Metrological stakes in the monitoring of air quality : PAH example in France

International audienceLa surveillance de la qualité de l'air représente un enjeu considérable pour prévenir et réduire les effets des polluants sur la santé humaine et l'environnement. Le Laboratoire Central de Surveillance de la Qualité de l'Air, créé par le Ministère chargé de l'environnement vise à apporter un appui technique au dispositif national de surveillance de la qualité de l'air en France, en particulier dans le cadre de la mise en oeuvre des Directives européennes. Le développement d'une stratégie nationale de surveillance des HAP est une des missions du LCSQA depuis plusieurs années, avec l'accompagnement d'un programme pilote, qui vise à mieux connaître les niveaux de concentration dans l'air ambiant, à définir et valider des stratégies de prélèvement et d'analyse, à quantifier les incertitudes et à évaluer les coûts

Sampling and analysis of PAH and oxygenated PAH in diesel exhaust and ambient air

Polycyclic Aromatic Hydrocarbons (PAH) and their oxygenated derivatives occur in particles or in the vapour phase in the atmosphere. Some of these compounds, particularly the PAH, are known as strong carcinogens and/or mutagens. Emissions from diesel engines are an important source of these contaminants in urban air. In this work, the chemical composition of diesel particles was studied from two different perspectives: the gaz/particule partitioning and the different size fractions of these compounds. A dilution tunnel, with a diesel car connected, was built for the purpose of this study. Measurements were carried out near a motorway in Paris for comparison to the tunnel test results. The results show, firstly, that the gaseous phase of the PAH is predominant (up to 20 times) with respect to the particulate phase, and that the PAH and their derivatives are mainly adsorbed in the very fine particulate fraction (for particle size under 0.4 urn). Secondly, the oxygenated PAH, neglected in the majority of previous studies, are predominant with respect to the PAH

Caractérisation des dérives du benzo[a]pyrène (B[a]P) en atmosphère réelle et en laboratoire

National audiencePolycyclic Aromatic Hydrocarbons (PAH) are emitted by all the combustion sources and are present in both the particulate and the gas phases. Since they are potentially carcinogenic and/or mutagenic they have been widely studied. Benzo[a]pyrene (B[a]P) have been chosen as a tracer for PAH because of his toxicity. It is mostly present in the particular phase (90%). Very reactive, it can be oxidized to form nitrated and oxygenated by-products which can be more toxic than B[a]P itself. These reactions can occur in the air and/or on the sampling support. The purpose of this work is to determine the major place of reaction, to identify the oxidizing species responsible for these degradations and by-products formation, for a better B[a]P quantification. Field campaign and reactor tests will allow to identify the reaction products and oxidants, to determine the major place of degradation, to improve B[a]P monitoring. Analytical and sampling methods will be described. The analysis of filters sampled with an impactor will be presented.Les Hydrocarbures Aromatiques Polycycliques (HAP) sont des composés émis sous forme gazeuse et particulaire, lors de combustions incomplètes. Ces composés potentiellement cancérigènes et/ou mutagènes sont réglementés. C'est le benzo[a]pyrène (B[a]P) qui a été choisi comme traceur pour cette famille de composé par la IVème directive fille européenne (2004/107/CE), en raison de sa forte toxicité. Ce composé qui est présent à plus de 90% en phase particulaire est très réactif. Il peut réagir avec la plupart des oxydants gazeux pour former des composés nitrés et oxygénés qui peuvent potentiellement être plus toxiques que le B[a]P lui-même. Ces réactions peuvent avoir lieu dans l'air (en amont du prélèvement) et/ou sur le support de prélèvement. Le but de l'étude est de déterminer le lieu de réaction majoritaire, puis d'identifier les espèces oxydantes responsables de ces dégradations, ainsi que les produits formés, afin de proposer des solutions permettant de mieux quantifier le B[a]P. Pour cela, une étude de terrain couplée à des tests en réacteur permettront dans un premier temps, d'identifier les produits de réactions et les oxydants, puis de déterminer le lieu majoritaire de dégradation. La méthode analytique, ainsi que les méthodes de prélèvements seront décrits. Les résultats présentés sont issus de filtres prélevés avec un impacteur en cascade

Polycyclic aromatic hydrocarbons (PAHs), nitrated PAHs and oxygenated PAHs in ambient air of the Marseilles area (South of France) : concentrations and sources

