WILMINGTON, Del. (AP) - Delaware's air quality has continued its steady improvement, but the state still gets a failing grade for having high levels of ozone on hot and sunny days.
The News Journal reports the American Lung Association gave all three Delaware counties a grade of F for having too many high-ozone days.
The report showed some improvement, with the county of New Castle earning a C grade on particle pollution, an improvement upon last year's D grade. The other two counties received A's in that category.
State officials estimate as much as 90 percent of the chemicals that produce ozone in Delaware come from out-of-state sources that are upwind.
Doctors says people with ongoing health problems such as asthma and cardiovascular disease have a higher risk of ending up in the emergency room due to high ozone.
