I used to live in Riverside, CA, so I know how bad the smog can get. Here is the money quote:
It was the first time since the committee was established under the Clean Air Act nearly 30 years ago that the committee had asked the EPA to change course, according to EPA staffers and committee members.
"We're in uncharted waters here," acknowledged committee Chairwoman Rogene Henderson, an inhalation toxicologist. She said their action was necessary because "the response of the administrator is unprecedented in that he did not take our advice. It's most unusual for him not to take the advice of his own science advisory body."
See the entire article here.