United States
Environmental Protection
Agency
Environmental Monitoring Systems
Laboratory
Research Triangle Park NC 27711
Research and Development
EPA-600/S4-83-003 Apr. 1983
Project Summary
Performance Test Results and
Comparative Data for Designated
Reference and Equivalent
Methods for Ozone
F. W. Sexton, R. M. Michie, Jr., F. F. McElroy, V. L. Thompson, and J. A. Bowen
This report summarizes the results
of both laboratory and field tests on
seven commercially available ambient
ozone analyzers to determine their per-
formance, reliability, and operational
peculiarities.
This Project Summary was developed
by EPA's Environmental Monitoring
Systems Laboratory, Research Triangle
Park. NC, to announce key findings of
the research project that is fully docu-
mented in a separate report of the
same title (see Project Report ordering
information at back).
Introduction
Under Part 53 of Title 40 of the Code of
Federal Regulations (40 CFR Part 53), the
U.S. Environmental Protection Agency
(EPA) designates specific ambient moni-
toring methods and analyzers as reference
or equivalent methods acceptable for use
in National Air Monitoring Stations (NAMS),
State and Local Air Monitoring Stations
(SLAMS), and Prevention of Significant
Deterioration (PSD) monitoring. The
Methods Standardization Branch (MSB)
of the Environmental Monitoring Systems
Laboratory (EMSL) of Research Triangle
Park, NC, is responsible for EPA's refer-
ence and equivalent method designation
program. In this capacity, MSB has ac-
quired performance data and other infor-
mation on these methods, most of which
are commercially available analyzer models.
To summarize this data and make it
available to those who may find it bene-
ficial in selecting analyzers, MSB, with the
assistance of the Research Triangle Insti-
tute, prepared this report on designated
methods for ozone. The data are offered
with minimum interpretation, leaving
readers to draw their own conclusions.
Types of Tests Conducted
Two principal types of postdesignation
tests were conducted by MSB. Phase I
tests were laboratory tests similar to the
predesignation tests required by 40 CFR
Part 53. Phase II tests simulated actual
use conditions and compared simultane-
ously operating analyzers. Results from
these postdesignation tests provide most
of the data in this report
The ozone analyzers that were tested
and their respective detection principles
are as follows:
Bendix 8002
MeloyOA 350-2 R
Beckman 950-A
Monitor Labs
8410E
McMillan 1100-2
Philips PW 9771
Dasibi 1003-AH
Ozone/ethylene
chemiluminescent
Ozone/ethylene
chemiluminescent
Ozone/ethylene
chemiluminescent
Ozone/ethylene
chemiluminescent
Ozone/ethylene
chemiluminescent
Ozone/rhodamine
B chemiluminescent
Ultraviolet absorption
Phase I Test Description and
Results
Phase I laboratory performance tests
were conducted in accordance with the
same procedures and specifications re-
quired for the applicant's predesignation
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tests, with the exception that fewer trials
(usually fou r) were performed for each test
parameter. All calibrations, apparatus,
pollutant standards, test procedures, test
atmospheres, and test documentation were
as specified in40 CFR Part53. (Individual
reports containing more detailed informa-
tion on the Phase I tests for each analyzer
are available from MSB.)
Analyzers undergoing Phase I tests were
first set up and allowed to operate for
several weeks prior to actual testing.
During this start-up period, preliminary
calibrations and linearity checks were per-
formed If a failure occurred during testing,
the manufacturer was notified and given
the opportunity to correct the failure. At
the conclusion of the test all failures and
manufacturer's involvement were included
in routine documentation. The following
analyzers were tested during the stated
periods:
Meloy OA 350-2 R
Monitor Labs
8410E
Bendix 8002
Dasibi 1003-AH
Philips PW9771
Beckman 950-A
McMillan 1110-2
May 1977 to
September 1977
November 197 7 to
April 1978
Phase I tests included output signal noise,
lower detectable limit (LDL), interference
equivalent 12 h and 24 h zero drifts, span
drift at 2096 and at 80% of full scale, lag
time, rise time, fall time, and precision.
Results are reported in Table 1. The total
interferent equivalent, zero drift, and span
drift data reported are averages of absolute
values; all other values represent the
arithmetic averages of four repetitions.
Phase I tests indicate that all ozone
analyzers tested met or exceeded the
performance specifications.
