&EPA
United States
Environmental Protection
Agency
Environmental Monitoring and Support EPA 600 4-79-015
Laboratory February 1979
Research Triangle Park NC 27711
Research and Development
Ozone
Calibration and
Audit by Gas Phase
Titration in Excess
Ozone
Bendix®
Transportable Field
Calibration System,
Models 8861 D and
8861 DA
-------
RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL MONITORING series.
This series describes research conducted to develop new or improved methods
and instrumentation for the identification and quantification of environmental
pollutants at the lowest conceivably significant concentrations. It also includes
studies to determine the ambient concentrations of pollutants in the environment
and/or the variance of pollutants as a function of time or meteorological factors.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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OZONE CALIBRATION AND AUDIT BY GAS PHASE TITRATION
IN EXCESS OZONE
(Bendix Transportable Field Calibration System, Models 8861D and 8861DA)
by
Thomas A. Lumpkin and Barry E. Martin
Field Studies Section
Environmental Monitoring and Support Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
ENVIRONMENTAL MONITORING AND SUPPORT LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
RESEARCH TRIANGLE PARK, NORTH CAROLINA 27711
-------
DISCLAIMER
This report has been reviewed by the Environmental Monitoring and Support
Laboratory, U.S. Environmental Protection Agency, and approved for publication.
Mention of trade names or commercial products does not constitute endorsement
or recommendation for use.
11
-------
ABSTRACT
Detailed procedures for the dynamic calibration and audit of chemilu-
minescence ozone analyzers are presented. These procedures were developed and
applied within the Environmental Monitoring Branch, Environmental Monitoring
and Support Laboratory, U.S. Environmental Protection Agency, Research Triangle
Park, North Carolina. The purpose of the procedures is to aid calibration and
audit personnel in performing calibrations and audits in exactly the same man-
ner with identical calibration systems.
The calibrations and audits are performed by means of a gas phase titration
technique utilizing the rapid gas phase reaction between nitric oxide and ozone
with excess ozone present. The nitric oxide is generated by using a cylinder
of nitric oxide in nitrogen that has been standardized against a National Bureau
of Standards Standard Reference Material. The instrument being calibrated or
audited must have a linear response to ozone. An ozone concentration is gener-
®
ated using a dynamic calibration system (Bendix Model 8861D or 8861DA) and
is introduced to the analyzer under calibration or audit to obtain an up-scale
response. A known concentration of nitric oxide is added to excess ozone in
the calibration system and the change in analyzer response noted. Under spe-
cifically controlled conditions, the decrease in analyzer response is equal
to both the concentration of ozone consumed and the concentration of nitric
oxide added. The original ozone concentration (before nitric oxide was added)
iii
-------
can then be calculated. Other calibration concentrations of ozone can be ob-
tained by diluting the original ozone concentration and repeating the gas phase
titration.
One of the advantages of these procedures is that chemiluminescence ozone
analyzers can be calibrated or audited in the field without the bulky equipment
required for the neutral buffered potassium iodide calibration procedure. A
second advantage is that more precise results can be obtained. A standardized
cylinder of nitric oxide replaces the potassium iodide solution, the set of
bubblers, the vacuum system, and the spectrophotometer required for the potas-
sium iodide method.
IV
-------
LIST OF ABBREVIATIONS AND SYMBOLS
ABBREVIATIONS
3
cm
GPT-0
hr
1
min
mol
NBKI
NBS
ppm
psig
s
SRM
URL
— cubic centimeter
— gas phase titration in excess ozone
— hour
- liter
— minute
— mole
— neutral buffered potassium iodide
— National Bureau of Standards
— parts per million
— pounds per square inch gauge
— second
— Standard Reference Material
— upper range limit
SYMBOLS
N2
NO
N02
NO
— nitrogen
— nitric oxide
— nitrogen dioxide
— total oxides of nitrogen
— oxygen
Vll
-------
0.
— ozone
— Input A pressure gauge setting
— Input B pressure gauge setting
— Input C pressure gauge setting
— triiodide ion
'NO
NO
V V F2
— cylinder NO concentration, ppm
— flow through 0 generator, cm /min
— NO flow rate, cm /min
— total dilution air flows, cm /min
— analyzer recorder response after
addition of NO to system, % chart
Z80' Z40'
— analyzer recorder response to 0 ,
% chart
' etc-
[03]80' [°3]60' etC'
(PAE)8(),
, etc.
— adjusted analyzer recorder response
to 0 , % chart
— 0 concentration at URL of 80%,
60%, etc., ppm
— percent audit error at URL of 80%,
60%, etc.
