MadSci Network: Earth Sciences |
Jenny; You were wondering why we need to wear masks at high elevations. Mountain climbers and high altitude pilots are usually the ones who reach such elevations, and we can usually find pictures of these people wearing their masks. The masks they wear supply oxygen, sometimes just as bottled air, sometimes as pure oxygen. They can't get oxygen from the air in the upper parts of our atmosphere. Down here, about 20% of the air we breathe is oxygen, the rest is nitrogen and other gasses-mostly nitrogen. Nitrogen and oxygen are really heavy compared to the other gasses up there, and most get attracted down here by gravity. The change in oxygen concentration happens pretty fast, as a lot of athletes know, when you exercise at sea level and then try to play a game or compete in a race at, say a mile above sea level, your body isn't used to the low oxygen concentrations and has a hard time compensating. You can do more research on the web through searching for sites about weather, atmosphere, troposphere and stratosphere (there's more to the layers, but those are the ones we most often visit with our planes and high-altitude weather balloons). That's the quick and simple answer to your question, but you might also want to look into how heavier molecules and pollutants get up there. -- Sarah
Try the links in the MadSci Library for more information on Earth Sciences.