That is due to all of the SUV's they drive on Venus. Which is also the reason that the atmosphere is ~97% Carbon Dioxide.
Oh by the way here is Earth's atmosphere.(dry)
Evidently, the CO2 here on earth is more deadly pound for pound than on Venus. Water vapor is not a threat even though it is present at 10 times the portion of CO2.
| Not included in above dry atmosphere: | |
| Water vapor (H2O) | ~0.40% over full atmosphere, typically 1%-4% at surface |