Étude de la dilution des aérosols de NaCl et du gaz traceur CO2 : application à l'échantillonnage des poussières de polissage des granites

Abstract

The use of sodium chloride aerosols (NaCl) or tracer gas (CO2) is a laboratory routine for the general study of aerosol behavior, ventilation dust, and filters performance while preserving the health and safety of persons. It is used to analyse the emission, the dispersion and the dilution of particles emitted during industrial processes and to reduce the high costs associated to field measurements. In this case, the present research focuses on a cylindrical diluter (with constant volume) which use controlled NaCl aerosols and tracer gas CO2 to identify the maximum dilution factor for sampling high concentrations. The study show that the maximum dilution factor is 5 for the diluter used and this parameter is applied to dust sampling during the polishing tape of two granite samples contain 10% and 50% silica, The maximum dilution factor is largely influenced by clean air injection flow and the polluted air injection flow. The applied dilution factor allowed us to reconstruct the primitive concentrations spectrums which is initially damaged by the overflow reading during high dust concentrations (over 400 mg/m3). The maximum dilution factor 5 applied to PM2.5 dust sampling allowed the normal operation of DUSTTRAK photometer and clearly differentiate emission level between "white" granite and "black" granite. In that case, the "total" dust of "white" granite are approximately 60,000 mg/m3 while those of "black" granite are approximately 40,000 mg/m3 under the same polishing conditions and sampling. This was not the case for dust sampling without dilution. These two level indicators combined with silica proportions of the two materials pollution show that the exposure of the worker could spend doubled when varying the shade of granite polishing workshop. This leads us to recommend extremely efficient means to capture the "white" granite dust.

Date	7 Aug 2014
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Victor Songmene (Supervisor) & Ali Bahloul (Co-supervisor)