Emissions and exposures of graphene nanomaterials, titanium dioxide nanofibers, and nanoparticles during down-stream industrial handling

Abstract

Today, engineered nanomaterials are frequently used. Nanosized titanium dioxide (TiO 2) has been extensively used for many years and graphene is one type of emerging nanomaterial. Occupational airborne exposures to engineered nanomaterials are important to ensure safe workplaces and to extend the information needed for complete risk assessments. The main aim of this study was to characterize workplace emissions and exposure of graphene nanoplatelets, graphene oxide, TiO 2 nanofibers (NFs) and nanoparticles (NPs) during downstream industrial handling. Surface contaminations were also investigated to assess the potential for secondary inhalation exposures. In addition, a range of different sampling and aerosol monitoring methods were used and evaluated. The results showed that powder handling, regardless of handling graphene nanoplatelets, graphene oxide, TiO 2 NFs, or NPs, contributes to the highest particle emissions and exposures. However, the exposure levels were below suggested occupational exposure limits. It was also shown that a range of different methods can be used to selectively detect and quantify nanomaterials both in the air and as surface contaminations. However, to be able to make an accurate determination of which nanomaterial that has been emitted a combination of different methods, both offline and online, must be used.

Real-Time Emission and Exposure Measurements of Multi-walled Carbon Nanotubes during Production, Power Sawing, and Testing of Epoxy-Based Nanocomposites

“…Even though CNT powder was handled openly in the chemical and manufacturing laboratories, surface contamination could only be detected on one surface (a door handle on the corridor side) outside these laboratories. The percentage of surface samples with CNT contamination was in the same range as reported by Lovén et al (2021) , in which TiO 2 nanofibres were tape sampled, but lower than reported in a previous study of CNTs ( Hedmer et al , 2015 ). The detected surface contamination could most likely be related to the different production steps of the nanocomposite as most of the contaminated surfaces were found in the near-field zone in the chemical and manufacturing laboratories, where the WTs were performed.…”

“…The method was modified with an extended oxidation time at the highest temperature in order to achieve complete oxidation of all carbonaceous nanomaterials. Further details of the analytical procedure are given elsewhere ( Hedmer et al , 2014 ; Lovén et al , 2021 ). The limit of detection (LOD) of the method for EC is 0.06 µg C cm −2 , corresponding to 0.6 and 0.5 µg C m −3 for a 4-h sample for the respirable and inhalable fraction, respectively.…”

“…Based on a previously developed method for sampling of surface contamination with CNTs, different surfaces at the company were sampled with tape stripping ( Hedmer et al , 2015 ; Isaxon et al , 2020 ; Lovén et al , 2021 ). In short, adhesive tape was used to collect single tape samples from different surface locations related to the monitored WTs.…”

Lung recovery from DNA damage induced by graphene oxide is dependent on size, dose and inflammation profile

“…1 ), we evaluated the potential genotoxicity of GO sheets after single (30 µg) or repeated (3 × 1 µg or 3 × 10 µg) pulmonary exposure. The low dose of 3 × 1 µg represented a realistic dose of exposure at the workplace when limited mitigating measures are applied, whereas 30 µg (or 3 × 10 µg) was used here as worst-case exposure scenario (accident) that may happen during specific tasks such as dry powder handling without protective measures [ 39 , 40 ]. The aim was to compare outcomes from standard exposure protocol (i.e., single exposure triggering acute response) to outcomes from chronic exposure that may better represent exposure at the workplace [ 26 ].…”

Underground emissions and miners’ personal exposure to diesel and renewable diesel exhaust in a Swedish iron ore mine

“…EC can also be estimated as equivalent black carbon (eBC) (Cai et al 2014 ; Yu et al 2015 ) and measured with direct-reading instruments. This enables the identification of high-exposure work tasks (Lovén et al 2020 ) that are not resolved with the time-integrated EC measurement. However, to the best of the authors’ knowledge, no studies of time-resolved personal exposure to eBC during underground mining have previously been published.…”