BISMARCK, N.D. (AP) -- The American Lung Association has given North Dakota high marks for air quality but the group says ''it's a mistake to presume there is no air pollution in the state.''
The group's says data was collected at air quality monitors in eight of the state's 53 counties.
All eight counties were given an ''A'' grade for ozone pollution, and six of the eight counties earned an ''A'' grade for particle pollution.
Ozone is a leading component of smog and comes from vehicle exhaust and solvents. Fine particle pollution comes from burning things such as coal and wood and can cause haze.
Association spokesman Robert Moffit says coal-fired power plants and the rapid development of North Dakota's oil patch are contributing to air pollution in the state and the region.