— adjusted analyzer recorder response,
% chart
U
— unadjusted analyzer recorder response,
% chart
Vlll
-------
ACKNOWLEDGMENTS
The personnel of the Field Studies Section, Environmental Monitoring
Branch, contributed important input after testing and using the procedures.
Special recognition is due Mr. Kenneth Rehme and Mr. Frederick Smith of the
Monitoring Techniques Evaluation Section, Environmental Monitoring Branch, for
the initial testing and evaluation of the gas phase titration in excess ozone
technique.
IX
-------
SECTION 1
INTRODUCTION
The Federal Register specifies the neutral buffered potassium iodide
(NBKI) method as the procedure for calibration of designated reference methods
for measurement of photochemical oxidants (1). This procedure consists of
passing a generated ozone (0 ) concentration through a NBKI solution and then
measuring the triiodide ion (I ) concentration with a calibrated spectrophoto-
meter. The 0 concentration can be determined from the I concentration and
the known volume of air passed through the NBKI. The basic equipment is an O
generator, a dilution air supply, a flowmeter, a bubbler train, a vacuum
system, and a spectrophotometer. Commercially available calibration systems
usually combine a dilution air supply with an 0 generator. The remaining
equipment can become difficult to manage and operate on field calibrations,
especially if air travel is involved. Often, due to lack of proper facilities,
the NBKI procedure cannot be performed as precisely in the field as in the
laboratory. Also, the spectrophotometer may require recalibration after being
moved from place to place in the field. Recalibration of the spectrophotometer
involves exact standards and is difficult to accomplish under field conditions.
This report describes procedures for performing O calibrations and audits.
These procedures — gas phase titration in excess ozone — utilize a standard
-------
nitric oxide (NO) gas cylinder as the reference standard. The only other
equipment necessary is a flowmeter and a calibration system capable of sup-
plying specified stable O concentrations at specified flow conditions. Al-
though a significant difference exists between these procedures and the NBKI
procedure, the difference is consistent. Thus the procedure can be referenced
to the NBKI procedure specified in the Federal Register.
-------
SECTION 2
CONCLUSIONS AND RECOMMENDATIONS
Using these procedures, the calibration and audit of 0 analyzers requires
less complicated equipment than with the NBKI procedure. In addition, more
consistent and more precise results can be obtained in the field. These pro-
cedures have been used successfully by the Environmental Monitoring Branch on
two previous studies: the 1975 Summer Ozone Study and the 1976 Washington,
D.C. Oxidant-Hydrocarbon Study. The procedures are presently being used on
the National Forest Ozone Study which began in 1976.
®
Although the procedures have been written for a modified Bendix Model
®
8861D or a Bendix Model 8861DA Transportable Field Calibration System, any
comparable calibration system can be used by modifying the procedures slightly.
Any different calibration system must be thoroughly tested and shown to be
consistent with the NBKI procedure.
-------
SECTION 3
PRINCIPLE
Ozone calibration by gas phase titration in excess ozone (GPT-0 ) is
based upon the rapid gas phase reaction between O and NO in accordance with
the following equation (1,2):
NO + O -»• NO +0 k = 1.0 x 10 1/mol s
An O concentration of unknown magnitude is generated in a dynamic calibration
system and sufficient NO of known concentration is added to decrease the O.
concentration by 90-95% of its original value as measured on an uncalibrated
chemiluminescence 0, analyzer. If the exact NO concentration is known, the
concentration of 0 can be determined and can then be used to calibrate the O
analyzer. The standardization of the NO cylinder used in this technique is
based on direct comparison with a certified National Bureau of Standards (NBS)
NO Standard Reference Material (SRM). The flow conditions used in the dynamic
calibration system are optimized to ensure the quantitative reaction of NO
with 0 and to minimize the reaction of nitrogen dioxide (N0?) and O which
can lead to errors in the calibration procedure. Erroneous results will also
occur if the analyzer response is nonlinear. The analyzer linearity is verified
by a dilution technique described in Section 6.
-------
SECTION 4
APPARATUS
/*v
BENDIX' TRANSPORTABLE FIELD CALIBRATION SYSTEM, MODEL 8861D OR MODEL 8861DA
Figures 1 and 2 illustrate Bendix Models 8861D and 8861DA, respectively.
The Model 8861D system should be modified as described below and as shown in
the flow diagram in Figure 3. In Figure 3, the modified sections are enclosed
in broken lines. The modifications make the calibration system more effective
and versatile in calibrating and auditing 0 analyzers by these procedures.
Modification of Bendix Model 8861D
Step 1—
Replace the 0-15 psig NO pressure gauge with a 0-25 psig gauge. Dismantle
the O generator-flow capillary compartment and replace the NO flow capillary
with one that will give a flow rate of about 20 cm /min at 25 psig. This
modification allows higher concentrations of NO to be obtained from the calibra-
tion system at the specified dilution flow rates.
