EPA is restarting review of a high-stakes decision on ground-level ozone standards in a step that short-circuits the prospects for any imminent action to tighten limits on the lung-damaging pollutant.

EPA has rounded out a panel of scientific advisers to aid in a new review of its ground-level ozone standards, marking a key step in the assessment of a particularly far-reaching air pollution ...

Colorado’s Front Range recorded fewer days with high levels of ozone pollution over the summer than in recent years, but environmentalists warn the region can’t rely on favorable weather conditions to ...