Colorado Department of Revenue
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Emissions Information

Emissions Quick Links

How Do I...

Gas Vehicles

Diesel Vehicles

...renew my registration when my vehicle is not in Colorado?

Gas Emissions Testing Locations and Costs

Diesel Emissions Testing Locations and Costs

...request an emissions waiver?

Gas Emissions Program Area

Diesel Emissions Program Area

...file an emissions complaint against a testing station or a dealer?


Who we are


The Colorado Department of Revenue (DOR) Motor Vehicle Emissions Section regulates emissions testing facilities and inspectors in Colorado. Emission testing facilities include independent diesel testing stations, self-certified gas fleet facilities, independent gas testing stations, Air Care Colorado (ACC), and ACC’s RapidScreen roadside vans.


The Emissions Section conducts regular undercover and scheduled overt quality assurance audits on all testing facilities as required by Colorado law. In addition, the Emissions Section is responsible for licensing emissions inspectors and stations, investigating complaints against emissions testing facilities and inspectors, and issuing emissions waivers.


Our office is comprised mainly of air emissions technicians who are specialists in the area of motor vehicle emissions testing and motor vehicle emissions control systems.


What we do


Our Mission: Conduct emissions audits on stations and inspectors, issue certifications of emissions waivers to vehicle owners, and resolve consumer complaints regarding emissions testing stations and motor vehicle dealers while ensuring vehicle owner, consumer, vendor, and section compliance with applicable emissions laws and regulations.


Our Vision: Maintain a commitment to clean air and compliance with applicable laws and regulations while focusing on vehicle owners’ interests as related to vehicle emissions testing.


Where we do it


Currently, the enhanced (gas) program area includes the entire counties of Boulder, Broomfield, Denver, Douglas and Jefferson, parts of Larimer and Weld counties, as well as those parts of the counties of Adams and Arapahoe that are west of Kiowa Creek.


The diesel program area includes the entire counties of Boulder, Broomfield, Denver, Douglas and Jefferson, parts of El Paso, Larimer, Weld counties, as well as those parts of the counties of Adams and Arapahoe that are west of Kiowa Creek.


Program History


The DOR Motor Vehicle Emissions Section was formed in 1981 in order to comply with federal requirements. DOR has been managing the Colorado Air Inspection and Readjustment (AIR) Program in conjunction with the Colorado Department of Public Health and Environment (CDPHE) since July 1, 1981.


Over the years, the vehicle emissions program has gone through significant changes. Originally, the program included the counties of Boulder, Denver, Douglas, Jefferson, and parts of Adams, Arapahoe, El Paso and Larimer counties. In January 1988, the metropolitan area of Greeley, within Weld County, was included. On November 15, 2001 Broomfield County was established and included in the existing AIR Program. Despite the classification as a new county, all vehicles were previously included in the program area. 


In August of 2004, the Clean Screen (RapidScreen) program was added as an alternative to conventional testing. The clean screen element of the Inspection and Maintenance (IM) Program uses Remote Sensing Device (RSD) systems to measure tailpipe emissions while a vehicle is being operated on the road. Those vehicle owners meeting the clean screen criteria are notified via the registration renewal card and may thereby bypass the conventional emissions test.


In February of 2005, the Air Quality Control Commission (AQCC) voted to discontinue the basic gasoline emissions program in Larimer, El Paso, and Weld counties. The basic area emissions program was terminated on January 1, 2007. Also, in October 2007, the AQCC promulgated rules to implement a high emitter identification pilot program. The high emitter program utilized clean screen technology to identify gross polluting vehicles. The high emitter pilot program was implemented in December 2007 and was terminated in April 2010.


In December of 2008, the AQCC reinstated the counties of Larimer and Weld into the enhanced emissions program. SB09-003 further expanded the boundaries of the regulatory changes made by the AQCC. The expansion of the Northern Front Range program was implemented on November 1, 2010.