UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION IX AIR DIVISION

Technical Support Document 

for

EPA’s Direct Final Rulemaking

for the

California State Implementation Plan

Antelope Valley Air Quality Management 

Rule 218 Continuous Emission Monitoring 

Prepared by: Stanley Tong

May 1, 2013
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RULE IDENTIFICATION -

Agency: Antelope Valley Air Quality Management District (AVAQMD)

SIP Approved Rule: Rule 218 – Stack Monitoring

Amended – May 17. 2005

Submitted – March 10, 2006

EPA Approved – September 2, 2008 (73 FR 51226)

Subject of this TSD: Rule 218 – Continuous Emission Monitoring

Amended – July 17, 2012

Submitted – February 6, 2013

BACKGROUND – EPA requested AVAQMD consider updating Rule 218 since the 

technical requirements in the rule had not been updated in several years and Rule 218

was being referenced in Rule 431.1 – Sulfur Content of Fuels, which was being 

amended.

EPA suggested the District may want to follow South Coast Rule 218 May 14, 1999 

amendments and EPA’s comments on the South Coast rule as a guide to updating

AVAQMD Rule 218. This would separate the existing AVAQMD Rule 218 into two 

separate rules, one containing administrative requirements and the other containing 

technical requirements.

RULE SUMMARY - Rule 218 as amended on May 17, 2005 was titled “Stack 

Monitoring”. The rule specified requirements for continuous emission monitoring 

systems to measure emissions of oxides of nitrogen (NOx), carbon dioxide (CO2), 

oxygen (O2), and sulfur dioxide (SO2) for certain types of operations such as those 

involving steam generators with a heat input of at least 250 MMBTU/hr and with a use 

factor of at least 30%.

At EPA’s request, AVAQMD updated the technical requirements of Rule 218 and 

separated it into two rules. Rule 218 – Continuous Emission Monitoring contains 

administrative requirements and Rule 218.1 – Continuous Emission Monitoring 

Performance Specifications contains technical requirements for continuous emissions 

monitoring systems. 

Changes from the SIP approved rule include:

1. Revised the applicability section of the rule to cover all sources that require 

continuous emissions monitoring systems (CEMS) as required by an AVAQMD 

regulation or permit condition except CEMS which are subject to: AVAQMD 

Regulation IX – Standards of Performance for New Stationary sources;

Regulation X – National Emissions Standards for Hazardous Air Pollutants; or 

Rule 3010 – Acid Rain Provisions of Federal Operating Permits.
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a. AVAQMD’s staff report1states that previously there were no sources subject 

to the applicability limits of Rule 218. The staff report further states that while 

several facilities will become subject to the amended rule, the District anticipates 

that the facilities will not have any additional requirements since their CEMS are 

already subject to the CEMS requirements in 40 CFR 60 Appendices B and F.

2. Rule 218 does not apply to CEMS subject to permit conditions whose purpose is 

to monitor the performance of basic control equipment rather than to meet an 

applicable limit or standard.

3. Rule 218 does not apply to CEMS where alternative performance specifications 

are required by another District rule.

4. Adds approval requirements for new and modified CEMS and semi-continuous 

emission monitoring systems (SCEMS).

5. Provides an option that CEMS may be certified and operated according to Rules 

218 and 218.1 or certified according to 40 CFR 60 Appendix B and operated and 

maintained in accordance with Rule 218 and 40 CFR 60 Appendix F.

6. Allowes the use of SCEMS in lieu of CEMS.

7. Requires existing CEMS and SCEMS be subject to standards for a new or 

modified CEMS when a modification is made that requires recertification.

8. Requires existing time-shared SCEMS be subject to standards for a new or 

modified CEMS when a modification is made that requires their recertification.

9. Adds recordkeeping provision for calculations, raw parameter data used for 

calculations, and emissions rates.

10.Changes the submission of CEMS data from once a month to once every six

months. 

11.Requires reporting exceedances and failure or shutdown within 24 hours, or by 

the next business day.

12.Updates several definitions.

