United States
Environmental Protection
Agency
Environmental Monitoring Systems
Laboratory
Research Triangle Park NC 27711
Research and Development
EPA-600/S4-81 -077 Dec. 1981
Project Summary
A Summary of the EPA
National Source Performance
Audit Program—1980
R. G. Fuerst, E. W. Streib, and M. R. Midgett
A national quality assurance audit
program for methods used in stationary
source tests was conducted in 1980
by the Quality Assurance Division of
the Environmental Monitoring Sys-
tems Laboratory, U.S. Environmental
Protection Agency, Research Triangle
Park, North Carolina. In this program,
quality assurance materials were sent
to interested participants for the mea-
surement of a gas volume (Method 5,
dry gas meter only) or the analysis of
liquid samples simulating collected
sulfur dioxide and nitrogen oxides
(Method 6 and 7, respectively). Each
participant returned the analytical
results to the Source Branch, Quality
Assurance Division, for evaluation. An
individual report was returned to each
participant after processing.
This report summarized the audit
results of 1980 for those three source
test methods.
This Project Summary was devel-
oped by EPA's Environmental Monitor-
ing Systems Laboratory, Research
Triangle Park, NC, to announce key
findings of the research project that is
fully documented in a separate report
of the same title (see Project Report
ordering information at back).
Introduction
To control the amount of contamina-
tion emitted to our atmosphere from
stationary sources, the U.S. Environ-
mental Protection Agency (EPA) promul-
gated on December 23, 1971, the first
five of its New Source Performance
Standards. These regulations gave EPA
the power to enforce certain emission
limitation levels using specific source
test methodology. But with any type of
compliance testing, validity of the data
must be shown. This is accomplished
through a quality assurance program.
To assist in this type of program, the
Environmental Monitoring Systems
Laboratory (EMSL) of EPA established in
1977 a nationwide performance audit
program to insure that source emission
data collected for compliance deter-
mination purposes are accurate and
reliable. This program had three main
purposes:
1) To verify that the analytical and
computational parts of the specific
reference methods were being
properly used;
2) to improve the accuracy of the
measurement being made by pro-
viding individual performance re-
ports with the availability of
practice audit sample sets; and
3) to aid the participating laborato-
ries in assessing their analytical
performance relative to that of
other laboratories conducting
similar analyses by providing an-
nual data summary reports.
These goals were realized by sending
specific performance materials to in-
terested laboratories for analysis.
In the semiannual source test method
audits conducted in the spring and fall of
1980, the technique of volume mea-
surement by a dry gas meter was ex-
amined. This measurement is essential
to Methods 5, 8, 12, 13, and 17. Also
examined were the analytical and
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computational parts of Method 6 for
sulfur dioxide (SOz) and Method 7 for
nitrogen oxides (NOX). This report
describes the preparation and evalua-
tion of these tests.
Audit Participants
Using a previously compiled master
list of laboratories from past audits,
invitations to participate in the semi-
annual source audit program for spring
and fall of 1980 were sent to all volun-
teers who had previously participated in
the audit program. Other laboratories
were added to the master list through
their direct contact with the Source
Branch, Quality Assurance Division
(QAD), or the Regional Quality Control
Coordinator (RQCC).
Audit Materials
To provide a check on the calibration
of the dry gas meter used in the Method
5 stack sampling train, a critical orifice
device was developed to pass a certain
flow rate of air through the dry gas
meter when the measured vacuum on
the orifice was at least 16 inches of
mercury. This device allows an analyst
to compare a volume measured at his
location with one measured at an EPA
location. Volumes measured at both
locations are compared to the original
calibration of the device, compensated
for the effect of ambient temperature
and pressure on the measurement at
both locations.
For the audits of Methods 6 and 7, five
different concentration levels of simu-
lated source sulfur dioxide (802) and
nitrogen oxides (NO,) samples were
prepared. These solutions enabled the
participants to analyze and calculate
different concentration levels of S02
and NOX, using Methods 6 and 7. The
true values of these samples were
based on theoretical concentrations
calculated from gravimetric prepara-
tions and certain assumed volume
measurements.
A summary of the Method 5 data
shows that an average of 75% of the
303 laboratories that requested samples
returned data for the spring and fall
studies. Comparing the reported results
from these laboratories to the 2% Federal
Register specification for dry gas meter
accuracy, we find that in Audit 0280,
34% of the laboratories came within 2%
of the EPA value, while in Audit 0880,
42% of the laboratories were able to do
so.
A summary of Method 6 data shows
an average of 70% of the 290 labora-
tories requesting samples returned data
for the spring and fall studies. Of those
laboratories reporting data, 50% of the
laboratories came within an average of
1.6% of the EPA value for Audit 0380.
For Audit 0980, they came within 1.9%.
A summary of Method 7 data shows
an average of 58% of the 240 labora-
tories requesting samples returned data
for the spring and fall audits. Of those
laboratories returning data, 50% were
able to come within an average of 5.3%
of the EPA value for Audit 0480, while in
Audit 1080, they came within 6.4%.
To examine previous audit data for
trends, a certain degree of accuracy was
chosen and plotted for each method.
They were: 2 percent and 5 percent
accuracy for Methods 5 and 6, and 5
percent and 10 percent accuracy for
Method 7.
Use was made in this report of an
outlier test (Chauvenet's Criterion) to
determine the values that lie outside the
bulk of the collected data.
The EPA authors R. G. Fuerst (also the EPA Project Officer, see below), E. W.
Streib, and M. Ft. Midgett are with the Environmental Monitoring Systems
Laboratory, Research Triangle Park, NC 27711.
The complete report, entitled "A Summary of the EPA National Source Per-
formance Audit Program—1980," (Order No. PB 82-108 127; Cost: $8.00,
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 Officer can be contacted at:
Environmental Monitoring Systems Laboratory
U. S. Environmental Protection Agency
Research Triangle Park. NC 27711
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
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