(a) The Governor of the State of Colorado submitted the 1990 carbon monoxide base year emission inventories for the Colorado Springs, Denver/Longmont, and Fort Collins nonattainment areas on December 31, 1992, as a revision to the State Implementation Plan (SIP). The Governor submitted revisions to the Colorado Springs and Fort Collins inventories by a letter dated March 23, 1995. The Governor submitted revisions to the Denver/Longmont inventory by letters dated July 11, 1994, and October 21, 1994. The inventories address emissions from point, area, on-road mobile, and non-road sources. These 1990 base year carbon monoxide inventories satisfy the requirements of section 187(a)(1) of the Clean Air Act for each of these nonattainment areas.

(b) On September 16, 1997, the Governor of Colorado submitted the 1993 Carbon Monoxide Periodic Emission Inventories for Colorado Springs, Denver, Fort Collins, and Longmont as revisions to the Colorado State Implementation Plan. These inventories address carbon monoxide emissions from stationary point, area, non-road mobile, and on-road mobile sources.

(c) On September 16, 1997, the Governor of Colorado submitted the 1990 Carbon Monoxide Base Year Emission Inventory for Greeley as a revision to the Colorado State Implementation Plan. This inventory addresses carbon monoxide emissions from stationary point, area, non-road, and on-road mobile sources.

(d) On May 10, 2000, the Governor of Colorado submitted the 1996 Carbon Monoxide Periodic Emission Inventories for Denver and Fort Collins, as a revision to the Colorado State Implementation Plan. The inventories address carbon monoxide emissions from stationary point, area, non-road mobile, and on-road mobile sources.