Document ID: EPA-HQ-OAR-2007-0164-0002
Agency: epa
Document Type: Rule
Title: Two Optional Methods for Relative Accuracy Test Audits of Mercury Monitoring Systems Installed on Combustion Flue Gas Streams and Several Amendments to Related Mercury Monitoring Provisions
Posted Date: 2007-09-07T04:00Z

[Federal Register: September 7, 2007 (Volume 72, Number 173)]
[Rules and Regulations]               
[Page 51493-51531]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr07se07-17]                         

[[Page 51493]]

-----------------------------------------------------------------------

Part II

Environmental Protection Agency

-----------------------------------------------------------------------

40 CFR Parts 60, 72 and 75

Two Optional Methods for Relative Accuracy Test Audits of Mercury 
Monitoring Systems Installed on Combustion Flue Gas Streams and Several 
Amendments to Related Mercury Monitoring Provisions; Final Rule

[[Page 51494]]

-----------------------------------------------------------------------

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 60, 72 and 75

[EPA-HQ-OAR-2007-0164, FRL-8459-8]
RIN 2060-AO01

 
Two Optional Methods for Relative Accuracy Test Audits of Mercury 
Monitoring Systems Installed on Combustion Flue Gas Streams and Several 
Amendments to Related Mercury Monitoring Provisions

AGENCY: Environmental Protection Agency (EPA).

ACTION: Direct final rule.

-----------------------------------------------------------------------

SUMMARY: EPA is taking direct final action on two optional methods for 
relative accuracy audits of mercury monitoring systems installed on 
combustion flue gas streams and several amendments to related mercury 
monitoring provisions. This action approves two optional mercury (Hg) 
emissions test methods for potential use in conjunction with an 
existing regulatory requirement for Hg emissions monitoring, as well as 
several revisions to the mercury monitoring provisions themselves. This 
action is in regard to the testing and monitoring requirements for 
mercury specified in the Federal Register on May 18, 2005. Since that 
publication, EPA has received numerous comments concerning the 
desirability of EPA evaluating and allowing use of the measurement 
techniques addressed in the two optional methods in lieu of the methods 
identified in the cited Federal Register publication, as they can 
produce equally acceptable measures of the relative accuracy achieved 
by Hg monitoring systems. This action allows use of these two optional 
methods entirely at the discretion of the owner or operator of an 
affected emission source in place of the two currently specified 
methods. This direct final rule also amends Performance Specification 
12A by adding Methods 30A and 30B to the list of reference methods 
acceptable for measuring Hg concentration and the Hg monitoring 
provisions of May 18, 2005, to reflect technical insights since gained 
by EPA which will help to facilitate implementation including 
clarification and increased regulatory flexibility for affected 
sources.

DATES: This rule is effective on November 6, 2007 without further 
notice, unless EPA receives adverse comment by October 9, 2007. If EPA 
receives adverse comment, EPA will publish a timely withdrawal in the 
Federal Register informing the public that some or all of the 
amendments in this rule will not take effect.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
OAR-2007-0164, by one of the following methods:
     http://www.regulations.gov. Follow the on-line instructions for 

submitting comments.
     E-mail: a-and-r-docket@epa.gov.
     Fax: (202) 566-9744.
     Mail: Two Optional Methods for Relative Accuracy Test 
Audits of Mercury Monitoring Systems Installed on Combustion Flue Gas 
Streams and Several Amendments to the Related Mercury Monitoring 
Provisions, Environmental Protection Agency, Mailcode: 2822T, 1200 
Pennsylvania Avenue, NW., Washington, DC 20460. Please include a total 
of two copies.
     Hand Delivery: EPA Docket Center, 1301 Constitution 
Avenue, NW., EPA Headquarters Library, Room 3334, EPA West Building, 
Washington, DC 20460. Such deliveries are only accepted during the 
Docket's normal hours of operation, and special arrangements should be 
made for deliveries of boxed information.
    Instructions: Direct your comments to Docket ID No. EPA-HQ-OAR-
2007-0164. EPA's policy is that all comments received will be included 
in the public docket without change and may be made available online at 
http://www.regulations.gov, including any personal information provided, 

unless the comment includes information claimed to be Confidential 
Business Information (CBI) or other information whose disclosure is 
restricted by statute. Do not submit information that you consider to 
be CBI or otherwise protected through http://www.regulations.gov or e-mail. 

The http://www.regulations.gov Web site is an ``anonymous access'' system, 

which means EPA will not know your identity or contact information 
unless you provide it in the body of your comment. If you send an e-
mail comment directly to EPA without going through http://www.regulations.gov, 

your e-mail address will be automatically captured and included as part 
of the comment that is placed in the public docket and made available 
on the Internet. If you submit an electronic comment, EPA recommends 
that you include your name and other contact information in the body of 
your comment and with any disk or CD-ROM you submit. If EPA cannot read 
your comment due to technical difficulties and cannot contact you for 
clarification, EPA may not be able to consider your comment. Electronic 
files should avoid the use of special characters, any form of 
encryption, and be free of any defects or viruses. For additional 
information about EPA's public docket, visit the EPA Docket Center 
homepage at http://www.epa.gov/epahome/dockets.htm.

    Docket: All documents in the docket are listed in the 
http://www.regulations.gov index. Although listed in the index, some 

information is not publicly available, e.g., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, will be publicly available only in hard copy. 
Publicly available docket materials are available either electronically 
in http://www.regulations.gov or in hard copy at the Two Optional Methods for 

Relative Accuracy Audits of Mercury Monitoring Systems Installed on 
Combustion Flue Gas Streams Air and Radiation Docket, EPA/DC, EPA West 
Building, EPA Headquaters Library, Room 3334, 1301 Constitution Avenue, 
NW., Washington, DC. The Public Reading Room is open from 8:30 a.m. to 
4:30 p.m., Monday through Friday, excluding legal holidays. The 
telephone number for the Public Reading Room is (202) 566-1744, and the 
telephone number for the Air and Radiation Docket is (202) 566-1742.

FOR FURTHER INFORMATION CONTACT: Either Mr. William Grimley, Office of 
Air Quality Planning and Standards, Air Quality Assessment Division, 
Measurement Technology Group (E143-02), EPA, Research Triangle Park, NC 
27711, telephone (919) 541-1065, facsimile number (919) 541-0516, e-
mail address: grimley.william@epa.gov or Ms. Robin Segall, Office of 
Air Quality Planning and Standards, Air Quality Assessment Division, 
Measurement Technology Group (E143-02), EPA, Research Triangle Park, NC 
27711, telephone (919) 541-0893, facsimile number (919) 541-0516, e-
mail address: segall.robin@epa.gov.

SUPPLEMENTARY INFORMATION: 

I. Why is EPA using a Direct Final Rule?

    EPA is publishing this rule without a prior proposed rule because 
we view this as a noncontroversial action and anticipate no adverse 
comment. The most important benefit of direct final rulemaking for this 
action is to provide: (1) Additional reference method options, and (2) 
judicious revisions to mercury monitoring provisions specified in the 
Federal Register on May 18, 2005 that, if successful, relieve affected 
facilities of uncertainty regarding final emission monitoring 
requirements and certification details as opposed to waiting through a 
potentially protracted proposal/final

[[Page 51495]]

rulemaking process. Insofar as the two methods are concerned, EPA 
believes that they contain the necessary elements to generate 
acceptable data quality without being unduly burdensome. Through 
experience gained from developing existing performance based methods 
and trading rules, EPA has learned to identify test method criteria 
significant to effective rule implementation. EPA believes each of the 
two methods adopted in this action contain adequate specific criteria 
and procedures essential to the accurate measurement of Hg emissions, 
without adversely compromising the goals of performance-based 
methodology. EPA will continue to support and advance the principles 
and practicality of these methods by adding detailed method application 
information to facilitate their use to the Web site http://www.epa.gov/airmarkets/
 as it becomes available. Since use of either of these 

methods is not mandatory, but optional, there should be no objection to 
their availability. Regarding the amendments to the Hg emission 
monitoring provisions of 40 CFR parts 72 and 75, these amendments 
reflect EPA's increased technical understanding since the May 18, 2005 
rulemaking. However, in the ``Proposed Rules'' section of today's 
Federal Register, we are publishing a separate document that will serve 
as the proposed rule to approve provisions, if any, of this direct 
final rule that receive relevant adverse comments on this direct final 
rule. We will not institute a second comment period on this action. Any 
parties interested in commenting must do so at this time. For further 
information about commenting on this rule, see the ADDRESSES section of 
this document.
    If EPA receives adverse comment on one or more distinct provisions 
of this rulemaking, we will publish a timely withdrawal in the Federal 
Register indicating which provisions we are withdrawing and informing 
the public that those provisions will not take effect. The provisions 
that are not withdrawn will become effective on the date set out above, 
notwithstanding adverse comment on any other provision. We would 
address all public comments in a subsequent final rule based on the 
proposed rule.

II. Does This Action Apply to Me?

    Regulated Entities. The regulated categories and entities affected 
by this direct final rule include:

------------------------------------------------------------------------
                                                  Examples of regulated
            Category                NAICS \a\            entities
------------------------------------------------------------------------
Industry.......................          221112  Fossil fuel-fired
                                                  electric utility steam
                                                  generating units.
Federal government.............      \b\ 221122  Fossil fuel-fired
                                                  electric utility steam
                                                  generating units owned
                                                  by the Federal
                                                  government.
State/local governments........      \b\ 221122  Fossil fuel-fired
                                                  electric utility steam
                                                  generating units owned
                                                  by municipalities.
Tribal governments.............          921150  Fossil fuel-fired
                                                  electric utility steam
                                                  generating units in
                                                  Indian country.
------------------------------------------------------------------------
\a\ North American Industry Classification System.
\b\ Federal, State, or local government-owned and operated
  establishments are classified according to the activity in which they
  are engaged.

    This table is not intended to be exhaustive, but rather provides a 
guide for readers regarding entities likely to be affected by this 
direct final rule. If you have any questions regarding the 
applicability of this direct final rule to a particular entity, consult 
either the air permit authority for the entity or your EPA regional 
representative as listed in 40 CFR 63.13.

III. Where Can I Obtain a Copy of This Action?

    In addition to being available in the docket, an electronic copy of 
this direct final rule is also available on the World Wide Web through 
the Technology Transfer Network (TTN). Following signature, a copy of 
this direct final rule will be posted on the TTN's policy and guidance 
page for newly proposed or promulgated rules at the following address: 
http://www.epa.gov/ttn/oarpg. The TTN provides information and 

technology exchange in various areas of air pollution control.

IV. How Is This Document Organized?

    The information presented in this preamble is organized as 
follows:

I. Why Is EPA Using a Direct Final Rule?
II. Does This Action Apply to Me?
III. Where Can I Obtain a Copy of This Action?
IV. How Is This Document Organized?
V. Background
VI. This Action
VII. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act
    D. Unfunded Mandates Reform Act
    E. Executive Order: 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From 
Environmental Health and Safety Risks
    H. Executive Order 13211: Actions That Significantly Affect 
Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act
    J. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations
    K. Congressional Review Act

V. Background

    On May 18, 2005, in the preamble of the Clean Air Mercury Rule 
(CAMR) (70 FR 28608), EPA stated its intention to propose and 
promulgate an instrumental reference method as an alternative to the 
use of ASTM Method D6784-02 (the Ontario Hydro Method) to perform 
Relative Accuracy Test Audits (RATAs) of Hg continuous emission 
monitoring systems (CEMS) and sorbent trap monitoring systems used to 
monitor Hg emissions from coal-fired power plants.
    In comments on the proposed CAMR, commenters had two primary 
objections to the use of the Ontario Hydro Method as the reference test 
method for RATAs. Some expressed concern that the complexity of this 
wet chemical method could lead to results that would cause a properly 
functioning Hg CEMS to fail a RATA. Other commenters noted that, unlike 
instrumental reference methods used to audit CEMS for SO2 
and NOX that provide real-time values, test results from the 
Ontario Hydro Method can take weeks to be received from the laboratory. 
Commenters stated that this time lag can lead to implementation 
problems with regard to both missing data and emissions reporting.
    Since the CAMR was promulgated, EPA has proposed changes to 40 CFR 
part 75, which would allow the use of EPA Method 29, with enhanced 
quality-assurance procedures, as an alternative Hg reference method (71 
FR 49257; August 22, 2006). Although Method 29 is somewhat simpler than 
the Ontario Hydro Method and is more familiar to stack testers and 
State regulatory agencies, it is also a wet chemistry method and is, 
therefore, subject to the same limitations that make the Ontario Hydro 
method less than optimal for RATA testing.
    In view of these considerations, EPA believes that for RATA 
testing, an instrumental Hg reference method

[[Page 51496]]

would be preferable to both the Ontario Hydro Method and to Method 29. 
An instrumental method would provide real-time data that would best 
facilitate implementation of a mercury cap and trade program. 
Therefore, this action approves a performance-based instrumental 
reference method for measuring Hg emission concentrations.
    Another commenter to the proposed CAMR recommended that the sorbent 
trap monitoring approach, now specified in 40 CFR part 75, appendix K, 
be considered for use as a reference method. Although EPA did not 
commit to establishing a sorbent trap reference method at the time of 
CAMR promulgation, stakeholder interest in this methodology has 
increased significantly. In an August 22, 2006 Federal Register notice, 
EPA solicited comment on the use of sorbent trap technology for Hg 
reference method testing, and numerous supportive comments were 
received. In view of this, we initiated a review of available 
historical test data where concurrent measurements of Hg concentration 
were made with sorbent trap systems and either the Ontario Hydro Method 
or Method 29. These data, taken together with additional supporting 
data from recent field tests that were performed after the CAMR was 
promulgated, suggest that using the sorbent trap methodology for Hg 
reference method testing is viable. The Hg sorbent trap approach is 
less onerous to use than either Ontario Hydro or Method 29, and 
although it does not measure real-time Hg concentrations, a thermal 
technique can be used to analyze the samples on the same day that they 
are collected, facilitating RATA testing in the context of a cap and 
trade program. Therefore, this action also approves a sorbent trap 
reference method for Hg, as an alternative to the Ontario Hydro Method 
and Method 29.
    This direct final rule also includes several carefully considered 
amendments to the Hg emission monitoring provisions of 40 CFR parts 72 
and 75. EPA believes these amendments will facilitate implementation of 
the CAMR by clarifying portions of that rule and by providing added 
regulatory flexibility to the affected sources.

VI. This Action

    This direct final rule allows for the earliest possible use of two 
optional reference test methods for measuring total vapor phase mercury 
emissions from stationary sources as well as several related amendments 
to the Hg monitoring provisions of the CAMR. Both an instrumental test 
method and a sorbent trap test method for measurement of total vapor 
phase mercury emissions are being added to Appendix A-8 of 40 CFR part 
60 as approved alternatives to the Ontario Hydro Method and EPA Method 
29 to perform RATAs of installed mercury monitoring systems. The two 
methods are discussed below, and the related amendments are explained 
in detail later in this section.
    The first method being added to appendix A-8 of 40 CFR part 60 
today is titled ``Method 30A--Determination of Total Vapor Phase 
Mercury Emissions from Stationary Sources (Instrumental Analyzer 
Procedure).'' In Method 30A, a sample of the effluent gas is 
continuously extracted and conveyed to an analyzer capable of measuring 
the total vapor phase Hg concentration. Elemental and oxidized mercury 
(i.e., Hg\0\ and Hg+\2\) may be measured separately or 
simultaneously but, for purposes of this method, total vapor phase Hg 
is the sum of Hg\0\ and Hg+\2\. Method 30A provides test 
program-specific verification of method performance using a dynamic 
spiking approach, coupled with other performance criteria, which 
include system calibration, interference testing, and system integrity/
drift checks. The dynamic spiking requirement, which is a gaseous 
``method of standard additions,'' is the only part of Method 30A not 
parallel to the routinely applied instrumental reference methods used 
to perform relative accuracy testing of CEMS for SO2 and 
NOX. The dynamic spiking procedure is included in Method 30A 
to characterize measurement bias for Hg, which can be highly reactive 
on a site-specific basis (i.e., for each emissions sample matrix), with 
recovery criteria set to ensure that the bias is held to a minimal 
level. All performance requirements of Method 30A must be met for the 
data to be considered valid. The availability of an instrumental 
reference method for Hg testing is consistent with the approach EPA has 
taken in the successful Acid Rain and NOX Budget emissions 
trading programs.
    Method 30A is performance based in keeping with the criteria 
established under our Notice of Intent to Implement Performance Based 
Measurement Systems for Environmental Monitoring (62 FR 52098, October 
6, 1997). Use of the performance-based measurement approach will allow 
for continued development and application of new, improved, and more 
cost-effective Hg measurement technologies while ensuring the 
collection of data of known quality.
    Based on EPA's experience in conducting test programs to evaluate 
the procedures and performance criteria included in Method 30A, EPA 
recognizes that although prototypes of all equipment needed to perform 
this method have been successfully demonstrated in the field, at 
present the equipment needed to follow all procedures required by the 
method is commercially available only on a limited basis, and is being 
further refined. One of the issues of greatest concern in the 
development of an instrumental reference method for Hg has been the 
design of the sampling probe. Most of the commercially-available probes 
suitable for Hg measurement are very heavy (over 100 lbs.) making it 
difficult to move the probe from point-to-point and port-to-port for Hg 
stratification testing and/or sample traverses. Much progress is being 
made in probe redesign. One manufacturer has recently developed a probe 
that weighs less than 40 lbs., samples at significantly lower flow 
rates, and is suitable for dynamic spiking. Additional field testing of 
this probe and others currently under development is underway, and EPA 
plans to continue to actively encourage equipment development and 
evaluation. To encourage the use of Method 30A, including further 
development of the supporting equipment, which we believe will 
eventually enable source testers to perform Hg monitoring system RATAs 
more efficiently and will become the reference method of choice for 
many testing companies and affected sources, we are deferring the 
requirement for implementation of the dynamic spiking and Hg 
stratification test procedures until January 1, 2009. EPA believes this 
deferral is reasonable because Hg monitoring data reported to EPA in 
2009 will not be used in the trading of Hg allowances, as allowance 
accounting under the CAMR does not begin until 2010. Source testers are 
encouraged to use this time to acquire the necessary equipment and 
familiarize themselves with these procedures. Also, for all emissions 
test programs and RATAs performed under CAMR prior to January 1, 2009, 
we are allowing either: (1) A 12-point traverse for sulfur dioxide 
(SO2) to be substituted for a 12-point Hg traverse, in cases 
where stratification testing is used to determine the appropriate 
number and location of the reference method sampling points, or (2) use 
of the alternate three-point traverse line (0.4, 1.2, and 2.0 meters 
from the stack wall) as specified in section 8.1.3.2 of Performance 
Specification 2 (40 CFR part 60, appendix B). We

[[Page 51497]]

believe that in the short-term, these temporary deferrals will 
encourage the application of Method 30A and will help affected CAMR 
sources meet the January 1, 2009 deadline for initial certification of 
the required Hg monitoring systems. Several additional Method 30A 
development considerations are worthy of note. A preliminary draft of 
Method 30A was first available for public consideration on an EPA Web 
site (http://www.epa.gov/ttn/emc/) on February 28, 2006. Since that time, EPA 

and several stakeholder groups have evaluated the various technical 
aspects of the method. Based on the combined laboratory and field 
observations, EPA has been able to simplify several procedural 
requirements that we believe are essential to the method. The dynamic 
spiking requirement (for test program-specific verification of 
measurement system data quality) has been reduced to only a pretest 
requirement. The interference test has been made optional. The three-
point system calibration error test using Hg+\2\ has been 
streamlined to a system integrity check using a zero gas and a single 
upscale Hg+\2\ gas. Another change has been to relax the 
Hg\0\ calibration error specification from 2 percent to 5 percent of 
span, in recognition of the fact that this procedure is a check of the 
entire measurement system, as well as the current knowledge regarding 
the uncertainty of NIST traceable standards. EPA does plan, however, to 
reconsider this specification relaxation as more field data become 
available. A final consideration in development of Method 30A has been 
the requirement for calibration with both Hg\0\ and Hg+\2\. 
Some stakeholders have recommended that we eliminate the Hg\0\ 
calibration and rely solely on the Hg+\2\ calibration. EPA, 
however, believes this approach would not be adequate, because if only 
Hg+\2\ were used, instrument calibration response adjustment 
could compensate for an unknown amount of converter inefficiency, which 
would then result in an inaccurate total mercury measurement in 
situations where Hg\0\ is an appreciable fraction of the total stack 
gas Hg.
    The second method being added to appendix A-8 of 40 CFR part 60 
today is titled ``Method 30B--Use of Sorbent Traps to Measure Total 
Vapor Phase Mercury Emissions from Coal-Fired Combustion Sources.'' In 
Method 30B, a sample of the effluent gas is continuously drawn through 
a series of tubes containing activated carbon or another sorbent 
material. After sampling, the tubes are sealed. The Hg captured by the 
sorbent is then either: (1) Thermally desorbed and analyzed; or (2) the 
tubes are transferred to a laboratory for extraction of Hg and 
analysis. Like Method 30A, Method 30B is a performance-based method and 
contains performance specifications and procedures for hardware 
selection and calibration, sorbent spiking, and analytical recovery/
analysis which allow for development and application of new, improved, 
and more cost-effective Hg measurement technologies while still 
ensuring the collection of data of known quality. In particular, Method 
30B contains five key measurement performance tests designed to ensure: 
(1) Selection of a sorbent and analytical technique combination capable 
of quantitative collection and analysis of gaseous Hg, (2) collection 
during field testing of enough Hg on each sorbent trap to be reliably 
quantified, and (3) adequate performance of the method for each test 
program.
    In considering development of a sorbent trap-based reference 
method, EPA has reviewed historical emissions data where sorbent trap 
measurement systems were operated concurrently with either the Ontario 
Hydro Method or Method 29 (40 CFR part 60, appendix A-8). EPA has also 
conducted several field test evaluations of sorbent trap systems versus 
the Ontario Hydro Method in collaboration with the Electric Power 
Research Institute (EPRI). Based on these efforts, we have concluded 
that a sorbent trap-based technique coupled with appropriate 
performance criteria and QA procedures can provide Hg emissions data of 
quality comparable to that produced by the Ontario Hydro Method. Data 
supporting this conclusion are presented in the docket, EPA-HQ-OAR-
2007-0164.
    As we have done for Method 30A, for Method 30B emission tests and 
RATAs performed prior to January 1, 2009, we are allowing either: (1) A 
12-point traverse for sulfur dioxide (SO2) to be substituted 
for a 12-point Hg traverse for the stratification testing used to 
determine the number and location of the reference method sampling 
points, or (2) use of the alternate three-point traverse line (0.4, 
1.2, and 2.0 meters from the stack wall) as specified in section 
8.1.3.2 of Performance Specification 2 (40 CFR part 60, appendix B). We 
also intend to extend this temporary deferral of mercury stratification 
testing to application of the Ontario Hydro Method and Method 29. EPA 
believes this deferral is reasonable because Hg monitoring data 
reported to EPA in 2009 will not be used in the trading of Hg 
allowances, as allowance accounting under the CAMR does not begin until 
2010.
    This direct final rule also amends Performance Specification 12A of 
appendix B to part 60 by adding Methods 30A and 30B to the list of 
reference methods acceptable for relative accuracy testing of Hg 
emissions monitoring systems. Once this direct final rule becomes 
effective, the reference methods acceptable for Hg measurement in 
Performance Specification 12A will include Methods 29, 30A, 30B, and 
ASTM D6784-02.
    With today's action, EPA is taking the opportunity to include 
several considered revisions to the Hg emission monitoring provisions 
of 40 CFR parts 72 and 75 as described in detail below. EPA is 
including these revisions in this direct final rule because we believe 
that they will facilitate implementation of the Hg monitoring under 
CAMR.
    First, Sec.  75.81(a) is being revised to confirm that the Hg CEMS 
and sorbent trap monitoring systems required under subpart I of part 75 
are to measure the total vapor phase mass concentration of Hg in the 
flue gas, including both the elemental and oxidized forms of Hg, 
expressed in units of micrograms per standard cubic meter ([mu]g/scm). 
Although it is generally understood that total vapor phase Hg is the 
regulated pollutant under CAMR, it recently was brought to EPA's 
attention that subpart I of part 75 does not explicitly state that Hg 
monitoring systems only need to measure total vapor phase Hg. The 
amended language in Sec.  75.81(a) clarifies this.
    Second, paragraph (i) in Sec.  75.15 is being revised and a new 
paragraph (d)(2)(ix) is being added to Sec.  75.20, to codify the rules 
for using optional non-redundant (``cold'') backup Hg monitoring 
systems and like-kind replacement Hg analyzers, when the primary Hg 
monitoring system is unable to provide quality-assured data. For the 
other types of monitoring systems required by part 75, these monitoring 
options have been in place since May 1999 (see 64 FR 28597, May 26, 
1999). Today's action simply extends these provisions to Hg monitoring 
systems. Through the years, the regulated community has found these 
backup monitoring options to be beneficial, in that they minimize the 
use of missing data substitution procedures during outages of the 
primary monitoring system.
    In particular, Sec.  75.20(d)(2)(ix) specifies that a non-redundant 
backup Hg monitoring system can either be a Hg CEMS or a sorbent trap 
monitoring system. The non-redundant backup Hg

