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Dans le cadre d'un projet transdisciplinaire alliant hygiénistes industriels, ergonomes et spécialistes de la métrologie des aérosols dont l'objectif principal était de proposer et tester une approche opérationnelle d'évaluation des expositions professionnelles alliant des phases de mesurage et d'observations de l'activité réelle de travail, des campagnes de mesurages en entreprises ont été effectuées. Nous présentons ici les éléments d'une démarche pour l'analyse des données issue des mesures en temps réel visant à mieux décrire et comprendre les niveaux d'exposition, à des fins d'utilisation épidémiologique ou de prévention., As part of a transdisciplinary project combining industrial hygienists, ergonomists, and specialists in aerosol metrology, whose main objective was to propose and test an operational approach to assess occupational inhalation exposures combining phases of measurement and observations of the actual work activity, field campaigns at workplaces were performed. Here, we present the elements of an integrated approach to analyze real-time measurement data aimed at better describing and understanding exposure levels for epidemiological use or prevention purposes.

Les méthodes dites de dustiness sont de plus en plus reconnues comme pertinentes dans le cadre de l'évaluation a priori des expositions des travailleurs manipulant des nanomatériaux en poudres. Or, dans une volonté de réduction du risque dès la conception des produits (approche « safe-by-design »), il serait intéressant de connaître les relations potentielles liant les propriétés physico-chimiques des poudres aux caractéristiques des aérosols qu'elles peuvent émettre lors d'une sollicitation mécanique. Dans ce travail, nous montrons que les indices de pulvérulence en nombre de quinze poudres nanométriques d'oxydes métallliques déterminés avec la méthode de dustiness Vortex Shaker augmentent avec les surfaces spécifiques des poudres et la diminution de leurs densités bulk. L'humidité de conditionnement des poudres n'affecte pas de manière significative les relations trouvées. La distribution granulométrique des aérosols n'est en revanche pas liées aux propriétés des poudres d'après nos résultats. La surface spécifique et la densité bulk pourraient à l'avenir être considérées dans une approche « safe by design » pour réduire les potentiels d'émission des nanomatériaux en poudres si ces tendances se confirment

The presently available protocol for evaluating the performance of personal aerosol samplers according to the inhalable convention is difficult to satisfy as it requires a large cross-section wind tunnel. The present study was initiated to simplify and reduce the cost of the test method by mounting the test samplers on a small, stationary torso instead of a full-size rotating manikin. The simplified torso consisted of a rectangular three-dimensional body (33 cm wide, 21 cm deep, 21 cm high). Replicates of the personal inhalable aerosol sampler under consideration were attached in the center of each vertical face of the simplified torso representing the three principal sampling orientations (facing the wind, turned 90°, and turned 180° to the wind). When the samplers were mounted on a full-size manikin, the air flow in the vicinity of the manikin was found to depend on the sampler location, symmetry of the manikin, and position of the manikin’s arms. On the simplified torso, the magnitude and direction of the air flow near the samplers were found to be comparable to that of the manikin. When subjected to nearly monodisperse aerosol flows (particle size of 70 μm, wind velocity of 50 and 200 cm s-1), both methods yielded aerosol sampling efficiencies that were statistically not different at three major sampling orientations. The advantages of the simplified torso are that fewer measurements need to be made; a smaller, less expensive wind tunnel can be used for the testing; and interlaboratory variability of personal inhalable samplers’ performance may be decreased.

A new experimental wind tunnel facility for aerosol sampling investigations has been built and its performance evaluated. Subsequently, an experimental methodology using a polydisperse test aerosol of glass beads to measure entry, transmission and overall sampling efficiencies has been developed and tested. The new facility is composed of a horizontal cylindrical pipe of 5 m long and 30 cm in diameter. The measurement zone is located just at the exit, allowing to take benefit of the whole cross-sectional area inside a stabilised aerosol flow. The working air velocity range is 0.5–4.5 m s−1 Air velocity and turbulence profiles are uniform within 10%. Turbulence in the working section is controlled with a square mesh grid. The test aerosol is generated by a fluidized-bed generator and dispersed into the clean air flow upstream of the horizontal part. Generated particles are within a size interval extending from a few μm to about 80 μm in aerodynamic diameter. Tests of time and space stability of the test aerosol in the working section were carried out. They have shown a reasonably uniform spatial distribution and time stability considering the size range of generated particles. The experimental method allows to obtain, simultaneously with the same technique entry, transmission, and overall sampling efficiencies of samplers from several μm up to 70 μm in particle aerodynamic diameter with a good accuracy. It is based on the measurement of the distribution of particle number concentration vs particle aerodynamic diameter of deposited and sampled aerosols in a reference probe and in the test sampler. To evaluate both the new wind tunnel facility and the methodology, measurements of the different efficiencies were achieved using a cylindrical sharp-edged thin-walled probe as a test sampler. This evaluation was performed in three steps. At first, the reproducibility of transmission efficiency measurements of the probe working in isokinetic conditions was determined. It appears fairly good between 10 and 70 μm in particle aerodynamic diameter. Then, the methodology was applied to the assessment of the aspiration efficiency of a probe working in subisokinetic conditions. Finally, a consistency test of the data was proposed and applied to our data; it consists in comparing the mass fractions of collected samples (deposited on the internal sampler walls, collected onto filters) calculated from the efficiency data and the distributions of particle concentrations, with those which are directly recovered after each experiment and weighed. This test yields an indicator of the quality of the whole efficiency data set.