Distribution Characteristics of nano-TiO2 Aerosol in the Workplace

Abstract

In this study, the distribution characteristics of nano-TiO 2 aerosol have been studied to get insight of the suspension, agglomeration and depositing performances of aerosol nanoparticles in the workplace. The number concentration and mass concentration of the aerosols have been characterized by using a wide-range particle spectrometer and cascade impactor samplers, respectively. Water based wet aerosol samplers, as well as its corresponding analysis approaches based on ultraviolet spectrometry, have also been developed to investigate the mass concentration and present an efficient sampling performance with the quite shorter sampling time than that by cascade impactors. To get a comparison of the test results with each other, sampling points have been set at the heights of breathing zone (1.0, 1.5 and 2.0 m) and at the distances of 1 to 5 m away from the discharge port of the assembly line. It is found that all the number concentration curves exhibit two peaks at the ranges of 10-200 nm and 500-900 nm. The aerosol particles with distance of 3 m exhibit the highest number concentration at all the diameter range except for the diameter less than 20 nm. While, aerosol at the distance of 5 m presents the highest number concentration, up to 18000 particles per cm 3 , in the diameter less than 20 nm. It is attributed to the spray forces of the discharge port and the suspending and depositing of aerosol nanoparticles in the air. The mass concentration and particle weight percentage at different diameter tested by cascade impactor show a strong dependence on the number concentration, which is well consistent with the results obtained by wet method.

Equivalent titanium dioxide nanoparticle deposition by intratracheal instillation and whole body inhalation: the effect of dose rate on acute respiratory tract inflammation

“…Many in vitro and in vivo studies use coatings, such as surfactants, in order to mimic the lung lining fluid in an in vivo scenario [ 44 ] and/or to obtain monodisperse, stabilized suspensions [ 45 ]. Here, we did not use coatings because: 1) real world RT exposures do not involve monodispersed NPs [ 46 ]; 2) upon deposition into the lung, particles will interact with lung lining fluid and become coated with proteins and other biomolecules; 3) regardless of the suspension coating or dispersion at the time of exposure, particles may agglomerate within the lung upon deposition [ 47 ]; 4) we wanted to keep the material as pristine as possible for better comparison to the uncoated, pristine material used for inhalation; and, 5) in a pilot study, we determined that pretreatments with coating or sonication can modify the inflammatory response (Additional file 1 : Figure S1). We found that pretreatment with dispersion medium (DM; 1,2-dipalmitoyl-sn-glycero-3-phosphocholine + albumin in saline [ 48 ]) resulted in significantly lower neutrophil influx than with saline alone (Additional file 1 : Figure S1A).…”

Ultrafine particles in scanning sprays: a standardized examination of five powders used for dental reconstruction

“…In nanoparticle research, especially titanium dioxide is under scrutiny. Though there is currently no epidemiologic proof for a dose-response relation between ultrafine TiO 2 and lung cancer in TiO 2 -exposed workers, animal studies (rats) have shown dose-response relationships for ultrafine TiO 2 and cancerous, as well as inflammatory endpoints [40][41][42]. Therefore, more information about ultrafine toxicity and effective preventive means are needed to reduce health threats at the workplace.…”

Distribution of Nanoparticle Number Concentrations at a Nano-TiO2 Plant

“…However, instruments capable of measuring aerosol surface areas in the field are not widely available. In addition, only a few research efforts are focused on the study of particle number concentrations (Tsang et al, 2008;Hussein et al, 2011;Yang et al, 2011). By measuring the number concentration distribution of aerosols in the workshop and the diameter of the primary particles, it is easy to display the agglomeration status of the aerosol particles, and to convert to the other two characteristics of the aerosol; i.e., the mass concentration and the surface area concentration.…”