Several sources suggest that "smart dust" could be used to make observations about someone's health and the environment around you.
Here are some sources that suggest you could make observations about your health or the environment around you:
Other sources suggests that this could be used to make observations specifically about the environment:
- “Smart dust” biosensors powered by biomolecular motors
- "Smart dust": nanostructured devices in a grain of sand
- Sample records for smart dust based
A podcast / novel featured a character that could taste the serotonin or dopamine from a person (I can't remember the name of -- possibly Children of the Revolution). I've never seen a source that suggests there are neurotransmitters in someone's sweat or breathe.
What about the health or condition of the body could you determine from an examination of breath and perspiration?