Emissions Limits for Passenger Vehicles
The following chart shows emissions limits for 1982 through 2001
model years for carbon monoxide (CO), hydrocarbons (HC) and oxides of nitrogen (NOx) by vehicle model year.
(See also pollution limits for 1981 and older model years.) The chart
includes projected fail rates for each model year. The projected fail rate includes all fails for
pollutants, missing or inoperable emissions control equipment, and smoke. 1982 and newer vehicles are
tested with the I/M 240 dynamometer test. Pollutants are collected and measured
in grams per mile. The following chart reflects the
standards change implemented on May 5, 2008.
Emissions Limits and Fail Rates for 1982 &
Newer Vehicles
| Model Year |
CO |
HC |
NOx |
Fail Rate |
| 2002 |
15.0 |
1.2 |
1.5 |
TBD |
| 2001 |
15.0 |
1.2 |
1.5 |
TBD |
| 2000 |
15.0 |
1.2 |
1.5 |
TBD |
| 1999 |
15.0 |
1.2 |
1.5 |
TBD |
| 1998 |
15.0 |
1.2 |
1.5 |
TBD |
| 1997 |
15.0 |
1.2 |
2.0 |
TBD |
| 1996 |
15.0 |
1.2 |
2.0 |
TBD |
| 1995 |
15.0 |
1.2 |
2.5 |
TBD |
| 1994 |
15.0 |
1.2 |
3.0 |
TBD |
| 1993 |
15.0 |
1.5 |
3.5 |
TBD |
| 1992 |
15.0 |
1.5 |
3.5 |
TBD |
| 1991 |
20.0 |
1.5 |
3.5 |
TBD |
| 1990 |
20.0 |
2.0 |
3.5 |
TBD |
| 1989 |
20.0 |
2.0 |
4.0 |
TBD |
| 1988 |
20.0 |
2.0 |
4.0 |
TBD |
| 1987 |
20.0 |
2.5 |
4.0 |
TBD |
| 1986 |
20.0 |
2.5 |
4.5 |
TBD |
| 1985 |
20.0 |
2.5 |
4.5 |
TBD |
| 1984 |
30.0 |
3.0 |
4.5 |
TBD |
| 1983 |
30.0 |
3.5 |
4.5 |
TBD |
| 1982 |
45.0 |
3.5 |
5.0 |
TBD |
CO: carbon monoxide HC: hydrocarbons
NOx: nitrogen oxides Fail Rate is calendar year 1999 data, & refers to initial tests only, not
retests. Source: Colorado Department of Public Health and Environment.
1981 and older vehicles are tested with the
two-speed idle test. Although emissions limits are listed on this page for only
1970 through 2001 model year vehicles, all older vehicles are subject to testing unless they fit
certain testing exemption categories. Pollutants are sampled and
measured in parts per million. Oxides of nitrogen are not measured in the idle test.
Emissions Limits for 1981 &
Older Vehicles
| Model Year |
CO |
HC |
| 1981 |
1.5 |
400 |
| 1980 |
1.5 |
400 |
| 1979 |
2.0 |
400 |
| 1978 |
3.0 |
400 |
| 1977 |
3.0 |
400 |
| 1976 |
3.5 |
600 |
| 1975 |
3.5 |
600 |
| 1974 |
4.5 |
1000 |
| 1973 |
4.5 |
1000 |
| 1972 |
4.5 |
1000 |
| 1971 |
4.5 |
1000 |
| 1970 and older |
5.5 |
1000 |
CO: carbon monoxide HC: hydrocarbons
Source: Colorado Department of Public Health and Environment.
View emissions limits for
light duty trucks and heavy duty trucks.
Back to I/M 240 Test page.
Back to Two-Speed Idle Test page.
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