-------
©
Figure 1. Modified Bendix Model 8861D Transportable Field Calibration System.
-------
-
Figure 2. Bendix Model 8861DA Transportable Field Calibration System.
-------
CLEAN
AIR
CLEAN-UP
LAMP
r
FILTER
( '
^ ,
AIR PUMP
WATER DROP-OUT
Figure 3. Flow Diagram for modified Bendix Transportable Field Calibration System.
-------
Step 2-
While the compartment is dismantled, remove the orifice fitting that con-
trols the flow through the 0 generator and plug the hole from which the fitting
was removed. Replace the fitting at the inlet to the 0 generator with the
®
orifice fitting. Connect an 18-in length of 1/8-in o.d. Teflon tubing to the
®
orifice fitting. Close the compartment, leaving the free end of the Teflon
tubing outside the compartment. Connect an additional pressure regulator and
gauge (0-25 psig, preferably similar to original equipment) to the zero air
supply upstream from the existing regulator and gauge that control the dilu-
®
tion air flow. Connect the Teflon tubing to the outlet of the pressure regu-
lator just installed. This modification allows the flow through the 0_ gener-
ator to be controlled separately by the new regulator and gauge. The modifica-
tion is needed primarily for calibrations and audits of 0 analyzers by the
GPT-0 procedure. Although the modification is not essential for calibrations
and audits of NO/NCv/NO analyzers, the system can still be used to calibrate
^ X
such analyzers.
Step 3-
Remove the condensing coil from the system. Cut the electrical wires to
the fan and remove it from the system. Insulate the ends of the cut wires.
Install a silica gel scrubber (0.5 1 or larger capacity) in line between the
water dropout and the cleanup lamp. This modification gives a drier calibra-
tion air than that obtained with the condenser-fan assembly.
11
-------
Step 4-
Replace the small charcoal-soda lime filter downstream from the surge
tank with one with a capacity of at least 0.5 1. This will allow the calibra-
tion system to be operated for a longer time between scrubber material changes.
0 ANALYZER
Any chemiluminescence 0- analyzer that has a rapid and linear response
to 0 can be calibrated by this technique. Ozone analyzers using other measure-
ment principles can be calibrated if they do not respond to NO or NO».
FLOWMETER
A bubble flowmeter kit and/or a wet-test meter capable of measuring abso-
lute flow rates between 1 and 5000 cm /min is required.
PRESSURE REGULATOR
The standard NO cylinder requires a pressure regulator with stainless
®
steel internal parts and Teflon seats.
SAMPLE MANIFOLD
A Kjeldahl mixing bulb (approximately 300 cm volume) with a multiport
glass manifold is recommended.
12
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SECTION 5
REAGENTS
STANDARD NO CYLINDER
The cylinder should contain approximately 100 ppm NO in nitrogen (N ).
The NO content of the cylinder is determined by comparison with a NBS NO SRM.
ZERO AIR
®
The Bendix Model 8861 Transportable Field Calibration Systems supply air
free of contaminants that would cause a detectable response in the 0 analyzer
or interfere with the 0 calibration. The zero air supply of the Model 8861D
System should include two scrubbing columns; the first column should contain
indicating silica gel and the second should contain 1/2 soda lime and 1/2
activated charcoal, in that order. These two scrubbing columns should be
replaced after 8 hr of actual use, or sooner (if indicated by the silica gel).
The Model 8861DA System should have one scrubbing column containing 1/2 soda
lime and 1/2 activated charcoal, in that order. This column should be re-
placed after 8 hr of actual use.
13
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SECTION 6
CALIBRATION PROCEDURE
®
The flow conditions in the Bendix Model 8861 Transportable Field Calibra-
tion Systems are optimized for this procedure and must be duplicated precisely
to ensure the validity of the calibration.
STEP 1
Record pertinent information about the analyzer being calibrated in the
space provided on the data sheet (see Appendix A). If a request for informa
tion does not apply, write "N/A" in the space. In the margins, record any
pertinent information needed for a particular analyzer but not specifically
requested on the data sheet. Adjust all analyzer flow rates to the manufac-
turer's specifications.
STEP 2
Connect the standard NO cylinder to the Bendix calibration system. Open
the cylinder valve and let the NO flow rate stabilize. The pull-to-test valve
for NO should be out while the 0 generator and dilution air flow rates are
measured. Place the sample manifold on the outlet of the calibration system.
15
-------
(See Figure 4 for the arrangement of the calibration apparatus.) Switch
capillaries 1, 2, 3, and 4 of Input C (dilution air) to the "OFF" position.
