U.S. Code of Federal Regulations
Regulations most recently checked for updates: Aug 27, 2025
Not-to-exceed emission standards apply as follows:
(a) Measure emissions using the not-to-exceed procedures in subpart F of this part:
(b) Determine the not-to-exceed standard, rounded to the same number of decimal places as the emission standard in Table 1 to this section from the following equation:
(c) For engines equipped with a catalyst, use NTE multipliers from the following table across the applicable zone specified in § 1045.515:
Table 1 to § 1045.107—NTE Multipliers for Catalyst-Equipped Engines
| Pollutant | Subzone 1 | Subzone 2 |
|---|---|---|
| HC + NO | 1.50 | 1.00 |
| CO | N/A | 1.00 |
(d) For two-stroke engines not equipped with a catalyst, use an NTE multiplier of 1.2 for HC + NO
(e) For engines not covered by paragraphs (c) and (d) of this section, use the NTE multipliers from the following table across the applicable zone specified in § 1045.515:
Table 2 to § 1045.107—NTE Multipliers for Four-Stroke Engines without Catalysts
| Pollutant | Subzone 1 | Subzone 2 |
|---|---|---|
| HC + NO | 1.40 | 1.60 |
| CO | 1.50 | 1.50 |
