Federal regulations · Through 2026-08-25 · Newer source version available

40 CFR Table C-4 to Subpart C of Part 53: 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

Specification PM10 PM2.5 PM10-2.5
Class I Class II Class III Class II Class III
Acceptable concentration range (Rj), µg/m3 5-300 3-200 3-200 3-200 3-200 3-200.
Minimum number of test sites 2 1 2 4 2 4.
Minimum number of candidate method samplers or analyzers per site 3 3 31 31 31 3.1
Number of reference method samplers per site 3 3 31 31 31 3.1
Minimum number of acceptable sample sets per site for PM10 methods:
Rj < 20 µg/m3 3
Rj > 20 µg/m3 3
Total 10
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. 3 3 3 3 3.
Rj > 15 µg/m3 for 24-hr or Rj > 8 µg/m3 for 48-hr samples 3 3 3 3 3.
Each season 10 23 23 23 23.
Total, each site 10 23 23 (46 for two-season sites) 23 23 (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, maximum 5 µg/m3 or 7%. 2 µg/m3 or 5%. 10%2 10%2 10%2 10%.2
Precision of PM2.5 or PM10-2.5 candidate method, CP, each site 10%2 15%2 15%2 15%.2
Slope of regression relationship 1 ±0.10 1 ±0.05 1 ±0.10 1 ±0.10 1 ±0.10 1 ±0.12.
Intercept 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.
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.

Where this section sits in the code

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

Specification PM10 PM2.5 PM10-2.5

Class I Class II Class III Class II Class III

Acceptable concentration range (Rj), µg/m3 5-300 3-200 3-200 3-200 3-200 3-200.

Minimum number of test sites 2 1 2 4 2 4.

Minimum number of candidate method samplers or analyzers per site 3 3 31 31 31 3.1

Number of reference method samplers per site 3 3 31 31 31 3.1

Minimum number of acceptable sample sets per site for PM10 methods:

Rj < 20 µg/m3 3

Rj > 20 µg/m3 3

Total 10

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. 3 3 3 3 3.

Rj > 15 µg/m3 for 24-hr or Rj > 8 µg/m3 for 48-hr samples 3 3 3 3 3.

Each season 10 23 23 23 23.

Total, each site 10 23 23 (46 for two-season sites) 23 23 (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, maximum 5 µg/m3 or 7%. 2 µg/m3 or 5%. 10%2 10%2 10%2 10%.2

Precision of PM2.5 or PM10-2.5 candidate method, CP, each site 10%2 15%2 15%2 15%.2

Slope of regression relationship 1 ±0.10 1 ±0.05 1 ±0.10 1 ±0.10 1 ±0.10 1 ±0.12.

Intercept 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.

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.

Collected 2026-08-27T02:26:04Z. Source file · JSON

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