Ø UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION IX

mII1Wj 75 Hawthorne Street

San Francisco, CA 94105

March31, 1999

Ms. Elaine Chang

Assistant Deputy Executive Officer

Office of Planning, Rule Development and Area Sources

South Coast Air Quality Management District

21865 E. Copley Drive

Diamond Bar, CA 91765-4182

Subject: Review of Proposed Amended Rule 218 and Proposed Rule 218.1

Dear Ms. Chang:

Thank you for the opportunity to comment on proposed amended Rule 218 (PAR 218-

December 11, 1998) and proposed Rule 218.1 (PR 218.1 - no date).

In your letter of September 24, 1998, you requested EPA reviewPAR 218 and PR 218.1,

particularly in “how EPA might perceive the currently proposed absolute de-minimus

concentration performance specification for Relative Accuracy . . .[and] would EPA state that the

requirements for PR 218.1 are equivalent to 40 CFR 60 requirements for Title V purposes, and

therefore federally enforceable.”

EPA considers that at medium to high emission limits, PR 218.1’s relative accuracy

criteria are equivalent to or are more stringent than the federal standards. However, at very low

emission limits, (e.g., at less than 5 ppm for NOX limits), PR 218.1’s relative accuracy criteria

becomes less stringent than the federal limits. EPA recognizes, however, that relative accuracy

values at very low levels, such as less than lppm, may not be meaningful due to limitations of

current technology. The enclosure provides additional comments to PAR 218 and PR 218.1.

EPA welcomes the opportunity to review PAR 218 and PR 218.1. If you have any

questions about these comments, please do not hesitate to call me at (415) 744-1185 or Stanley

Tong of my staff at (415) 744-1191.

Sincerely,

Andrew

Zi&(7

Steckel

4”

Chief, Rulemaking Office

Enclosure

cc: John Higuchi, SCAQMD

Cindy Castronovo, CARB
Comments to South Coast Proposed Amended Rule 218 and Proposed Rule 218.1

General Comment

1. Absolute de-minimus Value for Relative Accuracy

EPA considers that at medium to high emission limits, PR 218.1’s relative accuracy criteria are

equivalent to, or are more stringent than the federal standards. However, at very low emission

limits, (e.g., at less than 5 ppm for NOX limits), PR 2 18.1’s relative accuracy criteria becomes

less stringent than the federal limits. EPA recognizes that relative accuracy values at very low

levels, such as less than I ppm, may not be meaningful due to limitations of current technology.

These limitations include the availability and accuracy oflow concentration protocol calibration

gases and the degree ofprecision ofthe reference test methods at low concentrations. Therefore,

EPA does not object to PR 2 18.1’s use of an absolute de-minimus value.

Approvabiity Issues

1. Full Span Range

South Coast should add language to the rule on how to handle spikes. Such language should

indicate that if a value falls outside the acceptable full span range, the value is not valid for

quantification but must be reported and that the spike may be considered a violation ofthe

standard depending on the conditions under which the spike occurred.

2. Clarifications

a. Alternative Sampling Locations: PAR 218.1 (page 218.1-10, top ofpage) allows the

Executive Officer to evaluate and approve alternate sampling locations. South Coast should

clarify in the rule, the hierarchy that will be used to evaluate and approve alternate sampling

locations including referencing any applicable guidance document such as Emission

Measurement Center (EMC) guidance.

b. Full Span Range: PAR 218.1 (page 218.1-10, para (c) (ii)) allows an alternate full span range

(from the 150-200% of concentration limit) to be approved by the Executive Officer. South

Coast should specify acceptable conditions which would warrant going outside ofthe full span

range.

c. Alternative Certification Methods: PAR 218.1 (page 218.1-19, para (d)( 1 )(A)) allows the

Executive Officer to approve alternative certification methods for low concentration gases such

as 10 ppm NOX or CO. South Coast should clarify in the rule, the hierarchy that will be used to

evaluate and approve the alternative certification methods.

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Comments to South Coast Proposed Amended Rule 218 and Proposed Rule 218.1

3. Response time

PAR 218.1 (page 218.1-14 para (3)(A) and page 218.1-18 para (c) (1)(C)) states the response

time for all analyzers and flow monitors shall not exceedS minutes for any new or modified

CEMS and shall not exceed 10 minutes for existing CEMS. 40 CFR 60, Appendix A,

Performance Spec 4A for Carbon Monoxide specifies a response time of 1.5 minutes. The

reason for this short response time is to capture CO spikes which may be present, especially from

Municipal waste combustors. Longer response times may not capture CO spikes. Unless there is

a technical limitation, South Coast should include this shorter response time for CO CEMS.

Recommendations:

1. QAIQC plan: PAR 218. EPA recommends that for facilities who chose to continue to

operate under the existing CEMS option, that QAIQC plans be developed and implemented

within 1 year ofthe promulgation date ofthe rule. The QAIQC plan should be maintained on site

and be made available for inspection upon request by District personnel.

2. Record Retention: PAR 218 (page 218-17 para (e) (1)) states that records shall be maintained

for a minimum period oftwo years or as specified by the applicable rule or regulation. EPA

recommends a five year record retention period rather than the two year period in the rule. This

would make the record retention period consistent with the statue of limitations.

3. The rule is silent on quarterly cylinder gas audits. EPA strongly recommends that a quarterly

cylinder gas audit be required.

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