Set the air flow through the 0 generator to 150-200 cm /min by adjusting the
Input A gauge pressure. Measure the flow using a bubble flowmeter attached
to the outlet of the calibration system. (The sample manifold must be dis-
connected each time a flow measurement is made at the outlet of the system.)
Record the 0 generator air flow (F ) and the Input A pressure gauge setting
j G
(P ) on the data sheet.
STEP 3
Set the total air flow to approximately 2500 cm /min by adjusting the
Input C gauge pressure (any combination of capillaries 1, 2, 3, and 4 can be
used). Using a bubble flowmeter or wet-test meter, measure the total air flow
at the outlet of the calibration system. Record the total air flow (F ), Input
C pressure gauge setting (P ), and capillaries used on the data sheet.
STEP 4
Advance the O analyzer recorder chart a few inches from the last ambient
air trace and allow the analyzer under calibration to sample its internal zero
air (if applicable) until a stable response is obtained. Then allow the ana-
lyzer to sample calibration zero air until a stable response is obtained.
Record the unadjusted recorder response (Z ) for the analyzer's zero and for
calibration zero air. Make the proper zero adjustment to the analyzer using
16
-------
STAINLESS
STEEL
REGULATOR
CALIBRATION SYSTEM
(BENDIX , MODEL 886ll> OR
MODEL 886 IDA)
GLASS MIXING BULB AND MANIFOLD
FLOW
BUBBLE FLOWMETER
(OR WET TEST METER)
i—I n r~< r
STANDARD
NO CYLINDER
OZONE ANALYZER
Figure 4. Flow scheme for calibrations and audits by gas phase titration in excess ozone.
-------
the calibration zero air as the reference. Record the adjusted recorder
response (Z ) and adjusted zero setting on the data sheet.
STEP 5
Switch the 0 generator to the appropriate range and adjust the set point
dial to provide an 0 concentration of approximately 80% of the upper range
limit (URL) as measured on the 0 analyzer. Record the analyzer response (Ion)
•j oU
and the 0 generator set point on the data sheet.
STEP 6
Add the NO flow by pushing the pull-to-test valve in and adjust the Input
B pressure regulator until the O analyzer response has decreased by 90-95%
of its original value. For example, if I = 85% chart and Z = 5% chart, the
NO flow should be adjusted to yield an analyzer response of 9-13% chart. Re-
cord the analyzer response (I) after it has stabilized.
STEP 7
Measure the NO flow using a bubble flowmeter attached to the pull-to-test
valve. Record the NO flow (F ), cylinder NO concentration (C ), and Input B
NO NO
pressure gauge setting (P ) on the data sheet.
B
18
-------
STEP 8
Calculate the exact NO concentration from:
[NO] - (Eq.
NO 0
where [NO] = NO concentration, ppm
F ^ = NO flow, cm /min
NO
C = cylinder NO concentration, ppm
NO
F = total air flow, cm /min
Record the calculations on the data sheet.
STEP 9
Calculate the 0 concentration from:
I - Z
[°3]80 = I - I * tNO] (Eq- 2)
where [0-J0n = 80% URL 0 concentration, ppm
3 oU 3
[NO] = NO concentration, ppm
I0/. = original O_ analyzer response, % chart
bU 3
1=0 analyzer response after addition of NO, % chart
Z = adjusted zero air recorder response, % chart
19
-------
Calculate the response to which the recorder should be adjusted as follows:
[°3]80
J8o(A) = URT—+ZA (E^ 3)
where I (A) = adjusted recorder response, % chart
oU
URL = upper range limit, ppm
Record the calculations on the data sheet.
STEP 10
With the NO flow removed, the 0 analyzer response should return to its
original value (Ior.). If the response does not return to within ± 1% chart
80
of I , recheck I by adding NO to the system again. If I is exactly the same
oU
as before, remove the NO and let the 0 response return to its new value.
Record this new response as I and recalculate [O ] and I (A). If I is
oO 3 oU oO
not the same as before, measure the NO flow again and recalculate [NO], [O_]o
j o
and Iori(A). After the O response has stabilized up-scale, record this new
80 j
value as I . Adjust the span control until the analyzer recorder gives the
oU
desired response as .calculated in Equation 3. Record the adjusted recorder
response [I (A)] and adjusted span setting on the data sheet.