[[Page 51498]]

monitoring system must be initially certified at each unit or stack 
location where it will be used, in accordance with Sec.  
75.20(d)(2)(i). For a non-redundant backup Hg CEMS, all of the initial 
certification tests specified in Sec.  75.20(c)(1) are required, except 
for the 7-day calibration error test. However, for ongoing quality 
assurance (QA), a RATA is required only once every two years (8 
calendar quarters), as specified in Sec.  75.20(d)(2)(vi). For a non-
redundant backup sorbent trap monitoring system, a RATA is required for 
initial certification, and once every two years thereafter for ongoing 
QA.
    When a certified non-redundant backup Hg CEMS or a like-kind 
replacement Hg analyzer is brought into service, a three-point 
linearity check with elemental Hg standards and a single-point system 
integrity check will be required. Alternatively, a three-level system 
integrity check may be performed instead of these two tests. When a 
certified non-redundant backup sorbent trap monitoring system is 
brought into service, only the routine sampling and QA procedures of 
Sec.  75.15 and appendix K of part 75 will be required.
    Each non-redundant backup Hg monitoring system and each like-kind 
replacement Hg analyzer will be subject to the applicable ongoing QA 
requirements, restrictions and conditions specified in Sec.  
75.20(d)(2). For certified non-redundant backup Hg CEMS and like-kind 
replacement Hg analyzers, the weekly system integrity checks described 
in section 2.6 of appendix B of 40 CFR part 75 will also be required as 
long as the system or analyzer remains in service, unless the daily 
calibration error tests of the analyzer are done using NIST-traceable 
oxidized Hg standards.
    Third, a new paragraph (k) is being added to Sec.  75.15 that: (1) 
Clarifies that, when the RATA of an appendix K sorbent trap monitoring 
system is performed, the type of sorbent material used in the appendix 
K sorbent traps must be the same as that used for daily operation of 
the appendix K monitoring system, and (2) allows the appendix K traps 
used during RATA testing to be smaller than the traps used for daily 
operation of the appendix K monitoring system. This change will be 
particularly advantageous at very low Hg concentrations as it will 
facilitate shorter RATA test run times. Parallel changes are being made 
to section 6.5.7 of appendix A of part 75 to be consistent with the 
provisions of Sec.  75.15(k). Section 6.5.7 currently requires the 
appendix K sorbent traps used for the RATA to be the same size as the 
traps used for daily operation of the appendix K monitoring system.
    Fourth, today's action revises a number of sections of part 75, 
appendix K, pertaining to the use of sorbent trap monitoring systems. 
EPA is withdrawing the requirement to use the percentage recovery of 
the elemental Hg spike in section 3 of each sorbent trap to adjust or 
``normalize'' the Hg mass collected in sections 1 and 2 of the trap. 
The requirement to spike the third section of each trap is being 
retained and data from each pair of traps must still be invalidated if 
either or both spike recovery percentages fall outside the acceptable 
limits;\1\ however, the results of the spike recoveries will no longer 
be used to adjust the Hg mass collected in the first two sections of 
the traps. EPA is making this rule change based on an analysis of 
recent spike recovery data from long-term appendix K field 
demonstrations. Although the vast majority of the spike recoveries in 
these studies have been within the currently acceptable limits of 75 to 
125 percent, the requirement to normalize based on spike recovery could 
affect data precision. For a given pair of traps, if one spike recovery 
was high (e.g., 110 percent) and the other one low (e.g., 90 percent), 
normalization of the Hg mass collected in the first two trap sections 
using third section spike recoveries could make it difficult for a pair 
of sorbent traps to meet the relative deviation (RD) specifications in 
appendix K. In the example cited, normalization of the data would cause 
the Hg concentrations measured by the traps to be adjusted by 10 
percent in opposite directions, i.e., one upward and one downward. 
Thus, two Hg concentrations that may have been in close agreement 
without normalization now might not be able to meet the RD 
specifications. In view of this, EPA has concluded that evaluating the 
spike recovery data on a pass/fail basis instead of using the percent 
recovery values to adjust the emissions data is more technically sound 
and is also consistent with the way in which the results of daily and 
quarterly QA assessments of CEMS are interpreted.
---------------------------------------------------------------------------

    \1\ On August 22, 2006, EPA proposed to amend Appendix K to 
allow the data from a pair of sorbent traps to be validated in cases 
where the third section spike recovery from only one of the traps 
meets the percent recovery specifications (see 71 FR 49275). EPA 
proposed to allow the results from the trap that meets the 
specifications to be used for reporting, provided that a single trap 
adjustment factor (STAF) of 1.222 is applied. EPA is evaluating the 
comments received on this proposal and expects to publish the final 
rule in the summer of 2007.
---------------------------------------------------------------------------

    Regarding the range of acceptable third section spike recoveries, 
EPA is not changing the 75 to 125 percent acceptance criteria. As 
previously noted, early field experience with appendix K monitoring 
systems has demonstrated that spike recoveries within this range are 
achievable. However, recent appendix K data indicate that more 
stringent acceptance criteria may be justifiable. It appears that there 
has been a marked improvement in third section spike recovery 
percentages. Recoveries in the range from 85 to 115 percent are 
consistently being achieved. If this trend continues, EPA may propose 
to tighten the spike recovery acceptance criteria in a future 
rulemaking. Toward that end, EPA will continue to collect and evaluate 
third section spike recovery data from appendix K monitoring systems in 
the months ahead.
    To effect these changes to appendix K, section 11.5 is being 
removed and reserved; section 10.4 is being revised; Equations K-6 and 
K-7 are being redesignated as Equations K-5 and K-6, respectively; and 
the definition of ``M*'' in redesignated Equation K-5 is being revised.
    EPA is also revising appendix K to allow the owner or operator to 
use other types of gas flow meters besides the conventional dry gas 
meter (DGM) to quantify sample gas volume. Since the publication of 
appendix K (see 70 FR 28695, May 18, 2005), numerous requests have been 
received from the regulated community to allow this flexibility. In 
response to these requests, EPA initiated an investigation of the 
feasibility of replacing the DGM in a sorbent trap monitoring system 
with a thermal mass flow meter. As a result of its investigation, EPA 
has concluded that a properly calibrated thermal mass flow meter can be 
at least as accurate as a DGM. The mass flow meter is also a more 
modern technology than the DGM; since it has no moving parts, it may be 
more reliable than a DGM for continuous duty.
    Having found one type of gas flow meter that can measure as 
accurately as a DGM, EPA is persuaded that there may be other 
commercially available gas flow meter technologies that are equally 
capable and may be suitable for appendix K applications. Accordingly, 
EPA has decided that a performance-based approach, rather than a 
prescriptive one, is more appropriate for appendix K gas flow meters. 
Today's action allows the use of any type of gas flow meter that is 
capable of accurately measuring gas volumes to within 2 percent.
    Section 9.2.2.1 of appendix K now requires the manufacturer of the 
gas flow meter to perform all necessary set-

[[Page 51499]]

up, testing, programming, etc. of the meter and to provide any 
necessary instructions so that for the particular field application, 
the meter will give an accurate readout of dry gas volume in units of 
standard cubic meters. Then, prior to its initial use, the flow meter 
must be calibrated at a minimum of three settings covering the expected 
range of sample flow rates for the appendix K system. The initial 
calibration may be performed either by the manufacturer or by the end 
user. The calibration of the gas flow meter must be checked quarterly 
thereafter, at an intermediate flow rate. For mass flow meters, the 
initial three-point calibration must be performed by using either a 
compressed gas mixture containing CO2, O2, and 
N2 in proportions representative of the stack gas 
composition or by using the actual stack gas. However, when the initial 
calibration is done with a compressed gas mixture, the mass flow meter 
may not be used until an additional on-site calibration check of the 
flow meter at an intermediate flow rate is performed and passed, using 
the actual stack gas.
    To calibrate the gas flow meter, the owner or operator may either 
follow the basic procedures in section 10.3 or section 16 of Method 5 
in appendix A-3 of part 60 for calibration of dry gas meters, or 
alternatively, may temporarily install a reference gas flow meter 
(RGFM) at the discharge of the appendix K monitoring system while the 
monitoring system is in operation and make concurrent measurements of 
dry stack gas volume with the RGFM and the appendix K gas flow meter. 
If the latter option is chosen, the RGFM may either be a gas flow 
metering device that has been calibrated according to section 10.3.1 or 
section 16 of Method 5 or a NIST-traceable volumetric calibration 
device with an accuracy of 1 percent. Note that this 
alternative calibration technique allows required QA checks to be 
performed with little or no disruption of the operation of the sorbent 
trap monitoring system.
    Regardless of which calibration approach is used, a calibration 
factor, Yi, must be obtained at each tested flow rate, where 
Yi is the ratio of the volume measured by the reference 
meter to the volume measured by the flow meter being calibrated. For 
the initial three-point calibration, the three Yi values 
must be averaged, and each individual Yi must be within 
 0.02 of the average value. The average value, Y, must then 
be used to correct the gas volumes measured by the gas flow meter. For 
single-level calibration checks (e.g., the quarterly checks performed 
for routine QA), the Yi value obtained at the tested flow 
rate must be compared with the current value of Y. If Yi 
differs from Y by more than 5 percent, a full three-point recalibration 
is then required to determine a new Y value.
    In this direct final action, the majority of the revised rule 
provisions pertaining to gas flow meters can be found in sections 5.1.5 
and 9.2 of appendix K. Minor revisions to sections 7.2.3 and 7.2.5, 
Figure K-1, and Table K-1 are being made to be consistent with the 
changes to sections 5.1.5 and 9.2. In several other places throughout 
part 75 and in the definition of ``Sorbent trap monitoring system'' in 
part 72, the term ``dry gas meter,'' when used in reference to a 
sorbent trap monitoring system, is being replaced with the more general 
term ``gas flow meter.'' Revisions to section 1.5.2 of appendix B of 
part 75 will require the gas flow meter calibration procedures and 
protocols for periodic recalibration of reference gas flow meters to be 
included in the QA plan for the affected unit.
    This direct final action, which approves the use of two optional 
methods (Methods 30A and 30B) for determining total vapor phase Hg 
emissions from stationary sources, is being taken in response to 
numerous public comments concerning the desirability of allowing the 
use of these types of methods to comply with the Hg emission monitoring 
requirements of the CAMR for electric utility steam generating units. 
In the May 18, 2005 final rule (70 FR 28636), we summarized the public 
comments that we received regarding the use of an instrumental method 
as an alternative to the Ontario Hydro Method specified in the proposed 
CAMR. As noted earlier in this preamble, the commenters primarily 
objected to the required use of the Ontario Hydro Method as the 
reference method for the RATAs of Hg monitoring systems and expressed 
concern about the complexities in the method and the amount of time 
that is required to perform the testing and to receive the results. 
Commenters pointed out that it could take days to complete the testing 
and weeks to receive the results from a laboratory. Commenters claimed 
that for the cap and trade program proposed under CAMR, these delays 
could lead to significant implementation problems with respect to the 
timely reporting of emissions data. Further, if a RATA should be failed 
or invalidated (e.g., if fewer than nine test runs meet the relative 
deviation criterion for the paired Ontario Hydro trains), data from the 
Hg monitoring system would be invalidated from the hour of the failed 
or invalidated test until the hour of completion of a successful RATA. 
Conservatively high substitute data values would have to be reported 
during that entire time period. In our response to those comments in 
the final CAMR rule, we stated that the alternative use of an 
instrumental method for the required RATAs of Hg monitoring systems and 
sorbent trap monitoring systems is allowed by the final rule but is 
subject to approval by the Administrator. We also stated our commitment 
to propose and promulgate a Hg instrumental reference method once 
sufficient supporting field test data become available. We further 
stated that ``A Hg instrumental reference method for RATA testing is 
vastly preferable to the Ontario Hydro Method and will greatly 
facilitate the implementation of a Hg cap-and-trade program.''
    Since promulgation of CAMR, we have continued to communicate with 
stakeholders interested in the Hg monitoring requirements of the rule, 
and we have come to more clearly understand that it is of great 
interest to the affected entities to have additional reference method 
options available for relative accuracy testing of installed Hg 
monitoring systems as soon as possible. Accordingly, at the end of 
2005, we began developing an instrumental test method for Hg and 
solicited feedback from the stakeholders on a working draft of the 
method (referred to as PRE-009 at http://www.epa.gov/ttn/emc/prelim.html
). More recently, we have been developing a viable sorbent 

trap reference method. These efforts have resulted in Methods 30A and 
30B.
    The general beneficial impacts of this direct final rule to approve 
the two optional Hg test methods and amend targeted portions of 40 CFR 
parts 72 and 75 include: Allowing affected sources to choose the use of 
an alternative to the Ontario Hydro Method without the administrative 
burden of applying for Administrator approval on a case-by-case basis; 
providing the availability of real-time RATA results (Method 30A); 
reducing the overall RATA testing times; reducing costs relative to the 
Ontario Hydro Method; and providing additional flexibility in appendix 
K sorbent trap monitoring and backup monitoring approaches. The two 
optional methods being approved by this direct final rule are 
considered to be comparable to the Ontario Hydro Method in terms of the 
quality of the results produced. Over the last year, EPA has 
collaborated with EPRI and some of its members in a number of field 
test programs that have confirmed that the instrumental reference 
method approved/established in this notice will provide data comparable 
to or better

[[Page 51500]]

than that of the ``Ontario Hydro Method.''
    Assuming we do not receive adverse comment on this direct final 
rulemaking and Methods 30A and 30B become final, we plan to post 
information relevant to Method 30A and 30B applications and equipment 
advances on EPA's Web site at http://www.epa.gov/airmarkets.

VII. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

    This action is not a ``significant regulatory action'' under the 
terms of Executive Order (EO) 12866 (58 FR 51735, October 4, 1993) and 
is therefore not subject to review under the EO.

B. Paperwork Reduction Act

    This action does not impose an information collection burden under 
the provisions of the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. 
Burden means the total time, effort, or financial resources expended by 
persons to generate, maintain, retain, or disclose or provide 
information to or for a Federal agency. This includes the time needed 
to review instructions; develop, acquire, install, and utilize 
technology and systems for the purposes of collecting, validating, and 
verifying information, processing and maintaining information, and 
disclosing and providing information; adjust the existing ways to 
comply with any previously applicable instructions and requirements; 
train personnel to be able to respond to a collection of information; 
search data sources; complete and review the collection of information; 
and transmit or otherwise disclose the information.
    An agency may not conduct or sponsor, and a person is not required 
to respond to a collection of information, unless it displays a 
currently valid OMB control number. The OMB control numbers for EPA's 
regulations in 40 CFR are listed in 40 CFR part 9.

C. Regulatory Flexibility Act

    The Regulatory Flexibility Act (RFA) generally requires an agency 
to prepare a regulatory flexibility analysis of any rule subject to 
notice and comment rulemaking requirements under the Administrative 
Procedure Act or any other statute unless the agency certifies that the 
rule will not have a significant economic impact on a substantial 
number of small entities. Small entities include small businesses, 
small organizations, and small governmental jurisdictions.
    For purposes of assessing the impacts of today's rule on small 
entities, small entity is defined as: (1) A small business whose parent 
company has fewer than 100 or 1,000 employees, or fewer than 4 billion 
kilowatt-hr per year of electricity usage, depending on the size 
definition for the affected North American Industry Classification 
System code; (2) a small governmental jurisdiction that is a government 
of a city, county, town, school district or special district with a 
population of less than 50,000; and (3) a small organization that is 
any not-for-profit enterprise which is independently owned and operated 
and is not dominant in its field.
    After considering the economic impacts of today's direct final rule 
on small entities, I certify that this action will not have a 
significant economic impact on a substantial number of small entities. 
This direct final rule will not impose any requirements on small 
entities because it does not impose any additional regulatory 
requirements, but rather provides clarification and additional 
regulatory flexibilty.

D. Unfunded Mandates Reform Act

    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Pub. 
L. 104-4, establishes requirements for Federal agencies to assess the 
effects of their regulatory actions on State, local, and tribal 
governments and the private sector. Under section 202 of the UMRA, EPA 
generally must prepare a written statement, including a cost-benefit 
analysis, for proposed and final rules with ``Federal mandates'' that 
may result in expenditures to State, local, and tribal governments, in 
the aggregate, or to the private sector, of $100 million or more in any 
one year. Before promulgating an EPA rule for which a written statement 
is needed, section 205 of the UMRA generally requires EPA to identify 
and consider a reasonable number of regulatory alternatives and adopt 
the least costly, most cost-effective or least burdensome alternative 
that achieves the objectives of the rule. The provisions of section 205 
do not apply when they are inconsistent with applicable law. Moreover, 
section 205 allows EPA to adopt an alternative other than the least 
costly, most cost-effective, or least burdensome alternative if the 
Administrator publishes with the final rule an explanation why that 
alternative was not adopted. Before EPA establishes any regulatory 
requirements that may significantly or uniquely affect small 
governments, including tribal governments, it must have developed under 
section 203 of the UMRA a small government agency plan. The plan must 
provide for notifying potentially affected small governments, enabling 
officials of affected small governments to have meaningful and timely 
input in the development of EPA regulatory proposals with significant 
Federal intergovernmental mandates, and informing, educating, and 
advising small governments on compliance with the regulatory 
requirements.
    EPA has determined that this direct final rule does not contain a 
Federal mandate that may result in expenditures of $100 million or more 
for State, local, and tribal governments in the aggregate, or to the 
private sector in any 1 year, nor does this rule significantly or 
uniquely impact small governments, because it contains no requirements 
that impose new obligations upon them. Thus, this direct final rule is 
not subject to the requirements of sections 202 and 205 of the UMRA.

E. Executive Order 13132: Federalism

    Executive Order 13132, entitled ``Federalism'' (64 FR 43255, August 
10, 1999), requires EPA to develop an accountable process to ensure 
``meaningful and timely input by State and local officials in the 
development of regulatory policies that have federalism implications.'' 
``Policies that have federalism implications'' is defined in the 
Executive Order to include regulations that have ``substantial direct 
effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government.''
    This direct final rule does not have federalism implications. It 
will not have substantial direct effects on the States, on the 
relationship between the national government and the States, or on the 
distribution of power and responsibilities among the various levels of 
government, as specified in Executive Order 13132. The use of these 
methods is optional on the part of the regulated entities listed. Thus, 
Executive Order 13132 does not apply to this direct final rule.

F. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    Executive Order 13175, entitled ``Consultation and Coordination 
with Indian Tribal Governments'' (65 FR 67249, November 9, 2000), 
requires EPA to develop an accountable process to ensure ``meaningful 
and timely input by tribal officials in the development of regulatory 
policies that have tribal implications.'' This direct final rule does 
not have tribal implications, as specified in Executive Order 13175. It 
will not have substantial direct effects on tribal governments, on the

[[Page 51501]]

relationship between the Federal government and Indian tribes, or on 
the distribution of power and responsibilities between the Federal 
government and Indian tribes. Thus, Executive Order 13175 does not 
apply to this final rule.

G. Executive Order 13045: Protection of Children From Environmental 
Health and Safety Risks

    Executive Order 13045: ``Protection of Children from Environmental 
Health Risks and Safety Risks'' (62 FR 19885, April 23, 1997) applies 
to any rule that: (1) Is determined to be ``economically significant'' 
as defined under Executive Order 12866, and (2) concerns an 
environmental health or safety risk that EPA has reason to believe may 
have a disproportionate effect on children. If the regulatory action 
meets both criteria, the Agency must evaluate the environmental health 
or safety effects of the planned rule on children, and explain why the 
planned regulation is preferable to other potentially effective and 
reasonably feasible alternatives considered by the Agency. EPA 
interprets Executive Order 13045 as applying only to those regulatory 
actions that are based on health or safety risks, such that the 
analysis required under section 5-501 of the Order has the potential to 
influence the regulation. This rule is not subject to Executive Order 
13045 because it does not establish an environmental standard intended 
to mitigate health or safety risks.

H. Executive Order 13211: Actions That Significantly Affect Energy 
Supply, Distribution, or Use

    This rule is not subject to Executive Order 13211, ``Actions 
Concerning Regulations That Significantly Affect Energy Supply, 
Distribution, or Use'' (66 FR 28355, May 22, 2001) because it is not a 
significant regulatory action under Executive Order 12866.

I. National Technology Transfer Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (NTTAA), Public Law No. 104-113, section 12(d) (15 U.S.C. 
272 note) directs EPA to use voluntary consensus standards in its 
regulatory activities unless to do so would be inconsistent with 
applicable law or otherwise impractical. Voluntary consensus standards 
are technical standards (e.g., materials specifications, test methods, 
sampling procedures, and business practices) that are developed or 
adopted by voluntary consensus standards bodies. The NTTAA directs EPA 
to provide Congress, through OMB, explanations when the Agency decides 
not to use available and applicable voluntary consensus standards. This 
rulemaking involves technical standards. Consistent with the NTTAA, EPA 
in a previous related rulemaking (70 FR 28606, May 18, 2005) identified 
an acceptable VCS for measuring Hg emissions. The standard ASTM D6784-
02, Standard Test Method for Elemental, Oxidized, Particle-Bound and 
Total Mercury Gas Generated from Coal-Fired Stationary sources (Ontario 
Hydro Method) was cited in that final rule for measuring Hg emissions. 
After today's action becomes effective, the Ontario Hydro Method will 
remain an acceptable method for measuring Hg emissions.

J. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations

    Executive Order 12898 (59 FR 7629 (Feb. 16, 1994)) establishes 
federal executive policy on environmental justice. Its main provision 
directs federal agencies, to the greatest extent practicable and 
permitted by law, to make environmental justice part of their mission 
by identifying and addressing, as appropriate, disproportionately high 
and adverse human health or environmental effects of their programs, 
policies, and activities on minority populations and low-income 
populations in the United States.
    EPA has determined that this direct final rule will not have 
disproportionately high and adverse human health or environmental 
effects on minority or low-income populations because it does not 
affect the level of protection provided to human health or the 
environment. This direct final rule does not affect or relax the 
control measures on sources impacted by this rule and therefore will 
not cause emissions increases from these sources.

K. Congressional Review Act

    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the 
Small Business Regulatory Enforcement Fairness Act of 1996, generally 
provides that before a rule may take effect, the Agency promulgating 
the rule must submit a rule report, which includes a copy of the rule, 
to each House of the Congress and to the Comptroller General of the 
United States. EPA will submit a report containing this rule and other 
required information to the U.S. Senate, the U.S. House of 
Representatives, and the Comptroller General of the United States prior 
to publication of the rule in the Federal Register. A major rule cannot 
take effect until 60 days after it is published in the Federal 
Register. This action is not a ``major rule'' as defined by 5 U.S.C. 
804(2). This rule will be effective on November 6, 2007.

