Development of a self-cleaning dispersion and exposure chamber: application to the monitoring of simulated accidents involving the generation of airborne nanoparticles

Three Experimental Common High-Risk Procedures: Emission Characteristics Identification and Source Intensity Estimation in Biosafety Laboratory

Biosafety laboratory is an important place to study high-risk microbes. In biosafety laboratories, with the outbreak of infectious diseases such as COVID-19, experimental activities have become increasingly frequent, and the risk of exposure to bioaerosols has increased. To explore the exposure risk of biosafety laboratories, the intensity and emission characteristics of laboratory risk factors were investigated. In this study, high-risk microbe samples were substituted with Serratia marcescens as the model bacteria. The resulting concentration and particle size segregation of the bioaerosol produced by three experimental procedures (spill, injection, and sample drop) were monitored, and the emission sources' intensity were quantitatively analyzed. The results showed that the aerosol concentration produced by injection and sample drop was 103 CFU/m3, and that by sample spill was 102 CFU/m3. The particle size of bioaerosol is mainly segregated in the range of 3.3-4.7 μm. There are significant differences in the influence of risk factors on source intensity. The intensity of sample spill, injection, and sample drop source is 3.6 CFU/s, 78.2 CFU/s, and 664 CFU/s. This study could provide suggestions for risk assessment of experimental operation procedures and experimental personnel protection.

A versatile generator of nanoparticle aerosols. A novel tool in environmental and occupational exposure assessment

The increasing presence of nanotechnology on the market entails a growing probability of finding ENMs in the environment. Nanoparticles aerosols are a yet unknown risk for human and environmental exposure that may normally occur at any point during the nanomaterial lifecycle. There is a research gap in standardized methods to assess the exposure to airborne nanoparticles in different environments. The controllable generation of nanoparticle aerosols has long been a challenging objective for researchers and industries dealing with airborne nanoparticles. In this work, a versatile system to generate nanoparticulate aerosols has been designed. The system allows the production of both i) instantaneous nanoparticle clouds and ii) continuous nanoparticle streams with quasi-stable values of particle concentration and size distribution. This novel device uses a compressed-air pressure pulse to disperse the target material into either the testing environment (instantaneous cloud formation) or a secondary chamber, from which a continuous aerosol stream can be drawn, with a tunable nanoparticle concentration. The system is robust, highly versatile and easy to operate, enabling reproducible generation of aerosols from a variety of sources. The system has been verified with four dry nanomaterials: TiO₂, ZnO, CuO and CNT bundles.

A laboratory study of the performance of the handheld diffusion size classifier (DiSCmini) for various aerosols in the 15-400 nm range

In addition to chemical composition, particle concentration and size are among the main parameters used to characterize exposure to airborne ultrafine or nanoparticles. To assess occupational inhalation exposure, real-time instruments are recommended in recent strategies published. Among portable devices for personal exposure assessment in the workplace, DiSCmini (Matter Aerosol AG, Switzerland) has been identified as a potential candidate with its capacity to measure the airborne nanoparticle concentration and average particle size with good time-resolution. Monodisperse and polydisperse test nanoaerosols of varying compositions and morphologies were produced in the laboratory using the CAIMAN facility. These aerosols covered a range of particle sizes between 15 and 400 nm and number concentrations from 700 to 840,000 cm(-3). The aerosols were used to investigate the behavior of DiSCmini, comparing experimental data to reference data. In spite of a slight tendency to underestimate particle size, all particle diameters, number concentrations and surface area concentrations measured were in the same order of magnitude as reference data. Furthermore, no significant effect due to particle composition or morphology was noted.