Phase II Test Description and
Results
Phase II tests were intended to test the
analyzer in a more or less typical ambient
monitoring configuration where the analyzer s
stability, reliability, general performance,
and operational peculiarities can be ob-
served, recorded, and compared with other
analyzers. The tests were conducted
simultaneously on groups of ozone analyzers
over a period of several months. All
analyzers measured ambient air sampled
from a common manifold. The ambient
pollutant concentrations were sometimes
augmented with artificially generated pol-
lutant to increase the concentration read-
ings.
All test analyzers were installed, cali-
brated, operated, and maintained in strict
accordance with the manufacturer's in-
struction manual and good monitoring
practice. Analyzers received a multipoint
calibration initially and once per month
during the test period. Zero and span
checks were made two or three times per
week Zero adjustments were made only if
the zero response was not within ± 3% of
full scale response from nominal; span
adjustments were made only if the span
(slope of the calibration curve) changed by
more than ± 7% from nominal. For this
report, data were collected from strip chart
recorders, reduced by hand, and entered
weekly into a Hewlett-Packard 9821A
Desk Top Computer. The Phase II tests
were conducted during three periods with
three analyzers per test Because there
were seven analyzers to be tested, the
Bendix 8002 was chosen to run in all
three tests as a reference, with the re-
maining six analyzers segregated in groups
of two. Phase II test groups and correspon-
ding dates are listed below.
Group 1: Bendix 8002 Test period:
Meloy OA 350-2 R September
Monitor Labs 8410 1977 to
December
1977
Group 2: Bendix 8002
Philips PW 9771
Dasibi 1003-AH
Test period:
May 1978
to
September
1978
Group 3: Bendix 8002 Test period:
McMillian 1100-2 June 1978
Beckman 950-A to
September
1978
Similar procedures were used for each
analyzer group. A UV photometer was
used to verify the ozone working standard.
The frequency of calibrations, zero, and
span checks remained the same. Test data
indicate that the Bendix 8002 was stable
throughout the studies.
Phase II results indicate that the ozone
analyzers tested are among the most stable
and reliable of continuous air monitoring
analyzers. The comparative data presented
in Table 2 indicate consistently high cor-
relation coefficients of 0.99, mean differ-
ences of < 3 ppb, and standard deviations
of differences of < 3 ppb.
Table 1. Phase I Postdesignation Test Results-Designated Ozone Analyzers
Performance
parameters
Noise - 0% URL
Noise - 80% URL
Lower detectable limit
Interferents
H2O
H2S
CO2
Total
Zero drift - 12 h
Zero drift - 24 h
Span drift - 20% URL
Span drift - 80% URL
Lag time
Rise time
Fall time
Precision -20% URL
Precision -80% URL
EPA
specifications
0.005 ppm
0.005 ppm
0.01 ppm
±0.02 ppm
±0.02 ppm
±0.02 ppm
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Statistics
Correlation coefficients
Mean difference, ppb
Standard deviation of
differences, ppb
Number of absolute
differences >20
Bendix
0.99
-0.36
2.47
2
Meloy
0.99
0.49
2.44
4
Beckman
0.99
0.54
2.52
0
Monitor Labs
0.99
•0.41
2.10
2
McMillan
0.99
0.66
2.22
0
Philips
0.99
2.63
3.68
0
Dasibi
0.99
-0.11
2.72
0
CSI
Not tested
Not tested
Not tested
Not tested
F. W. Sexton and R. M. Michie, Jr. are with the Research Triangle Institute,
Research Triangle Park, NC 277O9; the EPA authors F. F. McElroy, V. L.
Thompson (also the EPA Project Officers, see below), andJ. A. Bowen are with
the Environmental Monitoring Systems Laboratory, Research Triangle Park, NC
27711.
The complete report, entitled "Performance Test Results and Comparative Data
for Designated Reference and Equivalent Methods for Ozone," (Order No. PB
83-166 686; Cost: $11.50, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield. VA 22161
Telephone: 703-487-4650
The EPA Project Officers can be contacted at:
Environmental Monitoring Systems Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
WJ.S. Government Printing Office: 1983-659-017/7029
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Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
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Fees Paid
Environmental
Protection
Agency
EPA 335
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Penalty for Private Use $300
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