The Denver region suffers from three major air pollutants: carbon monoxide (CO), ozone (O3), and PM-10 (very fine airborne dust or particulate matter).

More than 80% of carbon monoxide in the region is a result of motor vehicle emissions while the remaining 20% comes from industry and small area sources (like fireplaces and grills). Due to several innovative programs - like the vehicle emission inspection program, cleaner fuels and the manufacture of cleaner cars - carbon monoxide problems are in our region are under control.

Ozone (O3) is not a primary pollutant in itself but rather is a result of "volatile organic compounds" (such as the fumes that you can see and smell at a gas station) reacting with sunlight in the presence of NOx pollution (nitric oxide and nitrogen dioxide combined). Ozone is primarily a summertime phenomenon, seen as smog-like conditions. Very high temperatures during the summer of 1998 contributed to high ozone readings, particularly along the region's foothills. Our region is still below a new EPA standard for ozone, though there is not a large margin for error.

Approximately 60% of the small particulate matter in the region is a result of motor vehicles - both from tail pipe emissions and from road dust and sand "kicked up" into the air by tires.

The Denver region's air quality is a success story. As the graphs indicate, we have seen a downward trend over the years in the number of pollution "exceedance" days -- days that we violate the federal health standards. After many years, in 1996, the region achieved the health standards for three previously problem pollutants.