What is the minimum O2 level considered safe for a fit-testing atmosphere?

What is the minimum O2 level considered safe for a fit-testing atmosphere?

• A. Greater than 19.0%
• B. Greater than 19.5%
• C. Greater than 21.0%
• D. Greater than 23.0%

Answer: (B)

The important idea is that a fit-testing environment must have enough oxygen to keep you safe and able to complete the test. The minimum safe level is 19.5% oxygen by volume. This threshold is used because below it the atmosphere is considered oxygen-deficient, which can cause dizziness, fainting, or impaired performance during the test. Normal air is about 20.9% oxygen, so the lowest acceptable value is just above 19.5%. That’s why the option stating greater than 19.5% is the best choice. Levels greater than 21.0% or 23.0% aren’t the required minimum, and 19.0% is below the safe threshold.

The important idea is that a fit-testing environment must have enough oxygen to keep you safe and able to complete the test. The minimum safe level is 19.5% oxygen by volume. This threshold is used because below it the atmosphere is considered oxygen-deficient, which can cause dizziness, fainting, or impaired performance during the test. Normal air is about 20.9% oxygen, so the lowest acceptable value is just above 19.5%. That’s why the option stating greater than 19.5% is the best choice. Levels greater than 21.0% or 23.0% aren’t the required minimum, and 19.0% is below the safe threshold.