Environment News Service: Wildfires can hike ozone pollution to levels that violate U.S. public health and environmental standards, new research has determined. The study by scientists at the National Center for Atmospheric Research focused on California wildfires in 2007, finding that they repeatedly caused ground-level ozone to spike to unhealthy levels across a broad area, including much of rural California as well as neighboring Nevada. Fires worsen ozone levels by releasing nitrogen oxides and …