International audienceAmbient measurements (gas + particle phases) of 15 polycyclic aromatic hydrocarbons (PAHs), 17 nitrated PAHs (NPAHs) and 9 oxygenated PAHs (OPAHs) were carried out during July 2004 on three different sites (urban, sub-urban and rural) in the region of Marseilles (South of France). Atmospheric concentrations of these classes of polyaromatics are great of interest because of their high potential mutagenicity and carcinogenicity. OPAH concentrations were of the same order of magnitude as those of PAHs while NPAH concentrations were one to two orders lower. 9-Fluorenone and 9,10-anthraquinone were the most abundant OPAHs, accounting for about 60% and 20% of the total OPAH concentration. Respectively 1-and 2-nitronaphthalene were the most abundant NPAHs and were accounting for about 30-50% and 15-30% of the total NPAH concentration. NPAHs and OPAHs concentration levels were consistent with the characteristics of the sampling sites. Study of source specific ratios (2-nitrofluoranthene/1-nitropyrene) clearly showed those primary NPAH sources influence the urban and sub-urban sites whereas production of secondary NPAHs by gas phase reactions was prevalent at the rural site. The study of NPAH and OPAH sources suggested that gasoline engines were an important source of such compounds Whereas the dominant source of 1-nitropyrene, 2-nitrofluorene, 6-nitrochrysene and benz[a]anthracene-7,12-dione seems to be diesel vehicles. Finally, 9,10-anthraquinone presents a double origin: primary diesel emission and photochemical processes. Formation of 9,10-anthraquinone from anthracene ozonation was shown at the rural site. Further investigations will be necessary in order to discriminate when (before or during the sampling) the OPAHs are formed

Sampling precautions for the measurement of nitrated polycyclic aromatic hydrocarbons in ambient air

International audienceBecause of the toxicity of polycyclic aromatic hydrocarbons (PAHs) and of their oxidation products, such as nitrated and oxygenated PAHs (NPAHs and OPAHs), the determination of their concentrations is of great interest in terms of atmospheric pollution control. Then, normalisation of sampling procedures appears essential. In this context, this paper presents a comparison of particulate PAH, OPAH and NPAH concentrations determined with two different samplers (cascade impactor and conventional high volume sampler) installed in parallel during several field sampling campaigns carried out under different environmental conditions. For winter and summer periods, the PAH and OPAH concentrations determined with both sampling systems were considered as equivalent. In the summer period, NPAH concentrations quantified with both sampling devices were similar whereas in the winter period, the conventional high volume sampler underestimated their concentrations by a factor of 3-4. This underestimation was observed in the same proportion for all the 17 quantified NPAHs. Analytical error, NPAH formation during the sampling and NPAH degradation by reaction with gaseous oxidants associated to sampling methodology were unable to explain such differences between both samplers used in parallel. A probable hypothesis is that the heating of the PM10 head of the high volume sampler in the winter period generates an increase of the internal sampler temperature that could intensify the chemical degradation of the NPAHs inducing the underestimation of their concentrations in the atmosphere. Further investigations will be necessary to confirm the importance of the temperature on the chemical degradation of these compounds and to understand the different behaviour of PAHs and OPAHs. Consequently, we suggest using oxidant scrubber to prevent chemical degradation of PAHs and derivatives during their sampling. Moreover, we advise against the heating of the sampling head which could induce an increase of these reactions of degradation especially for NPAHs

Impact of residential wood burning on indoor air quality

International audienceThis study aims at characterizing indoor air quality in single family dwellings burning wood regularly, studying the air change rate during wood burning and analyzing impact on outdoor air. Field investigations were performed, in February and November 2007, in six occupied houses located in rural areas (two equipped with an opened fireplace, two with respectively an old closed fireplace and a recent one, and two with respectively an old woodstove and a recent one). Continuous measurements of air temperature, relative humidity, carbon monoxide, nitrogen oxides, polycyclic aromatic hydrocarbons (PAHs) were performed in the room equipped with the wood burning appliance. Moreover in this room and in the main bedroom, PM10 and PM2.5, PAHs (on PM10 fraction), volatile organic compounds (VOCs), aldehydes, ketones, and tracers of wood combustion such as levoglucosan and methoxyphenols on PM10 fraction, were also measured. Air exchange rates and building permeability were characterized through different means

Les impacts de la pollution de l’air

C’est la mise en évidence des effets induits par la pollution atmosphérique qui permet, grâce à une prise de conscience collective, la mise en place de politiques publiques visant à protéger les cibles de la pollution, à savoir la santé humaine et l’environnement, ou, plus largement, les écosystèmes dans leur ensemble. Des nombreuses études nationales et internationales permettent de mieux comprendre les mécanismes d’action de la pollution atmosphérique sur la santé humaine, mais également de chiffrer le nombre de personnes exposées à celle-ci. Les connaissances sur l’impact de la pollution atmosphérique sur les écosystèmes naturels et agricoles évoluent également et sont sous surveillance, notamment en Europe. En plus des effets observés sur les différents milieux, la pollution atmosphérique a également des conséquences économiques importantes. Enfin, le changement climatique et la pollution de l'air sont étroitement liés. Ainsi, il est nécessaire d’identifier les actions de réduction des émissions s’avérant cobénéfiques dans les deux cas

