What you don't know can kill you.
This is a quote by Jonathon Kaiman (an expert on air pollution in China)
Each of these gases can remain in the atmosphere for different amounts of time, ranging from a few years to thousands of years. All of these gases remain in the atmosphere long enough to become well mixed, meaning that the amount that is measured in the atmosphere is roughly the same all over the world, regardless of the source of the emissions.
Scary part is....
When people unknowingly release green house gases into the air, part of the atmosphere is destroyed and people lose rich air to breathe.