Automobile Emissions Testing

The Automobile Inspection and Readjustment (AIR) Program's purpose is to reduce motor vehicle related pollution through the inspection and emissions-related repair of gasoline powered motor vehicles.

Emissions testing of gas and diesel powered vehicles is required when registering, renewing registrations, or selling vehicles within the program areas in nine counties along Colorado's Front Range.

The current AIR Program covers the nine-county Front Range area, including all or portions of Adams, Arapahoe, Boulder, Broomfield, Denver, Douglas, Jefferson, Larimer, and Weld counties.

The RapidScreen program provides an opportunity for vehicles to forego testing if they are found to meet emissions standards after driving by a roadside monitor.

Program Administration

Denver Metro Area - Enhanced and Basic Vehicle Emissions Test

1982 and Newer Vehicles:

An enhanced test is required for gasoline powered passenger cars and light trucks 1982 and newer in the seven-county Denver metro area, which includes the counties of Broomfield, Denver, Jefferson, Boulder, Douglas, and western Arapahoe and Adams counties (west of Kiowa Creek). New cars are exempt from testing to the original owner for four years. The enhanced inspection is performed at any one of 14 inspection stations operated by AirCare Colorado. The inspection utilizes a dynamometer which simulates actual driving conditions. The test is good for two years. Motorists are alerted to the need for a test by a notice on their registration renewal forms.

See the AirCare Colorado website for emissions testing information

Older than 1982:

A basic two-speed idle test is required each year for vehicles older than 1982 and heavy trucks in the six-county Denver metro area. The basic test can be performed at Air Care Colorado facilities, or at an independent, licensed test station.

Locations of Independent, Licensed Test Stations

North Front Range - Enhanced Vehicle Emissions Test

The Enhanced Vehicle Emissions test expanded from the Denver area to parts of Larimer and Weld Counties in November of 2010 to control ground-level ozone. The Air Pollution Control Division made the following presentation during the public hearing that provides the regulatory and scientific basis for expanding the program to the north Front Range.

El Paso County - Basic Program Discontinued

The basic two-speed idle gasoline test emissions program in El Paso County was discontinued on January 1, 2007, based on long-term compliance with the carbon monoxide standards.