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U.S. Code of Federal Regulations
Regulations most recently checked for updates: Aug 27, 2025
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Title 40
Chapter I
Part 53 - PART 53—AMBIENT AIR MONITORING REFERENCE AND EQUIVALENT METHODS
Subpart A [§ 53.1 - § 53.16] - Subpart A—General Provisions
Subpart B [§ 53.20 - § 53.23] - Subpart B—Procedures for Testing Performance Characteristics of Automated Methods for SO2, CO, O3, and NO2
Subpart C [§ 53.30 - § 53.35] - Subpart C—Procedures for Determining Comparability Between Candidate Methods and Reference Methods
Subpart D [§ 53.40 - § 53.43] - Subpart D—Procedures for Testing Performance Characteristics of Methods for PM 10
Subpart E [§ 53.50 - § 53.59] - Subpart E—Procedures for Testing Physical (Design) and Performance Characteristics of Reference Methods and Class I and Class II Equivalent Methods for PM 2.5 or PM 10-2.5
Subpart F [§ 53.60 - § 53.66] - Subpart F—Procedures for Testing Performance Characteristics of Class II Equivalent Methods for PM 2.5
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