I always wonder about small acrylic hairs and such that float about the house. In a bright room just flex your jumper, there's thousands of these weird impurities, and I can't imagine they can be filtered out easily before or after getting into the lungs.
The biggest shocker is when you disturb loft insulation. They claim it's not terrible (specifically if undisturbed), but floating glass strands can't be all that nice.
This. We evolved in an environment with plenty of particulate matter. It's the exotic stuff that has no analog from the time when we evolved that causes problems.
Without knowing for sure, I imagine acrylic to be inert and most like any other dust on the time scale it takes for our bodies to expel it. But I could be wrong. Certainly, there are modern dangerous materials which do affect us, such as asbestos and heavy metals.
Interesting that fiberglass fibers are typically 5-25 micrometers (µm), while asbestos fibers can be 180A to 300A (1 angstrom = 1/10000th of a micrometer. So an asbestos fiber is between ~200 to 1400 times smaller than a glass fiber.
Acrylic fibers are 15 µm to 25 µm.
Merino wool fibers are 15 µm to 30 µm.
And human hairs diameters are between 20 to 200 µm.
Seems to be a biological limit to the body cleaning system e.g. nanoparticles, abestos
It all depends on how well your body is able to clean them out and what it does if it remains. Asbestos isn't bad because it's a fiber it's bad because it is hard for your lungs to move and damages the interior.
The biggest shocker is when you disturb loft insulation. They claim it's not terrible (specifically if undisturbed), but floating glass strands can't be all that nice.