Ground-level ozone (the primary constituent of smog) is the most complex, difficult to control, and pervasive of the six principal air pollutants. Unlike other pollutants, ozone is not usually emitted directly into the air, but at ground-level is formed via photochemical reactions among NOx and volatile organic compounds (VOCs) in the presence of sunlight. Scientific evidence indicates that ground-level ozone not only affects people with impaired...

These reports discusses results for ambient air toxics monitoring conducted by the Colorado Department of Public Health and Environment (CDPHE) at the long-term trends site at Grand Junction, Colorado. This site was established as part of the "rural" area component of the EPA National Air Toxics Trends Study. Since that time, the EPA has reconsidered, and decided that the site is more indicative of urban concentrations, and has changed the designation...

On Thursday May 22, 2008, Lamar Colorado recorded an exceedance of the twenty-four-hour PM10 standard with a concentration of 227 ug/m3 at the Lamar Power Plant. Sustained winds and gusts in eastern and southeastern Colorado exceeded blowing dust criteria. Winds at Lamar were above the blowing dust thresholds for several hours on May 22, and gusts were as high as 58 mph.

On Thursday October 30, 2003, Delta, Crested Butte, Mount Crested Butte, and Grand Junction recorded exceedances of the twenty-four-hour PM10 standard with readings of 215 ug/m3 at Delta, 177 ug/m3 at Crested Butte, 165 ug/m3 at Mount Crested Butte, and 234 ug/m3 at Grand Junction. The exceedances were caused by a combination of dense smoke transported from the massive wildfires in Southern California and blowing dust from the desert Southwest and...