard for PM, the understanding of these sources has become crucial in France. Indeed, during the months of March and April, several high concentration of PM are observed on a large scale throughout the national territory. During these specific events, the ammonium nitrate (NH4NO3) is a predominant component of the airborne PM. There are two main ways that produces NH4NO3 in air with many precursors as NH3 from specific primary sources (agricultural activity). The presence of these species in PM is the result of complex primary and secondary processes which are always investigated. In literature, many studies propose the nitrogen stable isotope ratio (?15N) of NOx as an indicator for NOx source apportionment ((Walters, Goodwin, et Michalski 2015; Felix, Elliott, et Shaw 2012) but there is a lack of information regarding the ?15N ratio of NH4. Thus, these last two years, the main objectives of the INAC and INCAS-2 programs were to collect various samples from ambient rural (2 sites) and urban (5 sites) background sites in order to quantify the nitrogen isotope ratio of nitrate and ammonium in PM. Then, subsequently the characterization of emissions of the different types of samples (traffic, biomass burning, and agriculture activity) was performed to provide clear information between the nitrogen isotope ratio and the sources. Currently, this study represents the most important French database (long-term and source data) on ?15N composition of particulate ammonium nitrate in PM. The first results show that ?15N-NOx has a high seasonal variability which is relatively difficult to interpret as the impact of the specific sources. Whereas, the ?15N of NH4 seems to contain information about the pollution sources. Indeed, this isotope composition appears to be negatively correlated with particulate NH4NO3 events on several sites as described on Figure 1 (urban site, Grenoble). We observed that the values of ?15N-NH4 ranged from 10‰ to 25‰ in large part of years and decreased significantly toward negative values during these periods of peak agricultural activity. Based on these first results, source apportionments of PM10 collected over one years at each sampling sites were conducted with Positive Matrix Factorization (US EPA PMF v5.0) and Multilinear-Engine (ME-2 SoFI from PSI). In this work, the interest to include such isotope measurements as input data for PMF will be discussed for the first time, focusing on their application to identify specific source of ammonium nitrate in PM

Nitrogen's stable isotopes as a proxy to determine ammonium sources in PM using a Monte Carlo's simulation

During cold periods (from November to April) in France, PM concentrations regularly exceed the standard prescribed 50 μg.m-3 limit, which about 50 % in mass is composed on ammonium nitrate (NH4NO3) (Rouïl et al. 2015). The continental scale of such events is a threat to human health and decrease significantly the quality of our environment. The ammonium (NH4 +) is suspected to come from different sources, especially from the agricultural ammonia (NH3) but there is no direct evidence of it. The INACS program aims to investigate the sources proportion in the PM using several methods. This work tries to distinguish and quantify the source apportionment using nitrogen stable isotopes from ammonium nitrate in the PM since previous studies (Felix et al. 2014) highlighted the high level of correlation between the NH4 + concentration and the δ15N of NH4 +. From 2011 to 2013, PM were collected at 7 stations in France at daily sampling rate. δ15N of NH4 + was measured at these sites, ranging from ambient rural to urban background. Besides these isotopic measurements on ambient aerosol samples, the isotopic characterization of different emissions sources (traffic, biomass burning, and agricultural activities) was performed to obtain their specific source isotopic signatures. To the best of our knowledge, this database constitutes probably the most extensive dataset studied so far, with more than 500 δ15N of NH4 + aerosols' observations. In order to take into account the isotopic variability of the sources, a stochastic Monte Carlo's simulation (MCS) was conducted. This approach has in the past demonstrated its applicability for source apportionment method (Sheesley et al. 2011). Applying MCS to our dataset gives a probability distribution function (PDF) for each source and observation day as shown in Fig. 1 for the 2nd March 2013 in a French rural background site..

A nickel–manganese catalyst as a biomimic of the active site of NiFe hydrogenases: a combined electrocatalytical and DFT mechanistic study

International audienceThe dinuclear nickel–manganese complex [Ni(xbsms)Mn(CO)3(H2O)]+ (H2xbsms = 1,2-bis(4-mercapto-3,3-dimethyl-2-thiabutyl)benzene) is reported as a bio-inspired mimic of the active site of NiFe hydrogenases catalyzing hydrogen evolution from trifluoroacetic acid in DMF with an overpotential requirement of 860 mV. This is higher than that displayed by Ni–Ru systems [Canaguier et al., Chem.–Eur. J., 2009, 15, 9350–9364] but similar to that found for related noble metal free Ni–Fe mimics [Canaguier et al., Chem. Commun. 2010, 46, 5876–5878]. A combined electrochemical and theoretical (DFT) study suggests a heterolytic mechanism for hydrogen evolution from a hydride derivative. The structure of the active intermediate, with a bridging hydride ligand between Ni and Mn, resembles that of the Ni–C active state of NiFe hydrogenases

Relevance of CO2-based IAQ indicators: Feedback from long-term monitoring of three nearly zero-energy houses

International audienceThere are a large number of indicators that use CO2 concentration as parameter to assess air stuffiness and, consequently, to asses IAQ. Their comparison is difficult since they are not usually linked to each other. The aim of this article is to compare the results of 10 CO2-based IAQ indicators and determine if they classify a house in a similar way during heating seasons. We propose a method to normalize the results based on the reference values of each indicator, and we highlight the sensitivity of the indicators to the choice of one occupancy scenario among several possibilities. The database used contains the CO2 concentration measured over 2–3 years in the living room and the parental bedroom of three new and occupied nearly-zero energy houses in France (COMEPOS project) with low-cost probes sampling every minute. The results indicate that the IAQ of the same house in the same heating season can be classified differently depending on the indicator and threshold chosen. Moreover, an indicator can show different results for the same room over the years. For example, the IAQ of the bedroom of House 2 is classified poor in 2017 and 2019 but good in 2018 according to the mean CO2 concentrations with a 1000-ppm threshold. The indicators also present different levels of sensitivity to occupancy scenarios, being the cumulative exposure the most sensitive by increasing up to 257% without an occupancy scenario, which highlight the importance of the systematic implementation of a standard occupancy scenario for the CO2-based IAQ performance indicators

Répartition et quantification des sources de HAP en vallées alpines par des composés organiques soufrés : impact industriel ?

National audienc