Federal Standards Court Decision - June 1, 1999

This page updated March 22, 2006

Background Information

District of Columbia Circuit Court Decision on New Federal Air Quality Standards

-- Impact on California Air Quality Programs --

On May 14, 1999, a three-judge panel of the U.S. Court of Appeals for the District of Columbia set aside the new ozone and particulate matter (PM) standards that the U.S. Environmental Protection Agency (U.S. EPA) issued in 1997. Essentially the Court removed the revised federal standard for particulate 10 microns and smaller (PM10), put a hold on implementing the eight-hour ozone standard, and asked for further comments on the fine particulate (PM2.5) standard. U.S. EPA has announced it intends to recommend an appeal to the Department of Justice (DOJ) and is reviewing its options. As a practical matter, California's air quality plans and control strategy development will not be delayed.

Q:	Which air quality standards still apply in California?
A:	The eight-hour ozone standard remains in place. However the Court did prohibit U.S. EPA from enforcing the standard. In addition, the previously existing one-hour ozone standard will continue to apply in areas that have not attained that standard.
	The court removed the new PM10 standard; however the previously existing PM10 standard will continue to apply. The Court left the new PM2.5 standards in place but invited comment on the appropriate remedy - which could range from retention to removal of the standard. The Court will set a briefing schedule for parties, and at some time in the future will decide what to do with the PM2.5 standard.
	In addition, California's state standards continue to apply. California's 1-hour ozone standard is similar but slightly more health protective than the federal 8-hour standard. Our PM10 standard is more health protective than the combination of the 1997 federal PM10 and PM2.5 standards.
Q:	What are the implications of this ruling on California's ozone program?
A:	Because most Californians live in areas that still violate the federal one-hour ozone standard and the state's one-hour ozone standard, ARB will continue to implement our existing programs and pursue new emission reduction measures to meet those standards.
Q:	What are the implications of this ruling on California's particulate programs?
A:	With the exception of four rural counties, the entire state is designated nonattainment for the California PM10 standards. Also, many areas of California violate the pre-existing federal PM10 standard including the South Coast, the San Joaquin Valley, and many desert regions. California's multi-pollutant control strategies are needed to reduce ozone and particulate matter, plus improve visibility. These efforts ensure progress toward meeting the state and federal PM10 standards that remain in place.
Q:	What is the impact of the ruling on particulate matter technical work in California?
A:	Our planned field study to better understand particulate pollution in central and northern California will continue on schedule. The information gained through this study, and a corresponding assessment of ozone pollution during the same time, will provide crucial data for understanding the nature of pollution - and transport - in the study area. This work will also complement a 1997 ozone and particulate field study in Southern California. ARB's technical work plan for particulate matter will remain on track. This workplan will include emission inventory studies to better understand particulate sources, development of new monitoring techniques to characterize the particulate pollution problem statewide, and health research to increase our knowledge about the effect of exposure to particulate. Together, these technical efforts will provide a more comprehensive picture of particulate pollution in the state, and help direct our future strategies to meet the federal PM10 standard, the state PM10 standard and any future federal particulate standards.
Q:	How does this decision affect control strategies for the future?
A:	We have not yet identified all the control measures we will need to meet the federal one-hour ozone standard and the state ozone and particulate matter standards. We will be updating our statewide control strategy in 2000, including specifying potential new measures. We intend to focus our efforts on advanced technology solutions. ARB is planning a symposium on zero- and near-zero emission technologies on October 5-7 to begin investigating promising areas for future control.

Historical Comments on Standards