Are there places in the world where the oxygen levels are dangerously low?
Yes there are places where the O2 level is dangerously low for life. They are underwater, and on tops of high mountains. Although the O2 content is relativly constant throughout the atmosphere we need O2 at a high enough pressure otherwise no matter how hard we breathe we can’t get enough. In the ocean there are anoxic areas, low oxygen. There is a big one in the gulf of mexico near the mouth of the mississippi. The area is very toxic to life because there isn’t enough oxygen to support it. There is debate as to why but it does happen. So the answer to you question is yes.
