Schiff Hardin LLP June 23, 2010
Environmental Header

USEPA Issues New Sulfur Dioxide NAAQS

On June 22, 2010, the U.S. Environmental Protection Agency ("USEPA") issued a new, tighter primary National Ambient Air Quality Standard ("NAAQS") for sulfur dioxide ("SO2"), based on its previous finding [see our link to the update on the November 2009 proposed rules here] that the existing standards are not adequate to protect public health. The NAAQS is effective August 3, 2010.

The new SO2 standard released on Tuesday is a 1-hour standard at 75 ppb, based on the three-year average of the annual 99th percentile (or fourth highest) of 1-hour daily maximum concentrations. The new standard also requires that attainment and nonattainment be shown not only by air quality data, but also by dispersion modeling data. The new standard also revokes the current 24-hour and annual primary standards as of August 3, 2011.

Designations are to be based on 2008-2010 data, and recommendations are to be submitted by the states by June 2, 2011. Areas with either monitoring or modeling data indicating nonattainment are to be designated nonattainment areas. Areas with both monitoring and modeling data showing attainment are to be designated attainment. Areas with no monitoring data or monitoring data showing attainment but no modeling data are to be designated as unclassifiable. The attainment deadline is five years after USEPA finalizes designations, which should be around June 2017, if everything is completed timely.

USEPA notes that New Source Review ("NSR") and Prevention of Significant Deterioration ("PSD") apply upon the effective date of the NAAQS but provides no new increments or significance thresholds.

These changes to the SO2 NAAQS will likely result in an increase in the number of areas designated as nonattainment, which in turn will likely require additional state regulations to achieve and maintain the SO2 NAAQS. The largest sources of SO2 emissions — those most likely impacted by the new standard — include cement manufacturing facilities, industrial boilers, industrial processes such as petroleum refining and metal processing, as well as fossil fuel combustion at electric generating units.

RECENT ENVIRONMENTAL PUBLICATIONS

"USEPA Issues Final Tailoring Rule," Environmental Update (May 19, 2010)
"USEPA Proposes Reconsideration of 2009 New Source Review Aggregation Rule,"Environmental Update (April 7, 2010)
"EPA Moves Forward on GHG Regulation," Environmental Update (April 1, 2010)
"California Supreme Court Rules that "Established Levels Of Particular Use" are Baseline for CEQA Analysis," Environmental Update (March 19, 2010)

ABOUT SCHIFF HARDIN LLP

Schiff Hardin's diverse environmental practice advises clients engaged in a wide variety of industries and commercial endeavors such as electric generation, natural gas distribution and production, chemical manufacturing, auto and auto parts manufacturing, consumer goods manufacturing, real estate development and investments by financial institutions and equity investors.