STEP 11
Adjust the Input C gauge pressure to give a total air flow of approximately
3300 cm /min. Using a bubble flowmeter or wet-test meter, measure the total
20
-------
air flow at the outlet of the calibration system. Record the total air flow
(F ) , Input C pressure gauge setting (P ) , and the capillaries used on the data
J. L-
sheet. Calculate the diluted O_ concentration at 60% URL ([0,]c.) from:
J 3 DU
[°3]60= [°3]80Xi (E<5' 4)
where [O.]rr. = 60% URL 0, concentration, ppm
3 60 3
[0 ] = 80% URL 0 concentration, ppm
380 3
F = original total air flow, cm /min
F = total air flow after dilution, cm /min
Record the calculations and the recorder response (I-.) on the data sheet.
oO
STEP 12
Readjust the Input C gauge pressure to give the original total air flow
(F ). Repeat Steps 5 through 10, substituting 40% URL for 80% URL, I for
I , and [O ] for [0 ] . Disregard the reference in Step 9 to adjusted
80 3 40 3 oO
recorder response. Make no further adjustment to the analyzer span control.
Note; In Step 6, the 0 response should be decreased by 90-95% of its new
3
value. For example, if I = 45% chart and Z = 5% chart, the NO flow should
^t \J f\
be adjusted to yield an analyzer response of 7-9% chart.
STEP 13
Adjust the Input C gauge pressure to give a total air flow of approximately
5000 cm /min. Using a bubble flowmeter or wet-test meter, measure the total
21
-------
air flow at the outlet of the calibration system. Record the total air flow
(F ) , Input C pressure gauge setting (P ), and the capillaries used on the
^ V-*
data sheet. Calculate the diluted 0 concentration ([0 ] ) from:
[°3]20= [°3]40X?7 (B* 5)
where [0 ] = 20% URL 0 concentration, ppm
[0 ] 0 = 40% URL 0 concentration, ppm
F = original total air flow, cm /min
F = total air flow after dilution, cm /min
Record the calculations and the recorder response (I5n) on the data sheet.
STEP 14: RECORDING RESULTS ON DATA SHEET
a. Record the 0, concentrations generated and the analyzer responses
obtained at these concentrations. Also record the zero and span settings
before and after adjustments were made.
b. Plot the analyzer response (y axis) versus 0 concentration (x axis)
(see Figure Al). The analyzer response should be linear within ± 1%.
c. Summarize any problems encountered during the calibration. If this
was a field calibration, name persons from local agencies present during the
calibration.
22
-------
d. Record on the 0 analyzer recorder chart the name of the station
calibrated, the date, information for each trace on the chart, and the time the
calibration was begun. If possible, remove the calibration segment of the
recorder chart and attach it to the data sheet. Advance the recorder chart,
synchronize the time, and date it. If a portion of the recorder chart is re-
moved, explain on remaining chart that a calibration took place. Do not destroy
any ambient air data while cutting the chart.
23
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SECTION 7
AUDIT PROCEDURE
If the Model 8861D Calibration System is used, it should be modified as
®
described in Section 4. The flow conditions in the Bendix Model 8861 Trans-
portable Field Calibration Systems are optimized for this procedure and must
be duplicated precisely to ensure the validity of the audit.
STEP 1
Record pertinent information about the analyzer being audited in the space
provided on the data sheet (see Appendix B). If a request for information does
not apply, write "N/A" in the space. In the margins, record any pertinent in-
formation needed for a particular analyzer but not specifically requested on
the data sheet. Do not make any adjustments to the analyzer.
STEP 2
Connect the NO cylinder to the Bendix Calibration System. Open the
cylinder valve and let the NO flow rate stabilize. The pull-to-test valve for
NO should be out while the 0 generator and dilution air flow rates are mea-
sured. Place the sample manifold on the outlet of the calibration system.
25
-------
(See Figure 4 for the arrangement of the calibration apparatus.) Switch
capillaries 1, 2, 3, and 4 of Input C (dilution air) to the "OFF" position.
Set the air flow through the 0 generator to 150-200 cm /min by adjusting the
Input A gauge pressure. Measure the flow using a bubble flowmeter attached
to the outlet of the calibration system. (The sample manifold must be dis-
connected each time a flow measurement is made at the outlet of the system.)
Record the 0 generator air flow (F ) and the Input A pressure gauge setting
3 Cj
(P ) on the data sheet.
STEP 3
Set the total air flow to approximately 2500 cm /min by adjusting the
Input C gauge pressure (any combination of capillaries 1, 2, 3, and 4 can be
used). Using a bubble flowmeter or wet-test meter, measure the total air flow
at the outlet of the calibration system. Record the total air flow (F ), In-
put C pressure gauge setting (P ), and capillaries used on the data sheet.
\*
STEP 4
Advance the O analyzer recorder chart a few inches from the last ambient
air trace and allow the analyzer under audit to sample zero air from the calibra-
tion system for about 30 min or until a stable response is obtained. Record
the unadjusted recorder response (Z ) for audit zero air.
