Originally Posted by Dr.
In theory, Supes can expel air out of his lungs with explosive force. But you’re correct - the amount of air he can hold in a single breath is limited to the physical size of his chest and lungs (i.e., “normal” for an adult male who’s roughly 6’2”, etc.). Mechanical devices with various valves, pistons and chambers can compress a lot of air into a small volume. But as far as we know, Supes’ internal anatomy is the same as ours. So he wouldn’t be able to compress large quantities of air any better than a typical human.
The idea of Superman expelling a long term wind in line with what we saw from the kryptonians in Superman 2 is an absolute impossibility.
Since Superman's physiology does seem similar to ours, there is a precedence for increased long capacity in regular humans as evidenced with free divers. They use a process of gulping air that I believe is called lung packing. This allows them to hold their breath for far longer periods than "normal" humans.
So, it is conceivable that Superman, with preparation could definitely pack in far more oxygen that a human because his lungs would be able to handle a far greater level of pressure. Pressurized air does dramatically cool but I would rather not see extended superbreath or freeze breath in the MoS/DCCU movies.