What gas must be present in adequate quantities for the multi-gas atmospheric monitor to accurately test for other items?

For a multi-gas atmospheric monitor to accurately test for other gases, it is essential that oxygen is present in adequate quantities. Oxygen is a key component of the atmosphere and is necessary for combustion and various gas reactions. Many gas detection technologies rely on the presence of oxygen to function correctly because the detection methods are often calibrated based on air composition, which typically consists of approximately 21% oxygen.

If oxygen levels fall below a certain threshold, it can compromise the performance of the monitor and lead to inaccurate readings for other gases. For example, in environments with low oxygen, the monitor may not accurately detect hazardous gases, since certain chemical reactions and the behavior of combustion are oxygen-dependent.

In contrast, while gases like carbon dioxide, nitrogen, and hydrogen are important in different contexts, they do not play the same critical role in the calibration and functionality of a multi-gas atmospheric monitor as oxygen does. Therefore, adequate levels of oxygen must be present to ensure accurate detection of other gases in the environment.