Originally Posted by Dr.
Earth is “home field advantage” for Kal-El, Black Zero is “home field advantage” for Zod.
THIS. This is a perfect answer to the thread in my opinion. And this is why, at the end of the film, when Zod takes off his helmet, he shows us his impressive capabilities. He can finally tolerate our atmosphere and we know then that the final battle will be very difficult to win for Superman.