List of Subjects

40 CFR Part 60

    Environmental protection, Administrative practice and procedures, 
Air pollution control, Continuous emission monitors, Electric 
utilities, Mercury, Test methods and procedures.

40 CFR Part 72

    Environmental protection, Administrative practice and procedures, 
Air pollution control, Continuous emission monitors, Electric 
utilities, Mercury, Test methods and procedures.

40 CFR Part 75

    Environmental protection, Administrative practice and procedures, 
Air pollution control, Continuous emission monitors, Electric 
utilities, Mercury, Test methods and procedures.

    Dated: August 17, 2007.
Stephen L. Johnson,
Administrator.

0
For the reasons set out in the preamble, title 40, chapter I, parts 60, 
72, and 75 of the Code of Federal Regulations are amended as follows:

PART 60--STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES

0
1. The authority citation for part 60 continues to read as follows:

    Authority: 42 U.S.C. 7401-7601.

Appendix A-8 [Amended]

0
2. Amend Appendix A-8 by revising the heading and adding in numerical 
order Methods 30A and 30B to read as follows:

APPENDIX A-8 TO PART 60--TEST METHODS 26 THROUGH 30B

* * * * *

Method 30A--Determination of Total Vapor Phase Mercury Emissions From 
Stationary Sources (Instrumental Analyzer Procedure)

1.0 Scope and Application

What Is Method 30A?

    Method 30A is a procedure for measuring total vapor phase 
mercury (Hg) emissions from stationary sources using an instrumental 
analyzer. This method is particularly appropriate for performing 
emissions testing and for conducting relative accuracy test audits 
(RATAs) of mercury continuous emissions monitoring systems (Hg CEMS) 
and sorbent trap monitoring systems at coal-fired combustion 
sources. Quality assurance and quality control

[[Page 51502]]

requirements are included to assure that you, the tester, collect 
data of known and acceptable quality for each testing site. This 
method does not completely describe all equipment, supplies, and 
sampling procedures and analytical procedures you will need but 
refers to other test methods for some of the details. Therefore, to 
obtain reliable results, you should also have a thorough knowledge 
of these additional methods which are also found in appendices A-1 
and A-3 to this part:
    (a) Method 1--Sample and Velocity Traverses for Stationary 
Sources.
    (b) Method 4--Determination of Moisture Content in Stack Gases.
    1.1 Analytes. What does this method determine? This method is 
designed to measure the mass concentration of total vapor phase Hg 
in flue gas, which represents the sum of elemental Hg (Hg\0\) and 
oxidized forms of Hg (Hg+\2\), in mass concentration 
units of micrograms per cubic meter ([mu]g/m\3\).

------------------------------------------------------------------------
              Analyte                   CAS No.          Sensitivity
------------------------------------------------------------------------
Elemental Hg (Hg\0\)..............       7439-97-6  Typically < 2% of
                                                     Calibration Span.
Oxidized Hg (Hg+\2\)..............  ..............  (Same).
------------------------------------------------------------------------

    1.2 Applicability. When is this method required? Method 30A is 
offered as a reference method for emission testing and for RATAs of 
Hg CEMS and sorbent trap monitoring systems at coal-fired boilers. 
Method 30A may also be specified for other source categories in the 
future, either by New Source Performance Standards (NSPS), National 
Emission Standards for Hazardous Air Pollutants (NESHAP), emissions 
trading programs, State Implementation Plans (SIP), or operating 
permits that require measurement of Hg concentrations in stationary 
source emissions to determine compliance with an applicable emission 
standard or limit, or to conduct RATAs of Hg CEMS and sorbent trap 
monitoring systems.
    1.3 Data Quality Objectives (DQO). How good must my collected 
data be? Method 30A has been designed to provide data of high and 
known quality for Hg emission testing and for relative accuracy 
testing of Hg monitoring systems including Hg CEMS and sorbent trap 
monitoring systems. In these and other applications, the principle 
objective is to ensure the accuracy of the data at the actual 
emission levels encountered. To meet this objective, calibration 
standards prepared according to an EPA traceability protocol must be 
used and measurement system performance tests are required.

2.0 Summary of Method

    In this method, a sample of the effluent gas is continuously 
extracted and conveyed to an analyzer capable of measuring the total 
vapor phase Hg concentration. Elemental and oxidized mercury (i.e., 
Hg\0\ and Hg+\2\) may be measured separately or 
simultaneously but, for purposes of this method, total vapor phase 
Hg is the sum of Hg\0\ and Hg+\2\. You must meet the 
performance requirements of this method (i.e., system calibration, 
interference testing, dynamic spiking, and system integrity/drift 
checks) to validate your data. The dynamic spiking requirement is 
deferred until January 1, 2009.

3.0 Definitions

    3.1 Calibration Curve means the relationship between an 
analyzer's response to the injection of a series of calibration 
gases and the actual concentrations of those gases.
    3.2 Calibration Gas means a gas standard containing Hg\0\ or 
HgCl2 at a known concentration that is produced and 
certified in accordance with an EPA traceability protocol for 
certification of Hg calibration standards.
    3.2.1 Zero Gas means a calibration gas with a concentration that 
is below the level detectable by the measurement system.
    3.2.2 Low-Level Gas means a calibration gas with a concentration 
that is 10 to 30 percent of the calibration span.
    3.2.3 Mid-Level Gas means a calibration gas with a concentration 
that is 40 to 60 percent of the calibration span.
    3.2.4 High-Level Gas means a calibration gas whose concentration 
is equal to the calibration span.
    3.3 Converter means a device that reduces oxidized mercury 
(Hg+\2\) to elemental mercury (Hg\0\).
    3.4 Calibration Span means the upper limit of valid instrument 
response during sampling. To the extent practicable the measured 
emissions are to be between 10 and 100 percent of the selected 
calibration span (i.e., the measured emissions should be within the 
calibrated range determined by the Low- and High-Level gas 
standards). It is recommended that the calibration span be at least 
twice the native concentration to accommodate the dynamic spiking 
procedure.
    3.5 Centroidal Area means the central area that has the same 
shape as the stack or duct cross section and is no greater than one 
percent of the stack or duct total cross-sectional area.
    3.6 Data Recorder means the equipment that permanently records 
the concentrations reported by the analyzer.
    3.7 Drift Check means the test to determine the difference 
between the measurement system readings obtained in a post-run 
system integrity check and the prior pre-run system integrity check 
at a specific calibration gas concentration level (i.e., zero, mid-
level, or high-level).
    3.8 Dynamic Spiking means a procedure in which a known mass or 
concentration of vapor phase HgCl2 is injected into the 
probe sample gas stream at a known flow rate, in order to assess the 
effects of the flue gas matrix on the accuracy of the measurement 
system.
    3.9 Gas Analyzer means the equipment that detects the total 
vapor phase Hg being measured and generates an output proportional 
to its concentration.
    3.10 Interference Test means the test to detect analyzer 
responses to compounds other than Hg, usually gases present in the 
measured gas stream, that are not adequately accounted for in the 
calibration procedure and may cause measurement bias.
    3.11 Measurement System means all of the equipment used to 
determine the Hg concentration. The measurement system may generally 
include the following major subsystems: sample acquisition, 
Hg+2 to Hg0 converter, sample transport, 
sample conditioning, flow control/gas manifold, gas analyzer, and 
data recorder.
    3.12 Native Concentration means the total vapor phase Hg 
concentration in the effluent gas stream.
    3.13 NIST means the National Institute of Standards and 
Technology, located in Gaithersburg, Maryland.
    3.14 Response Time means the time it takes for the measurement 
system, while operating normally at its target sample flow rate or 
dilution ratio, to respond to a known step change in gas 
concentration (from a low-level to a high-level gas) and to read 
within 5 percent of the stable high-level gas response.
    3.15 Run means a series of gas samples taken successively from 
the stack or duct. A test normally consists of a specific number of 
runs.
    3.16 System Calibration Error means the difference between the 
measured concentration of a low-, mid-, or high-level Hg\0\ 
calibration gas and the certified concentration of the gas when it 
is introduced in system calibration mode.
    3.17 System Calibration Mode means introducing the calibration 
gases into the measurement system at the probe, upstream of all 
sample conditioning components.
    3.18 Test refers to the series of runs required by the 
applicable regulation.

4.0 Interferences

    Interferences will vary among instruments and potential 
instrument-specific spectral and matrix interferences must be 
evaluated through the interference test and the dynamic spiking 
tests.

5.0 Safety

What safety measures should I consider when using this method?

    This method may require you to work with hazardous materials and 
in hazardous conditions. You are encouraged to establish safety 
procedures before using the method. Among other precautions, you 
should become familiar with the safety recommendations in the gas 
analyzer user's manual. Occupational Safety and Health 
Administration (OSHA) regulations concerning use of compressed gas 
cylinders and noxious gases may apply.

[[Page 51503]]

6.0 Equipment and Supplies

    6.1 What do I need for the measurement system? This method is 
intended to be applicable to multiple instrumental technologies. You 
may use any equipment and supplies that meet the following 
specifications.
    6.1.1 All wetted sampling system components, including probe 
components prior to the point at which the calibration gas is 
introduced, must be chemically inert to all Hg species. Materials 
such as perfluoroalkoxy (PFA) Teflon\TM\, quartz, treated stainless 
steel (SS) are examples of such materials. [Note: These materials of 
construction are required because components prior to the 
calibration gas injection point are not included in the system 
calibration error, system integrity, and interference tests.]
    6.1.2 The interference, system calibration error, system 
integrity, drift and dynamic spiking test criteria must all be met 
by the system used.
    6.1.3 The system must be capable of measuring and controlling 
sample flow rate.
    6.1.4 All system components prior to the Hg+\2\ to 
Hg\0\ converter must be maintained at a sample temperature above the 
acid gas dew point.
    6.2 Measurement System Components. Figure 30A-1 in Section 17.0 
is an example schematic of a Method 30A measurement system.
    6.2.1 Sample Probe. The probe must be made of the appropriate 
materials as noted in Section 6.1.1, heated when necessary (see 
Section 6.1.4), configured with ports for introduction of 
calibration and spiking gases, and of sufficient length to traverse 
all of the sample points.
    6.2.2 Filter or Other Particulate Removal Device. The filter or 
other particulate removal device is considered to be a part of the 
measurement system, must be made of appropriate materials as noted 
in Section 6.1.1, and must be included in all system tests.
    6.2.3 Sample Line. The sample line that connects the probe to 
the converter, conditioning system and analyzer must be made of 
appropriate materials as noted in Section 6.1.1.
    6.2.4 Conditioning Equipment. For dry basis measurements, a 
condenser, dryer or other suitable device is required to remove 
moisture continuously from the sample gas. Any equipment needed to 
heat the probe, or sample line to avoid condensation prior to the 
moisture removal component is also required. For wet basis systems, 
you must keep the sample above its dew point either by: (1) Heating 
the sample line and all sample transport components up to the inlet 
of the analyzer (and, for hot-wet extractive systems, also heating 
the analyzer) or (2) by diluting the sample prior to analysis using 
a dilution probe system. The components required to do either of the 
above are considered to be conditioning equipment.
    6.2.5 Sampling Pump. A pump is needed to push or pull the sample 
gas through the system at a flow rate sufficient to minimize the 
response time of the measurement system. If a mechanical sample pump 
is used and its surfaces are in contact with the sample gas prior to 
detection, the pump must be leak free and must be constructed of a 
material that is non-reactive to the gas being sampled (see Section 
6.1.1). For dilution-type measurement systems, an ejector pump 
(eductor) may be used to create a sufficient vacuum that sample gas 
will be drawn through a critical orifice at a constant rate. The 
ejector pump may be constructed of any material that is non-reactive 
to the gas being sampled.
    6.2.6 Calibration Gas System(s). One or more systems may be 
needed to introduce calibration gases into the measurement system. A 
system should be able to flood the sampling probe sufficiently to 
prevent entry of gas from the effluent stream.
    6.2.7 Dynamic Spiking Port. For the purposes of the dynamic 
spiking procedure described in Section 8.2.7, the measurement system 
must be equipped with a port to allow introduction of the dynamic 
spike gas stream with the sample gas stream, at a point as close as 
possible to the inlet of the probe so as to ensure adequate mixing. 
The same port used for system calibrations and calibration error 
checks may be used for dynamic spiking purposes.
    6.2.8 Sample Gas Delivery. The sample line may feed directly to 
a converter, to a by-pass valve (for speciating systems), or to a 
sample manifold. All valve and/or manifold components must be made 
of material that is non-reactive to the gas sampled and the 
calibration gas, and must be configured to safely discharge any 
excess gas.
    6.2.9 Hg Analyzer. An instrument is required that continuously 
measures the total vapor phase Hg in the gas stream and meets the 
applicable specifications in Section 13.0.
    6.2.10 Data Recorder. A recorder, such as a computerized data 
acquisition and handling system (DAHS), digital recorder, strip 
chart, or data logger, is required for recording measurement data.
    6.3 Moisture Measurement System. If correction of the measured 
Hg emissions for moisture is required (see Section 8.5), either 
Method 4 in appendix A-3 to this part or other moisture measurement 
methods approved by the Administrator will be needed to measure 
stack gas moisture content.

7.0 Reagents and Standards

    7.1 Calibration Gases. What calibration gases do I need? You 
will need calibration gases of known concentrations of Hg\0\ and 
HgCl2. Special reagents and equipment may be required to 
prepare the HgCl\2\ gas standards (e.g., a NIST-traceable solution 
of HgCl2 and a gas generator equipped with mass flow 
controllers).
    The following calibration gas concentrations are required:
    7.1.1 High-Level Gas. Equal to the selected calibration span.
    7.1.2 Mid-Level Gas. 40 to 60 percent of the calibration span.
    7.1.3 Low-Level Gas. 10 to 30 percent of the calibration span.
    7.1.4 Zero Gas. No detectable Hg.
    7.1.5 Dynamic Spike Gas. The exact concentration of the 
HgCl2 calibration gas used to perform the pre-test 
dynamic spiking procedure described in Section 8.2.7 depends on the 
native Hg concentration in the stack The spike gas must produce a 
spiked sample concentration above the native concentration, as 
specified in Section 8.2.7.2.2.
    7.2 Interference Test. What reagents do I need for the 
interference test? Use the appropriate test gases listed in Table 
30A-3 in Section 17.0 (i.e., the potential interferents for the 
source to be tested, as identified by the instrument manufacturer) 
to conduct the interference check. These gases need not be of 
protocol gas quality.

8.0 Sample Collection

Emission Test Procedure

    Figure 30A-2 in Section 17.0 presents an overview of the test 
procedures required by this method. Since you may choose different 
options to comply with certain performance criteria, you must 
identify the specific options and associated frequencies you select 
and document your results in regard to the performance criteria.
    8.1 Sample Point Selection. What sampling site and sampling 
points do I select?
    8.1.1 When this method is used solely for Hg emission testing 
(e.g., to determine compliance with an emission standard or limit), 
use twelve sampling points located according to Table 1-1 or Table 
1-2 of Method 1 in appendix A-1 to this part. Alternatively, you may 
conduct a stratification test as described in Section 8.1.3 to 
determine the number and location of the sampling points.
    8.1.2 When this method is used for relative accuracy testing of 
a Hg CEMS or sorbent trap monitoring system, follow the sampling 
site selection and sampling point layout procedures for gas monitor 
RATA testing described in the appropriate performance specification 
or applicable regulation (e.g., Performance Specification 2, section 
8.1.3 of appendix B to this part or section 6.5.6 of appendix A to 
part 75 of this chapter), with one exception. If you elect to 
perform stratification testing as part of the sampling point 
selection process, perform the testing in accordance with Section 
8.1.3 of this method (see also ``Summary Table of QA/QC 
Requirements'' in Section 9.0).
    8.1.3 Determination of Stratification. If you elect to perform 
stratification testing as part of the sampling point selection 
process and the test results show your effluent gas stream to be 
unstratified or minimally stratified, you may be allowed to sample 
at fewer points or at different points than would otherwise be 
required.
    8.1.3.1 Test Procedure. To test for stratification, use a probe 
of appropriate length to measure the total vapor phase Hg 
concentration at twelve traverse points located according to Table 
1-1 or Table 1-2 of Method 1 in appendix A-1 to this part. 
Alternatively, for a sampling location where stratification is 
expected (e.g., after a wet scrubber or at a point where dissimilar 
gas streams are combined together), if a 12-point Hg stratification 
test has been previously performed at that location and the results 
of the test showed the location to be minimally stratified or 
unstratified according to the criteria in section 8.1.3.2, you may 
perform an abbreviated 3-point or 6-point Hg stratification test at 
the points specified in

[[Page 51504]]

section 6.5.6.2(a) of appendix A to part 75 of this chapter in lieu 
of performing the 12-point test. Sample for a minimum of twice the 
system response time (see Section 8.2.6) at each traverse point. 
Calculate the individual point and mean Hg concentrations.
    8.1.3.2 Acceptance Criteria and Sampling Point Location.
    8.1.3.2.1 If the Hg concentration at each traverse point differs 
from the mean concentration for all traverse points by no more than: 
(a) 5 percent of the mean concentration; or (b) 0.2 [mu]g/m\3\ (whichever is less restrictive), the gas stream 
is considered to be unstratified and you may collect samples from a 
single point that most closely matches the mean.
    8.1.3.2.2 If the 5 percent or 0.2 [mu]g/m\3\ criterion in 
Section 8.1.3.2.1 is not met, but the Hg concentration at each 
traverse point differs from the mean concentration for all traverse 
points by no more than: (a)10 percent of the mean; or 
(b)0.5 [mu]g/m\3\ (whichever is less restrictive), the 
gas stream is considered to be minimally stratified, and you may 
take samples from three points, provided the points are located on 
the measurement line exhibiting the highest average Hg concentration 
during the stratification test. If the stack diameter (or equivalent 
diameter, for a rectangular stack or duct) is greater than 2.4 
meters (7.8 ft), locate the three sampling points at 0.4, 1.0, and 
2.0 meters from the stack or duct wall. Alternatively, if a RATA 
required by part 75 of this chapter is being conducted, you may 
locate the three points at 4.4, 14.6, and 29.6 percent of the duct 
diameter, in accordance with Method 1 in appendix A-1 to this part. 
For stack or duct diameters of 2.4 meters (7.8 ft) or less, locate 
the three sampling points at 16.7, 50.0, and 83.3 percent of the 
measurement line.
    8.1.3.2.3 If the gas stream is found to be stratified because 
the 10 percent or 0.5 [mu]g/m\3\ criterion in Section 8.1.3.2.2 is 
not met, then either locate three sampling points at 16.7, 50.0, and 
83.3 percent of the measurement line that exhibited the highest 
average Hg concentration during the stratification test, or locate 
twelve traverse points for the test in accordance with Table 1-1 or 
Table 1-2 of Method 1 in appendix A-1 to this part; or, if a RATA 
required by part 75 of this chapter is being conducted, locate six 
Method 1 points along the measurement line that exhibited the 
highest average Hg concentration.
    8.1.3.3 Temporal Variations. Temporal variations in the source 
Hg concentration during a stratification test may complicate the 
determination of stratification. If temporal variations are a 
concern, you may use the following procedure to normalize the 
stratification test data. A second Hg measurement system, i.e., 
either an installed Hg CEMS or another Method 30A system, is 
required to perform this procedure. Position the sampling probe of 
the second Hg measurement system at a fixed point in the stack or 
duct, at least one meter from the stack or duct wall. Then, each 
time that the Hg concentration is measured at one of the 
stratification test points, make a concurrent measurement of Hg 
concentration at the fixed point. Normalize the Hg concentration 
measured at each traverse point, by multiplying it by the ratio of 
CF,avg to CF, where CF is the 
corresponding fixed-point Hg concentration measurement, and 
CF,avg is the average of all of the fixed-point 
measurements over the duration of the stratification test. Evaluate 
the results of the stratification test according to section 8.1.3.2, 
using the normalized Hg concentrations.
    8.1.3.4 Stratification Testing Exemption. Stratification testing 
need not be performed at a test location where it would otherwise be 
required to justify using fewer sample points or different sample 
points, if the owner or operator documents that the Hg concentration 
in the stack gas is expected to be 3 [mu]g/m\3\ or less at the time 
of a Hg monitoring system RATA or an Hg emissions test. To 
demonstrate that a particular test location qualifies for the 
stratification testing exemption, representative Hg emissions data 
must be collected just prior to the RATA or emissions test. At least 
one hour of Hg concentration data is required for the demonstration. 
The data used for the demonstration shall be recorded at process 
operating conditions that closely approximate the operating 
conditions that will exist during the RATA or emissions test. It is 
recommended that collection of the demonstration data be integrated 
with the on-site pretest procedures required by the reference method 
being used for the RATA or emissions test (whether this method or 
another approved Hg reference method is used). Quality-assured data 
from an installed Hg monitoring system may also be used for the 
demonstration. If a particular test location qualifies for the 
stratification testing exemption, sampling shall be performed at 
three points, as described in section 8.1.3.2.2 of this method. The 
owner or operator shall fully document the method used to collect 
the demonstration data and shall keep this documentation on file 
with the data from the associated RATA or Hg emissions test.
    8.1.3.5 Interim Alternative Stratification Test Procedures. In 
the time period between the effective date of this method and 
January 1, 2009, you may follow one of the following two procedures. 
Substitute a stratification test for sulfur dioxide (SO2) 
for the Hg stratification test described in section 8.1.3.1. If this 
option is chosen, follow the test procedures in section 6.5.6.1 of 
appendix A to part 75 of this chapter. Evaluate the test results and 
determine the sampling point locations according to section 6.5.6.3 
of appendix A to part 75 of this chapter. If the sampling location 
is found to be minimally stratified or unstratified for 
SO2, it shall be considered minimally stratified or 
unstratified for Hg. Alternatively, you may forgo stratification 
testing, assume the gas stream is minimally stratified, and sample 
at three points as described in section 8.1.3.2.2 of this method.
    8.2 Initial Measurement System Performance Tests. What initial 
performance criteria must my system meet before I begin sampling? 
Before measuring emissions, perform the following procedures:
    (a) Interference Test;
    (b) Calibration Gas Verification;
    (c) Measurement System Preparation;
    (d) 3-Point System Calibration Error Test;
    (e) System Integrity Check;
    (f) Measurement System Response Time Test; and
    (g) Dynamic Spiking Test.
    8.2.1 Interference Test (Optional). Your measurement system 
should be free of known interferences. It is recommended that you 
conduct this interference test of your measurement system prior to 
its initial use in the field to verify that the candidate test 
instrument is free from inherent biases or interferences resulting 
from common combustion emission constituents. If you have multiple 
measurement systems with components of the same make and model 
numbers, you need only perform this interference check on one system 
and you may also rely on an interference test conducted by the 
manufacturer on a system having components of the same make and 
model(s) of the system that you use. The interference test procedure 
is found in Section 8.6 of this method.
    8.2.2 Calibration Gas Verification. How must I verify the 
concentrations of my calibration gases?
    8.2.2.1 Cylinder Gas Standards. When cylinder gas standards are 
used for Hg0, obtain a certificate from the gas 
manufacturer and confirm that the documentation includes all 
information required by an EPA traceability protocol (see Section 
16). Confirm that the manufacturer certification is complete and 
current. Ensure that the calibration gas certifications have not 
expired.
    8.2.2.2 Other Calibration Standards. All other calibration 
standards for HgCl2 and Hg0, such as gas 
generators, must meet the requirements of an EPA traceability 
protocol (see Section 16), and the certification procedures must be 
fully documented in the test report.
    8.2.2.3 Calibration Span. Select the calibration span (i.e., 
high-level gas concentration) so that the measured source emissions 
are 10 to 100 percent of the calibration span. This requirement is 
waived for applications in which the Hg concentrations are 
consistently below 1 [mu]g/m\3\; however, the calibration span for 
these low-concentration applications shall not exceed 5 [mu]g/m\3\.
    8.2.3 Measurement System Preparation. How do I prepare my 
measurement system for use? Assemble, prepare, and precondition the 
measurement system according to your standard operating procedure. 
Adjust the system to achieve the correct sampling rate or dilution 
ratio (as applicable). Then, conduct a 3-point system calibration 
error test using Hg0 as described in Section 8.2.4, an 
initial system integrity check using HgCl2 and a zero gas 
as described in Section 8.2.5, and a pre-test dynamic spiking test 
as described in Section 8.2.7.
    8.2.4 System Calibration Error Test. Conduct a 3-point system 
calibration error test before the first test run. Use Hg\0\ 
standards for this test. Introduce the low-, mid-, and high-level 
calibration gases in any order, in system calibration mode, unless 
you desire to determine the system response time during this test, 
in which case, inject the gases such that the high-level injection

