I don't think I've seen too much discussion of home dust, all told. Just going on a general view of what else could it be? Yes, dead skin and such makes up a lot. But as we use more and more synthetic fibers, those are spun far thinner than the thinnest plastic sheet. By design. Hard to believe that they don't make up a large portion of the microplastics out there.

Would be delighted to find out I'm wrong on this.