"Federal judges today upheld U.S. EPA's ozone air standard in a challenge from public health groups that said the agency ignored a scientific consensus pointing to a stricter limit."
"However, the U.S. Court of Appeals for the District of Columbia Circuit also sent EPA's secondary National Ambient Air Quality Standard, or NAAQS, back to the agency for review, holding that the agency erred in simply setting the secondary standard identical to the primary standard of 75 parts per billion.
The secondary standard is intended to protect public welfare, including vegetation, soil, water and related wildlife.
Environmental groups had pointed to documents that EPA's Clean Air Scientific Advisory Committee, or CASAC, provided to the agency before George W. Bush's administration set both standards at 75 ppb in 2008. CASAC recommended a primary standard of between 60 and 70 ppb."