In June 2016, the “Assessment of Individual Exposure to manufactured nanomaterials by means of personal monitors and samples” (nanoIndEx) project published a guidance document entitled Assessment of Personal Exposure to Airborne Nanomaterials. The three-year project was funded under the Safe Implementation of Innovative Nanoscience and Nanotechnology (SIINN) European Research Area Network (ERA-NET). Its aim was to determine the field readiness and usability of the instrumentation available for personal exposure assessment; use this information to generate reliable data on personal exposure in real workplaces; and distribute the findings to stakeholders. The guidance document summarizes the key findings of the project, and is intended to present the state of the art in personal exposure assessment for nanomaterials. The conclusions section states: “Unfortunately, many nanotoxicological studies have used excessive, unrealistically high doses of [manufactured nanomaterials] and it is therefore debatable what their findings mean for the lower real-world exposures of humans. Moreover, it is not clear how to establish realistic exposure dose testing in toxicological studies, as available data on occupational exposure levels are still sparse.” According to the guidance document, future studies should focus on the potentially adverse effects of low-level and realistic exposure to manufactured nanomaterials, especially through the use of exposure doses similar to those identified in environmental sampling.