On Friday May 2, 2008, Lamar Colorado recorded an exceedance of the twenty-four-hour PM10 standard with a concentration of 367 μg/m3 at the Lamar Power Plant. Wind speeds and gust speeds in Lamar exceeded blowing dust criteria, with speeds of 38 to 45 mph and gusts of at 47 to 60 mph for the two-hour period with greatly reduced visibilities during the late morning and early afternoon of May 2.
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 March 31 and April 9, 1999 and again on April 18 and December 17, 2000, the monitor located in Alamosa, Colorado recorded exceedances of the 24-hour National Ambient Air Quality Standard (NAAQS) for PM10 (particulate matter having a nominal aerodynamic diameter equal to or less than 10 microns).1 Each of these exceedances was associated with high winds and blowing dust in the Alamosa area.
Over the past eight years, the monitors located at the Municipal Power Plant and Municipal Building in Lamar, Colorado experienced exceedances of the 24-hour National Ambient Air Quality Standard (NAAQS) for PM10 (particulate matter having a nominal aerodynamic diameter equal to or less than 10 microns). Each of these exceedances was associated with unusually high winds and blowing dust in the Lamar area.
The Colorado Department of Public Health and Environment, Air Pollution Control Division, has prepared this report for the United States Environmental Protection Agency (EPA) to demonstrate that the elevated ozone concentrations along Colorado's Front Range and the exceedance of the 8-hour National Ambient Air Quality Standard (NAAQS) for ozone at Manitou Springs on May 24, 2010, was caused by a natural event, specifically a stratospheric intrusion of ozone.
This report addresses the impact on a regional scale of particulate emissions from the Energy Fuels Resources Corporation (Energy Fuels) proposed Piñon Ridge Mill located in Montrose County, Colorado. The regional dust analysis was completed in response to questions posed by the Colorado Department of Public Health and Environment (CDPHE) regarding the possible contribution from the operations of the proposed Piñon Ridge Mill to particulate matter concentrations at regional scale distances. Specifically, the CDPHE requested that Energy Fuels evaluate the effect of uncontrolled dust emissions from the tailings cells on regional concentrations and in particular on concentrations and deposition rates in the Telluride area.
On Sunday March 22, 2009, Pagosa Springs Colorado recorded an exceedance of the twenty-four-hour PM10 standard with a concentration of 225 μg/m3 at the Pagosa Springs School monitor. The Air Pollution Control Division (APCD), has prepared this report for the U.S. Environmental Protection Agency (EPA) to demonstrate that the elevated PM10 concentrations in Pagosa Springs and other areas of Colorado and the exceedance of the National Ambient Air Quality Standard (NAAQS) for PM10 in Pagosa Springs were caused by a natural event, specifically a dust storm.
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 respiratory systems (such as asthmatics), but healthy adults and children as well.
