Toxicity of fine and quasi-ultrafine particles: focus on the effects of extractable and non-extractable matter fractions

Air pollution represents today one of the major risk factors for human health. An important part of this threat is due to the presence in the atmosphere of fine particulate matter (PM$_{2.5}$). PM$_{2.5}$ forms a heterogeneous mixture of inorganic pollutants (metals, ions…), organic pollutants (volatile organic compounds (VOC), polycyclic aromatic hydrocarbons (PAHs), dioxins, polychlorobiphenyls (PCBs)…), and biological contaminants (pollen, bacteria, fungi…). To date many studies have demonstrated the toxicity of PAHs and some metals, but so far, no study has been able to clearly attribute the toxicological effects observed to a class of pollutants. Therefore, this study aims to determine the physicochemical characteristics of PM$_{2.5-0.3}$ and PM$_{0,3}$ and to compare the toxicity of native PM$_{2.5-0.3}$, organic fractions of fine (EOM$_{2.5-0.3}$) and quasi ultrafine particles (OEM$_{0.3}$), and PM$_{2.5-0.3}$ freed from this organic fraction (dPM$_{2.5-0.3}$) on BEAS-2B cells in culture. Fine and quasi-ultrafine particles were sampled in the southern suburb of Beirut, Lebanon. Chemical characterization showed that quasi-ultrafine particles were about 40 times more concentrated in PAHs than fines one suggesting a significant influence of anthropogenic activities and combustion sources (industries, road traffic and electric generators) on the emission of quasi-ultrafine particles. The influence of combustion sources was confirmed by investigation of PAHs diagnostic ratios. In addition, BEAS-2B cells exposed to PM$_{2.5-0.3}$, dPM$_{2.5-0.3}$, EOM$_{2.5-0.3}$ and EOM$_{0.3}$ lead to different results concerning metabolic activation of PAHs pathway and proteins expression of biomarkers implicated in the pathway of genotoxicity. Globally, EOM$_{0.3}$ was the most inducer for phase I and phase II enzymes implicated in the metabolic activation of PAHs (AhR, AhRR, ARNT, Cyp1A1, Cyp1B1, EPHX-1, GSTA-4) and EOM$_{0.3}$ induced DNA damage, felt by ATR and followed by a cascade of protein phosphorylations contributing to the cell cycle arrest (P21 and P53 induction)

Unusual presentation of neuralgic amyotrophy with impairment of cranial nerve XII

International audienceno abstrac

Les Mystères urbains: Anthologie

International audienceLe but de cette anthologie en ligne est de rendre plus accessibles et plus visibles les différents "mystères" publiés dans le monde suite au succès médiatique des "Mystères de Paris" d'Eugène Sue. Les contributeurs proposent une présentation de l'œuvre comprenant notamment un récit des conditions de sa genèse, une analyse de son histoire éditoriale, une brève sociobiographie de l'auteur, un résumé synthétique de l'œuvre et surtout quelques pistes de réflexion sur la place de l'œuvre dans l'histoire littéraire nationale et dans le paysage mondial tel qu'il est défini par la circulation internationale des mystères

Les Mystères urbains: Anthologie

International audienceLe but de cette anthologie en ligne est de rendre plus accessibles et plus visibles les différents "mystères" publiés dans le monde suite au succès médiatique des "Mystères de Paris" d'Eugène Sue. Les contributeurs proposent une présentation de l'œuvre comprenant notamment un récit des conditions de sa genèse, une analyse de son histoire éditoriale, une brève sociobiographie de l'auteur, un résumé synthétique de l'œuvre et surtout quelques pistes de réflexion sur la place de l'œuvre dans l'histoire littéraire nationale et dans le paysage mondial tel qu'il est défini par la circulation internationale des mystères

Secondary organic aerosol formation from the gas-phase reaction of guaiacol (2-methoxyphenol) with NO3 radicals

International audienceMethoxyphenols are oxygenated aromatic compounds emitted by wood combustion (consequently to the pyrolysis of lignin). The atmospheric reaction of nitrate radical (NO3) with guaiacol (2-methoxyphenol), one of the principal representatives of this class of compounds has been investigated in the dark at (294 ± 2) K, atmospheric pressure and low relative humidity (RH < 2%). The formation of secondary organic aerosols (SOAs) has been studied in two simulation chambers. The concentrations time profiles of guaiacol were followed with a PTR-ToF-MS (Proton Transfer Mass Reaction – Time of Flight – Mass Spectrometer) and those of SOAs by an SMPS (Scanning Mobility Particle Sizer). Aerosol yields (Y) were calculated from the ratio of the suspended aerosol mass concentration corrected for wall losses (M0), to the total reacted guaiacol concentration assuming a particle density of 1.4 g cm−3. The aerosol yield increases as the initial guaiacol concentration rises, leading to yield values ranging from 0.01 to 0.21. A very good agreement was observed between the experiments performed in both chambers which gives confidence in the data obtained in this study. The organic aerosol formation can be represented by a one-product gas/particle partitioning absorption model with a stoichiometric coefficient α = 0.32 ± 0.04 and an equilibrium constant K = (4.2 ± 1.0) × 10−3 m3 μg−1. The chemical composition of the aerosols formed was studied after sampling on quartz fiber filter, ultrasonic extraction and analysis by ESI-LC-QToF-MS-MS (ElectroSpray Ionization - Liquid Chromatography - Quadrupole - Time of Flight – Tandem Mass Spectrometry). The oxidation products observed in the condensed phase are mostly nitro-aromatics; they display chemical structures with one, two and three aromatic rings. A reaction mechanism leading to these products has been proposed. To our knowledge, this work represents the first study on the SOAs formation from the reaction of guaiacol with NO3 radicals