[[Page 51505]]

directly follows the low-level injection. For non-dilution systems, 
you may adjust the system to maintain the correct flow rate at the 
analyzer during the test, but you may not make adjustments for any 
other purpose. For dilution systems, you must operate the 
measurement system at the appropriate dilution ratio during all 
system calibration error checks, and you may make only the 
adjustments necessary to maintain the proper ratio. After each gas 
injection, wait until a stable response has been obtained. Record 
the analyzer's final, stable response to each calibration gas on a 
form similar to Table 30A-1 in Section 17.0. For each calibration 
gas, calculate the system calibration error using Equation 30A-1 in 
Section 12.2. The calibration error specification in Section 13.1 
must be met for the low-, mid-, and high-level gases. If the 
calibration error specification is not met for all three gases, take 
corrective action and repeat the test until an acceptable 3-point 
calibration is achieved.
    8.2.5 System Integrity Check. Perform a two-point system 
integrity check before the first test run. Use the zero gas and 
either the mid- or high-level HgCl2 calibration gas for 
the check, whichever one best represents the total vapor phase Hg 
concentration levels in the stack. Record the data on a form similar 
to Table 30A-2 in Section 17.0. The system integrity check 
specification in Section 13.2 must be met for both the zero gas and 
the mid- or high-level gas. If the system integrity specification is 
not met for both gases, take corrective action and repeat the test 
until an acceptable system integrity check is achieved.
    8.2.6 Measurement System Response Time. The measurement system 
response time is used to determine the minimum sampling time for 
each sampling point and is equal to the time that is required for 
the measured Hg concentration to increase from the stable low-level 
calibration gas response to a value within 5 percent of the stable 
high-level calibration gas response during the system calibration 
error test in Section 8.2.4. Round off the measured system response 
time to the nearest minute.
    8.2.7 Dynamic Spiking Test. You must perform dynamic spiking 
prior to the first test run to validate your test data. The purpose 
of this procedure is to demonstrate that the site-specific flue gas 
matrix does not adversely affect the accuracy of the measurement 
system. The specifications in Section 13.5 must be met to validate 
your data. If these specifications are not met for the pre-test 
dynamic spiking, you may not proceed with the test until 
satisfactory results are obtained. For the time period between the 
effective date of this method and January 1, 2009, the dynamic 
spiking requirement is waived.
    8.2.7.1 How do I perform dynamic spiking? Dynamic spiking is a 
gas phase application of the method of standard additions, which 
involves injecting a known quantity of Hg into the measurement 
system upstream of all sample conditioning components, similar to 
system calibration mode, except the probe is not flooded and the 
resulting sample stream includes both effluent gas and the spike 
gas. You must follow a written procedure that details how the spike 
is added to the system, how the spike dilution factor (DF) is 
measured, and how the Hg concentration data are collected and 
processed.
    8.2.7.2 Spiking Procedure Requirements.
    8.2.7.2.1 Spiking Gas Requirements. The spike gas must also be a 
HgCl2 calibration gas certified by an EPA traceability 
protocol. You must choose concentrations that can produce the target 
levels while being injected at a volumetric flow rate that is < =20 
percent of the total volumetric flow rate through the measurement 
system (i.e., sample flow rate plus spike gas flow rate).
    8.2.7.2.2 Target Spiking Level. The target level for spiking 
must be 150 to 200 percent of the native Hg concentration; however, 
if the native Hg concentration is < 1 [mu]g/m\3\, set the target 
level to add between 1 and 4 [mu]g/m\3\ Hg+\2\ to the 
native concentration. Use Equation 30A-5 in Section 12.5 to 
calculate the acceptable range of spike gas concentrations at the 
target level. Then select a spike gas concentration in that range.
    8.2.7.2.3 Spike Injections. You must inject spikes in such a 
manner that the spiking does not alter the total volumetric sample 
system flow rate and dilution ratio (if applicable). You must 
collect at least 3 data points, and the relative standard deviation 
(RSD) specification in Section 13.5 must be met. Each data point 
represents a single spike injection, and pre- and post-injection 
measurements of the native Hg concentration (or diluted native 
concentration, as applicable) are required for each spike injection.
    8.2.7.2.4 Spike Dilution Factor (DF). For each spike injection, 
DF, the dilution factor must be determined. DF is the ratio of the 
total volumetric flow rate of gas through the measurement system to 
the spike gas flow rate. This factor must be >=5. The spiking mass 
balance calculation is directly dependent on the accuracy of the DF 
determination. As a result, high accuracy total volumetric flow rate 
and spike gas flowrate measurements are required. These flow rates 
may be determined by direct or indirect measurement. Calibrated flow 
meters, venturies, orifices or tracer gas measurements are examples 
of potential flow measurement techniques.
    8.2.7.2.5 Concentrations. The measurement system must record 
total vapor phase Hg concentrations continuously during the dynamic 
spiking procedure. It is possible that dynamic spiking at a level 
close to 200 percent of the native Hg concentration may cause the 
measured Hg concentration to exceed the calibration span value. 
Avoid this by choosing a lower spiking level or by recalibration at 
a higher span. The measurements shall not exceed 120 percent of the 
calibration span. The ``baseline'' measurements made between spikes 
may represent the native Hg concentration (if spike gas flow is 
stopped between injections) or the native Hg concentration diluted 
by blank or carrier gas flowing at the same rate as the spike gas 
(if gas flow cannot be stopped between injections). Each baseline 
measurement must include at least 4 readings or 1 minute (whichever 
is greater) of stable responses. Use Equation 30A-10 or 30A-11 in 
Section 12.10 (as applicable) to convert baseline measurements to 
native concentration.
    8.2.7.2.6 Recovery. Calculate spike recoveries using Equation 
30A-7 in Section 12.7. Mass recoveries may be calculated from stable 
responses based on injected mass flows or from integrated response 
peaks based on total mass injected. Calculate the mean and RSD for 
the three (or more) spike injections and compare to the 
specifications in Section 13.5. 
    8.2.7.2.7 Error Adjustment Option. You may adjust the 
measurement data collected during dynamic spiking for the system 
calibration error using Equation 30A-3 in Section 12. To do this, 
perform the initial system integrity check prior to the dynamic 
spiking test, and perform another system integrity check following 
the dynamic spiking test and before the first test run. If you 
choose this option, you must apply Equation 30A-3 to both the spiked 
sample concentration measurement (Css) and the baseline 
or native concentration measurement (Cnative), each 
substituted in place of Cavg in the equation.
    8.2.7.3 Example Spiking Procedure Using a Hot Vapor Calibration 
Source Generator.
    (a) Introduce the spike gas into the probe using a hot vapor 
calibration source generator and a solution of HgCl2 in 
dilute HC1 and HNO3. The calibrator uses a mass flow 
controller (accurate within 2 percent) to measure the gas flow, and 
the solution feed is measured using a top-loading balance accurate 
to 0.01g. The challenges of injecting oxidized Hg may make it 
impractical to stop the flow of gas between spike injections. In 
this case, operate the hot vapor calibration source generator 
continuously during the spiking procedure, swapping blank solutions 
for HgCl2 solutions when switching between spiking and 
baseline measurements.
    (b) If applicable, monitor the measurement system to make sure 
the total sampling system flow rate and the sample dilution ratio do 
not change during this procedure. Record all data on a data sheet 
similar to Table 30A-5 in Section 17.0. If the Hg measurement system 
design makes it impractical to measure the total volumetric flow 
rate through the system, use a spike gas that includes a tracer for 
measuring the dilution factor, DF (see Equation 30A-9 in Section 
12.9). Allow the measurements to stabilize between each spike 
injection, average the pre- and post-injection baseline 
measurements, and calculate the native concentration. If this 
measurement shifts by more than 5 percent during any injection, it 
may be necessary to discard that data point and repeat the injection 
to achieve the required RSD among the injections. If the spikes 
persistently show poor repeatability, or if the recoveries are not 
within the range specified in Section 13.5, take corrective action.
    8.2.8 Run Validation. How do I confirm that each run I conduct 
is valid?
    8.2.8.1 System Integrity Checks.
    (a) Before and after each test run, perform a two-point system 
integrity check using the same procedure as the initial system 
integrity check described in Section 8.2.5. You may use data from 
that initial system integrity

[[Page 51506]]

check as the pre-run data for the first test run, provided it is the 
most recent system integrity check done before the first run. You 
may also use the results of a successful post-run system integrity 
check as the pre-run data for the next test run. Do not make any 
adjustments to the measurement system during these checks, other 
than to maintain the target calibration gas flow rate and the proper 
dilution ratio.
    (b) As a time-saving alternative, you may, at the risk of 
invalidating multiple test runs, skip one or more integrity checks 
during a test day. Provided there have been no auto-calibrations or 
other instrument alterations, a single integrity check may suffice 
as a post-run check to validate (or invalidate) as many consecutive 
test runs as can be completed during a single test day. All 
subsequent test days must begin with a pre-run system integrity 
check subject to the same performance criteria and corrective action 
requirements as a post-run system integrity check.
    (c) Each system integrity check must meet the criteria for 
system integrity checks in Section 13.2. If a post-run system 
integrity check is failed, all test runs since the last passed 
system integrity check are invalid. If a post-run or a pre-run 
system integrity check is failed, you must take corrective action 
and pass another 3-point Hg\0\ system calibration error test 
(Section 8.2.4) followed by another system integrity check before 
conducting any additional test runs. Record the results of the pre- 
and post-run system integrity checks on a form similar to Table 30A-
2 in Section 17.0.
    8.2.8.2 Drift Check. Using the data from the successful pre- and 
post-run system integrity checks, calculate the zero and upscale 
drift, using Equation 30A-2 in Section 12.3. Exceeding the Section 
13.3 specification does not invalidate the run, but corrective 
action must be taken and a new 3-point Hg\0\ system calibration 
error test and a system integrity check must be passed before any 
more runs are made.
    8.3 Dilution-Type Systems--Special Considerations. When a 
dilution-type measurement system is used, there are three important 
considerations that must be taken into account to ensure the quality 
of the emissions data. First, the critical orifice size and dilution 
ratio must be selected properly so that the sample dew point will be 
below the sample line and analyzer temperatures. Second, a high-
quality, accurate dilution controller must be used to maintain the 
correct dilution ratio during sampling. The dilution controller 
should be capable of monitoring the dilution air pressure, orifice 
upstream pressure, eductor vacuum, and sample flow rates. Third, 
differences between the molecular weight of calibration gas 
mixtures, dilution air, and the stack gas molecular weight must be 
considered because these can affect the dilution ratio and introduce 
measurement bias.
    8.4 Sampling.
    (a) Position the probe at the first sampling point. Allow the 
system to flush and equilibrate for at least two times the 
measurement system response time before recording any data. Then, 
traverse and record measurements at all required sampling points. 
Sample at each traverse point for an equal length of time, 
maintaining the appropriate sample flow rate or dilution ratio (as 
applicable). For all Hg instrumental method systems, the minimum 
sampling time at each sampling point must be at least two times the 
system response time, but not less than 10 minutes. For 
concentrating systems, the minimum sampling time must also include 
at least 4 concentration measurement cycles.
    (b) After recording data for the appropriate period of time at 
the first traverse point, you may move the sample probe to the next 
point and continue recording, omitting the requirement to allow the 
system to equilibrate for two times the system response time before 
recording data at the subsequent traverse points. You must, however, 
sample at this and all subsequent traverse points for the required 
minimum amount of time specified in this section. If you must remove 
the probe from the stack for any reason, you must again allow the 
sampling system to equilibrate for at least two times the system 
response time prior to resuming data recording.
    (c) If at any point the measured Hg concentration exceeds the 
calibration span value, you must at a minimum identify and report 
this as a deviation from the method. Depending on the data quality 
objectives of the test, this event may require corrective action 
before proceeding. If the average Hg concentration for any run 
exceeds the calibration span value, the run is invalidated.
    8.5 Moisture Correction. If the moisture basis (wet or dry) of 
the measurements made with this method is different from the 
moisture basis of either: (1) The applicable emission limit; or (2) 
a Hg CEMS or sorbent trap monitoring system being evaluated for 
relative accuracy, you must determine the moisture content of the 
flue gas and correct the measured gas concentrations to a dry basis 
using Method 4 in appendix A-3 of this part or other appropriate 
methods, subject to the approval of the Administrator.
    8.6 Optional Interference Test Procedure.
    (a) Select an appropriate calibration span that reflects the 
source(s) to be tested and perform the interference check at 40 
percent of the lowest calibration span value anticipated, e.g., 10 
[mu]g/m\3\. Alternatively, successfully conducting the interference 
test at an absolute Hg concentration of 2 [mu]g/m\3\ will 
demonstrate performance for an equivalent calibration span of 5 
[mu]g/m\3\, the lowest calibration span allowed for Method 30A 
testing. Therefore, performing the interference test at the 2 [mu]/
m\3\ level will serve to demonstrate acceptable performance for all 
calibration spans greater than or equal to 5 [mu]g/m\3\.
    (b) Introduce the interference test gases listed in Table 30A-3 
in Section 17.0 into the measurement system separately or as a 
mixture. The interference test gases HCl and NO must be introduced 
as a mixture. The interference test gases must be introduced into 
the sampling system at the probe such that the interference gas 
mixtures pass through all filters, scrubbers, conditioners, and 
other components as would be configured for normal sampling.
    (c) The interference test must be performed using 
HgCl2, and each interference test gas (or gas mixture) 
must be evaluated in triplicate. This is accomplished by measuring 
the Hg response first with only the HgCl2 gas present and 
then when adding the interference test gas(es) while maintaining the 
HgCl2 concentration of the test stream constant. It is 
important that the equipment used to conduct the interference test 
be of sufficient quality so as to be capable of blending the 
HgCl2 and interference gases while maintaining the Hg 
concentration constant. Gas blending system or manifolds may be 
used.
    (d) The duration of each test should be for a sufficient period 
of time to ensure the Hg measurement system surfaces are conditioned 
and a stable output is obtained. Measure the Hg response of the 
analyzer to these gases in [mu]g/m3. Record the responses and 
determine the overall interference response using Table 30A-4 in 
Section 17.0 and the equations presented in Section 12.11. The 
specification in Section 13.4 must be met.
    (e) A copy of these data, including the date completed and a 
signed certification, must be included with each test report. The 
intent of this test is that the interference test results are 
intended to be valid for the life of the system. As a result, the Hg 
measurement system should be operated and tested in a configuration 
consistent with the configuration that will be used for field 
applications. However, if the system used for field testing is not 
consistent with the system that was interference-tested, the 
interference test must be repeated before it is used for any field 
applications. Examples of such conditions include, but are not 
limited to: major changes in dilution ratio (for dilution based 
systems), changes in catalyst materials, changes in filtering device 
design or materials, changes in probe design or configuration, and 
changes in gas conditioning materials or approaches.

9.0 Quality Control

What quality control measures must I take?

    The table which follows is a summary of the mandatory, 
suggested, and alternative quality assurance and quality control 
measures and the associated frequency and acceptance criteria. All 
of the QC data, along with the run data, must be documented and 
included in the test report.

[[Page 51507]]

                                       Summary Table of QA/QC Requirements
----------------------------------------------------------------------------------------------------------------
     Status \1\       Process or element    QA/QC specification     Acceptance criteria      Checking frequency
----------------------------------------------------------------------------------------------------------------
S..................  Identify Data User..  ....................  Regulatory Agency or       Before designing
                                                                  other primary end user     test.
                                                                  of data.
M..................  Analyzer Design.....  Analyzer range......  Sufficiently > high-level  ....................
                                                                  gas to allow
                                                                  determination of system
                                                                  calibration error.
S..................  ....................  Analyzer resolution   <  2.0 % of full-scale      Manufacturer design.
                                            or sensitivity.       range.
S..................  ....................  Interference          Overall response < = 3% of
                                            response.             calibration span.
                                                                 Alternatively, overall
                                                                  response < = 0.3 [mu]g/
                                                                  m\3\.
M..................  Calibration Gases...  Traceability          Validation of
                                            protocol.             concentration required.
M..................  ....................  High-level Hg\0\ gas  Equal to the calibration   Each calibration
                                                                  span.                      error test.
M..................  ....................  Mid-level Hg\0\ gas.  40 to 60% of calibration   Each calibration
                                                                  span.                      error test.
M..................  ....................  Low-level Hg\0\ gas.  10 to 30% of calibration   Each calibration
                                                                  span.                      error test.
M..................  ....................  High-level HgCl2 gas  Equal to the calibration   Each system
                                                                  span.                      integrity check (if
                                                                                             it better
                                                                                             represents Cnative
                                                                                             than the mid level
                                                                                             gas).
M..................  ....................  Mid-level HgCl2.....  40 to 60% of calibration   Each system gas
                                                                  span.                      integrity check (if
                                                                                             it better
                                                                                             represents Cnative
                                                                                             than the high level
                                                                                             gas).
M..................  ....................  Zero gas............  .........................  Each system
                                                                                             integrity check.
M..................  ....................  Dynamic spike gas     A high-concentration       Pre-test; dynamic
                                            (Cnative >= 1 [mu]g/  HgCl2 gas, used to         spiking not
                                            m\3\).                produce a spiked sample    required until 1/1/
                                                                  concentration that is      09.
                                                                  150 to 200% of the
                                                                  native concentration.
M..................  ....................  Dynamic spike gas     A high-concentration       Pre-test; dynamic
                                            (Cnative <  1 [mu]g/   HgCl2 gas, used to         spiking not
                                            m\3\).                produce a spiked sample    required until 1/1/
                                                                  concentration that is 1    09.
                                                                  to 2 [mu]g/m\3\ above
                                                                  the native concentration.
S..................  Data Recorder Design  Data resolution.....  < = 0.5% of full-scale....  Manufacturer design.
M..................  Sample Extraction...  Probe material......  Inert to sample            Each run.
                                                                  constituents (e.g., PFA
                                                                  Teflon, or quartz if
                                                                  stack > 500 [deg]F).
M..................  Sample Extraction...  Probe, filter and     For dry-basis analyzers,   Each run.
                                            sample line           keep sample above the
                                            temperature.          dew point, by heating
                                                                  prior to moisture
                                                                  removal.
                                                                 For wet-basis analyzers,
                                                                  keep sample above dew
                                                                  point at all times, by
                                                                  heating or dilution.
M..................  Sample Extraction...  Calibration valve     Inert to sample            Each test.
                                            material.             constituents (e.g., PFA
                                                                  Teflon or PFA Teflon
                                                                  coated).
S..................  Sample Extraction...  Sample pump material  Inert to sample            Each test.
                                                                  constituents.
M..................  Sample Extraction...  Manifold material...  Inert to sample            Each test.
                                                                  constituents.
M..................  Particulate Removal.  Filter inertness....  Pass calibration error     Each calibration
                                                                  check.                     error check.
M..................  System Calibration    System calibration    CE < = 5.0 % of the         Before initial run
                      Performance.          error (CE) test.      calibration span for the   and after a failed
                                                                  low-, mid-or high-level    system integrity
                                                                  Hg\0\ calibration gas.     check or drift
                                                                 Alternative                 test.
                                                                  specification: < = 0.5
                                                                  [mu]g/m\3\ absolute
                                                                  difference between
                                                                  system response and
                                                                  reference value.
M..................  System Calibration    System integrity      Error < = 5.0% of the       Before initial run,
                      Performance.          check.                calibration span for the   after each run, at
                                                                  zero and mid- or high-     the beginning of
                                                                  level HgCl2 calibration    subsequent test
                                                                  gas.                       days, and after a
                                                                 Alternative                 failed system
                                                                  specification: < = 0.5      integrity check or
                                                                  [mu]g/m\3\ absolute        drift test.
                                                                  difference between
                                                                  system response and
                                                                  reference value.
M..................  System Performance..  System response time  Used to determine minimum  During initial 3-
                                                                  sampling time per point.   point system
                                                                                             calibration error
                                                                                             test.
M..................  System Performance..  Drift...............  < = 3.0% of calibration     At least once per
                                                                  span for the zero and      test day.
                                                                  mid- or high-level gas.
                                                                 Alternative
                                                                  specification: < = 0.3
                                                                  [mu]g/m\3\ absolute
                                                                  difference between pre-
                                                                  and post-run system
                                                                  calibration error
                                                                  percentages..
M..................  System Performance..  Minimum sampling      The greater of two times   Each sampling point.
                                            time.                 the system response time
                                                                  or 10 minutes.
                                                                  Concentrating systems
                                                                  must also include at
                                                                  least 4 cycles.
M..................  System Performance..  Percentage spike      Percentage spike           Before initial
                                            recovery and          recovery, at the target    dynamic spiking not
                                            relative standard     level: 100     required until 1/1/
                                            deviation.            10%.                       09.
                                                                 Relative standard
                                                                  deviation: < = 5 percent.
                                                                 Alternative
                                                                  specification: absolute
                                                                  difference between
                                                                  calculated and measured
                                                                  spike values < = 0.5
                                                                  [mu]g/m\3\.

