EPA Publishes Testing Provisions for Air Emission Sources in Federal Register

On April 26, 2022, EPA published the proposed Testing Provisions for Air Emission Sources in the Federal Register. The proposed regulation includes corrections to inaccurate testing provisions, revisions to outdated test procedures as well as approved alternate test procedures designed to provide testers with added flexibility when conducting performance tests. The proposed rule includes revisions to several Reference Methods, Performance Specifications, Procedures 1 and 5 as well as various Subparts to 40 CFR Part 63. A few selected proposed revisions are discussed below.

Procedure 1, Quality Assurance Requirements for Gas Continuous Emissions Monitoring Systems Used for Compliance Determination. Section 4.1, CD Requirement, has been revised to clarify that the references gases used for the test must be introduced prior to any conditioning or filtration equipment and must pass through as much of the sampling system as possible. Section 5.2.3(1) has been revised to include alternate cylinder gas audit (CGA) pass/fail criteria for low analyzer span values (e.g., analyzer span values ≥50 ppm; >20 ppm but ≤50 ppm; and ≤20 ppm). Additionally, Section 5.2.3(3) now states: “For the RRA, ±15% of the three-run average or ±7.5% of the applicable standard, whichever is greater.”

Procedure 5, Quality Assurance Requirements for Vapor Phase Mercury Continuous Emissions Monitoring Systems and Sorbent Trap Monitoring Systems Used for Compliance Determination at Stationary Sources. A significant change to Procedure 5 is the addition of specific procedures to Section 4.4 for conducting weekly system integrity checks for Hg CEMS. Section 4.4 now states that a system integrity check must be conducted “at least once every 7 calendar days, using the procedures described in section 8.3.3 of Performance Specification 12A.” Section 4.4 also now includes a performance criteria for the system integrity checks where the absolute difference between the Hg CEMS response and the reference gas value, as a percentage of span, must not be greater than 10.0%. This is a key change since Procedure 5 previously excluded defined procedures for this test as well as any performance criteria.

Performance Specification 1, Specifications and Test Procedures for Continuous Opacity Monitoring Systems in Stationary Sources. Throughout Performance Specification 1 references to “ASTM D6216-98” have been replaced with “ASTM D6216.” Section 2.1 now states: If the initial certification of the opacity monitor occurred before [the effective date of the final rule] using ASTM D6216-98, ASTM D6216-03, ASTM D6216-07, ASTM D6216-12, it is not necessary to recertify using ASTM D6216-20.” The calibration error test procedures in 8.3(1)(ii) now states: “If your applicable limit is less than 10% opacity, use attenuators described in ASTM D6216, section 7.5 for applicable standards of 10 to 19%.”

Subpart UUUUU to 40 CFR Part 63, The MATS Rule. Table 5 – Performance Testing Requirements has been revised.

A copy of the proposed rule is available here. Comments on the proposed rule must be received on or before June 27, 2022.