Once every five years, EPA is required by law to revise the national standards for ground-level ozone, a.k.a. smog. As the agency prepares its revisions, another scientific body has urged EPA to tighten the standard. In a letter to EPA administrator Stephen Johnson, a group of 111 medical scientists called for tighter rules on smog, according to BNA news service (subscription). The scientists point out the current standard allows exposures which can cause serious adverse health effects. This group of scientists joins two EPA science panels — the Children's Health Protection Advisory Committee and the Clean Air Scientific Advisory Committee — in recommending tighter standards. Considering the obvious consensus, EPA should revise the national smog standards to reflect the scientific recommendations. EPA's final decision is due in early 2008.