Is air a mixture or a solution or a compound or an element? Air is a mixture of gases (and not a compound), about 78% being  nitrogen (an element) , about 21% oxygen (another element), and all  other gases present in much lesser amou…nts. The remaining 1% is  made up of argon (0.93%), carbon dioxide (0.039% as of 2010) and  other trace gases (0.003%).