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WildEarth Guardians Targets Dangerously Dusty Skies in Eight Western States

Petition Filed with EPA to Clean up Particulate Pollution in 21 Dirty Air Areas

Denver—WildEarth Guardians today petitioned the U.S. Environmental Protection Agency to rein in dangerous levels of particulate matter air pollution in 21 areas in eight western states, including Arizona, Colorado, Montana, Nevada, New Mexico, Oklahoma, Utah, and Wyoming.

“We need the EPA to step up and put these areas on the path to clean up,” said Jeremy Nichols, Climate and Energy Program Director for WildEarth Guardians.  “These dusty skies are not only dangerous, they’re a sign that air quality throughout the west is at risk.  We need relief.”

Air quality monitoring data for the 21 areas shows that health-based standards limiting particulate matter less than 10 microns in diameter, or 1/7th the width of a human hair, also known as PM-10, are being violated. 

Breathing PM-10 can lead to a number of adverse health effects, including irritation of the airways, coughing, or difficulty breathing, decreased lung function, aggravated asthma, development of chronic bronchitis, nonfatal heart attacks; and premature death in people with heart or lung disease (see the EPA’s website,

Under the Clean Air Act, if an area violates any ambient air quality standard, the EPA is required to ensure States clean up the air pollution.  Despite violating PM-10 standards, the EPA has yet to put the 21 areas on the path to clean up.

The areas violating PM-10 standards, by state, include:

  • Arizona:  Douglas, Nogales, Tucson, and Yuma.
  • Colorado:  Alamosa, Durango, Grand Junction, Lamar, Pagosa Springs, and Parachute.
  • Montana:  A portion of Jefferson County south of Helena.
  • Nevada:  Pahrump.
  • New Mexico:  Anthony, Chaparral, Deming, Las Cruces, and Sunland Park.
  • Oklahoma:  Tulsa.
  • Utah:  Salt Lake and Utah Counties.
  • Wyoming:  A portion of Sweetwater County near Point of Rocks.

An interactive Google Earth map showing the location of these areas and the air quality monitors can be viewed at

Under the Clean Air Act, if an area violates PM-10 standards, the EPA is required to designate the area as “nonattainment,” which triggers deadlines for States to clean up the air pollution and protect public health.  Where an area that is already designated as “nonattainment” violates PM-10 air quality standards, the EPA must reclassify its designation as “Serious,” which imposes more stringent clean up requirements.  In this case, WildEarth Guardians called for 15 areas to be designated as “nonattainment” and for six additional areas to be reclassified as “Serious” nonattainment areas, including Douglas, AZ, Nogales, AZ, Yuma, AZ, Anthony, NM, Salt Lake County, UT, and Utah County, UT. 

The sources of PM-10 pollution in these areas include dust blown from disturbed lands, mining operations, coal-fired power plants and oil refineries, dirt roads, and other kinds of burning (e.g., wood stoves, industrial boilers).  For example, in Salt Lake County, copper mining at Kennecott Utah Copper’s Bingham Canyon Mine and coal-fired smelter have contributed to violations.

“These air quality violations are a sign of out control air pollution,” said Nichols.  “These sources—whether they be coal-fired power plants or dusty roads—need to be reined in.  It’s time for clean air to come first in these areas.”

In some cases, violations of PM-10 standards have been ongoing.  For example, Salt Lake County, which includes Salt Lake City, has violated PM-10 standards every year since 1999.  A violation of the PM-10 standards occurs whenever the three-year average of the number of exceedances of the standards exceeds 1.0.  The PM-10 standards are exceeded whenever concentrations exceed 150 micrograms/cubic meter over a 24-hour period. 

WildEarth Guardians petitioned the EPA under the Administrative Procedure Act, a federal law that provides any citizen the right to petition the government to issue a rule.  In this case, Guardians petitioned the EPA to issue a rule to ensure PM-10 pollution in the 21 areas is cleaned up.  The petition calls on the EPA to respond within 90 days.



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