EPA Protocol Calibration
Model 400E Ozone Analyzer
Instruction Manual
198
P/N 04316 Rev: B
Audit Procedure:
1.
Turn on the zero-air flow in the audit device.
2.
After stabilization, record the analyzer zero.
3.
Generate an up-scale audit point.
4.
After stabilization, record the O
3
analyzer response.
5.
Assay the audit concentration using an audit UV photometer or certified transfer
standard.
6.
Repeat steps 4 and 5 for the two remaining up-scale audit points. If analyzer is
operated on 0-1.0 ppm range, four up-scale audit points must be used.
Results:
Results of the audit will be used to estimate the accuracy of the ambient air quality
data. Calculation of accuracy is described in Appendix 15 of the Q.A. Handbook
(Reference 11).
8.5.2.
Data Processing Audit
Data processing audit involves reading a strip chart record, calculating an average,
and transcribing or recording the results on the SAROAD form. The data processing
audit should be performed by an individual other than the one who originally
reduced the data. Initially, the audit should be performed 1 day out of every 2
weeks of data. For two 1 -hour period within each day audited, make independent
readings of the strip chart record and continue through the actual transcription of
the data on the SAROAD form. The 2 hours selected during each day audited should
be those for which either the trace is most dynamic (in terms of spikes) or the
average concentration is high.
The data processing audit is made by calculating the difference,
d
= [O
3
]R - [O
3
]A
where
d
= the difference between measured and audit values, ppm,
[O
3
]R = the recorded analyzer response, ppm, and
[O
3
]A = the data processing O
3
concentration, ppm.
If
d
exceeds
±
0.02 ppm, check all of the remaining data in the 2 week period.