Wednesday, January 31, 2007

EPA Document Calls For Stricter Ozone Standards

Jan 31: U.S. EPA announced that a key document in its review of national air quality standards for ozone will recommend the administrator consider strengthening the current ozone standards to better protect public health. The document, known as the "final staff paper," contains staff recommendations for the administrator to consider in upcoming decisions about revising the Agency's ozone standards. The Clean Air Act requires EPA to periodically review its air quality standards to ensure they continue to protect health and the environment, and to update the standards if necessary. EPA last updated the standards for ozone in 1997. The final ozone staff paper addresses a primary standard, designed to protect public health; and a secondary standard, set to protect the public welfare, including crop health.

For the primary standard, staff recommends a range of levels for the administrator to consider in setting the ozone standard. That range extends from below 0.080 ppm down to 0.060 ppm. The previous draft of the staff paper identified options that included retaining the current standard of 0.084 ppm, along with a range of alternative levels down to 0.064 (the lowest level analyzed), with a focus on a level of 0.07 ppm.

For the secondary standard, staff recommends a standard that is a cumulative, weighted total of daily 12-hour exposures over a three-month period within the growing season. It would give greater weight to exposures at higher ozone concentrations. Staff recommended a range for this standard, from 21 parts per million-hours to 7 parts per million-hours.

EPA is making the final ozone staff paper available at this time and said it will release technical documents used in developing the staff paper sometime this week. The documents include a health risk assessment for meeting the current ozone standards along with potential alternative standards, and an assessment of the effects of ozone on vegetation. EPA notes that the assessments, conclusions and recommendations included in the staff paper are staff judgments. They do not represent Agency decisions on the ozone standards. EPA will propose action on the ozone standards by June 20, 2007 and take final action by March 12, 2008.

On October 25, 2006, U.S. EPA's Clean Air Scientific Advisory Committee (CASAC) Ozone Panel issued new recommendations for limiting ozone, or smog pollution. The 23-member scientific advisory panel unanimously presented their view that there was no scientific justification for retention of the current 8-hour ozone standard of 0.08 parts per million (ppm); and recommended instead that a substantially stronger standard in the range of 0.060 to 0.070 ppm be adopted. Under a court-ordered schedule, EPA must propose action on the ozone standard by May 30, 2007, and take final action by February 2008 [See WIMS 10/25/06].

Access a release (click here). Access links to a fact sheet and the final staff document (click here, posted 1/31/07). Access links to the ozone technical documents to be posted later this week (click here). [*Air]