We blogged earlier this year about two developments concerning the National Ambient Air Quality Standards (NAAQS) for sulfur dioxide (SO2). Either just in time for the holidays (or, as is more likely, just before a new administration takes over in Washington), those developments have resurfaced at the Environmental Protection Agency (EPA).
Here’s an update on them:
First, back in February, we blogged about EPA’s proposal to designate portions of both Cambria and Westmoreland Counties as being in nonattainment for the 2010 primary NAAQS for SO2 (a primary NAAQS is designed to protect human health) based on the results of a modelling analysis; these areas are directly downwind from three coal-burning power plants (as well as a fourth that has shut down since the modelling was performed) that emit a lot of SO2.
On Dec. 17, EPA published the rule that finalized that designation in the Federal Register. As a result, the state Department of Environmental Protection (DEP) will be required to develop revisions to its State Implementation Plan (the SIP, which includes all of Pennsylvania’s EPA-approved air pollution regulations and facility-based emission limits) that demonstrate the area will attain the 2010 primary NAAQS for SO2 by no later than Dec. 17, 2029, and submit those revisions to EPA for its approval.
“But don’t hold your breath waiting for big changes,” GASP Senior Attorney John Baillie said. “One of the coal burners that contributed to high levels of SO2 that were modelled in the nonattainment area has already shut down (the Homer City Generating Station), and another two (the Keystone and Conemaugh Generating Stations) are scheduled to shut down by no later than 2028.”
He continued:
“Further, as we blogged in June, EPA has proposed a rule that would impose new limits on emissions of sulfur dioxide from these plants. The emission reductions from the plant shutdowns and the proposed new limits may very well be sufficient to demonstrate attainment.”
Second, back in April, we blogged about an EPA proposal to reduce the secondary NAAQ S for SO2 from 500 parts per billion (ppb) not to be exceeded during any three-hour period more than once a year, to an annual average of only 10-15 ppb, measured over a three year period; a secondary NAAQS is designed to protect public welfare, meaning, mainly, plants, animals, and other property.
The 500 ppb standard had been on the books, unchanged, since 1971. On Dec. 10, EPA announced it had finalized a new secondary NAAQS for SO2, which will be an annual average of 10 ppb measured over three years.
“There are areas in both Allegheny County and other parts of southwestern Pennsylvania that may not attain this standard,” Baillie explained. “DEP will have one year to submit designations of those areas to EPA, and (assuming EPA accepts those designations) up to three years to submit revisions to the SIP that include new regulations or limits on facility emissions that will reduce SO2 levels enough to bring all areas of the Commonwealth into attainment of the new standard.”
We will keep you posted on new developments related to these as they occur.