Calculate residence time of chemical species in atmosphere having a mixing ratio of one parts per billion (1ppb) by mass.
[given: Total flux of species by natural and anthropogenic sources is 200 x 1012 g/yr. Mass of atmosphere is 4 x 1021 g]
1
∼ 0.1 week
2
∼ 1 week
3
∼ 10 week
4
∼ 50 week