AS 3580.19:2020 Methods for sampling and analysis of ambient air Method 19: Ambient air quality data validation and reporting.
2.8 Calibration, check and maintenance criteria
2.8.1 General
Calibration, check and maintenance criteria are defined as critical, operational or systematic, as follows:
(a) Critical criteria — Where non-conformance requires data invalidation (see Clause 2.8.2).
(b) Operational criteria — Where non-conformance may require data invalidation (see Clause 2.8.3).
(c) Systematic criteria — Where non-conformance does not require data invalidation (see Clause 2.8.4).
The criteria listed in Tables 5 to i summarize those specified in current AS 3580 and AS/NZS 3580 Standards. However, additional requirements have been added in some instances, or alterations made.
2.8.2 Critical criteria
AS 3580 and AS/NZS 3580 series standards contain a list of instrument performance specifications. Conformance with manufacturer’s published performance specifications shall be deemed acceptable evidence of conformance to the given requirements.
Instrument performance specifications are considered critical criteria. Data collected by instruments that do not conform to the critical criteria shall be invalidated, as the method used does not conform to the applicable Standard.
Both manual and continuous methods for monitoring particulate matter specify control limits for the instrument flow rate, aimed at ensuring that the sampler inlet or size selective inlet fractionates the collected particles appropriately. Particulate matter samples or data obtained when the flow rate is outside the specified control limits shall consequently be invalidated.
For each data averaging period, a minimum data capture percentage of 75 % is a critical criterion (see Clause 3.3.2).
Critical criteria for pollutant concentration and meteorological measurements that require data validation shall be as set out in Tables 5 and 6. Additional criteria may be specified in the relevant Standard.
2.8.3 Operational criteria
If an operational criterion is not met, further checks or calibrations shall be conducted in order to validate the affected data, with reported data flagged, noting the non-conformance, and the check/calibration outcome documented. If non-conformance with the operational criterion cannot be clearly demonstrated to allow the reported method measurement uncertainty to be met, due to the magnitude of the non-conformance, the data shall be invalidated.
For example, AS/NZS 3580.9.6 and AS/NZS 3580.9.14 specify that HVS temperature sensor checks are required to be within ±1 °C. When the measured temperature is used to control the mass flow rate, a measured temperature sensor error of ±1.5 °C would alter the sample volumetric flow rate by only approximately 0.5 %, for an average ambient temperature of 20 °C. Provided the corrected flow rate is still within the limits for the size selective inlet and the overall measurement uncertainty remains within the reported limits, the data can be considered valid and consequently reported and flagged.AS 3580.19 pdf download.