[[Page 51508]]

M..................  Sample Point          Number and Location   For emission testing       Prior to first run.
                      Selection.            of Sample Points.     applications, use 12
                                                                  points, located
                                                                  according to Method 1 in
                                                                  appendix A-1 to this
                                                                  part, unless the results
                                                                  of a stratification test
                                                                  allow fewer points to be
                                                                  used.
                     ....................  ....................  For Part 60 RATAs, follow
                                                                  the procedures in
                                                                  Performance
                                                                  Specification 2, section
                                                                  8.1.3, and for Part 75
                                                                  RATAs, follow the
                                                                  procedures in section
                                                                  6.5.6 of appendix A to
                                                                  Part 75. That is:
                     ....................  ....................   At any test
                                                                  location, you may use 3
                                                                  sample points located at
                                                                  16.7, 50.0, and 83.3% of
                                                                  a ``long'' measurement
                                                                  line passing through the
                                                                  centroidal area; or
                     ....................  ....................   At any test
                                                                  location, you may use 6
                                                                  sample points along a
                                                                  diameter, located
                                                                  according to Method 1
                                                                  (Part 75 RATAs, only);
                                                                  or
                     ....................  ....................   At a location
                                                                  where stratification is
                                                                  not expected and the
                                                                  measurement line is >
                                                                  2.4 m (7.8 ft), you may
                                                                  use 3 sample points
                                                                  located along a
                                                                  ``short'' measurement
                                                                  line at 0.4, 1.0, and
                                                                  2.0 m from the stack or
                                                                  duct wall or, for Part
                                                                  75 only, sample points
                                                                  may be located at 4.4,
                                                                  14.6, and 29.6% of the
                                                                  measurement line; or
                     ....................  ....................   After a wet
                                                                  scrubber or at a point
                                                                  where dissimilar gas
                                                                  streams are combined,
                                                                  either locate 3 sample
                                                                  points along the
                                                                  ``long'' measurement
                                                                  line or locate 6 Method
                                                                  1 points along a
                                                                  diameter (Part 75,
                                                                  only), unless the
                                                                  results of a
                                                                  stratification test
                                                                  allow you to use a
                                                                  ``short'' 3-point
                                                                  measurement line or to
                                                                  sample at a single point.
                     ....................  ....................   If it can be
                                                                  demonstrated that stack
                                                                  gas concentration is < =
                                                                  3 [mu]g/m\3\, then the
                                                                  test site is exempted
                                                                  from stratification
                                                                  testing. Use the 3-point
                                                                  ``short'' measurement
                                                                  line if the stack
                                                                  diameter is > 2.4 m (7.8
                                                                  ft) and the 3-point
                                                                  ``long'' line for stack
                                                                  diameters < = 2.4 m (7.8
                                                                  ft).
A..................  Sample Point          Stratification Test   If the Hg concentration    Prior to first run.
                      Selection.            (see Section 8.1.3).  \2\ at each traverse
                                                                  point during the
                                                                  stratification test is:
                                                                  Within  5% of mean, use 1-
                                                                  point sampling (at the
                                                                  point closest to the
                                                                  mean); or.
                                                                  Not within  5% of mean, but
                                                                  is within 
                                                                  10% of mean, use 3-point
                                                                  sampling. Locate points
                                                                  according to Section
                                                                  8.1.3.2.2 of this method.
                     ....................  ....................  Alternatively, if the Hg   Prior to 1/1/09, you
                                                                  concentration at each      may (1) forgo
                                                                  point is:                  stratification
                                                                  Within  0.2 [mu]g/m\3\ of   sampling points (as
                                                                  mean, use 1-point          per Section
                                                                  sampling (at the point     8.1.3.2.2) or (2)
                                                                  closest to the mean); or.  perform a SO2
                                                                  Not within  0.2 [mu]g/m\3\ of   (see Sections
                                                                  mean, use 3-point          6.5.6.1 and 6.5.6.3
                                                                  sampling. Locate points    of appendix A to
                                                                  according to Section       part 75), in lieu
                                                                  8.1.3.2.2 of this method.  of a Hg
                                                                                             stratification
                                                                                             test. If the test
                                                                                             location is
                                                                                             unstratified or
                                                                                             minimally
                                                                                             stratified for SO2,
                                                                                             it can be
                                                                                             considered
                                                                                             unstratified or
                                                                                             minimally
                                                                                             stratified for Hg
                                                                                             also.

[[Page 51509]]

                     ....................  ....................  If the Hg concentration    On and after 1/1/09,
                                                                  is > 10% of the mean at    only Hg
                                                                  any point, then, if the    stratification
                                                                  alternative                tests are
                                                                  specification is not met   acceptable for the
                                                                  or if the stack diameter   purposes of this
                                                                  is < = 2.4 m (7.8 ft):      method.
                                                                  Perform sampling
                                                                  at 12 Method 1 points;
                                                                  or.
                                                                  Sample at 3
                                                                  points located at 16.7,
                                                                  50.0 and 83.3% of the
                                                                  measurement line that
                                                                  exhibited the highest
                                                                  average Hg concentration
                                                                  during stratification
                                                                  test; or.
                                                                  Sample at 6
                                                                  Method 1 points along
                                                                  the line that exhibited
                                                                  the highest average Hg
                                                                  concentration (Part 75
                                                                  RATAs, only).
M..................  Data Recording......  Frequency...........  Once per cycle...........  During run.
S..................  Data Parameters.....  Sample concentration  All analyzer readings      Each run.
                                            and calibration       during each run within
                                            span.                 calibration span.
M..................  Data Parameters.....  Sample concentration  All analyzer readings      Each spike
                                            and calibration       during dynamic spiking     injection.
                                            span.                 tests within 120% of
                                                                  calibration span.
M..................  Data Parameters.....  Sample concentration  Average Hg concentration   Each run.
                                            and calibration       for the run < =
                                            span.                 calibration span.
----------------------------------------------------------------------------------------------------------------
\1\ M = Mandatory; S = Suggested; A = Alternative.
\2\ These may either be the unadjusted Hg concentrations or concentrations normalized to account for temporal
  variations.

10.0 Calibration and Standardization

What measurement system calibrations are required?

    Your analyzer must be calibrated with Hg[deg] standards. The 
initial 3-point system calibration error test described in Section 
8.2.4 is required before you start the test. Also, prior to and 
following test runs, the two-point system integrity checks described 
in Sections 8.2.5 and 8.2.8 are required. On and after January 1, 
2009, the pre-test dynamic spiking procedure described in section 
8.2.7 is also required to verify that the accuracy of the 
measurement system is suitable and not adversely affected by the 
flue gas matrix.

11.0 Analytical Procedures

    Because sample collection and analysis are performed together 
(see Section 8), additional discussion of the analytical procedure 
is not necessary.

12.0 Calculations and Data Analysis

    You must follow the procedures for calculations and data 
analysis listed in this section.

    12.1 Nomenclature. The terms used in the equations are defined 
as follows:
Bws = Moisture content of sample gas as measured by 
Method 4 in Appendix A-3 to this part, percent/100.
Cavg = Average unadjusted Hg concentration for the test 
run, as indicated by the data recorder [mu]g/m\3\.
Cbaseline = Average Hg concentration measured before and 
after dynamic spiking injections, [mu]g/m\3\.
Cd = Hg concentration, dry basis, [mu]g/m\3\.
Cdif = Absolute value of the difference between the 
measured Hg concentrations of the reference HgCl2 
calibration gas, with and without the individual or combined 
interference gases, [mu]g/m\3\.
Cdif avg = Average of the 3 absolute values of the 
difference between the measured Hg concentrations of the reference 
HgCl2 calibration gas, with and without the individual or 
combined interference gases, [mu]g/m\3\.
Cgas = Average Hg concentration in the effluent gas for 
the test run, adjusted for system calibration error, [mu]g/m\3\.
Cint = Measured Hg concentration of the reference 
HgCl2 calibration gas plus the individual or combined 
interference gases, [mu]g/m\3\.
Cm = Average of pre- and post-run system integrity check 
responses for the upscale (i.e., mid- or high-level) calibration 
gas, [mu]g/m\3\.
Cma = Actual concentration of the upscale (i.e., mid- or 
high-level) calibration gas used for the system integrity checks, 
[mu]g/m\3\.
C0 = Average of pre- and post-run system integrity check 
responses from the zero gas, [mu]g/m\3\.
Cnative = Vapor phase Hg concentration in the source 
effluent, [mu]g/m\3\.
Cref = Measured Hg concentration of the reference 
HgCl2 calibration gas alone, in the interference test, 
[mu]g/m\3\.
Cs = Measured concentration of a calibration gas (zero-, 
low-, mid-, or high-level), when introduced in system calibration 
mode, [mu]g/m\3\.
Cspike = Actual Hg concentration of the spike gas, [mu]g/
m\3\.
C*spike = Hg concentration of the spike gas required to 
achieve a certain target value for the spiked sample Hg 
concentration, [mu]g/m\3\.
Css = Measured Hg concentration of the spiked sample at 
the target level, [mu]g/m\3\.
C*ss = Expected Hg concentration of the spiked sample at 
the target level, [mu]g/m\3\.
Ctarget = Target Hg concentration of the spiked sample, 
[mu]g/m\3\.
CTnative = Measured tracer gas concentration present in 
native effluent gas, ppm.
CTdir = Tracer gas concentration injected with spike gas, 
ppm.
CTv = Diluted tracer gas concentration measured in a 
spiked sample, ppm.
Cv = Certified Hg[deg] or HgCl2 concentration 
of a calibration gas (zero, low, mid, or high), [mu]g/m\3\.
Cw = Hg concentration measured under moist sample 
conditions, wet basis, [mu]g/m\3\.
CS = Calibration span, [mu]g/m\3\.
D = Zero or upscale drift, percent of calibration span.
DF = Dilution factor of the spike gas, dimensionless.
I = Interference response, percent of calibration span.
Qprobe = Total flow rate of the stack gas sample plus the 
spike gas, liters/min.
Qspike = Flow rate of the spike gas, liters/min.
Ri = Individual injection spike recovery, %;.
R= Mean value of spike recoveries at a particular target level, %;.
RSD = Relative standard deviation, %;.
SCE = System calibration error, percent of calibration span.
SCEi = Pre-run system calibration error during the two-
point system integrity check, percent of calibration span.
SCEf = Post-run system calibration error during the two-
point system integrity check, percent of calibration span.

    12.2 System Calibration Error. Use Equation 30A-1 to calculate 
the system calibration error. Equation 30A-1 applies to: 3-point 
system calibration error tests performed with Hg[deg] standards; and 
pre- and post-run two-point system integrity checks performed with 
HgCl2.
[GRAPHIC] [TIFF OMITTED] TR07SE07.005

    12.3 Drift Assessment. Use Equation 30A-2 to separately 
calculate the zero and upscale drift for each test run.
[GRAPHIC] [TIFF OMITTED] TR07SE07.006

    12.3 Effluent Hg Concentration. For each test run, calculate 
Cavg, the arithmetic average of all valid Hg 
concentration values recorded during the run. Then, adjust the value 
of Cavg

[[Page 51510]]

for system calibration error, using Equation 30A-3.
[GRAPHIC] [TIFF OMITTED] TR07SE07.007

    12.4 Moisture Correction. Use Equation 30A-4a if your 
measurements need to be corrected to a dry basis.
[GRAPHIC] [TIFF OMITTED] TR07SE07.008

    Use Equation 30A-4b if your measurements need to be corrected to 
a wet basis.
[GRAPHIC] [TIFF OMITTED] TR07SE07.009

    12.5 Dynamic Spike Gas Concentrations. Use Equation 30A-5 to 
determine the spike gas concentration needed to produce a spiked 
sample with a certain ``target'' Hg concentration.
[GRAPHIC] [TIFF OMITTED] TR07SE07.010

    12.6 Spiked Sample Concentration. Use Equation 30A-6 to 
determine the expected or theoretical Hg concentration of a spiked 
sample.
[GRAPHIC] [TIFF OMITTED] TR07SE07.011

    12.7 Spike Recovery. Use Equation 30A-7 to calculate the 
percentage recovery of each spike.
[GRAPHIC] [TIFF OMITTED] TR07SE07.012

    12.8 Relative Standard Deviation. Use Equation 30A-8 to 
calculate the relative standard deviation of the individual 
percentage spike recovery values from the mean.
[GRAPHIC] [TIFF OMITTED] TR07SE07.013

    12.9 Spike Dilution Factor. Use Equation 30A-9 to calculate the 
spike dilution factor, using either direct flow measurements or 
tracer gas measurements.
[GRAPHIC] [TIFF OMITTED] TR07SE07.014

    12.10 Native Concentration. For spiking procedures that inject 
blank or carrier gases (at the spiking flow rate, Qspike) 
between spikes, use Equation 30A-10 to calculate the native 
concentration.
[GRAPHIC] [TIFF OMITTED] TR07SE07.015

    For spiking procedures that halt all injections between spikes, 
the native concentration equals the average baseline concentration 
(see Equation 30A-11).
[GRAPHIC] [TIFF OMITTED] TR07SE07.016

    12.11 Overall Interference Response. Use equation 30A-12 to 
calculate the overall interference response.
[GRAPHIC] [TIFF OMITTED] TR07SE07.017

    Where, for each interference gas (or mixture):
    [GRAPHIC] [TIFF OMITTED] TR07SE07.018
    
    [GRAPHIC] [TIFF OMITTED] TR07SE07.019
    

[[Page 51511]]

13.0 Method Performance

    13.1 System Calibration Error Test. This specification applies 
to the 3-point system calibration error tests using Hg0. 
At each calibration gas level tested (low-, mid-, or high-level), 
the calibration error must be within 5.0 percent of the 
calibration span. Alternatively, the results are acceptable if 
[bond] Cs - Cv [bond] <=0.5 [mu]g/
m3.
    13.2 System Integrity Checks. This specification applies to all 
pre- and post-run 2-point system integrity checks using 
HgCl2 and zero gas. At each calibration gas level tested 
(zero and mid- or high-level), the error must be within < plus-
minus>5.0 percent of the calibration span. Alternatively, the 
results are acceptable if [bond] Cs - Cv 
[bond] <=0.5 [mu]g/m3.
    13.3 Drift. For each run, the low-level and upscale drift must 
be less than or equal to 3.0 percent of the calibration span. The 
drift is also acceptable if the pre- and post-run system integrity 
check responses do not differ by more than 0.3 [mu]g/m3 
(i.e., [bond] Cs post-run - Cs pre-run [bond] 
<=0.3 [mu]g/m3).
    13.4 Interference Test. Summarize the results following the 
format contained in Table 30A-4. For each interference gas (or 
mixture), calculate the mean difference between the measurement 
system responses with and without the interference test gas(es). The 
overall interference response for the analyzer that was used for the 
test (calculated according to Equation 30A-12), must not be greater 
than 3.0 percent of the calibration span used for the test (see 
Section 8.6). The results of the interference test are also 
acceptable if the sum of the absolute average differences for all 
interference gases (i.e., [Sigma] Cdif avg) does not 
exceed 0.3 [mu]g/m3.
    13.5 Dynamic Spiking Test. For the pre-test dynamic spiking, the 
mean value of the percentage spike recovery must be 100 < plus-
minus>10 percent. In addition, the relative standard deviation (RSD) 
of the individual percentage spike recovery values from the mean 
must be < =5.0 percent. Alternatively, if the mean percentage 
recovery is not met, the results are acceptable if the absolute 
difference between the theoretical spiked sample concentration (see 
Section 12.6) and the actual average value of the spiked sample 
concentration is <=0.5 [mu]g/m3.

14.0 Pollution Prevention [Reserved]

15.0 Waste Management [Reserved]

16.0 References

    1. EPA Traceability Protocol for Qualification and Certification 
of Elemental Mercury Gas Generators, expected publication date 
December 2008, see http://www.epa.gov/ttn/emc.

    2. EPA Traceability Protocol for Qualification and Certification 
of Oxidized Mercury Gas Generators, expected publication date 
December 2008, see http://www.epa.gov/ttn/emc.

    3. EPA Traceability Protocol for Assay and Certification of 
Gaseous Calibration Standards, expected revision publication date 
December 2008, see http://www.epa.gov/ttn/emc.

17.0 Figures and Tables

BILLING CODE 6560-50-C

[[Page 51512]]

[GRAPHIC] [TIFF OMITTED] TR07SE07.020

[[Page 51513]]

[GRAPHIC] [TIFF OMITTED] TR07SE07.021

[[Page 51514]]

[GRAPHIC] [TIFF OMITTED] TR07SE07.022

[[Page 51515]]

[GRAPHIC] [TIFF OMITTED] TR07SE07.023

           Table 30A-3.--Interference Check Gas Concentrations
------------------------------------------------------------------------
                                     Concentration,  tentative--(balance
   Potential interferent gas \1\                     N2)
------------------------------------------------------------------------
CO2...............................  15%  1% CO2
CO................................  100  20 ppm
HCl \2\...........................  100  20 ppm
NO \2\............................  250  50 ppm
SO2...............................  200  20 ppm
O2................................  3%  1% O2
H2O...............................  10%  1% H2O
Nitrogen..........................  Balance
Other ............................
------------------------------------------------------------------------
\1\ Any of these specific gases can be tested at a lower level if the
  manufacturer has provided reliable means for limiting or scrubbing
  that gas to a specified level.
\2\ HCl and NO must be tested as a mixture.

[[Page 51516]]

[GRAPHIC] [TIFF OMITTED] TR07SE07.024

[[Page 51517]]

[GRAPHIC] [TIFF OMITTED] TR07SE07.025

[[Page 51518]]

Method 30B--Determination of Total Vapor Phase Mercury Emissions From 
Coal-Fired Combustion Sources Using Carbon Sorbent Traps

1.0 Scope and Application

What is Method 30B?

    Method 30B is a procedure for measuring total vapor phase 
mercury (Hg) emissions from coal-fired combustion sources using 
sorbent trap sampling and an extractive or thermal analytical 
technique. This method is only intended for use only under 
relatively low particulate conditions (e.g., sampling after all 
pollution control devices). Quality assurance and quality control 
requirements are included to assure that you, the tester, collect 
data of known and acceptable quality for each testing program. This 
method does not completely describe all equipment, supplies, and 
sampling and analytical procedures you will need, but instead refers 
to other test methods for some of the details. Therefore, to obtain 
reliable results, you should also have a thorough knowledge of these 
additional methods which are found in Appendices A-1 and A-3 to this 
part:
    (a) Method 1--Sample and Velocity Traverses for Stationary 
Sources.
    (b) Method 4--Determination of Moisture Content in Stack Gases.
    (c) Method 5--Determination of Particulate Matter Emissions from 
Stationary Sources
    1.1 Analytes. What does this method determine? This method is 
designed to measure the mass concentration of total vapor phase Hg 
in flue gas, including elemental Hg (Hg\0\) and oxidized forms of Hg 
(Hg+\2\), in micrograms per dry standard cubic meter 
([mu]g/dscm).

------------------------------------------------------------------------
                                                   Analytical range and
              Analyte                  CAS No.          sensitivity
------------------------------------------------------------------------
Elemental Hg (Hg \0\ ).............    7439-97-6  Typically 0.1 [mu]g/
                                                   dscm to >50 [mu]g/
                                                   dscm.
Oxidized Hg (Hg+\2\)...............  ...........  (Same)
------------------------------------------------------------------------

    1.2 Applicability. When is this method required? Method 30B is a 
reference method for relative accuracy test audits (RATAs) of vapor 
phase Hg CEMS and sorbent trap monitoring systems installed at coal-
fired boilers and is also appropriate for Hg emissions testing at 
such boilers. It is intended for use only under relatively low 
particulate conditions (i.e., sampling after all pollution control 
devices); in cases where significant amounts of particle-bound Hg 
may be present, an isokinetic sampling method for Hg should be used. 
Method 30B may also be specified by New Source Performance Standards 
(NSPS), National Emission Standards for Hazardous Air Pollutants 
(NESHAP), emissions trading programs, State Implementation Plans 
(SIPs), and operating permits that require measurement of Hg 
concentrations in stationary source emissions, either to determine 
compliance with an applicable emission standard or limit, or to 
conduct RATAs of Hg CEMS and sorbent trap monitoring systems.
    1.3 Data Quality Objectives (DQO). How good must my collected 
data be? Method 30B has been designed to provide data of high and 
known quality for Hg emissions testing and for RATA testing of Hg 
monitoring systems, including CEMS and sorbent trap monitors. In 
these and other applications, the principal objective is to ensure 
the accuracy of the data at the actual emissions levels and in the 
actual emissions matrix encountered. To meet this objective, NIST-
traceable calibration standards must be used and method performance 
tests are required.

2.0 Summary of Method

    Known volumes of flue gas are extracted from a stack or duct 
through paired, in-stack sorbent media traps at an appropriate flow 
rate. Collection of mercury on the sorbent media in the stack 
mitigates potential loss of mercury during transport through a 
probe/sample line. For each test run, paired train sampling is 
required to determine measurement precision and verify acceptability 
of the measured emissions data. A field recovery test which assesses 
recovery of an elemental Hg spike to determine measurement bias is 
also used to verify data acceptability. The sorbent traps are 
recovered from the sampling system, prepared for analysis as needed, 
and analyzed by any suitable determinative technique that can meet 
the performance criteria.

3.0 Definitions

    3.1 Analytical System is the combined equipment and apparatus 
used to perform sample analyses. This includes any associated sample 
preparation apparatus e.g., digestion equipment, spiking systems, 
reduction devices, etc., as well as analytical instrumentation such 
as UV AA and UV AF cold vapor analyzers.
    3.2 Calibration Standards are the Hg containing solutions 
prepared from NIST traceable standards and are used to directly 
calibrate analytical systems.
    3.3 Independent Calibration Standard is a NIST traceable 
standard obtained from a source or supplier independent of that for 
the calibration standards and is used to confirm the integrity of 
the calibration standards used.
    3.4 Method Detection Limit (MDL) is the lowest mass of Hg 
greater than zero that can be estimated and reported by your 
candidate analytical technique. The MDL is statistically derived 
from replicate low level measurements near your analytical 
instrument's detection level.
    3.5 NIST means the National Institute of Standards and 
Technology, located in Gaithersburg, Maryland.
    3.6 Run means a series of gas samples taken successively from 
the stack or duct. A test normally consists of a specific number of 
runs.
    3.7 Sorbent Trap means a cartridge or sleeve containing a 
sorbent media (typically activated carbon treated with iodine or 
some other halogen) with multiple sections separated by an inert 
material such as glass wool. These sorbent traps are optimized for 
the quantitative capture of elemental and oxidized forms of Hg and 
can be analyzed by multiple techniques.
    3.8 Test refers to the series of runs required by the applicable 
regulation.
    3.9 Thermal Analysis means an analytical technique where the 
contents of the sorbent traps are analyzed using a thermal technique 
(desorption or combustion) to release the captured Hg in a 
detectable form for quantification.
    3.10 Wet Analysis means an analytical technique where the 
contents of the sorbent tube are first leached or digested to 
quantitatively transfer the captured Hg to liquid solution for 
subsequent analysis.

4.0 Interferences

    Interferences may result from the sorbent trap material used as 
well as from the measurement environment itself. The iodine present 
on some sorbent traps may impart a negative measurement bias. High 
levels of sulfur trioxide (SO3) are also suspected to 
compromise the performance of sorbent trap Hg capture. These, and 
other, potential interferences are assessed by performing the 
analytical matrix interference, Hg\0\ and HgCl2 
analytical bias and field recovery tests.

5.0 Safety

    What safety measures should I consider when using this method? 
This method may require you to work with hazardous materials and in 
hazardous conditions. You are encouraged to establish safety 
procedures before using the method. Among other precautions, you 
should become familiar with the safety recommendations in the gas 
analyzer user's manual. Occupational Safety and Health 
Administration (OSHA) regulations concerning use of compressed gas 
cylinders and noxious gases may apply.
    5.1 Site Hazards. Prior to applying these procedures/
specifications in the field, the potential hazards at the test site 
should be considered; advance coordination with the site is critical 
to understand the conditions and applicable safety policies. At a 
minimum, portions of the sampling system will be hot, requiring 
appropriate gloves, long sleeves, and caution in handling this 
equipment.
    5.2 Laboratory Safety. Policies should be in place to minimize 
risk of chemical exposure and to properly handle waste disposal in 
the laboratory. Personnel shall wear appropriate laboratory attire 
according to a Chemical Hygiene Plan established by the laboratory.
    5.3 Reagent Toxicity/Carcinogenicity. The toxicity and 
carcinogenicity of any reagents used must be considered. Depending 
upon the sampling and analytical technologies selected, this 
measurement may involve hazardous materials, operations, and 
equipment and this method does not address all of the safety 
problems associated with implementing this approach. It is the 
responsibility of the user to establish appropriate safety and 
health practices and determine the applicable regulatory limitations 
prior to performance. Any chemical should be regarded as a potential 
health hazard and exposure to these compounds should be minimized. 
Chemists should refer to the Material Safety Data Sheet (MSDS) for 
each chemical used.
    5.4 Waste Disposal. Any waste generated by this procedure must 
be disposed of

[[Page 51519]]

according to a hazardous materials management plan that details and 
tracks various waste streams and disposal procedures.