26
-------
STEP 5
Switch the 0, generator to the appropriate range and adjust the set point
dial to provide an 0 concentration of approximately 80% of URL as measured
on the 0_ analyzer. Record the analyzer response (Ior.) and the O_ generator
j oU j
set point on the data sheet.
STEP 6
Add the NO flow and adjust the Input B pressure regulator until the 0
analyzer response has been decreased by 90-95% of its original value. For
example, if I = 85% chart and Z = 5% chart, the NO flow should be adjusted
OU U
to yield an analyzer response of 9-13% chart. Record the analyzer response
(I) after it has stabilized.
STEP 7
Measure the NO flow using a bubble flowmeter attached to the pull-to-test
valve. Record the NO flow (F ), cylinder NO concentration (C ), and Input B
NO NO
pressure gauge setting (P ) on the data sheet.
B
STEP 8
Calculate the exact NO concentration from:
27
-------
where [NO] = NO concentration, ppm
F _ = NO flow, cm /min
NO
C = cylinder NO concentration, ppm
F = total air flow, cm /min
Record the calculations on the data sheet.
STEP 9
Calculate the 0. concentration from:
I ~ Z
[°3]80 = i80 - j" x [NO] (E(5' 2)
80
where [0-]on = 80% URL 0_ concentration, ppm
-3 oU J
[NO] =.NO concentration, ppm
I = original 0 analyzer response, % chart
ou j
I = O analyzer response after addition of NO, % chart
Z = unadjusted zero air recorder response, % chart
Record the calculations on the data sheet.
STEP 10
With the NO flow removed, the 0 analyzer response should return to its
original value (Ion) . If the response does not return to within ± 1% of I.,.,
oU 80
recheck I by adding NO to the system again. If I is exactly the same as before,
remove the NO and let the 0 response return to its new value. Record this new
28
-------
response as I and recalculate [0 ] . If I is not the same as before, mea-
oO 3 oU
sure the NO flow again and recalculate [NO] and [0 ] . After the O response
3 80 3
has stabilized up-scale, record this new value as I0_. Calculate and record
oO
the percent audit error (PAE) from:
URL (I - Z )
(PAE)80 = [0
where (PAE)0l_ = percent audit error at.80% URL
oU
URL = full scale range
I = original O analyzer response, % chart
oO 3
[0 ] = 80% URL O concentration, ppm
3 oU 3
Z = unadjusted zero air response, % chart
STEP 11
Adjust the set point dial on the 0 generator to give an 0 concentration
of approximately 50% of the URL and repeat Steps 5 through 10, substituting
40% URL for 80% URL, I^Q for IQQ, [0^ 4Q for [0^^, and (PAE)4Q for (PAE)8Q.
STEP 12: RECORDING RESULTS ON DATA SHEET
a. Record the O concentrations generated and the analyzer responses
and PAE values obtained at these concentrations.
29
-------
b. Plot the analyzer response (y axis) versus O concentration (x axis)
(see Figure Bl). The audit limits shown are ± 2% of full scale for zero and
± 15% difference between actual and observed values for up-scale readings.
c. Summarize any problems encountered during the audit. If this was a
field audit, name persons from local agencies present during the audit.
d. Record on the 0 analyzer recorder chart the name of the station
audited, the date, information for each trace on the chart, and the time the
audit was begun. If possible, remove the audit segment of the recorder chart
and attach it to the data sheet. Advance the recorder chart, synchronize the
time, and date it. If a portion of the chart is removed, explain on the re-
maining chart that an audit took place. Do not destroy any ambient air data
while cutting the chart.
30
-------
REFERENCES
1. Hodgeson, J. A., R. E. Baumgardner, B. E. Martin, and K. A. Rehme. Stoi-
chiometry in the Neutral lodometric Procedure for Ozone by Gas Phase
Titration with Nitric Oxide. Anal. Chem., 43(8):1123-1126, 1971.
2. Rehme, K. A., B. E. Martin, and J. A. Hodgeson. Tentative Method for
the Calibration of Nitric Oxide, Nitrogen Dioxide, and Ozone Analyzers
by Gas Phase Titration. EPA-R2-73-246, U.S. Environmental Protection
Agency, Research Triangle Park, North Carolina, 1974.
3. Rehme, K. A. Application of Gas Phase Titration in the Calibration of
Nitric Oxide, Nitrogen Dioxide and Ozone Analyzers. In: Calibration
in Air Monitoring, ASTM STP 598, American Society for Testing and
Materials, 1976. pp. 198-209.
31
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1.
