What does an oxygen indicator measure?

An oxygen indicator is designed to measure the amount of oxygen present in a gaseous environment, which is essential for various applications, including combustion processes, environmental monitoring, and safety in confined spaces. By measuring the concentration of oxygen, it helps ensure adequate air quality for breathing or optimal conditions for combustion.

The focus on oxygen levels is crucial because insufficient oxygen can lead to hazardous situations, particularly in confined areas where ventilation may be poor. This makes the correct answer beneficial in both practical applications and safety protocols. The other options focus on different parameters that do not involve direct measurement of oxygen concentration. For example, water purity, gas temperature, and carbon dioxide levels pertain to entirely different aspects of gas and liquid analysis. Understanding the precise role of an oxygen indicator reinforces the importance of monitoring oxygen concentrations in various environments.