Definition of ammonia

1) The molecular formula for ammonia is NH3. Ammonia is one of the most important inorganic nitrogen compounds in atmospheric water droplets. It reacts with strong acids and is one of the only known basic, gas phase atmospheric components. Atmospheric ammonia can also enhance the nucleation rate and the production of new particles in the atmosphere. These new particles can be activated to become condensation nuclei and then, through various processes, grow to a particle size of 0.05 micrometer or larger which can then be effective as cloud condensation nuclei. This process can, therefore, affect the global radiation budget. The major sources of ammonia are decaying natural organic matter, livestock wastes, fertilizers, and industrial activity.

source: [Atmospheric Change: an Earth system perspective; T.E. Graedel, Paul J. Crutzen; page 157; 1993; W.H. Freeman and Company; New York.]