Most research on nanoplastics in the body has looked at what we swallow. A new laboratory inhalation study looks at what we breathe instead.

In a paper published online October 5, 2026 in Environmental Science & Technology, Shuang Liu and colleagues report that chronic inhalation of PET nanoplastics in a lab exposure model was followed by particles reaching the brain, loss of myelin (the insulating sheath around nerve fibers), neuroinflammation and cognitive deficits.

What the researchers did

PET (polyethylene terephthalate) is the plastic used in most single-use drink bottles. The team writes that earlier work has mostly relied on oral exposure and on commercial particle models that may not reflect real-world particles. Instead, they used "environmentally simulated" PET nanoplastics and an aerosol inhalation model at three concentrations: 0.1, 1 and 10 milligrams per cubic metre of air.

The effects were most pronounced at the highest dose, 10 mg/m³, which the authors describe as relevant to occupational settings.

A pathway, and a possible block

The study also points to a mechanism. Exposure triggered astrocytes, a type of brain support cell, to release a signalling molecule called CXCL12. That activated microglia, the brain's immune cells, through a receptor called CXCR4. In lab-dish experiments, blocking CXCR4 with a drug called AMD3100 reduced microglial migration and the loss of myelin basic protein in oligodendrocytes, the cells that make myelin. The authors say this pathway could inform exposure-based prevention, and they call for further assessment of airborne nanoplastic risks, especially at work.

What this study does not show

It is a laboratory inhalation study. It does not show that nanoplastics cause demyelinating disease, such as multiple sclerosis, in people.
It is about inhalation, not drinking water. The particles were breathed in as an aerosol. The study tells us nothing about water from the tap or the bottle.
The clearest effects came at a high, workplace-level dose. Lower doses were tested, but the strongest signal was at 10 mg/m³.

The water experts' take

Plastic exposure doesn't arrive by one route. This paper adds air, and specifically particles from a common bottle plastic, to a picture that has mostly centred on food and water. For water professionals, it's a reminder to keep exposure routes separate when you talk about risk: what's shown for inhaled particles doesn't transfer automatically to ingested ones, and the reverse holds too.

Read the paper in ES&T →