A U.S. District Court of Appeals has ruled that the EPA must reconsider a 2006 decision on national soot –or particulate matter—standards. The American Lung Association sued the agency when it decided to keep those standards at 1997 levels. Association spokeswoman Janice Nolan says her organization believed those levels were unsafe for human health.“EPA had said that the standard since 1997 was fine, despite the fact that there was plenty of evidence and unanimous scientific opinion that it was not, and that we needed to have a much, much lower level," says Nolan.The EPA is required to review certain air quality standards regularly. But the agency has failed to keep many of those reviews on schedule.