APPENDIX A
SAMPLE GPT-O CALIBRATION DATA SHEET
STATION
CALIBRATION PERSONNEL
ADDRESS
DATE
Analyzer Calibrated
Ethylene Cylinder: Mfgr.
Ethylene Flow Rate
Sample Flow Rate
Zero Base Line
S/N
S/N Pressure psig
cm /min
3. .
cm /nun
% chart
Unadjusted Zero Setting
Unadjusted Span Setting
Full Scale Range Selector Switch Position
Time Constant Selector Switch Position
Mode Selector Switch Position
Calibration System
NO Cylinder: Mfgr.
Room Temperature
S/N
S/N
Pressure psig Cone.
ppm
°C Barometric Pressure
in Hg
NOTE: Refer to the "Ozone Calibration by Gas Phase Titration in Excess
Ozone" procedure.
33
-------
2. 0_ Generator Flow: F
j
Vol. Meas.
FG=
)cra3/(
_cm Time
)min =
mm
Input A Pressure Gauge Setting: P =
cm /min
% gauge
3. Total Air Flow: F,
Time (min)
Avg. Time (min) Vol. Meas. (cm )
1)
2)
3)
)cm /(
)min =
Input C Pressure Gauge Setting: P =
L^
cm /min
% gauge
Capillaries Used: 1234 (Circle)
4. Zero Air Data
Analyzer
Calibration
Unadjusted Recorder Response:
Adjusted Recorder Response:
% chart
Adjusted Zero Setting:
% chart
5. 80% URL Data
O Analyzer Recorder Response: I =
3 80
O Generator Setting:
% chart
34
-------
6. 0 Analyzer Recorder Response (with NO present): I = % chart
7. NO Flow: F^
NO
Time (min) Avg. Time (min) Vol. Meas. (cm )
1)
2)
3)
F _ = ( )cm /( )min = cm /min
NO -
Cylinder NO Concentration: C = _ ppm
Input B Pressure Gauge Setting: P = _ % gauge
B -
FNO X CNO ( ) ( ) ( )
- - = - • - ppm
9. [0 , = x [HO] , - 1 - x , , , = _ ppn,
* 80 v - ; v ;
10. Span Data
Unadjusted Recorder Response: I = % chart
oU
Adjusted Recorder Response: Iori(A) = % chart
ou ^^^^^^^—^^—^—^^—^^—^^—^^-~—
Adjusted Span Setting:
35
-------
11. 60% URL Data
New Total Air Flow: F
Time (min)
1)
2)
3)
)cm3/(
Avg. Time (min)
)min =
Input C Pressure Gauge Setting: P =
Capillaries Used: 123
Vol. Meas. (cm )
(Circle)
cm /min
% gauge
t03]60
ppm
0. Analyzer Recorder Response: I
3
% chart
12. 40% URL Data
0 Analyzer Recorder Response: I
40
0 Generator Setting:
% chart
0 Analyzer Recorder Response (with NO present): I =
NO Flow: F
NO
Time (min)
% chart
Avg. Time (min)
Vol. Meas. (cm )
1)
2)
3)
FNO=
)cm3/(
)min =
Cylinder NO Concentration: C =
Input B Pressure Gauge Setting: P =
B
cm /min
ppm
% gauge
36
-------
Input C Pressure Gauge Setting:
Capillaries Used: 1 2
P =
[NO] =
F x C
NO NO
F + F
NO 0
% gauge
(Circle)
ppm
- Z
[°3]40
ppm
13. 20% URL Data
New Total Air Flow: F,
<:
Time (min)
1)
2)
3)
F2 =
)cm3/(
Avg. Time (min)
Vol. Meas. (cm )
)min =
Input C Pressure Gauge Setting: P =
Capillaries Used: 123
cm /min
% gauge
(Circle)
[°3]20
) x
0 Analyzer Recorder Response: I =
ppm
% chart
14. Results
a. 03 Concentration, ppm
[03]Q = 0.00
[°3]20=
[°3]40=
[°3]60=
[°3]80=
Analyzer Response, % chart
37
-------
Before Adjustment . After Adjustment
Zero Setting .
Span Setting
b. (See Figure Al)
c. (Remarks)
38
-------
cc
<
X
o
100-
90-
80-
o
cr
UJ
Q.
70-
S 60~
z
o
°- 50-
co ^^ '
LJ
ir
cr 40-
N
V
30-
o
N
O
20-
o-
u 1
0
0
0.05
0.10
0.10
0.20
0,15
0.30
0.20
0.40
0.25
0.50
OZONE CONCENTRATION, ppm
Figure Al. Calibration curve — analyzer response versus 0 concentration.
39
-------
1. STATION
ADDRESS
APPENDIX B
SAMPLE GPT-0 AUDIT DATA SHEET
AUDITOR
DATE
Analyzer Audited
Ethylene Cylinder: Mfgr.
