Table 9-4:
Chemical Compositions of Three Planetary Atmospheres
Venus
Earth
Mars
Nitrogen (N
2
)
3.5%
78.08%
2.7%
Oxygen (O
2
)
almost zero
20.95%
almost zero
Carbon dioxide (CO
2
)
96.5%
0.035%
95.3%
Water vapor (H
2
O)
0.003%
about 1%
0.03%
Other gases
almost zero
almost zero
2%