Calibration Calibration of the analyzer establishes the relationship between actual pollutant concentration input and the analyzer response. Should be carried out at the field monitoring site by allowing the analyzer to sample test atmospheres containing known pollutant concentrations.

Points should appear as “walkable stairsteps” on the electronic chart. The calibration includes the zero concentration and five upscale concentrations spaced equally over the measurement scale range of the analyzer (0-0.500 PPM). Ozone or SO2 Calibrations: Set internal zero/span Generate 5 points NOx Calibration: Generate 5 points NO-NOx Generate 5 points NO2 0.400 PPM (span) 0.300 PPM 0.200 PPM 0.100 PPM 0.065 PPM 0.000 PPM (zero) Points should appear as “walkable stairsteps” on the electronic chart.

Example of a properly conducted and correctly documented ozone calibration.

Example of a properly conducted and correctly documented NOx calibration.

Recalibrations Should be performed after any of the following: Unacceptable QC precision check Unacceptable QA performance audit An extended interruption in analyzer operation Any repairs that might affect its calibration Physical relocation of the analyzer   Excessive zero or span drift Any other indication of possible significant inaccuracy of the analyzer