I'm afraid I don't know anything about them except that there are suddenly thousands of them invading my house since about a week ago, and I'd like to repel them. Found in Cambridge, UK.
They are really tiny, about 3 mm long and smaller than a dry grain of rice. I've never seen them fly, just crawl around slowly. They get into everything, including the screen of my monitor!
I tried searching Google for tiny insects but none of the pictures or descriptions that I found seem to match these (I'm pretty sure they are not ants, lice, bed bugs, termites or silverfish).
If you have any idea how to repel or kill them humanely and without dangerous chemicals, I'd really appreciate that too.