Which statement is correct regarding air monitoring?

Which statement is correct regarding air monitoring?

• A. There are standard response curves that include all monitors.
• B. Conversion factors apply the same to every monitor.
• C. They all measure in upper explosive limits.
• D. Each is calibrated to a specific gas.

Answer: (D)

Gas detectors are calibrated for individual gases because sensor chemistry responds differently to each gas. Calibrating with a known concentration of the specific gas sets the sensor’s reading to match the actual amount in the air, so measurements are accurate and reliable. Even in multi-gas devices, each sensor channel detects a particular gas and requires its own calibration gas and procedure. Using the wrong calibration gas or a generic, one-size-fits-all curve can produce readings that misrepresent danger levels. That’s why calibration is tied to a specific gas. The other statements aren’t accurate because there isn’t a universal response curve for all monitors, conversion factors vary by gas and sensor type, and monitors don’t all measure only in upper explosive limits—many operate in ppm, percent oxygen, or percent LEL depending on the sensor.

Gas detectors are calibrated for individual gases because sensor chemistry responds differently to each gas. Calibrating with a known concentration of the specific gas sets the sensor’s reading to match the actual amount in the air, so measurements are accurate and reliable. Even in multi-gas devices, each sensor channel detects a particular gas and requires its own calibration gas and procedure. Using the wrong calibration gas or a generic, one-size-fits-all curve can produce readings that misrepresent danger levels. That’s why calibration is tied to a specific gas. The other statements aren’t accurate because there isn’t a universal response curve for all monitors, conversion factors vary by gas and sensor type, and monitors don’t all measure only in upper explosive limits—many operate in ppm, percent oxygen, or percent LEL depending on the sensor.