For the first time, Pima County, Arizona is violating federal rules governing the noxious, lung-scarring pollutant ozone, local officials say.

Preliminary data show ozone levels at one of the county’s air monitors violates federal standards regulating the air pollutant. The monitor is at Saguaro National Park-East, on Tucson’s far east side.

That means that on some days in a part of the community, our air is bad enough to potentially cause major health problems for children, older adults and people of all ages with existing respiratory problems.

Legally, continued high ozone levels could put the Tucson area at risk of being designated in formal noncompliance with federal rules from the Environmental Protection Agency, a local planning agency says. That would make it harder for the region to spend federal dollars for needed transportation projects unless the air quality improves, says the Pima Association of Governments.