EPA lowers federal ozone standard; Colorado, other states face more difficult compliance

Mark Salley | 303-692-2013 | mark.salley@state.co.us
DENVER—The U.S. Environmental Protection Agency today revised the federal health-based air quality standards for ozone, lowering the threshold to 70 parts per billion (ppb).
The decision will challenge Colorado and other states around the country that already have regions not meeting the previous standard.
Currently, the Denver-metro and North Front Range region is designated as “nonattainment” for ozone under the previous standard of 75 ppb. As a result, the Colorado Department of Public Health and Environment’s Air Pollution Control Division and the Regional Air Quality Council already are engaged in an extensive planning and implementation effort, using both voluntary and mandatory air pollution control measures to reduce ground-level ozone concentrations.
“Coloradans want and deserve clean air in all areas of our state,” said Gov. John Hickenlooper. “We will continue to work to ensure protection of all of Colorado’s precious resources while growing Colorado’s economy. At the same time, the EPA must recognize the unique challenges that lower ozone standards pose to the Rocky Mountain West."
Dr. Larry Wolk, executive director and chief medical officer at the department, said, “We’ve been anticipating this change for a while. Given the process already well underway, Colorado is in a good position moving forward to address ozone. There are important health benefits associated with lower ozone concentrations. However, this is going to be a significant challenge for a variety of reasons. We will work to build on the progress already made in a way that is both cost-effective and protective of public health and the environment.”
Wolk indicated one of the primary concerns in Colorado is the transport of ground-level ozone into the state from hundreds or even thousands of miles away.
“There’s strong scientific evidence that the ‘background’ ozone concentrations in some Colorado locales on certain days are 50 parts per billion or higher,” he said. “This background pollution comes from out of state and in some cases out of the country. It needs to be accounted for somehow, and requires flexibility in the planning and implementation process.”
Currently, the only area of the state out of compliance with the previous ozone standard is the Denver-metro and North Front Range region. 
Ground level ozone is unique in that it is not emitted directly into the air by pollution sources; rather, it is formed when emissions of other pollutants like nitrogen oxides (NOx) and volatile organic compounds (VOCs) react with sunlight. These “precursor” pollutants are emitted by a variety of man-made and natural sources, including oil and gas operations, power plants and vehicles. Even smaller sources, such as home lawn and garden equipment, smaller engines and combustion sources and paints and household chemicals, contribute pollutants that lead to ground-level ozone.
Exposure to elevated ozone concentrations can trigger a variety of health problems, including chest pain, coughing, throat irritation and reduced lung function. Ozone can worsen symptoms associated with respiratory conditions and diseases such as asthma, bronchitis and emphysema, and can permanently damage lung tissue.
Those most at risk from ozone exposure include children, people with asthma and other respiratory diseases, the elderly and people active outdoors.
Colorado currently is involved in a number of clean air initiatives, including efforts around the recently announced federal Clean Power Plan. Colorado is recognized as a leader in significantly reducing air pollutant emissions based upon previous actions such as the adoption of the nation’s first Renewable Energy Standard (2004), the passage of the Clean Air Clean Jobs Act (2010), the Regional Haze Plan (2012) and revisions to oil and gas regulations (2014).
These efforts already are significantly reducing NOx emissions through the retirement of older coal-fired electric generating units, the conversion of others to natural gas and the addition of advanced pollution controls.
For more specific information on the new standard, go to the EPA’s website at www.epa.gov. For daily air quality information across Colorado, go to www.colorado.gov/airquality.