Certified Transport Registered Nurse Certification Practice Exam

At what altitude does the stratosphere start?

1. 0 - 30,000 ft

2. 30,000 - 35,000 ft

3. 35,000 - 264,000 ft

4. Above 264,000 ft

The correct answer is: 35,000 - 264,000 ft

The stratosphere begins at an altitude of approximately 30,000 feet above the Earth's surface, extending up to about 264,000 feet. This layer of the atmosphere is characterized by a temperature increase with altitude, which is a key distinction from the troposphere beneath it, where temperature decreases with height. The range given in the correct answer accurately reflects the accepted scientific consensus on the boundary of the stratosphere, where it meets the mesosphere. Understanding the layers of the atmosphere is fundamental for transport nurses, especially for those involved in air and ground transport where altitude can significantly affect patient care and treatment considerations such as oxygenation, pressure changes, and thermal regulation. The other options do not accurately represent the start of the stratosphere. The first option incorrectly states that the stratosphere starts at or below 30,000 feet, which in fact describes the upper range of the troposphere. The second option proposes a range that begins at 30,000 feet, but concludes at a lower boundary than the true extent of the stratosphere. The last option incorrectly starts above the upper limit of the stratosphere, as it is not within the atmospheric layers that surround the Earth.