EPA Protocol Calibration
Model 400E Ozone Analyzer
Instruction Manual
196
P/N 04316 Rev: B
To determine O
3
loss:
1.
Calibrate a stable ozone analyzer with the UV calibration system, assuming no
losses.
2.
Generate an O
3
concentration, and measure it with the analyzer as close as
possible to the actual inlet of the photometer cell.
3.
Measure the concentration as close as possible to the outlet of the cell.
4.
Repeat each measurement several times to get a reliable average.
5.
Measure the concentration at the output manifold. The tests should be repeated
at several different O
3
concentrations.
The percentage of O
3
loss is calculated as,
%
(
)
O loss
C
C
C
C
m
i
o
m
3
2
100
=
−
+
×
where
C
i
= O
3
concentration measured at cell inlet, ppm
C
o
= O
3
concentration measured at cell outlet, ppm, and
C
m
= O
3
concentration measured at output manifold, ppm.
For other configurations, the % O
3
loss may have to be calculated differently. The
ozone loss correction factor is calculated as:
L = 1 - 0.01 × % O
3
loss.
8.4.3.
Span Drift Check
The first level of data validation should accept or reject monitoring data based upon
routine periodic analyzer checks. It is recommended that results from the Level 1
span checks be used as the first level of data validation. This means up to two
weeks of monitoring data may be invalidated if the span drift for a Level 1 span
check is
≥
25%. For this reason, it may be desirable to perform Level 1 checks
more often than the minimum recommended frequency of every 2 weeks.