Structure and Results of Colorado's I/M (AIR) Program

The AIR Program has been in full operation in the Front Range counties of Colorado since January 1, 1982. Data from the first 477,905 vehicles tested indicate an average reduction in idle tailpipe carbon monoxide (CO) concentration for re tested vehicles of 56%, while the reduction for hydrocarbons (HC) averages 42%. This represents a reduction of approximately 151 tons of CO per day. The average cost of adjustments for 1968 to 1980 vehicles has been $9.23 and the average repair cost for 1981 and newer vehicles has been $22.30.