Site Feedback

Title 40

Displaying title 40, up to date as of 6/15/2026. Title 40 was last amended 6/15/2026.
eCFR Content

The Code of Federal Regulations (CFR) is the official legal print publication containing the codification of the general and permanent rules published in the Federal Register by the departments and agencies of the Federal Government. The Electronic Code of Federal Regulations (eCFR) is a continuously updated online version of the CFR. It is not an official legal edition of the CFR.

Learn more about the eCFR, its status, and the editorial process.

§ 53.2 General requirements for a reference method determination.

The following general requirements for a Federal reference method (FRM) determination are summarized in table A-1 of this subpart.

(a) Manual methods

(1) Sulfur dioxide (SO2 ) and Lead. For measuring SO2 and lead, appendixes A-2 and G of part 50 of this chapter specify unique manual FRM for measuring those pollutants. Except as provided in § 53.16, other manual methods for lead will not be considered for a reference method determination under this part.

(2) PM10. A FRM for measuring PM10 must be a manual method that meets all requirements specified in appendix J of part 50 of this chapter and must include a PM10 sampler that has been shown in accordance with this part to meet all requirements specified in this subpart A and subpart D of this part.

(3) PM2.5. A FRM for measuring PM2.5 must be a manual method that meets all requirements specified in appendix L of part 50 of this chapter and must include a PM2.5 sampler that has been shown in accordance with this part to meet the applicable requirements specified in this subpart A and subpart E of this part. Further, FRM samplers must be manufactured in an ISO 9001-registered facility, as defined in § 53.1 and as set forth in § 53.51.

(4) PM10-2.5. A FRM for measuring PM10-2.5 must be a manual method that meets all requirements specified in appendix O of part 50 of this chapter and must include PM10C and PM2.5 samplers that have been shown in accordance with this part to meet the applicable requirements specified in this subpart A and subpart E of this part. Further, PM10-2.5 FRM samplers must be manufactured in an ISO 9001-registered facility, as defined in § 53.1 and as set forth in § 53.51.

(b) Automated methods. An automated FRM for measuring SO2, CO, O3, or NO2 must utilize the measurement principle and calibration procedure specified in the appropriate appendix to part 50 of this chapter (appendix A-1 only for SO2 methods) and must have been shown in accordance with this part to meet the requirements specified in this subpart A and subpart B of this part.

[71 FR 61271, Oct. 17, 2006, as amended at 75 FR 35597, June 22, 2010]