Whenever these bags aren't recycled, the third factor in calculating environmental impact comes into play: degradability.

每当这些袋子不再被回收了，计算环境影响的第三个因素就会开始发挥作用：即可降解性。

Each of these three materials has a unique environmental impact that's determined by its carbon footprint, its potential to be reused and recycled, and its degradability.

这三种材料中的每一种都有其独特的环境影响，这取决于其碳足迹、可重复利用和再循环的潜力，以及其可降解性。