system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Does all the dust and dirt we breathe in during our lives just build up in our lungs?

My furniture is constantly collecting dust so I assume since I breathe the same air that deposits the dust on my furniture I must be inhaling that stuff too.  Where does it all go? Does it somehow make it to our digestive systems to be purged out of our bodies that way, or does it just build up over our lives, or something else?
gpt
The purpose of the mucous in our nose and throat is to trap particulate matter.  Most of the dust and dirt gets trapped there.  From there it can be coughed up, swallowed, or blown into a tissue.

Some dirt and dust invariably still makes it to your lungs, but any time you cough, you'll eject a bit of it as well.