Which is a typical QA/QC plan element for an ambient monitoring program?

• A. Regular instrument calibration (zero/span)
• B. Ignoring field blanks to save time
• C. Relying on a single instrument without calibration
• D. Delaying data reporting

Answer: (A)

Regular instrument calibration is a fundamental QA/QC element for an ambient monitoring program. Performing zero and span checks keeps the instrument’s baseline and its response to known concentrations accurate, so drift from aging sensors or shifts in sensitivity can be detected and corrected. This ongoing verification makes the data reliable, comparable over time, and defensible for regulatory reporting. If calibration isn’t routine, measurements can drift away from true ambient concentrations, leading to biased results and undermining data quality. While other QA/QC practices like field blanks and timely data handling are important, calibration is the primary mechanism that ensures each instrument is producing trustworthy data, rather than relying on an unverified tool.