You&#x27;re right about the reduced oxygen, but perhaps it could get people away from the dirty city air in some places.  For example:  <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;1939_St._Louis_smog" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;1939_St._Louis_smog</a>