The National Parks in England are called "England's Breathing Spaces" because they are places where people can go to be in the open air, away from the dirt and noise of cities.

Do you want your child walking on the streets or in the park barefoot, where there might be dog poo, dirt and possible hazards like glass?

In an idealized situation, where the threads contained all the primary colors in equal amounts, and were not obscured by dirt and other residues, the lint would appear to be white, not gray.