By Lawrence Hurley

WASHINGTON (Reuters) - A federal appeals court on Tuesday partially upheld U.S. Environmental Protection Agency regulations issued by former President George W. Bush's administration that set standards for ozone pollution.

The U.S. Court of Appeals for the District of Columbia Circuit sent a portion of the regulations back to the agency for further consideration but left the entirety of the rule in place while the revisions are carried out.

Ozone pollution forms when air pollutants react with sunlight and has been linked to health problems that include decreased lung function.

The 2008 rule was challenged by states, industry groups and environmental groups, with some saying it was too strict and others that it was too lenient. The ruling was a partial victory for environmental groups that said it was not stringent enough, although the court did not embrace all their arguments.

In the unanimous decision by a three-judge panel, the court upheld the so-called primary air quality standards designed to protect public health but sent the secondary standards that are required to protect the vegetation, crops and animals back to the EPA for revision.

The court held that the EPA had "failed to determine what level of protection" was required to meet the requirements of the Clean Air Act.

Tuesday's decision comes at a time when the EPA is considering new ozone standards. The agency was on the verge of issuing a new rule in September 2011 but the White House rejected the proposal.

(Reporting by Lawrence Hurley; Editing by Howard Goller and Christopher Wilson)