Diving without oxygen tanks requires you to enact some very weird and very strange and not all that well understood physiological feats just to stay alive.
Breathing in through your nose has many medical benefits over mouth breathing. As usual, be wary of misinformation and bias when looking up health on the internet.
Canada rushed to counter a deadly lung disease afflicting gold miners in the early 20th century. The "quick fix" cure that was invented is a symbol of the lurch towards global industrialization.
Understanding the bugs in our lungs could help treat certain diseases, including asthma.