Ethylene Flow Rate
Sample Flow Rate
Zero Base Line
S/N
S/N
Pressure
psig
cm /min
_cm /min
% chart
Unadjusted Zero Setting
Unadjusted Span Setting
Full Scale Range Selector Switch Position
Time Constant Selector Switch Position
Mode Selector Switch Position
Calibration System
NO Cylinder: Mfgr.
Room Temperature
S/N
S/N
Pressure psig Cone.
C Barometric Pressure in Hg
ppm
NOTE: This is an audit. Do not make any adjustments to the analyzer.
(Refer to the "Ozone Audit by Gas Phase Titration in Excess Ozone"
Procedure.)
41
-------
2.
0_ Generator Flow: F
3 G
Vol. Meas. cm Time
F^, = ( )cm /( )min =
it A Pressure Gauge Setting: P =
min
cm /min
% gauge
3. Total Air Flow: F
0
Time (min)
Avg. Time (min)
Vol. Meas. (cm )
1)
2)
3)
Fo =
)cm3/(
)min =
Input C Pressure Gauge Setting: P =
\^
cm /min
% gauge
Capillaries Used:
(Circle)
4. Unadjusted Recorder Response: Z =
% chart (audit zero air)
5. 80% URL 0 Data
0. Analyzer Recorder Response: I =
3 o(J
% chart
0- Generator Setting:
6. 0 Analyzer Recorder Response (with NO present): I =
% chart
42
-------
7. NO Flow: FNQ
Time (min) Avg. Time (min) Vol. Meas. (cm )
1)
2)
3)
3 3
F = ( )cm /( )min = cm /min
Cylinder NO Concentration: C = ppm
Input B Pressure Gauge Setting: P = % gauge
g
FNO X CNO ( ) ( ) ( )
8. [NO] = M" N" = ] 4 f = + f = ppm
NO 0 V ' ^ '
9- [03]Qo = i^r* [NO] H ~- fx( > = ( ( )( ) } =—K»
ou
Recorder Response: Ior> = % chart
URL
(rAE)80
(I80-V „„ « ,
'°3'80 ' <
( - )
)
- 100 =
11. 40% URL 0 Data
0 Analyzer Recorder Response: I = % chart
O Generator Setting:
O Analyzer Recorder Response (with NO present): I = % chart
NO Flow: FNQ
Time (min) Avg. Time (min) Vol. Meas. (cm )
1)
2)
3)
F = ( )cm /( )min = cm /min
43
-------
Cylinder NO Concentration: C = _ ppm
Input B Pressure Gauge Setting: P = _ % gauge
B
. , FNO X CNO ()()()
11)01 = - - = - -
Recorder Response: I = _ % chart
URL II40 - V
12. Results
a. 03 Concentration, ppm Analyzer Response, % Chart PAE
[03]Q = 0.000
i40-
i80=
b. (See Figure Bl) .
c. (Remarks)
44
-------
—
a:
<
T.
O
—
Z
LU
U
cr
1 1
-%
j_
i
LU
Z
o
a.
C/)
LU
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
REPORT NO.
EPA 600/4-79-015
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
Ozone Calibration and Audit by Gas Phase Titration In
Excess Ozone Bendix Transportable Field Calibration
JLvstem. Models RSfiin and 8861 DA
5. REPORT DATE
February 1979
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Thomas A. Lumpkin
Barry E. Martin
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Field Studies Section
Environmental Monitoring and Support Laboratory
U. S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
10. PROGRAM ELEMENT NO.
1AD606
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
Environmental Monitoring and Support Laboratory/RTP
Office of Research and Development
U. S. Environmental Protection Agency
Research Triangle Park, N. C. 27711
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
EPA/600/08
15. SUPPLEMENTARY NOTES
16. ABSTRACT
Detailed procedures for the dynamic calibration and audit of chemiluminescence
ozone analyzers are presented. The calibrations and audits are performed by means
of a gas phase titration technique utilizing the rapid gas phase reaction between
nitric oxide and ozone with excess ozone present.
The purpose of this report is to aid calibration personnel in performing
calibrations and audits in exactly the same manner with identical calibration systems.
One of the advantages of the procedures is that chemiluminescence ozone analyzers
can be calibrated or audited in the field without the bulky equipment required for
the neutral buffered potassium iodide calibration procedure. A second advantage is
that more precise results can be obtained.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Croup
air pollution
calibration
gaseous pollutants
ozone
gas phase titration
43 F
68 A
18. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (This Report)
Unclassified
21. NO. OF PAGES
56
20. SECURITY CLASS (Thispage)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
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