Caractérisation chimique de la fraction polaire des particules dans l’air ambiant

Several studies on the toxicity of particles in ambient air show that the polar phase, which contains the oxygenated and nitrated polycyclic aromatic hydrocarbons (OPAHs and NPAHs), is more toxic than the aromatic fraction containing the PAH. In that context, the objective of our study was to chemically characterise the NPAHs and OPAHs in ambient air at various sites (traffic, urban, suburban, rural and altitude). Samplings were performed within the framework of the French research program POllution des Vallées Alpines (POVA) during the winter 2002-2003 and the summer 2003 and in the area of Marseilles in summer 2004. Both, ambient air particulate and gas phases were sampled and particle size distribution was also studied. The results obtained contribute to increase the data base on these compounds. First, we developed an analytical method for the simultaneous quantitative determination of NPAHs and OPAHs in complex environmental matrices, using GC/NICI-MS. Results from the field campaigns show that OPAH concentration levels were of the same order of magnitude as PAHs while NPAH concentrations were one to two orders of magnitude lower. The corresponding carcinogenic risk for NPAH was estimated using toxic equivalent factors (TEF). NPAHs could contribute to 20% of the total risk. No TEF were found for OPAH, which leaves entire the question of the risk they pose. Study of source specific ratios clearly showed that these compounds have a primary origin at the sites close to the sources of pollution whereas the production of secondary NPAHs by gas phase reactions was prevalent at the rural sites far from the direct sources of pollution and initiated by OH (daytime reactions). The study of NPAH and OPAH sources suggested that gasoline engines were an important source of such compounds. The OPAH 9,10-anthraquinone presents a double origin: primary diesel emission and photochemical processes. The fraction of PAHs, OPAHs and NPAHs associated with the particle phase was strongly depending on their vapour pressure and the ambient temperature. Sources of these compounds take a part in their gas/particle partitioning which can bring information on their primary or secondary origin. Finally, during both winter and summer, PAHs, OPAHs and NPAHs were mainly associated with fine particles (Dp<1.3 μm). The differences of chemical properties of the classes of compounds (polarity…) could account for their particle size distribution.Les particules atmosphériques contiennent de nombreux composés organiques toxiques adsorbés à leur surface. Parmi eux, les Hydrocarbures Aromatiques Polycycliques (HAP) émis lors des combustions incomplètes ou de la pyrolyse de la matière organique et des combustibles fossiles, ont des propriétés cancérigènes et/ou mutagènes avérées. Cependant, les produits d’oxydation de ceux-ci, les HAP nitrés (NHAP) et oxygénés (OHAP), semblent plus toxiques que leurs HAP parents, car certains d’entre eux ont été identifiés comme ayant un caractère mutagène direct. Les NHAP et les OHAP sont formés soit, durant le processus de combustion, soit par réaction dans l’atmosphère en phase gazeuse et hétérogène entre les HAP, l’ozone, et les oxydes d’azote initiés par le radical OH ou NO3. Malgré leur caractère hautement toxique, les dérivés polaires des HAP dans l’atmosphère font l’objet de très peu de publications. Le nombre d’études concernant leur formation, leur sources ainsi que leur caractérisation dans l’air ambiant est limité. Ainsi, l’objectif général de ce travail réalisé à l’INERIS était de caractériser chimiquement les NHAP et OHAP dans différents milieux de l’air ambiant : trafic, urbain, péri-urbain, rural et altitude. La répartition entre les phases gazeuse et particulaire de ces composés, leur répartition en fonction de la taille des particules mais aussi leur origine (primaire ou secondaire) ont été étudiées. Ce travail a été réalisé en collaboration avec le Laboratoire de Physico et Toxico-Chimie des systèmes naturels (LPTC) et le Laboratoire de Physico-Chimie Moléculaire (LPCM) de l’Université de Bordeaux 1, notamment en ce qui concerne la réactivité des HA

Mise au point d’une nouvelle méthode de prélèvement pour l’analyse des composés organiques semi-volatils

