Evidence of Indoor Dust Acting as Carrier for Metal-Based Nanoparticles: A Study of Exposure and Oxidative Risks

The wide application of nanotechnology has led to the inevitable release and transport of metal-based nanoparticles (MNPs) into the environment. However, very few studies have examined the occurrence of MNPs in indoor dust. Here, we report the occurrence of 10 distinct types of MNPs in indoor dust, confirming its carrier role for MNPs. In particular, up to similar to 4000 mu g of MNPs/g of dust, including Fe-based MNPs (similar to 200 nm, equivalent spherical diameter), were found in indoor dust samples collected from both residential and public areas. Though the collected indoor dust exhibited a magnetic response, negligible differences were observed in the composition of MNPs, particle concentrations, and size distributions before and after magnetic separation, which suggested that MNPs in indoor dust were clusters containing multiple elements. Furthermore, indoor dust-associated MNPs easily aggregated when being exposed to lung fluid (e.g., the size of Fe-based MNPs increased similar to 2.8-fold). Indoor dust with multielement MNPs can induce oxidative stress by generating more reactive oxygen species, and the estimated center dot OH concentration was increased by 1.5 times compared with the control. Long-term exposure to MNPs in indoor habitats may induce health risks, highlighting the need to better characterize these indoor contaminants.