6.0 Equipment and Supplies

    The following list is presented as an example of key equipment 
and supplies likely required to measure vapor-phase Hg using a 
sorbent trap sampling system. It is recognized that additional 
equipment and supplies may be needed. Collection of paired samples 
is required.
    6.1 Sorbent Trap Sampling System. A typical sorbent trap 
sampling system is shown in Figure 30B-1 in Section 17.0. The 
sorbent trap sampling system shall include the following components:
    6.1.1 Sorbent Traps. The sorbent media used to collect Hg must 
be configured in a trap with at least two distinct segments or 
sections, connected in series, that are amenable to separate 
analyses. Section 1 is designated for primary capture of gaseous Hg. 
Section 2 is designated as a backup section for determination of 
vapor phase Hg breakthrough. Each sorbent trap must be inscribed or 
otherwise permanently marked with a unique identification number, 
for tracking purposes. The sorbent media may be any collection 
material (e.g., carbon, chemically-treated filter, etc.) capable of 
quantitatively capturing and recovering for subsequent analysis, all 
gaseous forms of Hg in the emissions from the intended application. 
Selection of the sorbent media shall be based on the material's 
ability to achieve the performance criteria contained in this method 
as well as the sorbent's vapor phase Hg capture efficiency for the 
emissions matrix and the expected sampling duration at the test 
site. The sorbent media must be obtained from a source that can 
demonstrate their quality assurance and quality control (see Section 
7.2). The paired sorbent traps are supported on a probe (or probes) 
and inserted directly into the flue gas stream.
    6.1.2 Sampling Probe Assembly. Each probe assembly shall have a 
leak-free attachment to the sorbent trap(s). Each sorbent trap must 
be mounted at the entrance of or within the probe such that the gas 
sampled enters the trap directly. Each probe/sorbent trap assembly 
must be heated to a temperature sufficient to prevent liquid 
condensation in the sorbent trap(s). Auxiliary heating is required 
only where the stack temperature is too low to prevent condensation. 
Use a calibrated thermocouple to monitor the stack temperature. A 
single probe capable of operating the paired sorbent traps may be 
used. Alternatively, individual probe/sorbent trap assemblies may be 
used, provided that the individual sorbent traps are co-located to 
ensure representative Hg monitoring.
    6.1.3 Moisture Removal Device. A moisture removal device or 
system shall be used to remove water vapor from the gas stream prior 
to entering dry gas flow metering devices.
    6.1.4 Vacuum Pump. Use a leak-tight, vacuum pump capable of 
operating within the system's flow range.
    6.1.5 Gas Flow Meter. A gas flow meter (such as a dry gas meter, 
thermal mass flow meter, or other suitable measurement device) shall 
be used to determine the total sample volume on a dry basis, in 
units of standard cubic meters. The meter must be sufficiently 
accurate to measure the total sample volume to within 2 percent and 
must be calibrated at selected flow rates across the range of sample 
flow rates at which the sampling train will be operated. The gas 
flow meter shall be equipped with any necessary auxiliary 
measurement devices (e.g., temperature sensors, pressure measurement 
devices) needed to correct the sample volume to standard conditions.
    6.1.6 Sample Flow Rate Meter and Controller. Use a flow rate 
indicator and controller for maintaining necessary sampling flow 
rates.
    6.1.7 Temperature Sensor. Same as Section 6.1.1.7 of Method 5 in 
Appendix A-3 to this part.
    6.1.8 Barometer. Same as Section 6.1.2 of Method 5 in Appendix 
A-3 to this part.
    6.1.9 Data Logger (optional). Device for recording associated 
and necessary ancillary information (e.g., temperatures, pressures, 
flow, time, etc.).
    6.2 Gaseous Hg\0\ Sorbent Trap Spiking System. A known mass of 
gaseous Hg\0\ must be either present on or spiked onto the first 
section of sorbent traps in order to perform the Hg\0\ and 
HgCl2 analytical bias test and the field recovery study. 
Any approach capable of quantitatively delivering known masses of 
Hg\0\ onto sorbent traps is acceptable. Several spiking technologies 
or devices are available to meet this objective. Their practicality 
is a function of Hg mass spike levels. For low levels, NIST-
certified or NIST-traceable gas generators or tanks may be suitable. 
An alternative system, capable of delivering almost any mass 
required, makes use of NIST-certified or NIST-traceable Hg salt 
solutions (e.g., HgCl2, Hg(NO3)2). 
With this system, an aliquot of known volume and concentration is 
added to a reaction vessel containing a reducing agent (e.g., 
stannous chloride); the Hg salt solution is reduced to Hg\0\ and 
purged onto the sorbent trap using an impinger sparging system. When 
available, information on example spiking systems will be posted at 
http://www.epa.gov/ttn/emc.

    6.3 Sample Analysis Equipment. Any analytical system capable of 
quantitatively recovering and quantifying total Hg from the sorbent 
media selected is acceptable provided that the analysis can meet the 
performance criteria described in this method. Example recovery 
techniques include acid leaching, digestion, and thermal desorption/
direct combustion. Example analytical techniques include, but are 
not limited to, ultraviolet atomic fluorescence (UV AF), ultraviolet 
atomic absorption (UV AA) with and without gold trapping, and X-ray 
fluorescence (XRF) analysis.
    6.3 Moisture Measurement System. If correction of the measured 
Hg emissions for moisture is required (see Section 8.3.3.7), either 
Method 4 in Appendix A-3 to this part or other moisture measurement 
methods approved by the Administrator will be needed to measure 
stack gas moisture content.

7.0 Reagents and Standards

    7.1 Reagents and Standards. Only NIST-certified or NIST-
traceable calibration standards, standard reference materials, and 
reagents shall be used for the tests and procedures required by this 
method.
    7.2 Sorbent Trap Media. The sorbent trap media shall be prepared 
such that the material used for testing is of known and acceptable 
quality. Sorbent supplier quality assurance/quality control measures 
to ensure appropriate and consistent performance such as sorptive 
capacity, uniformity of preparation treatments, and background 
levels shall be considered.

8.0 Sample Collection and Handling

    This section presents the sample collection and handling 
procedures along with the pretest and on-site performance tests 
required by this method. Since you may choose different options to 
comply with certain performance criteria, each test report must 
identify the specific options selected and document the results with 
respect to the performance criteria of this method.
    8.1 Sample Point Selection. What sampling site and sampling 
points do I select? Same as Section 8.1 of Method 30A of this 
appendix.
    8.2 Measurement System Performance Tests. What performance 
criteria must my measurement system meet? The following laboratory 
and field procedures and associated criteria of this section are 
designed to ensure (1) selection of a sorbent and analytical 
technique combination capable of quantitative collection and 
analysis of gaseous Hg, (2) collection of an adequate amount of Hg 
on each sorbent trap during field tests, and (3) adequate 
performance of the method for each test program: The primary 
objectives of these performance tests are to characterize and verify 
the performance of your intended analytical system and associated 
sampling and analytical procedures, and to define the minimum amount 
of Hg (as the sample collection target) that can be quantified 
reliably.
    (a) Analytical Matrix Interference Test;
    (b) Determination of Minimum Sample Mass;
    (c) Hg\0\ and HgCl2 Analytical Bias Test;
    (d) Determination of Nominal Sample Volume;
    (e) Field Recovery Test.
    8.2.1 Analytical Matrix Interference Test and Minimum Sample 
Dilution.
    (a) The analytical matrix interference test is a laboratory 
procedure. It is required only if you elect to use a liquid 
digestion analytical approach and needs to be performed only once 
for each sorbent material used. The purpose of the test is to verify 
the presence or absence of known and potential analytical matrix 
interferences, including the potential negative bias associated with 
iodine common to many sorbent trap materials. The analytical matrix 
interference test determines the minimum dilution (if any) necessary 
to mitigate matrix effects on the sample digestate solutions.
    (b) The result of the analytical matrix interference test, i.e., 
the minimum sample dilution required (if any) for all sample

[[Page 51520]]

analyses, is used to establish the minimum sample mass needed for 
the Hg\0\ and HgCl2 analytical bias test and to determine 
the nominal sample volume for a test run. The analytical matrix 
interference test is sorbent material-specific and shall be 
performed for each sorbent material you intend to use for field 
sampling and analysis. The test shall be performed using a mass of 
sorbent material comparable to the sorbent mass typically used in 
the first section of the trap for sampling. Similar sorbent 
materials from different sources of supply are considered to be 
different materials and must be tested individually. You must 
conduct the analytical matrix interference test for each sorbent 
material prior to the analysis of field samples.
    8.2.1.1 Analytical Matrix Interference Test Procedures. Digest 
and prepare for analysis a representative mass of sorbent material 
(unsampled) according to your intended laboratory techniques for 
field samples. Analyze the digestate according to your intended 
analytical conditions at the least diluted level you intend to use 
for sample analysis (e.g., undiluted, 1 in 10 dilution, etc.). 
Determine the Hg concentration of the undiluted digestate solution. 
Prepare a series of solutions with a fixed final volume containing 
graduated aliquots of the sample digestate and, a fixed aliquot of a 
calibration standard (with the balance being Hg-free reagent or 
H20) to establish solutions of varied digestate dilution 
ratio (e.g., 1:2, 1:5, 1:10, 1:100, etc.--see example in Section 
8.2.1.3, below). One of these solutions should contain only the 
aliquot of the calibration standard in Hg-free reagent or 
H2O. This will result in a series of solutions where the 
amount of Hg is held relatively constant and only the volume of 
digestate diluted is varied. Analyze each of these solutions 
following intended sample analytical procedures and conditions, 
determining the concentration for each solution.
    8.2.1.2 Analytical Matrix Interference Test Acceptance Criteria. 
Compare the measured concentration of each solution containing 
digestate to the measured concentration of the digestate-free 
solution. The lowest dilution ratio of any solution having a Hg 
concentration within 5 percent of the digestate-free 
solution is the minimum dilution ratio required for analysis of all 
samples. If you desire to measure the digestate without dilution, 
the  5 percent criterion must be met at a dilution ratio 
of at least 9:10 (i.e., >=90% digestate).
    8.2.1.3 Example Analytical Matrix Interference Test. An example 
analytical matrix interference test is presented below. Additional 
information on the conduct of the analytical matrix interference 
test will be posted at http://www.epa.gov/ttn/emc. Determine the 

most sensitive working range for the analyzer to be used. This will 
be a narrow range of concentrations. Digest and prepare for analysis 
a representative mass of sorbent material (unsampled) according to 
your intended laboratory techniques for sample preparation and 
analysis. Prepare a calibration curve for the most sensitive 
analytical region, e.g., 0.0, 0.5, 1.0, 3.0, 5.0, 10 ppb. Using the 
highest calibration standard, e.g., 10.0 ppb, prepare a series of 
solutions by adding successively smaller increments of the digestate 
to a fixed volume of the calibration standard and bringing each 
solution to a final fixed volume with mercury-free deionized water 
(diH2O). To 2.0 ml of the calibration standard add 18.0, 
10.0, 4.0, 2.0, 1.0, 0.2, and 0.0 ml of the digestate. Bring the 
final volume of each solution to a total volume of 20 ml by adding 
0.0, 8.0, 14.0, 16.0, 17.0, 17.8, and 18.0 ml of diH2O. 
This will yield solutions with dilution ratios of 9:10, 1:2, 1:5, 
1:10, 1:20, 1:100, and 0:10, respectively. Determine the Hg 
concentration of each solution. The dilution ratio of any solution 
having a concentration that is within 5 percent of the 
concentration of the solution containing 0.0 ml of digestate is an 
acceptable dilution ratio for analyzing field samples. If more than 
one solution meets this criterion, the one with the lowest dilution 
ratio is the minimum dilution required for analysis of field 
samples. If the 9:10 dilution meets this criterion, then no sample 
dilution is required.
    8.2.2 Determination of Minimum Sample Mass. The minimum mass of 
Hg that must be collected per sample must be determined. This 
information is necessary in order to effectively perform the Hg\0\ 
and HgCl2 Analytical Bias Test, to estimate target sample 
volumes/sample times for test runs, and to ensure the quality of the 
measurements. The determination of minimum sample mass is a direct 
function of analytical technique, measurement sensitivity, 
dilutions, etc. This determination is required for all analytical 
techniques. Based on the analytical approach you employ, you should 
determine the most sensitive calibration range. Based on a 
calibration point within that range, you must consider all sample 
treatments (e.g., dilutions) to determine the mass of sample that 
needs to be collected to ensure that all sample analyses fall within 
your calibration curve.
    8.2.2.1 Determination of Minimum Calibration Concentration or 
Mass. Based on your instrument's sensitivity and linearity, 
determine the calibration concentrations or masses that make up a 
representative low level calibration range. Verify that you are able 
to meet the multipoint calibration performance criteria in section 
11.0 of this method. Select a calibration concentration or mass that 
is no less than 2 times the lowest concentration or mass in your 
calibration curve. The lowest point in your calibration curve must 
be at least 5, and preferably 10, times the Method Detection Limit 
(MDL), which is the minimum amount of the analyte that can be 
detected and reported. The MDL must be determined at least once for 
the analytical system using an MDL study such as that found in 
section 17.0 of the proposed amendments to EPA Method 301 (69 FR 
76642, 12/22/2004).
    Note to Section 8.2.2.1: While it might be desirable to base the 
minimum calibration concentration or mass on the lowest point in the 
calibration curve, selecting a higher concentration or mass is 
necessary to ensure that all analyses of the field samples will fall 
within the calibration curve. Therefore, it is strongly recommended 
that you select a minimum calibration concentration or mass that is 
sufficiently above the lowest point of the calibration curve (see 
examples in sections 8.2.2.2.1 and 8.2.2.2.2 below).
    8.2.2.2 Determination of Minimum Sample Mass. Based on your 
minimum calibration concentration or mass and other sample 
treatments including, but not limited to, final digestate volume and 
minimum sample dilution, determine the minimum sample mass. 
Consideration should also be given to the Hg levels expected to be 
measured in Section 2 of the sorbent traps and to the breakthrough 
criteria presented in Table 9-1.
    8.2.2.2.1 Example Determination of Minimum Sample Mass for 
Thermal Desorption Analysis. A thermal analysis system has been 
calibrated at five Hg mass levels: 10 ng, 20 ng, 50 ng, 100 ng, 200 
ng, and shown to meet the calibration performance criteria in this 
method. Based on 2 times the lowest point in the calibration curve, 
20 ng is selected as the minimum calibration mass. Because the 
entire sample is analyzed and there are no dilutions involved, the 
minimum sample mass is also 20 ng.
    Note: In this example, if the typical background (blank) Hg 
levels in section 2 were relatively high (e.g., 3 to 5 ng), a sample 
mass of 20 ng might not have been sufficient to ensure that the 
breakthrough criteria in Table 9-1 would be met, thereby 
necessitating the use of a higher point on the calibration curve 
(e.g., 50 ng) as the minimum calibration and sample mass.
    8.2.2.2.2 Example Determination of Minimum Sample Mass for Acid 
Leachate/Digestate Analysis. A cold vapor analysis system has been 
calibrated at four Hg concentration levels: 2 ng/L, 5 ng, 10 ng/L, 
20 ng/L, and shown to meet the calibration performance criteria in 
this method. Based on 2 times the lowest point in the calibration 
curve, 4 ng/L was selected as the minimum calibration concentration. 
The final sample volume of a digestate is nominally 50 ml (0.05 L) 
and the minimum dilution necessary was determined to be 1:100 by the 
Analytical Matrix Interference Test of Section 8.2.1. The following 
calculation would be used to determine the minimum sample mass.

Minimum sample mass = (4 ng/L) x (0.05 L) x (100) = 20 ng

    Note: In this example, if the typical background (blank) Hg 
levels in section 2 were relatively high (e.g., 3 to 5 ng), a sample 
mass of 20 ng might not have been sufficient to ensure that the 
breakthrough criterion in Table 9-1 would be met, thereby 
necessitating the use of a higher point on the calibration curve 
(e.g., 10 ng/L) as the minimum calibration concentration.
    8.2.3 Hg\0\ and HgCl2 Analytical Bias Test. Before 
analyzing any field samples, the laboratory must demonstrate the 
ability to recover and accurately quantify Hg\0\ and 
HgCl2 from the chosen sorbent media by performing the 
following analytical bias test for sorbent traps spiked with Hg\0\ 
and HgCl2. The analytical bias test is performed at a 
minimum of two distinct sorbent trap Hg loadings that will: (1) 
Represent the lower and upper bound of sample Hg loadings for 
application of the analytical technique to the

[[Page 51521]]

field samples, and (2) be used for data validation.
    8.2.3.1 Hg\0\ and HgCl2 Analytical Bias Test 
Procedures. Determine the lower and upper bound mass loadings. The 
minimum sample mass established in Section 8.2.2.2 can be used for 
the lower bound Hg mass loading although lower Hg loading levels are 
acceptable. The upper bound Hg loading level should be an estimate 
of the greatest mass loading that may result as a function of stack 
concentration and volume sampled. As previously noted, this test 
defines the bounds that actual field samples must be within in order 
to be valid.
    8.2.3.1.1 Hg\0\ Analytical Bias Test. Analyze the front section 
of three sorbent traps containing Hg\0\ at the lower bound mass 
loading level and the front section of three sorbent traps 
containing Hg\0\ at the upper bound mass loading level. In other 
words, analyze each mass loading level in triplicate. You may refer 
to Section 6.2 for spiking guidance. Prepare and analyze each spiked 
trap, using the same techniques that will be used to prepare and 
analyze the field samples. The average recovery for the three traps 
at each mass loading level must be between 90 and 110 percent. If 
multiple types of sorbent media are to be analyzed, a separate 
analytical bias test is required for each sorbent material.
    8.2.3.1.2 HgCl2 Analytical Bias Test. Analyze the 
front section of three sorbent traps containing HgCl2 at 
the lower bound mass loading level and the front section of three 
traps containing HgCl2 at the upper bound mass loading 
level. HgCl2 can be spiked as a gas, or as a liquid 
solution containing HgCl2. However the liquid volume 
spiked must be < 100 [mu]L. Prepare and analyze each spiked trap, 
using the techniques that will be used to prepare and analyze the 
field samples. The average recovery for three traps at each spike 
concentration must be between 90 and 110 percent. Again, if multiple 
types of sorbent media are to be analyzed, a separate analytical 
bias test is required for each sorbent material.
    8.2.4 Determination of Target Sample Volume. The target sample 
volume is an estimate of the sample volume needed to ensure that 
valid emissions data are collected (i.e., that sample mass Hg 
loadings fall within the analytical calibration curve and are within 
the upper and lower bounds set by the analytical bias tests). The 
target sample volume and minimum sample mass can also be determined 
by performing a diagnostic test run prior to initiation of formal 
testing.
    Example: If the minimum sample mass is 50 ng and the 
concentration of mercury in the stack gas is estimated to be 2 
[mu]g/m\3\ (ng/L) then the following calculation would be used to 
determine the target sample volume:

Target Sample Volume = (50 ng)/(2 ng/L) = 25 L

    Note: For the purposes of relative accuracy testing of Hg 
monitoring systems under part 75 of this chapter and Performance 
Specification 12A in appendix B to this part, when the stack gas Hg 
concentration is expected to be very low (< 0.5 [mu]g/dscm) you may 
estimate the Hg concentration at 0.5 [mu]g/dscm.
    8.2.5 Determination of Sample Run Time. Sample run time will be 
a function of minimum sample mass (see Section 8.2.2), target sample 
volume and nominal equipment sample flow rate. The minimum sample 
run time for conducting relative accuracy test audits of Hg 
monitoring systems is 30 minutes and for emissions testing to 
characterize an emission source is 1 hour. The target sample run 
time can be calculated using the following example.
    Example: If the target sample volume has been determined to be 
25 L, then the following formula would be used to determine the 
sampling time necessary to acquire 25 L of gas when sampling at a 
rate of 0.4 L/min.

Sampling time (min) = 25 L / 0.4 L/min = 63 minutes

    8.2.6 Field Recovery Test. The field recovery test provides a 
test program-specific verification of the performance of the 
combined sampling and analytical approach. Three sets of paired 
samples, one of each pair which is spiked with a known level of Hg, 
are collected and analyzed and the average recovery of the spiked 
samples is used to verify performance of the measurement system 
under field conditions during that test program. The conduct of this 
test requires an estimate or confirmation of the stack Hg 
concentrations at the time of testing.
    8.2.6.1 Calculation of Pre-sampling Spiking Level. Determine the 
sorbent trap spiking level for the field recovery test using 
estimates of the stack Hg concentration, the target sample flow 
rate, and the planned sample duration. First, determine the Hg mass 
expected to be collected in section 1 of the sorbent trap. The pre-
sampling spike must be within 50 to 150 percent of this expected 
mass.
    Example calculation: For an expected stack Hg concentration of 5 
ug/m\3\ (ng/L) a target sample rate of 0.40 liters/min, and a sample 
duration of 1 hour:

(0.40 L/min)*(60 min)*(5ng/L) = 120 ng

    A Hg spike of 60 to 180 ng (50-150% of 120 ng) would be 
appropriate.
    8.2.6.2 Procedures. Set up two identical sampling trains. One of 
the sampling trains shall be designated the spiked train and the 
other the unspiked train. Spike Hg\0\ onto the front section of the 
sorbent trap in the spiked train before sampling. The mass of Hg 
spiked shall be 50 to 150 percent of the mass expected to be 
collected with the unspiked train. Sample the stack gas with the two 
trains simultaneously using the same procedures as for the field 
samples (see Section 8.3). The total sample volume must be within 
20 percent of the target sample volume for the field 
sample test runs. Analyze the sorbent traps from the two trains 
utilizing the same analytical procedures and instrumentation as for 
the field samples (see Section 11.0). Determine the fraction of 
spiked Hg recovered (R) using the equations in Section 12.7. Repeat 
this procedure for a total of three runs. Report the individual R 
values in the test report; the average of the three R values must be 
between 85 and 115 percent.
    Note to section 8.2.6.2: It is acceptable to perform the field 
recovery test concurrent with actual test runs (e.g., through the 
use of a quad probe). It is also acceptable to use the field 
recovery test runs as test runs for emissions testing or for the 
RATA of a Hg monitoring system under part 75 of this chapter and 
Performance Specification 12A in appendix B to this part, if certain 
conditions are met. To determine whether a particular field recovery 
test run may be used as a RATA run, subtract the mass of the Hg\0\ 
spike from the total Hg mass collected in sections 1 and 2 of the 
spiked trap. The difference represents the mass of Hg in the stack 
gas sample. Divide this mass by the sample volume to obtain the Hg 
concentration in the effluent gas stream, as measured with the 
spiked trap. Compare this concentration to the corresponding Hg 
concentration measured with the unspiked trap. If the paired trains 
meet the relative deviation and other applicable data validation 
criteria in Table 9-1, then the average of the two Hg concentrations 
may be used as an emissions test run value or as the reference 
method value for a RATA run.
    8.3 Sampling. This section describes the procedures and criteria 
for collecting the field samples for analysis. As noted in Section 
8.2.6, the field recovery test samples are also collected using 
these procedures.
    8.3.1 Pre-test leak check. Perform a leak check of the sampling 
system with the sorbent traps in place. For each of the paired 
sampling trains, draw a vacuum in the train, and adjust the vacuum 
to ~15 Hg; and, using the gas flow meter, determine leak 
rate. The leak rate for an individual train must not exceed 4 
percent of the target sampling rate. Once the leak check passes this 
criterion, carefully release the vacuum in the sample train, then 
seal the sorbent trap inlet until the probe is ready for insertion 
into the stack or duct.
    8.3.2 Determination of Flue Gas Characteristics. Determine or 
measure the flue gas measurement environment characteristics (gas 
temperature, static pressure, gas velocity, stack moisture, etc.) in 
order to determine ancillary requirements such as probe heating 
requirements (if any), initial sampling rate, moisture management, 
etc.
    8.3.3 Sample Collection
    8.3.3.1 Remove the plug from the end of each sorbent trap and 
store each plug in a clean sorbent trap storage container. Remove 
the stack or duct port cap and insert the probe(s). Secure the 
probe(s) and ensure that no leakage occurs between the duct and 
environment.
    8.3.3.2 Record initial data including the sorbent trap ID, date, 
and the run start time.
    8.3.3.3 Record the initial gas flow meter reading, stack 
temperature, meter temperatures (if needed), and any other 
appropriate information, before beginning sampling. Begin sampling 
and target a sampling flow rate similar to that for the field 
recovery test. Then, at regular intervals (< =5 minutes) during the 
sampling period, record the date and time, the sample flow rate, the 
gas meter reading, the stack temperature, the flow meter 
temperatures (if using a dry gas meter), temperatures of heated 
equipment such as the vacuum lines and the probes (if heated), and 
the sampling system vacuum readings. Adjust the sampling flow rate 
as necessary to maintain the initial sample flow

[[Page 51522]]

rate. Ensure that the total volume sampled for each run is within 20 
percent of the total volume sampled for the field recovery test.
    8.3.3.4 Data Recording. Obtain and record any essential 
operating data for the facility during the test period, e.g., the 
barometric pressure must be obtained for correcting sample volume to 
standard conditions when using a dry gas meter. At the end of the 
data collection period, record the final gas flow meter reading and 
the final values of all other essential parameters.
    8.3.3.5 Post-Test Leak Check. When sampling is completed, turn 
off the sample pump, remove the probe(s) with sorbent traps from the 
port, and carefully seal the end of each sorbent trap. Perform 
another leak check of each sampling train with the sorbent trap in 
place, at the maximum vacuum reached during the sampling period. 
Record the leakage rates and vacuums. The leakage rate for each 
train must not exceed 4 percent of the average sampling rate for the 
data collection period. Following each leak check, carefully release 
the vacuum in the sample train.
    8.3.3.6 Sample Recovery. Recover each sampled sorbent trap by 
removing it from the probe and sealing both ends. Wipe any deposited 
material from the outside of the sorbent trap. Place the sorbent 
trap into an appropriate sample storage container and store/preserve 
in appropriate manner (see Section 8.3.3.8).
    8.3.3.7 Stack Gas Moisture Determination. If the moisture basis 
of the measurements made with this method (dry) is different from 
the moisture basis of either: (1) the applicable emission limit; or 
(2) a Hg CEMS being evaluated for relative accuracy, you must 
determine the moisture content of the flue gas and correct for 
moisture using Method 4 in appendix A-3 to this part. If correction 
of the measured Hg concentrations for moisture is required, at least 
one Method 4 moisture determination shall be made during each test 
run.
    8.3.3.8 Sample Handling, Preservation, Storage, and Transport. 
While the performance criteria of this approach provide for 
verification of appropriate sample handling, it is still important 
that the user consider, determine, and plan for suitable sample 
preservation, storage, transport, and holding times for these 
measurements. Therefore, procedures in ASTM WK223 ``Guide for 
Packaging and Shipping Environmental Samples for Laboratory 
Analysis'' shall be followed for all samples, where appropriate. To 
avoid Hg contamination of the samples, special attention should be 
paid to cleanliness during transport, field handling, sampling, 
recovery, and laboratory analysis, as well as during preparation of 
the sorbent cartridges. Collection and analysis of blank samples 
(e.g., reagent, sorbent, field, etc.,) is useful in verifying the 
absence or source of contaminant Hg.
    8.3.3.9 Sample Custody. Proper procedures and documentation for 
sample chain of custody are critical to ensuring data integrity. The 
chain of custody procedures in ASTM D4840-99 ``Standard Guide for 
Sampling Chain-of-Custody Procedures'' shall be followed for all 
samples (including field samples and blanks).

