Large amounts of pure nitrogen are isolated through factional distillation. This is the most common massive scale production method of pure nitrogen. Nitrogen gas is the largest component, up to 78%, of the air that we breathe. To extract pure nitrogen through fractional distillation, the air is first liquefied than distilled to separate out the nitrogen from the rest of the gases present in the air. Two other methods can be used to obtain nitrogen, but these reactions can be hazardous and should only be performed by professions. The first method involves heating sodium azide to 572 °F to produce two parts of sodium to three parts of pure nitrogen gas. The second method involves heating ammonium dichromate to produce pure nitrogen gas, Cr203, and water. Commercial amounts of nitrogen can also be collected as a by-product of processing industrial concentrations of oxygen through the air. Pure nitrogen, liquid and gas, is dangerous and needs to be handled with care.