Aerosol sampling techniques using TEM grids
Résumé
Non-intentional nanoparticle (NP) may occur in aerosol production process. Occupational safety and environment protection associated with the nano-aerosol exposureare serious issues. Nano-aerosol measurement is a key point to characterize NP exposure. Transmission electron microscopy (TEM) is the only technique for gaining sizes distribution and individual particle analysis. However, observation with techniques allowing sampling on TEM grids is crucial to aerosol analysis. There is a need to develop sampling devices that will make possible aerosol speciation and quantification according to class sizes for efficient characterization. Make the measurements quantitative when sample aerosol and analyse particles on TEM grids using MPS developed by INERIS both through experiments and modelling is important. Assess the sampling efficiency and optimize the set up based on TEM analyses technique are the main work. Aerosol generators, mini particle sampler (MPS) and scanning mobility particle sizer (SMPS) are carried out to evaluate the sampling efficiency. In this way measurement and analysis can be carried out at real time. Three set up method plays an important role. NaClatomizer and WOx nano-aerosol generator are used to generate NP with diameter 10-130nm and 0.8- 30nm. For the TEM grid filtration, “Holey” type and “Quantifoil” typecarbon films are fitted with a 400 “mesh” copper grid then installed in the MPS. The overall collection efficiency of each gridand collection efficiency of the holey carbon filmare compared to get the best efficiency. By using MPS and TEM analysis, sampling is made directly and easily. The influence factors are taken into account. According to the experiment and the empirical approach, a theory model is developed to assess the sampling efficiency. Furthermore, the expose risk of the nanoparticles during the processing of the nanoparticles is evaluated using the Short Time Sampling (STS) approach.