9.0 Quality Assurance and Quality Control

    Table 9-1 summarizes the QA/QC performance criteria that are 
used to validate the Hg emissions data from Method 30B sorbent trap 
measurement systems.

                      Table 9-1.--Quality Assurance/Quality Control Criteria for Method 30B
----------------------------------------------------------------------------------------------------------------
     QA/QC test or specification         Acceptance criteria           Frequency         Consequences if not met
----------------------------------------------------------------------------------------------------------------
Gas flow meter calibration (At 3       Calibration factor (Yi)  Prior to initial use     Recalibrate at 3 points
 settings or points).                   at each flow rate must   and when post-test       until the acceptance
                                        be within    check is not within      criteria are met.
                                        2% of the average         5% of Y.
                                        value (Y).
Gas flow meter post-test calibration   Calibration factor (Yi)  After each field test.   Recalibrate gas flow
 check (Single-point).                  must be within < plus-    For mass flow meters,    meter at 3 points to
                                        minus> 5% of the Y       must be done on-site,    determine a new value
                                        value from the most      using stack gas.         of Y. For mass flow
                                        recent 3-point                                    meters, must be done
                                        calibration.                                      on-site, using stack
                                                                                          gas. Apply the new Y
                                                                                          value to the field
                                                                                          test data.
Temperature sensor calibration.......  Absolute temperature     Prior to initial use     Recalibrate; sensor may
                                        measures by sensor       and before each test     not be used until
                                        within       thereafter.              specification is met.
                                        1.5% of a reference
                                        sensor.
Barometer calibration................  Absolute pressure        Prior to initial use     Recalibrate; instrument
                                        measured by instrument   and before each test     may not be used until
                                        within  10   thereafter.              specification is met.
                                        mm Hg of reading with
                                        a mercury barometer.
Pre-test leak check..................  < = 4% of target          Prior to sampling......  Sampling shall not
                                        sampling rate.                                    commence until the
                                                                                          leak check is passed.
Post-test leak check.................  < = 4% of average         After sampling.........  Sample invalidated.*
                                        sampling rate.
Analytical matrix interference test    Establish minimum        Prior to analyzing any   Field sample results
 (wet chemical analysis, only).         dilution (if any)        field samples; repeat    not validated.
                                        needed to eliminate      for each type of
                                        sorbent matrix           sorbent used.
                                        interferences.
Analytical bias test.................  Average recovery         Prior to analyzing       Field samples shall not
                                        between 90% and 110%     field samples and        be analyzed until the
                                        for Hg\0\ and HgCl2 at   prior to use of new      percent recovery
                                        each of the 2 spike      sorbent media.           criteria has been met.
                                        concentration levels.
Multipoint analyzer calibration......  Each analyzer reading    On the day of analysis,  Recalibrate until
                                        withini      before analyzing any     successful.
                                        10% of true value and    samples.
                                        r\2\ >= 0.99.
Analysis of independent calibration    Within  10%  Following daily          Recalibrate and repeat
 standard.                              of true value.           calibration, prior to    independent standard
                                                                 analyzing field          analysis until
                                                                 samples.                 successful.
Analysis of continuing calibration     Within  10%  Following daily          Recalibrate and repeat
 verification standard (CCVS).          of true value.           calibration, after       independent standard
                                                                 analyzing < =10 field     analysis, reanalyze
                                                                 samples, and at end of   samples until
                                                                 each set of analyses.    successful, if
                                                                                          possible; for
                                                                                          destructive
                                                                                          techniques, samples
                                                                                          invalidated.
Test run total sample volume.........  Within  20%  Each individual sample.  Sample invalidated.
                                        of total volume
                                        sampled during field
                                        recovery test.
Sorbent trap section 2 breakthrough..  < 10% of section 1 Hg     Every sample...........  Sample invalidated.*
                                        mass for Hg
                                        concentrations > 1
                                        [mu]g/dscm;.

[[Page 51523]]

                                       < = 20% of section 1 Hg
                                        mass for Hg
                                        concentrations < = 1
                                        [mu]g/dscm.
Paired sorbent trap agreement........  < = 10% Relative          Every run..............  Run invalidated.*
                                        Deviation (RD) mass
                                        for Hg concentrations
                                        > 1 [mu]g/dscm;
                                       < = 20% RD or < = 0.2
                                        [mu]g/dscm absolute
                                        difference for Hg
                                        concentrations < = 1
                                        [mu]g/dscm.
Sample analysis......................  Within valid             All Section 1 samples    Reanalyze at more
                                        calibration range        where stack Hg           concentrated level if
                                        (within calibration      concentation is >= 0.5   possible, samples
                                        curve).                  [mu]g/dscm.              invalidated if not
                                                                                          within calibrated
                                                                                          range.
Sample analysis......................  Within bounds of Hg\0\   All Section 1 samples    Expand bounds of Hg\0\
                                        and HgCl2 Analytical     where stack Hg           and HgCl2 Analytical
                                        Bias Test.               concentration is >=      Bias Test; if not
                                                                 0.5 [mu]g/dscm.          successful, samples
                                                                                          invalidated.
Field recovery test..................  Average recovery         Once per field test....  Field sample runs not
                                        between 85% and 115%                              validated without
                                        for Hg\0\.                                        successful field
                                                                                          recovery test.
----------------------------------------------------------------------------------------------------------------
* And data from the pair of sorbent traps are also invalidated.

10.0 Calibration and Standardization

    10.1 Only NIST-certified and NIST-traceable calibration 
standards (i.e., calibration gases, solutions, etc.) shall be used 
for the spiking and analytical procedures in this method.
    10.2 Gas Flow Meter Calibration.
    10.2.1 Preliminaries. The manufacturer or equipment supplier of 
the gas flow meter should perform all necessary set-up, testing, 
programming, etc., and should provide the end user with any 
necessary instructions, to ensure that the meter will give an 
accurate readout of dry gas volume in standard cubic meters for this 
method.
    10.2.2 Initial Calibration. Prior to its initial use, a 
calibration of the gas flow meter shall be performed. The initial 
calibration may be done by the manufacturer, by the equipment 
supplier, or by the end user. If the flow meter is volumetric in 
nature (e.g., a dry gas meter), the manufacturer or end user may 
perform a direct volumetric calibration using any gas. For a mass 
flow meter, the manufacturer, equipment supplier, or end user may 
calibrate the meter using either: (1) A bottled gas mixture 
containing 12 0.5% CO2, 7 0.5% 
O2, and balance N2 (when this method is 
applied to coal-fired boilers); (2) a bottled gas mixture containing 
CO2, O2, and N2 in proportions 
representative of the expected stack gas composition; or (3) the 
actual stack gas.
    10.2.2.1 Initial Calibration Procedures. Determine an average 
calibration factor (Y) for the gas flow meter by calibrating it at 
three sample flow rate settings covering the range of sample flow 
rates at which the sampling system will be operated. You may either 
follow the procedures in section 10.3.1 of Method 5 in appendix A-3 
to this part or in section 16 of Method 5 in appendix A-3 to this 
part. If a dry gas meter is being calibrated, use at least five 
revolutions of the meter at each flow rate.
    10.2.2.2 Alternative Initial Calibration Procedures. 
Alternatively, you may perform the initial calibration of the gas 
flow meter using a reference gas flow meter (RGFM). The RGFM may be: 
(1) A wet test meter calibrated according to section 10.3.1 of 
Method 5 in appendix A-3 to this part; (2) a gas flow metering 
device calibrated at multiple flow rates using the procedures in 
section 16 of Method 5 in appendix A-3 to this part; or (3) a NIST-
traceable calibration device capable of measuring volumetric flow to 
an accuracy of 1 percent. To calibrate the gas flow meter using the 
RGFM, proceed as follows: While the Method 30B sampling system is 
sampling the actual stack gas or a compressed gas mixture that 
simulates the stack gas composition (as applicable), connect the 
RGFM to the discharge of the system. Care should be taken to 
minimize the dead volume between the gas flow meter being tested and 
the RGFM. Concurrently measure dry stack gas volume with the RGFM 
and the flow meter being calibrated for at least 10 minutes at each 
of three flow rates covering the typical range of operation of the 
sampling system. For each set of concurrent measurements, record the 
total sample volume, in units of dry standard cubic meters (dscm), 
measured by the RGFM and the gas flow meter being tested.
    10.2.2.3 Initial Calibration Factor. Calculate an individual 
calibration factor Yi at each tested flow rate from 
section 10.2.2.1 or 10.2.2.2 of this method (as applicable) by 
taking the ratio of the reference sample volume to the sample volume 
recorded by the gas flow meter. Average the three Yi 
values, to determine Y, the calibration factor for the flow meter. 
Each of the three individual values of Yi must be within 
0.02 of Y. Except as otherwise provided in sections 
10.2.2.4 and 10.2.2.5 of this method, use the average Y value from 
the initial 3-point calibration to adjust subsequent gas volume 
measurements made with the gas flow meter.
    10.2.2.4 Pretest On-Site Calibration Check (Optional). For a 
mass flow meter, if the most recent 3-point calibration of the flow 
meter was performed using a compressed gas mixture, you may want to 
conduct the following on-site calibration check prior to testing, to 
ensure that the flow meter will accurately measure the volume of the 
stack gas: While sampling stack gas, check the calibration of the 
flow meter at one intermediate flow rate setting representative of 
normal operation of the sampling system. If the pretest calibration 
check shows that the value of Yi, the calibration factor 
at the tested flow rate, differs from the current value of Y by more 
than 5 percent, perform a full 3-point recalibration of the meter 
using stack gas to determine a new value of Y, and (except as 
otherwise provided in section 10.2.2.5 of this method) apply the new 
Y value to the data recorded during the field test.
    10.2.2.5 Post-Test Calibration Check. Check the calibration of 
the gas flow meter following each field test at one intermediate 
flow rate setting, either at, or in close proximity to, the average 
sample flow rate during the field test. For dry gas meters, ensure 
at least three revolutions of the meter during the calibration 
check. For mass flow meters, this check must be performed before 
leaving the test site, while sampling stack gas. If a one-point 
calibration check shows that the value of Yi at the 
tested flow rate differs by more than 5 percent from the current 
value of Y, repeat the full 3-point calibration procedure to 
determine a new value of Y, and apply the new Y value to the gas 
volume measurements made with the gas flow meter during the field 
test that was just completed. For mass flow meters, perform the 3-
point recalibration while sampling stack gas.
    10.3 Thermocouples and Other Temperature Sensors. Use the 
procedures and criteria in Section 10.3 of Method 2 in Appendix A-1 
to this part to calibrate in-stack temperature sensors and 
thermocouples. Dial thermometers shall be calibrated against 
mercury-in-glass thermometers. Calibrations must be performed prior 
to initial use and before each field test thereafter. At each 
calibration point, the absolute temperature measured by the 
temperature sensor must agree to within 1.5 percent of 
the temperature measured with the reference sensor, otherwise the 
sensor may not continue to be used.

[[Page 51524]]

    10.4 Barometer. Calibrate against a mercury barometer as per 
Section 10.6 of Method 5 in appendix A-3 to this part. Calibration 
must be performed prior to initial use and before each test program, 
and the absolute pressure measured by the barometer must agree to 
within +10 mm Hg of the pressure measured by the mercury barometer, 
otherwise the barometer may not continue to be used.
    10.5 Other Sensors and Gauges. Calibrate all other sensors and 
gauges according to the procedures specified by the instrument 
manufacturer(s).
    10.6 Analytical System Calibration. See Section 11.1 of this 
method.

11.0 Analytical Procedures

    The analysis of Hg in the field and quality control samples may 
be conducted using any instrument or technology capable of 
quantifying total Hg from the sorbent media and meeting the 
performance criteria in this method. Because multiple analytical 
approaches, equipment and techniques are appropriate for the 
analysis of sorbent traps, it is not possible to provide detailed, 
technique-specific analytical procedures. As they become available, 
detailed procedures for a variety of candidate analytical approaches 
will be posted at http://www.epa.gov/ttn/emc. 

    11.1 Analytical System Calibration. Perform a multipoint 
calibration of the analyzer at three or more upscale points over the 
desired quantitative range (multiple calibration ranges shall be 
calibrated, if necessary). The field samples analyzed must fall 
within a calibrated, quantitative range and meet the performance 
criteria specified below. For samples suitable for aliquotting, a 
series of dilutions may be needed to ensure that the samples fall 
within a calibrated range. However, for sorbent media samples 
consumed during analysis (e.g., when using thermal desorption 
techniques), extra care must be taken to ensure that the analytical 
system is appropriately calibrated prior to sample analysis. The 
calibration curve range(s) should be determined such that the levels 
of Hg mass expected to be collected and measured will fall within 
the calibrated range. The calibration curve may be generated by 
directly introducing standard solutions into the analyzer or by 
spiking the standards onto the sorbent media and then introducing 
into the analyzer after preparing the sorbent/standard according to 
the particular analytical technique. For each calibration curve, the 
value of the square of the linear correlation coefficient, i.e., 
r\2\, must be [gteqt]0.99, and the analyzer response must be within 
10 percent of the reference value at each upscale 
calibration point. Calibrations must be performed on the day of the 
analysis, before analyzing any of the samples. Following 
calibration, an independent standard shall be analyzed. The measured 
value of the independently prepared standard must be within < plus-
minus>10 percent of the expected value.
    11.2 Sample Preparation. Carefully separate the sections of each 
sorbent trap. Combine for analysis all materials associated with 
each section; any supporting substrate that the sample gas passes 
through prior to entering a media section (e.g., glass wool 
separators, acid gas traps, etc.) must be analyzed with that 
segment.
    11.3 Field Sample Analyses. Analyze the sorbent trap samples 
following the same procedures that were used for conducting the 
Hg\0\ and HgCl2 analytical bias tests. The individual 
sections of the sorbent trap and their respective components must be 
analyzed separately (i.e., section 1 and its components, then 
section 2 and its components). All sorbent trap section 1 sample 
analyses must be within the calibrated range of the analytical 
system. For wet analyses, the sample can simply be diluted to fall 
within the calibrated range. However, for the destructive thermal 
analyses, samples that are not within the calibrated range cannot be 
re-analyzed. As a result, the sample cannot be validated, and 
another sample must be collected. It is strongly suggested that the 
analytical system be calibrated over multiple ranges so that 
thermally analyzed samples do fall within the calibrated range. The 
total mass of Hg measured in each sorbent trap section 1 must also 
fall within the lower and upper mass limits established during the 
initial Hg\0\ and HgCl2 analytical bias test. If a sample 
is analyzed and found to fall outside of these limits, it is 
acceptable for an additional Hg\0\ and HgCl2 analytical 
bias test to be performed that now includes this level. However, 
some samples (e.g., the mass collected in trap section 2 or the mass 
collected in trap section 1 when the stack gas concentration is < 0.5 
[mu]g/m3), may have Hg levels so low that it may not be possible to 
quantify them in the analytical system's calibrated range. Because a 
reliable estimate of these low-level Hg measurements is necessary to 
fully validate the emissions data, the MDL (see section 8.2.2.1 of 
this method) is used to establish the minimum amount that can be 
detected and reported. If the measured mass or concentration is 
below the lowest point in the calibration curve and above the MDL, 
the analyst must do the following: estimate the mass or 
concentration of the sample based on the analytical instrument 
response relative to an additional calibration standard at a 
concentration or mass between the MDL and the lowest point in the 
calibration curve. This is accomplished by establishing a response 
factor (e.g., area counts per Hg mass or concentration) and 
estimating the amount of Hg present in the sample based on the 
analytical response and this response factor.
    Example: The analysis of a particular sample results in a 
measured mass above the MDL, but below the lowest point in the 
calibration curve which is 10 ng. An MDL of 1.3 ng Hg has been 
established by the MDL study. A calibration standard containing 5 ng 
of Hg is analyzed and gives an analytical response of 6,170 area 
counts, which equates to a response factor of 1,234 area counts/ng 
Hg. The analytical response for the sample is 4,840 area counts. 
Dividing the analytical response for the sample (4,840 area counts) 
by the response factor gives 3.9 ng Hg, which is the estimated mass 
of Hg in the sample.
    11.4 Analysis of Continuing Calibration Verification Standard 
(CCVS). After no more than 10 samples and at the end of each set of 
analyses, a continuing calibration verification standard must be 
analyzed. The measured value of the continuing calibration standard 
must be within 10 percent of the expected value.
    11.5 Blanks. The analysis of blanks is optional. The analysis of 
blanks is useful to verify the absence of, or an acceptable level 
of, Hg contamination. Blank levels should be considered when 
quantifying low Hg levels and their potential contribution to 
meeting the sorbent trap section 2 breakthrough requirements; 
however, correcting sorbent trap results for blank levels is 
prohibited.

12.0 Calculations and Data Analysis

    You must follow the procedures for calculation and data analysis 
listed in this section.
    12.1 Nomenclature. The terms used in the equations are defined 
as follows:

B = Breakthrough (%).
Bws = Moisture content of sample gas as measured by 
Method 4, percent/100.
Ca = Concentration of Hg for the sample collection 
period, for sorbent trap ``a'' ([mu]g/dscm).
Cb = Concentration of Hg for the sample collection 
period, for sorbent trap ``b'' ([mu]g/dscm).
Cd = Hg concentration, dry basis ([mu]g/dscm).
Crec = Concentration of spiked compound measured ([mu]g/
m\3\).
Cw = Hg concentration, wet basis ([mu]g/m\3\).
m1 = Mass of Hg measured on sorbent trap section 1 
([mu]g).
m2 = Mass of Hg measured on sorbent trap section 2 
([mu]g).
mrecovered = Mass of spiked Hg recovered in Analytical 
Bias or Field Recovery Test ([mu]g).
ms = Total mass of Hg measured on spiked trap in Field 
Recovery Test ([mu]g).
mspiked = Mass of Hg spiked in Analytical Bias or Field 
Recovery Test ([mu]g).
mu = Total mass of Hg measured on unspiked trap in Field 
Recovery Test ([mu]g).
R = Percentage of spiked mass recovered (%).
RD = Relative deviation between the Hg concentrations from traps 
``a'' and ``b'' (%).
vs = Volume of gas sampled, spiked trap in Field Recovery 
Test (dscm).
Vt = Total volume of dry gas metered during the 
collection period (dscm); for the purposes of this method, standard 
temperature and pressure are defined as 20 [deg]C and 760 mm Hg, 
respectively.
vu = Volume of gas sampled, unspiked trap in Field 
Recovery Test (dscm).

    12.2 Calculation of Spike Recovery (Analytical Bias Test). 
Calculate the percent recovery of Hg\0\ and HgCl2 using 
Equation 30B-1.
[GRAPHIC] [TIFF OMITTED] TR07SE07.028

    12.3 Calculation of Breakthrough. Use Equation 30B-2 to 
calculate the percent breakthrough to the second section of the 
sorbent trap.
[GRAPHIC] [TIFF OMITTED] TR07SE07.029

[[Page 51525]]

    12.4 Calculation of Hg Concentration. Calculate the Hg 
concentration measured with sorbent trap ``a'', using Equation 30B-
3.
[GRAPHIC] [TIFF OMITTED] TR07SE07.030

    For sorbent trap ``b'', replace ``Ca '' with 
``Cb '' in Equation 30B-3. Report the average 
concentration, i.e., \1/2\ (Ca + Cb).
    12.5 Moisture Correction. Use Equation 30B-4 if your 
measurements need to be corrected to a wet basis.
[GRAPHIC] [TIFF OMITTED] TR07SE07.031

    12.6 Calculation of Paired Trap Agreement. Calculate the 
relative deviation (RD) between the Hg concentrations measured with 
the paired sorbent traps using Equation 30B-5.
[GRAPHIC] [TIFF OMITTED] TR07SE07.032

    12.7 Calculation of Measured Spike Hg Concentration (Field 
Recovery Test). Calculate the measured spike concentration using 
Equation 30B-6.
[GRAPHIC] [TIFF OMITTED] TR07SE07.033

    Then calculate the spiked Hg recovery, R, using Equation 30B-7.
    [GRAPHIC] [TIFF OMITTED] TR07SE07.034
    
13.0 Method Performance

    How do I validate my data? Measurement data are validated using 
initial, one-time laboratory tests coupled with test program-
specific tests and procedures. The analytical matrix interference 
test and the Hg\0\ and HgCl2 analytical bias test 
described in Section 8.2 are used to verify the appropriateness of 
the selected analytical approach(es) as well as define the valid 
working ranges for sample analysis. The field recovery test serves 
to verify the performance of the combined sampling and analysis as 
applied for each test program. Field test samples are validated by 
meeting the above requirements as well as meeting specific sampling 
requirements (i.e., leak checks, paired train agreement, total 
sample volume agreement with field recovery test samples) and 
analytical requirements (i.e., valid calibration curve, continuing 
calibration performance, sample results within calibration curve and 
bounds of Hg\0\ and HgCl2 analytical bias test). Complete 
data validation requirements are summarized in Table 9-1.

14.0 Pollution Prevention [Reserved]

15.0 Waste Management [Reserved]

16.0 References

    1. EPA Traceability Protocol for Qualification and Certification 
of Elemental Mercury Gas Generators, expected publication date 
December 2008, see http://www.epa.gov/ttn/emc.

