40 CFR Part 53, Table C-1 — Test Concentration Ranges, Number of Measurements Required, and Maximum Discrepancy Specifications
Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
| Pollutant | Concentration range, parts per million (ppm) | Simultaneous measurements required | Maximumdiscrepancyspecification, parts per million |
|---|---|---|---|
| 1-hour | 24-hour | ||
| First set | Second set | First set | Second set |
| Ozone | Low 0.06 to 0.10 | 5 | 6 | | | 0.02 |
| Med. 0.15 to 0.25 | 5 | 6 | | | 0.03 | |
| High 0.35 to 0.46 | 4 | 6 | | | 0.04 | |
| Total | 14 | 18 | | | | |
| Carbon monoxide | Low 7 to 11 | 5 | 6 | | | 1.5 |
| Med. 20 to 30 | 5 | 6 | | | 2 | |
| High 25 to 45 | 4 | 6 | | | 3 | |
| Total | 14 | 18 | | | | |
| Sulfur dioxide | Low 0.02 to 0.05 | 5 | 6 | 3 | 3 | 0.02 |
| Med. 0.10 to 0.15 | 5 | 6 | 2 | 3 | 0.03 | |
| High 0.30 to 0.50 | 4 | 6 | 2 | 2 | 0.04 | |
| Total | 14 | 18 | 7 | 8 | | |
| Nitrogen dioxide | Low 0.02 to 0.08 | | | 3 | 3 | 0.02 |
| Med. 0.10 to 0.20 | | | 2 | 2 | 0.02 | |
| High 0.25 | | | 2 | 2 | 0.03 | |
| Total | | | 7 | 8 | |
[75 FR 35601, June 22, 2010]