system
Given the following post, respond as if you're commenting on Reddit:
human
Why does most garbage have that same garbage smell?

It's seems that no matter what I put in my garbage it seems to have that same garbage smell. Also when I put my trash in the dumpster, the dumpster always seems to smell about the same? 
Is there some common denominator that makes garbage all have that garbagey smell?
gpt
Mostly because most garbage is actually the same basic components. Normally, garbage contains inorganic components (glass, metal) and organic components (plastics, paper, animal and plant products, etc.). When this organic material, especially the animal and plant products (food) are left outside, under the sun (which radiates UV spectrum light) and in the presence of bacteria, it begins to decompose, commonly producing compounds like methane, trimethylamine, cadaverine, and putrescine. The mixture of these compounds is what creates the "garbage" smell. Since people need to eat to survive, there's almost always some kind of food product in every garbage bag, and since a small amount of these chemicals are needed for the human nose to detect the smell, you will almost always smell the characteristic "garbage" when there's trash around.