    2. EPA Traceability Protocol for Qualification and Certification 
of Oxidized Mercury Gas Generators, expected publication date 
December 2008, see http://www.epa.gov/ttn/emc.

    3. EPA Traceability Protocol for Assay and Certification of 
Gaseous Calibration Standards, expected revision publication date 
December 2008, see http://www.epa.gov/ttn/emc.

17.0 Figures and Tables

BILLING CODE 6560-50-C

[[Page 51526]]

[GRAPHIC] [TIFF OMITTED] TR07SE07.026

[[Page 51527]]

Appendix B [Amended]

0
3. Amend Performance Specification 12A in Appendix B to part 60 by 
revising sections 8.6.2, 8.6.4, 8.6.5, and 8.6.6.1 to read as follows:

Performance Specification 12A--Specifications and Test Procedures for 
Total Vapor Phase Mercury Continuous Emission Monitoring Systems in 
Stationary Sources

* * * * *
    8.6.2 RM. Unless otherwise specified in an applicable subpart of 
the regulations, use Method 29, Method 30A, or Method 30B in 
appendix A to this part or American Society of Testing and Materials 
(ASTM) Method D6784-02 (incorporated by reference, see Sec.  60.17) 
as the RM for Hg concentration. Do not include the filterable 
portion of the sample when making comparisons to the CEMS results. 
When Method 29, Method 30B, or ASTM D6784-02 is used, conduct the RM 
test runs with paired or duplicate sampling systems. When Method 30A 
is used, paired sampling systems are not required. If the RM and 
CEMS measure on a different moisture basis, data derived with Method 
4 in appendix A to this part shall also be obtained during the RA 
test.
* * * * *
    8.6.4 Number and Length of RM and Tests. Conduct a minimum of 
nine RM test runs. When Method 29, Method 30B, or ASTM D6784-02 is 
used, only test runs for which the paired RM trains meet the 
relative deviation criteria (RD) of this PS shall be used in the RA 
calculations. In addition, for Method 29 and ASTM D6784-02, use a 
minimum sample time of 2 hours and for Method 30A use a minimum 
sample time of 30 minutes.

    Note: More than nine sets of RM tests may be performed. If this 
option is chosen, paired RM test results may be excluded so long as 
the total number of paired RM test results used to determine the 
CEMS RA is greater than or equal to nine. However, all data must be 
reported including the excluded data.

    8.6.5 Correlation of RM and CEMS Data. Correlate the CEMS and 
the RM test data as to the time and duration by first determining 
from the CEMS final output (the one used for reporting) the 
integrated average pollutant concentration for each RM test period. 
Consider system response time, if important, and confirm that the 
results are on a consistent moisture basis with the RM test. Then, 
compare each integrated CEMS value against the corresponding RM 
value. When Method 29, Method 30A, Method 30B, or ASTM D6784-02 is 
used, compare each CEMS value against the corresponding average of 
the paired RM values.
    8.6.6 * * *
    8.6.6.1 When Method 29, Method 30B, or ASTM D6784-02 is used, 
outliers are identified through the determination of relative 
deviation (RD) of the paired RM tests. Data that do not meet the 
criteria should be flagged as a data quality problem. The primary 
reason for performing paired RM sampling is to ensure the quality of 
the RM data. The percent RD of paired data is the parameter used to 
quantify data quality. Determine RD for two paired data points as 
follows:
[GRAPHIC] [TIFF OMITTED] TR07SE07.035

where Ca and Cb are concentration values 
determined from each of the two samples, respectively.
* * * * *

PART 72--PERMITS REGULATION

0
4. The authority citation for part 72 continues to read as follows:

    Authority: 42 U.S.C. 7601 and 7651, et seq.

0
5. Revise the definition of ``sorbent trap monitoring system'' in Sec.  
72.2 as follows:

Sec.  72.2  Definitions.

* * * * *
    Sorbent trap monitoring system means the equipment required by part 
75 of this chapter for the continuous monitoring of Hg emissions, using 
paired sorbent traps containing iodated charcoal (IC) or other suitable 
reagents. This excepted monitoring system consists of a probe, the 
paired sorbent traps, an umbilical line, moisture removal components, 
an air tight sample pump, a gas flow meter, and an automated data 
acquisition and handling system. The monitoring system samples the 
stack gas at a rate proportional to the stack gas volumetric flowrate. 
The sampling is a batch process. Using the sample volume measured by 
the gas flow meter and the results of the analyses of the sorbent 
traps, the average mercury concentration in the stack gas for the 
sampling period is determined, in units of micrograms per dry standard 
cubic meter ([mu]g/dscm). Mercury mass emissions for each hour in the 
sampling period are calculated using the average Hg concentration for 
that period, in conjunction with contemporaneous hourly measurements of 
the stack gas flow rate, corrected for the stack moisture content.
* * * * *

PART 75--CONTINUOUS EMISSION MONITORING

0
6. The authority citation for part 75 continues to read as follows:

    Authority:  42 U.S.C. 7601, 7651k, and 7651k note.

0
7. Amend Sec.  75.15 as follows:
0
a. Revise paragraph (f);
0
b. Revise paragraph (i); and
0
c. Add new paragraph (k).
    The revisions and additions read as follows:

Sec.  75.15  Special provisions for measuring Hg mass emissions using 
the excepted sorbent trap monitoring methodology.

* * * * *
    (f) At the beginning and end of each sample collection period, and 
at least once in each unit operating hour during the collection period, 
the gas flow meter reading shall be recorded.
* * * * *
    (i) All unit operating hours for which valid Hg concentration data 
are obtained with the primary sorbent trap monitoring system (as 
verified using the quality assurance procedures in appendix K to this 
part) shall be reported in the electronic quarterly report under Sec.  
75.84(f). For hours in which data from the primary monitoring system 
are invalid, the owner or operator may, in accordance with Sec.  
75.20(d), report valid Hg concentration data from: A certified 
redundant backup CEMS or sorbent trap monitoring system; a certified 
non-redundant backup CEMS or sorbent trap monitoring system; or an 
applicable reference method under Sec.  75.22. If no quality-assured Hg 
concentration are available for a particular hour, the owner or 
operator shall report the appropriate substitute data value in 
accordance with Sec.  75.39.
* * * * *
    (k) During each RATA of a sorbent trap monitoring system, the type 
of sorbent material used by the traps shall be the same as for daily 
operation of the monitoring system. A new pair of traps shall be used 
for each RATA run. However, the size of the traps used for the RATA may 
be smaller than the traps used for daily operation of the system.
* * * * *

0
8. Amend Sec.  75.20 by adding new paragraph (d)(2)(ix) to read as 
follows:

Sec.  75.20  Initial certification and recertification procedures.

* * * * *
    (d)* * *
    (2)* * *
    (ix) For non-redundant backup Hg CEMS and sorbent trap monitoring 
systems, and for like-kind replacement Hg analyzers, the following 
provisions apply in addition to, or, in some cases, in lieu of, the 
general requirements in paragraphs (d)(2)(i) through (d)(2)(viii) of 
this section:
    (A) When a certified sorbent trap monitoring system is brought into 
service as a regular non-redundant backup monitoring system, the system 
shall be operated according to the procedures in Sec.  75.15 and 
appendix K of this part;
    (B) When a regular non-redundant backup Hg CEMS or a like-kind

[[Page 51528]]

replacement Hg analyzer is brought into service, a linearity check with 
elemental Hg standards, as described in paragraph (c)(1)(ii) of this 
section and section 6.2 of appendix A of this part, and a single-point 
system integrity check, as described in section 2.6 of appendix B of 
this part, shall be performed. Alternatively, a 3-level system 
integrity check, as described in paragraph (c)(1)(vi) of this section 
and paragraph (g) of section 6.2 in appendix A of this part, may be 
performed in lieu of these two tests.
    (C) The weekly single-point system integrity checks described in 
section 2.6 of appendix B of this part are required as long as a non-
redundant backup Hg CEMS or like-kind replacement Hg analyzer remains 
in service, unless the daily calibrations of the Hg analyzer are done 
using a NIST-traceable source of oxidized Hg.
* * * * *

0
9. Amend Sec.  75.57 by revising paragraph (j)(7) to read as follows:

Sec.  75.57  General recordkeeping provisions.

* * * * *
    (j) * * *
    (7) Record the gas flow meter reading (in dscm, rounded to the 
nearest hundreth) at the beginning and end of the collection period and 
at least once in each unit operating hour during the collection period.
* * * * *

0
10. Amend Sec.  75.81 by revising paragraph (a)(1) to read as follows:

Sec.  75.81  Monitoring of Hg mass emissions and heat input at the unit 
level.

* * * * *
    (a) * * *
    (1) A Hg concentration monitoring system (as defined in Sec.  72.2 
of this chapter) or a sorbent trap monitoring system (as defined in 
Sec.  72.2 of this chapter), to measure the mass concentration of total 
vapor phase Hg in the flue gas, including the elemental and oxidized 
forms of Hg, in micrograms per standard cubic meter ([mu]g/scm); and
* * * * *

0
11. Amend Sec.  75.84 by revising paragraph (f)(1)(ii)(J) to read as 
follows:

Sec.  75.84  Recordkeeping and Reporting.

* * * * *
    (f) * * *
    (1) * * *
    (ii) * * *
    (J) For units using sorbent trap monitoring systems, the hourly gas 
flow meter readings taken between the initial and final meter readings 
for the data collection period; and
* * * * *

Appendix A to Part 75--[Amended]

0
12. Amend Appendix A to part 75 by removing the twentieth sentence in 
paragraph (a) of section 6.5.7 which currently reads ``For the RATA of 
a sorbent trap monitoring system, use the same size trap that is used 
for daily operation of the monitoring system.'' and adding in its place 
``For the RATA of a sorbent trap monitoring system, the type of sorbent 
material used by the traps shall be the same as for daily operation of 
the monitoring system; however, the size of the traps used for the RATA 
may be smaller than the traps used for daily operation of the 
system.''.

0
13. Amend Appendix B to part 75 by revising section 1.5.2 to read as 
follows:

Appendix B to Part 75--Quality Assurance and Quality Control Procedures

* * * * *

1.5.2 Monitoring System Integrity and Data Quality

    Explain the procedures used to perform the leak checks when 
sorbent traps are placed in service and removed from service. Also 
explain the other QA procedures used to ensure system integrity and 
data quality, including, but not limited to, gas flow meter 
calibrations, verification of moisture removal, and ensuring air-
tight pump operation. In addition, the QA plan must include the data 
acceptance and quality control criteria in section 8 of appendix K 
to this part. All reference meters used to calibrate the gas flow 
meters (e.g., wet test meters) shall be periodically recalibrated. 
Annual, or more frequent, recalibration is recommended. If a NIST-
traceable calibration device is used as a reference flow meter, the 
QA plan must include a protocol for ongoing maintenance and periodic 
recalibration to maintain the accuracy and NIST-traceability of the 
calibrator.
* * * * *

0
14. Amend Appendix K to part 75 as follows:
0
a. Amend section 5.1 by revising Figure K-1;
0
b. Revise section 5.1.3;
0
c. Revise section 5.1.5;
0
d. Revise section 7.1.3;
0
e. Revise section 7.2.3;
0
f. Revise section 7.2.5;
0
g. Amend section 8.0 by revising Table K-1;
0
h. Revise section 9.2;
0
i. Revise section 10.4;
0
j. Remove and reserve section 11.5;
0
k. Revise section 11.6; and
0
l. Revise section 11.7.
    The revisions and additions read as follows:

Appendix K to Part 75--Quality Assurance and Operating Procedures for 
Sorbent Trap Monitoring Systems

* * * * *

5.1 * * *

BILLING CODE 6560-50-C

[[Page 51529]]

[GRAPHIC] [TIFF OMITTED] TR07SE07.027

[[Page 51530]]

* * * * *

5.1.3 Moisture Removal Device

    A robust moisture removal device or system, suitable for 
continuous duty (such as a Peltier cooler), shall be used to remove 
water vapor from the gas stream prior to entering the gas flow 
meter.
* * * * *

5.1.5 Gas Flow Meter

    A gas flow meter (such as a dry gas meter, thermal mass flow 
meter, or other suitable measurement device) shall be used to 
determine the total sample volume on a dry basis, in units of 
standard cubic meters. The meter must be sufficiently accurate to 
measure the total sample volume to within 2 percent and must be 
calibrated at selected flow rates across the range of sample flow 
rates at which the sorbent trap monitoring system typically 
operates. The gas flow meter shall be equipped with any necessary 
auxiliary measurement devices (e.g., temperature sensors, pressure 
measurement devices) needed to correct the sample volume to standard 
conditions.
* * * * *

7.1.3 Pre-test Leak Check

    Perform a leak check with the sorbent traps in place. Draw a 
vacuum in each sample train. Adjust the vacuum in the sample train 
to ~15[sec] Hg. Using the gas flow meter, determine leak rate. The 
leakage rate must not exceed 4 percent of the target sampling rate. 
Once the leak check passes this criterion, carefully release the 
vacuum in the sample train then seal the sorbent trap inlet until 
the probe is ready for insertion into the stack or duct.
* * * * *

7.2.3 Flow Rate Control

    Set the initial sample flow rate at the target value from 
section 7.1.1 of this appendix. Record the initial gas flow meter 
reading, stack temperature (if needed to convert to standard 
conditions), meter temperatures (if needed), etc. Then, for every 
operating hour during the sampling period, record the date and time, 
the sample flow rate, the gas flow meter reading, the stack 
temperature (if needed), the flow meter temperatures (if needed), 
temperatures of heated equipment such as the vacuum lines and the 
probes (if heated), and the sampling system vacuum readings. Also, 
record the stack gas flow rate, as measured by the certified flow 
monitor, and the ratio of the stack gas flow rate to the sample flow 
rate. Adjust the sampling flow rate to maintain proportional 
sampling, i.e., keep the ratio of the stack gas flow rate to sample 
flow rate constant, to within 25 percent of the 
reference ratio from the first hour of the data collection period 
(see section 11 of this appendix).
* * * * *

7.2.5 Essential Operating Data

    Obtain and record any essential operating data for the facility 
during the test period, e.g., the barometric pressure for correcting 
the sample volume measured by a dry gas meter to standard 
conditions. At the end of the data collection period, record the 
final gas flow meter reading and the final values of all other 
essential parameters.
* * * * *

8.0 * * *

           Table K-1.--Quality Assurance/Quality Control Criteria for Sorbent Trap Monitoring Systems
----------------------------------------------------------------------------------------------------------------
     QA/QC test or specification         Acceptance criteria           Frequency         Consequences if not met
----------------------------------------------------------------------------------------------------------------
Pre-test leak check..................  < =4% of target sampling  Prior to Sampling......  Sampling shall not
                                        rate.                                             commence until the
                                                                                          leak check is passed.
Post-test leak check.................  < =4% of average          After sampling.........  Sample check
                                        sampling rate.                                    invalidated.**
Ratio of stack gas flow rate to        Maintain within < plus-   Every hour throughout    Case-by-case
 sample flow rate.                      minus>25% of initial     data collection period.  evaluation.
                                        ratio from first hour
                                        of data collection
                                        period.
Sorbent trap section 2 breakthrough..  < =5% of Section 1 Hg     Every sample...........  Sample invalidated.**
                                        mass.
Paired sorbent trap agreement........  < =10% Relative           Every sample...........  Sample invalidated.**
                                        Deviation (RD).
Spike recovery study.................  Average recovery         Prior to analyzing       Field samples shall not
                                        between 85% and 115%     field samples and        be analyzed until the
                                        for each of the 3        prior to use of new      percent recovery
                                        spike concentration      sorbent media.           criterion has been
                                        levels.                                           met.
Multipoint analyzer calibration......  Each analyzer reading    On the day of analysis,  Recalibrate until
                                        within 10%   before analyzing any     successful.
                                        of true value and r\2\   samples.
                                        >=0.99.
Analysis of independent calibration    Within 10%   Following daily          Recalibrate and repeat
 standard.                              of true value.           calibration, prior to    independent standard
                                                                 analyzing field.         analysis samples until
                                                                                          successful.
Spike recovery from section 3 of       75-125% of spike amount  Every sample...........  Sample invalidated.**
 sorbent trap.
RATA.................................  RA < =20.0% or Mean       For initial              Data from the system
                                        difference < =1.0         certification and        are invalidated until
                                        [mu]gm/dscm for low      annually thereafter.     a RATA is passed.
                                        emitters.
Gas flow meter calibration (At 3       Calibration factor (Y)   Prior to initial use     Recalibrate the meter
 settings initially, and 1 setting      within 5%    and at least quarterly   at three settings to
 thereafter).                           of average value from    thereafter.              determine a new value
                                        the initial (3-point)                             of Y.
                                        calibration.
Temperature sensor calibration.......  Absolute temperature     Prior to initial use     Recalibrate. Sensor may
                                        measured by sensor       and at least quarterly   not be used until
                                        within < plus-            thereafter.              specification is met.
                                        minus>1.5% of a
                                        reference sensor.
Barometer calibration................  Absolute pressure        Prior to initial use     Recalibrate. Instrument
                                        measured by instrument   and at least quarterly   may not be used until
                                        within 10    thereafter.              specification is met.
                                        mm Hg of reading with
                                        a mercury barometer.
----------------------------------------------------------------------------------------------------------------
** And data from the pair of sorbent traps are also invalidated.

* * * * *

9.2 Gas Flow Meter Calibration

    9.2.1 Preliminaries. The manufacturer or supplier of the gas 
flow meter should perform all necessary set-up, testing, 
programming, etc., and should provide the end user with any 
necessary instructions, to ensure that the meter will give an 
accurate readout of dry gas volume in standard cubic meters for the 
particular field application.
    9.2.2 Initial Calibration. Prior to its initial use, a 
calibration of the flow meter shall be performed. The initial 
calibration may be done by the manufacturer, by the equipment 
supplier, or by the end user. If the flow meter is volumetric in 
nature (e.g., a dry gas meter), the manufacturer, equipment 
supplier, or end user may perform a direct volumetric calibration 
using any gas. For a mass flow meter, the manufacturer, equipment 
supplier, or end user may calibrate the meter using a bottled gas 
mixture containing 12  0.5% CO2, 7  0.5% O2, and balance N2, or these

[[Page 51531]]

same gases in proportions more representative of the expected stack 
gas composition. Mass flow meters may also be initially calibrated 
on-site, using actual stack gas.
    9.2.2.1 Initial Calibration Procedures. Determine an average 
calibration factor (Y) for the gas flow meter, by calibrating it at 
three sample flow rate settings covering the range of sample flow 
rates at which the sorbent trap monitoring system typically 
operates. You may either follow the procedures in section 10.3.1 of 
Method 5 in appendix A-3 to part 60 of this chapter or the 
procedures in section 16 of Method 5 in appendix A-3 to part 60 of 
this chapter. If a dry gas meter is being calibrated, use at least 
five revolutions of the meter at each flow rate.
    9.2.2.2 Alternative Initial Calibration Procedures. 
Alternatively, you may perform the initial calibration of the gas 
flow meter using a reference gas flow meter (RGFM). The RGFM may 
either be: (1) A wet test meter calibrated according to section 
10.3.1 of Method 5 in appendix A-3 to part 60; (2) a gas flow 
metering device calibrated at multiple flow rates using the 
procedures in section 16 of Method 5 in appendix A-3 to part 60; or 
(3) a NIST-traceable calibration device capable of measuring 
volumetric flow to an accuracy of 1 percent. To calibrate the gas 
flow meter using the RGFM, proceed as follows: While the sorbent 
trap monitoring system is sampling the actual stack gas or a 
compressed gas mixture that simulates the stack gas composition (as 
applicable), connect the RGFM to the discharge of the system. Care 
should be taken to minimize the dead volume between the sample flow 
meter being tested and the RGFM. Concurrently measure dry gas volume 
with the RGFM and the flow meter being calibrated the for a minimum 
of 10 minutes at each of three flow rates covering the typical range 
of operation of the sorbent trap monitoring system. For each 10-
minute (or longer) data collection period, record the total sample 
volume, in units of dry standard cubic meters (dscm), measured by 
the RGFM and the gas flow meter being tested.
    9.2.2.3 Initial Calibration Factor. Calculate an individual 
calibration factor Yi at each tested flow rate from 
section 9.2.2.1 or 9.2.2.2 of this appendix (as applicable), by 
taking the ratio of the reference sample volume to the sample volume 
recorded by the gas flow meter. Average the three Yi 
values, to determine Y, the calibration factor for the flow meter. 
Each of the three individual values of Yi must be within 
0.02 of Y. Except as otherwise provided in sections 
9.2.2.4 and 9.2.2.5 of this appendix, use the average Y value from 
the three level calibration to adjust all subsequent gas volume 
measurements made with the gas flow meter.
    9.2.2.4 Initial On-Site Calibration Check. For a mass flow meter 
that was initially calibrated using a compressed gas mixture, an on-
site calibration check shall be performed before using the flow 
meter to provide data for this part. While sampling stack gas, check 
the calibration of the flow meter at one intermediate flow rate 
typical of normal operation of the monitoring system. Follow the 
basic procedures in section 9.2.2.1 or 9.2.2.2 of this appendix. If 
the on-site calibration check shows that the value of Yi, 
the calibration factor at the tested flow rate, differs by more than 
5 percent from the value of Y obtained in the initial calibration of 
the meter, repeat the full 3-level calibration of the meter using 
stack gas to determine a new value of Y, and apply the new Y value 
to all subsequent gas volume measurements made with the gas flow 
meter.
    9.2.2.5 Ongoing Quality Assurance. Recalibrate the gas flow 
meter quarterly at one intermediate flow rate setting representative 
of normal operation of the monitoring system. Follow the basic 
procedures in section 9.2.2.1 or 9.2.2.2 of this appendix. If a 
quarterly recalibration shows that the value of Yi, the 
calibration factor at the tested flow rate, differs from the current 
value of Y by more than 5 percent, repeat the full 3-level 
calibration of the meter to determine a new value of Y, and apply 
the new Y value to all subsequent gas volume measurements made with 
the gas flow meter.
* * * * *

10.4 Field Sample Analysis

    Analyze the sorbent trap samples following the same procedures 
that were used for conducting the spike recovery study. The three 
sections of each sorbent trap must be analyzed separately (i.e., 
section 1, then section 2, then section 3). Quantify the total mass 
of Hg for each section based on analytical system response and the 
calibration curve from section 10.1 of this appendix. Determine the 
spike recovery from sorbent trap section 3. The spike recovery must 
be no less than 75 percent and no greater than 125 percent. To 
report the final Hg mass for each trap, add together the Hg masses 
collected in trap sections 1 and 2.
* * * * *

11.5 [Reserved]

11.6 Calculation of Hg Concentration

    Calculate the Hg concentration for each sorbent trap, using the 
following equation:
[GRAPHIC] [TIFF OMITTED] TR07SE07.036

Where:

C = Concentration of Hg for the collection period, ([mu]gm/dscm)
M\*\ = Total mass of Hg recovered from sections 1 and 2 of the 
sorbent trap, ([mu]g)
Vt = Total volume of dry gas metered during the 
collection period, (dscm). For the purposes of this appendix, 
standard temperature and pressure are defined as 20 [deg]C and 760 
mm Hg, respectively.

11.7 Calculation of Paired Trap Agreeement

    Calculate the relative deviation (RD) between the Hg 
concentrations measured with the paired sorbent traps:
[GRAPHIC] [TIFF OMITTED] TR07SE07.037

Where:

RD = Relative deviation between the Hg concentrations from traps 
``a'' and ``b'' (percent)
Ca = Concentration of Hg for the collection period, for 
sorbent trap ``a'' ([mu]gm/dscm)
Cb = Concentration of Hg for the collection period, for 
sorbent trap ``b'' ([mu]gm/dscm)
* * * * *
[FR Doc. 07-4147 Filed 9-6-07; 8:45 am]

BILLING CODE 6560-50-P