system
Given the following post, respond as if you're commenting on Reddit:
human
What happens when piece of food fall in lungs?

What if you choke on and little piece of food fall in lungs? Is there difference be it lollypop or bread?

What about small insect?
gpt
In your aerial paths (trachea, bronchi, etc...) there are cells producing mucus wich engulfs the dust, small bugs,  (small) pieces of food. And those cells present cilia which move back and forth to make this mucus go up. Once it reaches the back of your mouth, you swallow it and let your digestive system deal with it. 
         
Inside your alveoli, there are no cils but macrophages can digest most of what comes here. Some compounds are problematic though like silica, asbestos, cigarette smoke,  smoke from exhaust pipes... When macrophages digest those, they die and release toxic compounds which can destroy the cells and create scar tissue or even tumors.