system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: do hairs and dust ever get into our lungs? And if so what does our body do about it?

Thought randomly because I'm sick and sniffled. When I coughed I coughed up some nose hairs but was wondering if they could get into our lungs. Legitimately curious.
gpt
Most natural dust particles are caught in the nose hairs and cilia that mucus that lines your nose and trachea. Most living creatures have evolved ways to filter that from reaching the lungs in first place, and that that does, gets filtered out by the body.

Dust particles 2.5 - 10 microns wide, often made from industrial activity can get into the lungs, and might not always get removed. Typical examples are crushed gravel dust that gets stirred into the air from roads, construction and farming. 

Less that 2.5 microns is often soot from industrial, vehicles, and wildfires. This stuff can cause all kinds of respiratory problems, heart attacks and cancer. Some of the new materials, such as carbon nanotubes are extremely small, and like asbestos fibers, deeply enter the lungs. It's currently not fully known what the long term effects are.