It is now recognised that indoor environments contribute significantly to human exposure to airborne pollutants. Among the chemicals released in indoor environments, some of them have been identified as hormonally active or carcinogens. The objective of this study has been to develop an analytical method based on thermal desorption (TD) for the measurement of semivolatile organic compounds (SVOCs) to be use for indoor and personal measurements. The sampler consists of a small PM2.5 impactor upstream of a sample tube filled with the adsorbent Tenax TA to collect the particulate and gaseous phases respectively. The experimental work focused on the development of a vapour generation system, the development of the analytical method for the analysis of both the gaseous and particulate phases and the evaluation of the performance of the developed method. The analytical method was developed for 16 PAHs, 6 OPAHs, 5 phthalates, 2 organophosphate esters, 3 alkylphenols and 5 pesticides. Its applicability for PAHs measurements was verified with a standard reference material and by comparison of indoor air filter strips analysed by the TD method and a conventional solvent extraction method. The TD method was shown to be quantifiable for PAHs up to benzo[a]pyrene but less effective for less volatile PAHs. A small demonstration study consisting of twenty four hours indoor and personal measurements was carried during six days. The results obtained in this demonstration study were in agreement with most previous studies reporting indoor heavy PAHs concentrations lower or similar than outdoor PAHs concentrations and light PAHs concentrations higher indoors than in outdoor environments. This demonstration study also confirmed that phthalates and organophosphate esters are ubiquitous in indoor environment.Il est maintenant reconnu que l’air intérieur contribue à l’exposition individuelle aux polluants atmosphériques de façon très significative. Le temps passé dans les environnements intérieurs est largement supérieur à celui passé à l’extérieur, de plus, certaines sources de pollution y sont spécifiques. Parmi les nombreux composés identifiés dans les environnements intérieurs plusieurs sont considérés comme toxiques voire cancérogènes. Parmi les sources de polluants spécifiques aux environnements intérieurs on peut citer : la combustion (fioul, gaz, charbon, bois, tabac), les matériaux de construction et de décoration (peintures, bois aggloméré, colle), les détergents, les produits d’entretien. À ces sources se rajoutent bien évidemment les sources de pollution extérieure. Les différentes substances organiques ainsi présentes peuvent être classées dans quatre catégories distinctes, afin de faciliter leur identification et leur caractérisation : • les composés organiques très volatils, • les composés organiques volatils (COV), • les composés organiques semi-volatils (COSV), • les composés organiques particulaires (adsorbés sur les particules présentes dans l’air). Par ailleurs, l’utilisation des appareils de mesure portatifs se développe pour caractériser l’exposition individuelle de manière globale, en intégrant les différents lieux de vie et les déplacements. Cependant, si des appareils portatifs de mesure pertinents sont disponibles sur le marché, d’une part pour les polluants gazeux, et d’autre part pour les particules, les appareils disponibles pour la mesure de COSV ne permettent pas d’atteindre les limites de détection suffisantes pour appréhender les expositions individuelles, alors qu’il s’agit parfois de substances représentant des potentiels de risques sanitaires préoccupants. Dans ce contexte, l’objectif de la présente étude était de s’intéresser à la mesure des COSV, qui se trouvent, par définition, à la fois en phase gazeuse ou en phase particulaire (tension de vapeur de 10-2 à 10-8 kPa)

Simultaneous analysis of oxygenated and nitrated polycyclic aromatic hydrocarbons on standard reference material 1649a (urban dust) and on natural ambient air samples by gas chromatography-mass spectrometry with negative ion chemical ionisation

International audienceThis study deals with the development of a routine analytical method using gas chromatography-mass spectrometry with negative ion chemical ionisation (GC/NICI-MS) for the determination of 17 nitrated polycyclic aromatic hydrocarbons (NPAHs) and 9 oxygenated polycyclic aromatic hydrocarbons (OPAHs) present at low concentrations in the atmosphere. This method includes a liquid chromatography purification procedure on solid-phase extraction (SPE) cartridge. Application of this analytical procedure has been performed on standard reference material (SRM 1649a: urban dust), giving results in good agreement with the few data available in the literature. The analytical method was also applied on ambient air samples (on both gas and particulate phases) from the French POVA program (POllution des Vallees Alpines). NPAHs concentrations observed for a rural site during the Winter period are about 0.2-100.0 pg m(-3) in the particulate phase and about 0.0-20.0 pg m(-3) in the gas phase. OPAHs present concentrations 10- 100 times higher (0.1-2.0 ng m(-3) and 0.0-1.4 ng m(-3) for the particulate and the gas phases, respectively). These preliminary results show a good correlation between the characteristics of the sampling site and the compound origins (primary or secondary)