When does oxygen stop how far up?

Answer 1

Oxygen does not abruptly "stop" at a specific altitude, but rather its concentration decreases gradually with increasing altitude. Here's a general idea of how oxygen levels vary with altitude:

1. **Troposphere (up to 12 km / 7.5 miles)**: This is the lowest layer of the Earth's atmosphere where almost all weather occurs. Oxygen levels gradually decrease with altitude, but there is still enough oxygen to sustain life throughout the troposphere.

2. **Stratosphere (12 km to 50 km / 7.5 miles to 31 miles)**: Oxygen levels continue to decrease in the stratosphere, but they are still present. However, the air is very thin at these altitudes.

3. **Mesosphere and Thermosphere (above 50 km / 31 miles)**: Oxygen levels are extremely low in these layers, and the atmosphere is extremely thin. Although there are trace amounts of oxygen molecules present, the concentration is insufficient to sustain human life or most forms of aerobic life.

To summarize, while oxygen levels decrease significantly with altitude, there is no precise boundary where oxygen "stops." Instead, the atmosphere gradually thins out with increasing altitude until the concentration of oxygen becomes too low to support life as we know it.

Answer 2

Oxygen concentration decreases with increasing altitude. The level at which oxygen becomes limited for humans is around 8,000 to 12,000 feet above sea level, depending on individual tolerance. Above this altitude, additional oxygen may be required for proper breathing.