Les Mystères urbains: Anthologie

International audienceLe but de cette anthologie en ligne est de rendre plus accessibles et plus visibles les différents "mystères" publiés dans le monde suite au succès médiatique des "Mystères de Paris" d'Eugène Sue. Les contributeurs proposent une présentation de l'œuvre comprenant notamment un récit des conditions de sa genèse, une analyse de son histoire éditoriale, une brève sociobiographie de l'auteur, un résumé synthétique de l'œuvre et surtout quelques pistes de réflexion sur la place de l'œuvre dans l'histoire littéraire nationale et dans le paysage mondial tel qu'il est défini par la circulation internationale des mystères

Study of polycyclic aromatic hydrocarbons, carbon monoxide, nitrogen monoxide and soot emissions from biomass combustion in a wood-fired boiler under varying boiler conditions

International audienc

Thermochemical recovery of waste wood in a domestic wood stove: influence of the geometry of wood batch in the fireplace on pollutant emissions

In the current energy context, pallet boards represent a wood of opportunity strongly used on an individual scale as a means of heating at a low cost. However, French stoves are certified to burn only hardwood species. The main objective of this work is to study the combustion behavior of pallet boards in a commercial stove designed to burn hardwood. The novelty of this work lies in the study of the influence of the wood surface exposed to fire and the identification of the conditions that promote the production of ultrafine particles. The results of the combustion tests show that the surface exposed to the fire influences the combustion. Of the six wood dispositions tested, two stand out with gaseous and particulate emissions at similar levels of a conventional hornbeam log and a densified log. Low temperature conditions and high levels of unburned gaseous products were identified as promoters of ultrafine particles. Overall conclusion of the study is that it is possible to use pallets in a non-designed stove, provided that the user carefully manages the combustion. This opens the way to the clean and rational use of a new type of fuel in a low carbon circular economy.</p

Wood washing: influence on gaseous and particulate emissions during wood combustion in a domestic pellet stove

International audienceNowadays, the use of biomass increasingly replaces the fossil fuels for the domestic heating production. In order to reduce pollutant emissions from biomass combustion, wood was washed at room temperature in order to represent natural rain leaching before burning in a recent pellet stove (2010s) of nominal output of 6.3 kW. Raw and washed woods were combusted for three different types of wood (oak, beech and fir) and the study focused on their particulate and gaseous emissions (Total Suspended Particles (TSP), Particulate Matter with diameter below 2.5 μm (PM2.5), carbon monoxide (CO), nitrogen oxides (NOx) and Total Volatile Organic Compounds (TVOC)). Polycyclic Aromatic Hydrocarbons (PAH), aldehydes and wood tracers as phenols compounds were also measured. In addition, considering the toxic equivalent factor, the human health impact of adsorbed and gaseous PAH is considerably reduced (96%) in the case of washed fir combustion. Emission factors of CO and TSP for washed wood combustion also show a decrease up to 50% depending on the type of wood used. Furthermore, phenolic compounds, Benzene, Toluene, Ethylbenzene, Xylenes and Trimethylbenzene (BTEXT) emissions can also be reduced by the washing of biomass. Washed oak combustion leads to a clear decrease by 60% of the total of BTEXT. In the case of phenols emissions, phenol shows a significant decrease by 91% during the combustion of washed fir wood

Source contributions to PM10 levels in a coastal area in northern France: a one year study

International audienceThe Hauts-de-France Region is one of the most concerned areas in France by exceedances of the PM 10 daily mean limit value (50 µg.m-3). For a better understanding of these phenomena, the identification as exhaustive as possible of sources contributing to PM10 concentration is an essential step. Numerous studies were performed on the identification of particles from terrestrial sources. The objective of this work is to fill the lack of knowledge about the impact of emissions resulting from the marine compartment. It includes natural emissions such as sea salts [1] and anthropogenic emissions linked to the marine traffic especially in the English Channel, that forms a narrow corridor with one of the greatest concentrations of shipping in the world (up to 800 vessels sailing per day) [2]. PM10 sampling and measurement campaign were performed continuously during one year in 2013 at Cape Gris-Nez, a coastal French site located in front of the Straits of Dover. PM10 levels were measured using MP101 analyzer (Environment SA®) and collected using the DA80 sampler (Digitel®, 30 m 3 /h) on a daily basis. The characterization of PM10 was performed considering major and trace elements, water soluble ions, EC/OC as well as tracers of biomass burning (levoglusan), primary biogenic emissions (arabitol, mannitol) and marine biogenic emissions (methanesulfonate ions). These chemical parameters were used to explain PM10 levels on the coastal site, identify PM10 sources and estimate their contributions. Sources profiles were identified from the use of a Constrained Weighted non Negative Matrix Factorization (CW-NMF) model [3,4]: fresh sea-salts, aged sea-salts, secondary nitrates, secondary sulphates, crustal, biomass combustion, primary biogenic emission, marine traffic, combustion, metal source. The monthly evolution of their contribution evidenced different behaviours between the sources: secondary nitrates were predominant during the cold season and appeared to be the most involved in the PM10 concentration peaks. The impact of marine traffic and a high proportion of aged sea-salts versus fresh sea-salts were mainly evidenced during the summer season. For the year 2013, the mean contribution of the different sources were 37% for sea salts and aged sea-salts, 43% for the secondary inorganic aerosols, 7% for biomass combustion, 5% for marine traffic. This distribution varies highly depending on the period and more particularly during exceedances of daily PM10 limits values