Nitrogen

"Generating Nitrogen: Take some air, burn some carbon-rich material in it until no further burning occurs. Then pass the remaining **gas ** through an alkaline solution to remove the carbon dioxide. The remaining **gas ** will be more than 95% **nitrogen **. And you get this with no expensive chemicals."

http://arstechnica.com/science/2014/10/earths-nitrogen-rich-atmosphere-linked-to-plate-tectonics/

http://www.worldofchemicals.com/44/chemistry-articles/daniel-rutherford-discoverer-of-nitrogen-gas.html