What is the O2 percent at 7000 feet above sea level?

Answer 1

Standard oxygen concentration for earth's atmosphere is 20.9%

Theoretically, this percentage does not change at varying altitudes. What changes is the density of the oxygen (and other gases, such as nitrogen) present in the air. At sea level or on a mountain top, oxygen concentration is 20.9%

However, depending on things like air pollution and location (indoors vs. outdoors), O2 concentration can vary widely, down to as little as 10% in polluted indoor environments.

Answer 2

At 7000 feet above sea level, the percentage of oxygen in the air is approximately 14.3%. This is lower than at sea level due to the decrease in atmospheric pressure with increasing altitude.