U.S. Environmental Protection Agency
                    Office of Inspector General

                   At  a  Glance
                                                              09-P-0235
                                                       September 16, 2009
                                                                   Catalyst for Improving the Environment
why we Did This Review      EPA /Veec/s a/7 Oversight Program for Protocol Gases
The accuracy of continuous
emissions monitors is critical
to the U.S. Environmental
Protection Agency's (EPA's)
Acid Rain Program because
data from these monitors
determine the number of
allowances a utility can bank,
sell, or trade. Specialized
gases known as "EPA
Protocol Gases" are used to
calibrate and assure the quality
of these monitors. We sought
to determine whether certified
concentrations of these gases
are accurate.

Background

Vendors produce and certify
EPA Protocol Gases in high-
pressure cylinders according
to EPA procedures.  EPA
regulations require the use of
these gases, or National
Institute of Standards and
Technology (NIST)-certified
reference materials, when
conducting quality assurance
for continuous emissions and
ambient air monitoring
systems. EPA's Acid Rain
Program requires that the
certified concentration of the
I gases be within ± 2 percent of
the true concentration.

For further information, contact
our Office of Congressional,
Public Affairs and Management
at (202) 566-2391.

To view the full report,
click on the following link:
www.epa.qov/oiq/reports/2009/
20090916-09-P-0235.pdf
 What We Found
We purchased 87 cylinders of EPA Protocol Gases and had NIST analyze each
cylinder to determine whether the three gaseous mixtures contained in each
cylinder (carbon dioxide, nitric oxide, and sulfur dioxide) met the Acid Rain
Program's accuracy criterion. We found that 89 percent (233 components) met
the Acid Rain Program's accuracy criterion and 11 percent (28 components) did
not. Of the 28 components that did not meet the criterion, 17 were within 3.0
percent of the NIST-determined true concentration; 7 were within 3.0 to 5.0
percent; and 4 exceeded the true concentration by more than 5.0 percent.

Our sample was not designed to estimate the impact of the test results on the Acid
Rain Program.  However inaccurately certified concentrations could cause system
operators to unknowingly calibrate their monitoring systems to record inaccurate
measurements. For example, if a utility overstates  its emissions, it could lose the
opportunity to sell allowances to other utilities.  If a utility understates its
emissions, the utility and regulators may incorrectly conclude that the source is
complying with emissions standards.  With respect to ambient air monitoring, the
accuracy of these monitors is important because the data are used to determine
whether areas are in compliance with the Nation's ambient air quality standards.

EPA has conducted only two tests  of the accuracy of EPA Protocol Gases since
1997, when EPA's Office of Research and Development discontinued its annual
testing program. Thus, EPA does not have reasonable assurance that the gases
used to calibrate emissions monitors for the Acid Rain Program and continuous
ambient monitors for the Nation's  air monitoring network are accurate.
 What We Recommend
We recommend that the Office of Air and Radiation (OAR) implement oversight
programs to assure the quality of EPA Protocol Gases used to calibrate continuous
emissions monitoring systems and ambient air monitors. We also recommend that
the Office of Research and Development (ORD) update and maintain the protocol
gas procedures to ensure that the protocol meets the objectives of the Acid Rain,
ambient air, and stationary source air programs.  OAR and ORD concurred with
our recommendations. OAR has initiated efforts to conduct another gas audit later
this year.  OAR also plans to propose a rule later in 2009 to establish a largely
self-supported, annual gas audit program of protocol gases used for the Acid Rain
Program.  Further, OAR plans to implement a separate verification program to
address the lower concentration protocol gases used to calibrate continuous
ambient air monitors. ORD  will update and maintain the protocol gas procedures.
EPA's planned actions meet the intent of our recommendations.

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