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Table C-4 to Subpart C of Part 53—Test Specifications for PM <sub>10</sub>, PM <sub>2.5</sub> and PM <sub>10-2.5</sub> Candidate Equivalent Methods

Test Specifications for PM <sub>10</sub>, PM <sub>2.5</sub> and PM <sub>10-2.5</sub> Candidate Equivalent Methods

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  3. Title 40
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  5. Chapter I
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  7. Part 53
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  9. Subpart C
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  11. Appendix Table C-4 to Subpart C of Part 53
CorpusDaily eCFR
Displayed edition2026-04-27
Last updated2026-04-27

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

SpecificationPM10PM2.5PM10-2.5
Class IClass IIClass IIIClass IIClass III
Acceptable concentration range (Rj), µg/m35-3003-2003-2003-2003-2003-200.
Minimum number of test sites212424.
Minimum number of candidate method samplers or analyzers per site333131313.1
Number of reference method samplers per site333131313.1
Minimum number of acceptable sample sets per site for PM10 methods:
Rj < 20 µg/m33
Rj > 20 µg/m33
Total10
Minimum number of acceptable sample sets per site for PM2.5 and PM10-2.5 candidate equivalent methods:
Rj < 15 µg/m3 for 24-hr or Rj < 8 µg/m3 for 48-hr samples.33333.
Rj > 15 µg/m3 for 24-hr or Rj > 8 µg/m3 for 48-hr samples33333.
Each season1023232323.
Total, each site102323 (46 for two-season sites)2323 (46 for two-season sites).
Precision of replicate reference method measurements, PRj or RPRj, respectively; RP for Class II or III PM2.5 or PM10-2.5, maximum5 µg/m3 or 7%.2 µg/m3 or 5%.10%210%210%210%.2
Precision of PM2.5 or PM10-2.5 candidate method, CP, each site10%215%215%215%.2
Slope of regression relationship1 ±0.101 ±0.051 ±0.101 ±0.101 ±0.101 ±0.12.
Intercept of regression relationship, µg/m30 ±50 ±1Between: 13.55—(15.05 × slope), but not less than—1.5; and 16.56—(15.05 × slope), but not more than +1.5Between: 15.05—(17.32 × slope), but not less than—2.0; and 15.05—(13.20 × slope), but not more than +2.0Between: 62.05—(70.5 × slope), but not less than—3.5; and 78.95—(70.5 × slope), but not more than +3.5Between: 70.50—(82.93 × slope), but not less than—7.0; and 70.50—(61.16 × slope), but not more than +7.0.
Correlation 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
1 Some missing daily measurement values may be permitted; see test procedure.
2 Calculated as the root mean square over all measurement sets.

[89 FR 16386, Mar. 6, 2024]