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  1. Physicochemical characterisation of diesel exhaust particles : Factors for assessing biological activity.

    Article - En anglais

    A range of microscopy and analytical techniques have been used to investigate the physicochemical properties of diluted DEP (diesel exhaust particles) that may be important in determining its biological activity.

    Transmission electron microscopy demonstrated four basic categories of particle morphology :

    • (1) « spherulites » (individual particles) ;

    • (2) « chains » or « clusters » of spherulites ;

    • (3) « spherules », (large bodies of spherulites) ;

    • (4) « flake-like bodies ».

    Image analysis of TEM photomicrographs determined empirical morphological parameters (30 nm mean spherulite diameter, aspect ratio 1.5, mean particle area 0.078 mum, equivalent spherical diameter 0.23 mum, roundness 2.76) and derived parameters (0.313 mum2 surface area, 3.7 mum2 pg surface area per mass and 0.042 mum3 volume) of DEP.

    Distributions of the particle sizes by number showed 10.1% were ultrafine (<0.1 mum), 89.5% fine (0.1-2.0 mum), 0.4% coarse (>2.5 mum), but distributions based on a mass value were different (0.01% ultrafine ; 52.6% fine, 47.4% coarse).

    In contrast, impacted DEP contained 60.87% ultrafine, 39.13% fine and 0% coarse particles by number.

    Field emission scanning electron microscopy of spherulites revealed smooth surfaces and flocculated spherules with large surface areas.

    Electron probe X-ray micro-analysis demonstrated the presence of C, O, Na, Mg, K, Al, Si, P, S, Cl, Ca along with a range of metals (Ti, Mn, Fe, Zn, Cr), that were heterogeneous in distribution. (...)

    Mots-clés Pascal : Zone urbaine, Trafic routier urbain, Véhicule à moteur, Moteur diesel, Gaz échappement, Particule en suspension, Aérosol, Emission polluant, Pollution air, Caractérisation, Propriété physicochimique, Morphologie, Propriété surface, Distribution dimension particule, Analyse chimique, Analyse élémentaire, Microscopie électronique transmission, Microscopie électronique balayage, Microscopie émission champ, Analyse image, Diffraction RX, Microanalyse, Microsonde électronique, Rayon X, Spectrométrie ICP, Spectrométrie émission atomique

    Mots-clés Pascal anglais : Urban area, Urban road traffic, Motor vehicle, Diesel engine, Exhaust gas, Suspended particle, Aerosols, Pollutant emission, Air pollution, Characterization, Physicochemical properties, Morphology, Surface properties, Particle size distribution, Chemical analysis, Elementary analysis, Transmission electron microscopy, Scanning electron microscopy, Field emission microscopy, Image analysis, X ray diffraction, Microanalysis, Electron microprobe, X ray, Inductive coupling plasma spectrometry, Atomic emission spectroscopy

    Logo du centre Notice produite par :
    Inist-CNRS - Institut de l'Information Scientifique et Technique

    Cote : 99-0168188

    Code Inist : 001D16C04C. Création : 16/11/1999.