Is Consumption Different from Production?

Economists usually consider consumption opposite to production. From the viewpoint of entropy, however, there is no difference between them. You can describe both of them as an increase in entropy of environment in compensation for reducing the entropy of a system.
What is Value?

What makes merchandise valuable is usefulness and scarcity. Air is useful, but has no value, as anyone can get it easily. Trash is, even if it is very unique and hard to obtain, valueless, as it is useless. What then do both have in common?