{"data":{"id":"us/40-cfr-table-c-4-to-subpart-c-of-part-53","jurisdiction":"us","citation":"40 CFR Table C-4 to Subpart C of Part 53","heading":"Table C-4 to Subpart C of Part 53—Test Specifications for PM 10, PM 2.5 and PM 10-2.5 Candidate Equivalent Methods","body":"Specification PM10 PM2.5 PM10-2.5\nClass I Class II Class III Class II Class III\nAcceptable concentration range (Rj), µg/m3 5-300 3-200 3-200 3-200 3-200 3-200.\nMinimum number of test sites 2 1 2 4 2 4.\nMinimum number of candidate method samplers or analyzers per site 3 3 31 31 31 3.1\nNumber of reference method samplers per site 3 3 31 31 31 3.1\nMinimum number of acceptable sample sets per site for PM10 methods:\nRj \u003c 20 µg/m3 3\nRj \u003e 20 µg/m3 3\nTotal 10\nMinimum number of acceptable sample sets per site for PM2.5 and PM10-2.5 candidate equivalent methods:\nRj \u003c 15 µg/m3 for 24-hr or Rj \u003c 8 µg/m3 for 48-hr samples. 3 3 3 3 3.\nRj \u003e 15 µg/m3 for 24-hr or Rj \u003e 8 µg/m3 for 48-hr samples 3 3 3 3 3.\nEach season 10 23 23 23 23.\nTotal, each site 10 23 23 (46 for two-season sites) 23 23 (46 for two-season sites).\nPrecision of replicate reference method measurements, PRj or RPRj, respectively; RP for Class II or III PM2.5 or PM10-2.5, maximum 5 µg/m3 or 7%. 2 µg/m3 or 5%. 10%2 10%2 10%2 10%.2\nPrecision of PM2.5 or PM10-2.5 candidate method, CP, each site 10%2 15%2 15%2 15%.2\nSlope of regression relationship 1 ±0.10 1 ±0.05 1 ±0.10 1 ±0.10 1 ±0.10 1 ±0.12.\nIntercept of regression relationship, µg/m3 0 ±5 0 ±1 Between: 13.55—(15.05 × slope), but not less than—1.5; and 16.56—(15.05 × slope), but not more than +1.5 Between: 15.05—(17.32 × slope), but not less than—2.0; and 15.05—(13.20 × slope), but not more than +2.0 Between: 62.05—(70.5 × slope), but not less than—3.5; and 78.95—(70.5 × slope), but not more than +3.5 Between: 70.50—(82.93 × slope), but not less than—7.0; and 70.50—(61.16 × slope), but not more than +7.0.\nCorrelation of reference method and candidate method measurements ≥ 0.97 ≥ 0.97 ≥ 0.93—for CCV ≤ 0.4; ≥ 0.85 + 0.2 × CCV—for 0.4 ≤ CCV ≤ 0.5; ≥ 0.95—for CCV ≥ 0.5\n1 Some missing daily measurement values may be permitted; see test procedure.\n2 Calculated as the root mean square over all measurement sets.","path":["Title 40—Protection of Environment","CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY","SUBCHAPTER C—AIR PROGRAMS","PART 53—AMBIENT AIR MONITORING REFERENCE AND EQUIVALENT METHODS","Subpart C—Procedures for Determining Comparability Between Candidate Methods and Reference Methods"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-40.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:04Z","sha256":"7392789f5d44f4b2e791dc75a2d79ebbbbb18d2e8df5ae9b230bfc19f5938726","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-table-c-3-to-subpart-c-of-part-53","next":"us/40-cfr-table-c-5-to-subpart-c-of-part-53"},"notice":"GroundRules: Original legal text. Not legal advice."}