Indoor Air sciences CSMI Practice Exam

Which type of respirator should be used if the oxygen concentration is below safe levels?

1. Standard surgical mask

2. Gas mask

3. SCBA

4. Half-face respirator

The correct answer is: SCBA

In environments where the oxygen concentration is below safe levels, the use of a self-contained breathing apparatus (SCBA) is essential. An SCBA provides a supply of breathable air from a tank carried by the user, allowing them to operate safely in atmospheres with insufficient oxygen or where contaminants are present. This type of respirator is specifically designed to protect the user from inhaling hazardous gases and to ensure that they can breathe freely while avoiding the dangers of low oxygen levels. In contrast, standard surgical masks and half-face respirators are not designed to provide oxygen; they merely filter out particulates and may not protect against all harmful gases or low oxygen environments. A gas mask may offer some level of protection against airborne contaminants, but it does not supply oxygen and would not be suitable where oxygen levels are critically low. Therefore, SCBA is the only option that guarantees both air supply and respiratory protection in such situations.