https://blog.gongquiz.com/2020/12/04/co2-32vol-o2-5vol-n2-63vol%ec%9d%98-%ed%98%bc%ed%95%a9%ea%b8%b0%ec%b2%b4%ec%9d%98-%ed%8f%89%ea%b7%a0-%eb%b6%84%ec%9e%90%eb%9f%89%ec%9d%80-%ec%96%bc%eb%a7%88-%ea%b0%80%ec%8a%a4%ec%82%b0%ec%97%85/