Ammonia

Ammonia is a chemical compound composing of one nitrogen atom and three hydrogen atoms NH₃. Ammonia is foul smelling and is toxic to humans. However, ammonia is often used as an artificial fertilizer for plants to provide nitrogen. Ammonia could be used as a coolant or refrigerant and is useful in industry. Ammonia can be generated from human and animal waste, but first, the Nitrogen needs to be extracted from the Martian atmosphere by atmospheric processing.