Ozone restrictions not enough
The us government has tightened federal air quality standards for smog-forming ozone, but not to the extent recommended by the us Environmental Protection Agency's scientific advisers.
The rules, which cover average concentrations of ground-level ozone, have lowered the current standard of 80-84 parts per billion (ppb) to 75 ppb. Air quality officials and environmental groups say the rules will hardly help protect the public or the environment from serious health hazards of smog.