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State Air Regulators, National Parks Service, Raise Red Flags over EPA’s Handling of Background Ozone


In response to the White Paper released by the Environmental Protection Agency (EPA) on background ozone, over a dozen state air regulators, air quality experts, and business groups submitted comments highlighting serious flaws and concerns with how EPA will account for background levels of ozone when implementing the new National Ambient Air Quality Standard (NAAQS).  Background ozone is a problem for some states because it cannot be controlled within a state’s borders.  It is pollution wafting over from another state, is imported from other countries, or is a result of natural events such as wildfires or stratospheric intrusions.

The comments submitted to the docket mirror the strong opposition raised at EPA’s two-day workshop (the first day of which was closed to the public) in Phoenix, Arizona in February.  At the workshop, participants, including state air regulators, researchers, tribal members, elected officials, and business leaders, told the EPA that failure to adequately account for background ozone would unfairly punish Western states and compromise their ability to comply with the stringent, new 70 parts per billion (ppb) standard announced last October.  Counties that are unable to meet the new standard due to background ozone could face harsh federal sanctions that could block new economic development and transportation projects.  Responding to criticism, the EPA admitted that it’s “a very complicated puzzle to untangle as we get into how to obtain the 70 ppb standard.”

Even the National Park Service is concerned with EPA’s handling of background ozone.  Under EPA’s new lower standard, pristine National Parks such as the Grand Canyon, Sequoia, and Big Bend could be out of compliance due to background ozone.  Accordingly, the agency submitted comments noting that “EPA should provide more specific guidance how to deal with implications of background ozone” and that “credible emissions inventories for international sources are critical.”

Several business groups, editorial boards, and elected leaders have called on the EPA to halt implementation of the new standard until there is a better understanding of the role and impact of background ozone.  Democratic Colorado Governor John Hickenlooper last week said suspending implementation of the rule was “a great idea.”

Highlights of comments submitted to EPA on background ozone: