The average home collects about 40 pounds of dust per year. That is what a 5 gallon jug of water weights. That is why you need your home carpet cleaned in Metro Detroit at least once a year because you never know what is creeping in your carpet.
Dust is made up of mostly skin flakes and a human sheds about 1.5 million skin flakes an hour. That is a lot of dust and another reason you need to get your carpet cleaned.
If your a smoker the smoke particles end up in the carpet and that can be bad for kids and babies because kids and babies play on the floor and they inhale the smoke particles and in connection with that they are at a higher risk for lung cancer.
You should also vacuum your carpet on a regular basis and carpet clean your home on the regular.