Emissions Limits for 1981 and Older Light-Duty Vehicles
1981 and older vehicles are tested with the two-speed idle test. Pollutants are sampled and measured in parts per million. Oxides of nitrogen are not measured in the idle test.
1981 & Older Light-Duty Passenger Vehicle Limits
(Includes Light-Duty Trucks)
| Model Year | CO | HC |
|---|---|---|
| 1970 & Earlier | 3.5 | 1000 |
| 1971 | 3.0 | 1000 |
| 1972 | 3.0 | 1000 |
| 1973 | 3.0 | 1000 |
| 1974 | 3.0 | 1000 |
| 1975 | 2.0 | 600 |
| 1976 | 2.0 | 600 |
| 1977 | 1.5 | 400 |
| 1978 | 1.5 | 400 |
| 1979 | 1.5 | 400 |
| 1980 | 1.5 | 400 |
| 1981 & Newer | 1.2 | 220 |
CO: carbon monoxide HC: hydrocarbons
Source: Colorado Department of Public Health and Environment
