Personal Ozone Monitor Manual Rev. E-2
27
•
Setup check
•
Ozone loss test
•
Linearity check
•
Intercomparison test
11.4.1. Setup Check
A visual inspection of the calibration setup should be performed before calibration to
verify that the setup is in proper order. All plumbing connections should be checked
and verified to follow the manufacturer's instructions. Any obvious leaks should be
fixed and the manifold and sampling lines should be checked for general cleanliness.
For more information, refer to the manufacturer's User Manual for the primary ozone
standard or ozone transfer standard.
11.4.2. Ozone Loss Test
Some ozone may be lost in the calibration setup due to reaction with the walls of the
manifold and sampling lines. Any significant loss of ozone must be measured and be
subsequently applied to correct the calibration measurements. For more information,
refer to the manufacturer's User Manual for the primary ozone standard or ozone
transfer standard.
11.4.3. Linearity Check
Since the Personal Ozone Monitor is inherently linear over several orders of magnitude,
a linearity check provides a test that the instrument is operating properly. Instrument
linearity can be checked by comparison to an ozone standard (see Section 12.4,
“Calibration Procedure – Calibration Curve”) or by dilution of an ozone measurement.
To check the instrument linearity by dilution of an ozone measurement, generate and
measure a concentration of ozone near the upper range of ozone concentrations to be
measured using the POM. Additional ozone concentrations should be generated by
accurately diluting the ozone flow with zero air and each concentration should be
measured once the instrument reaches a stable response. The accuracy of the linearity
test relies on the accuracy of the flow meters used to perform the dilution. The percent
of non-linearity is calculated from the formula:
d
o
o
F
F
F
R
(2)
%
100
1
2
1
x
C
R
C
C
E
(3)
where:
R = Dilution ratio
F
o
= Ozone generator flow
F
d
= Diluent zero air flow
E = Linearity error, in percent
C
1
= Measured concentration of original concentration
C
2
= Measured concentration of diluted concentration