EVALUATION CRITERIA - The following criteria were used to evaluate the submitted 

rules

1. 40 CFR 60 Appendix B – Performance Specifications

 

1 See AVAQMD Rule 218 and 218.1 Continuous Emission Monitoring Final Staff Report: 

08/24/12, page 11.
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2. 40 CFR 60 Appendix F – Quality Assurance Procedures

3. Enforceability - The Bluebook (Issues Relating to VOC Regulation Cutpoints, 

Deficiencies, and Deviations, EPA, May 25, 1988) and the Little Bluebook 

(Guidance Document for Correcting Common VOC & Other Rule Deficiencies,

EPA Region 9, August 21, 2001) were used to help evaluate compliance with the 

CAA §110(a)(2)(A) requirement for enforceability. 

4. SIP Relaxation - CAA §110(l) prohibits EPA from approving any SIP revision that 

would interfere with any applicable requirement concerning attainment and 

reasonable further progress (RFP) or any other applicable requirement of the 

CAA. In addition, CAA §193 prohibits the modification of any SIP-approved 

control requirement in effect before November 15, 1990, in a nonattainment area.

EPA EVALUATION - A summary of our evaluation follows.

1. Changes to Rule 218 include defining "continuous monitoring" as a minimum of 

one measurement taken and recorded each minute. Semi-continuous emission 

monitoring systems (SCEMS) are allowed a minimum of one measurement taken 

and recorded every 15 minutes. Measurements may be concentration, mass 

emission rate, stack gas flow rate and/or fuel flow rate. The requirements for the 

application submittal and approval of CEMS in Rule 218, Section (D)(1) also 

applies to SCEMS.

2. CEMS owners or operators are required to submit a CEMS report once every six 

months within 30 days following the end of the six month period. This reporting 

requirement relaxes the original monthly reporting requirement to be consistent 

with reducing the burden of recordkeeping and reporting as discussed in 64 FR 

7458, February 12, 1999.

3. EPA reviewed draft amendments to Rule 218 and asked AVAQMD whether 

facilities with existing CEMS already comply with the proposed standards, and if 

they do, the District should consider removing the grace period existing CEMS are 

given to comply with the new standards. The grace period provision was 

subsequently removed from the final version of Rule 218.

4. The rule requirements and applicability are clear, and the monitoring, 

recordkeeping, reporting and other provisions sufficiently ensure that affected 

sources and regulators can evaluate and determine compliance with Rule 218 

consistently. 

5. We propose to determine that our approval of the submittal would comply with 

CAA §§110(l) and 193 because (1) the proposed SIP revision would not interfere 

with the on-going process for ensuring that requirements for reasonable further 

progress and attainment of the National Ambient Air Quality Standards are met, 
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and (2) the administrative requirements for continuous monitoring systems in the 

submitted rule are more stringent than the existing SIP-approved control 

requirements that they would replace.

EPA ACTION - The submitted Rule 218 strengthens the SIP. There are no expected 

emission reductions from this rule as it primarily updates administrative requirements 

for continuous emission monitoring systems. The rule largely fulfills the relevant CAA 

§110 and part D requirements. EPA staff recommends approval of Rule 218 pursuant 

to CAA §110(k)(3) and §301(a).

REFERENCES -

1. “Issues Relating to VOC Regulation Cutpoints, Deficiencies, and Deviations,”

(a.k.a., Bluebook) EPA OAQPS, May 25, 1988.

(http://www.epa.gov/ttn/naaqs/ozone/ozonetech/voc_bluebook.pdf). 

2. “Guidance Document for Correcting Common VOC & Other Rule Deficiencies,”

(a.k.a., Little Bluebook), EPA Region 9, August 21, 2001 

(http://www.epa.gov/region09/air/sips/littlebluebook2001.pdf).

3. AVAQMD Rule 218, Continuous Emission Monitoring, amended July 17, 2012, 

submitted on February 6, 2013.

4. AVAQMD Rule 218, Continuous Emission Monitoring, amended May 17, 2005.