system
Given the following post, respond as if you're commenting on Reddit:
human
eli5: How do your lungs filter out dust in the air?

I was cleaning out an A.C. Units air filter and it got me thinking. We breath in the same air so how do we clean out our filter?
gpt
Naturally, the hair in your nose doesn’t get everything. Big things, like grit or dirt will get caught in your mouth or throat, finer particles will get stuck in membranes further in your lungs and coughed back up as mucus. We catch and spit up most.

When it comes to work, If you can see it in the air, you are breathing it and need a mask. If it’s a manufactured material, it likely contains toxins you won’t cough up.