40 CFR Part 53, Table C-4
Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
| 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 | 31 |
| Number of reference method samplers per site | 3 | 3 | 31 | 31 | 31 | 31 |
| 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.
[89 FR 16386, Mar. 6, 2024]