The air in many parts of Southern Oregon is unhealthy to breathe this morning, according to the state Department of Environmental Quality.

The air in many parts of Southern Oregon is unhealthy to breathe this morning, according to the state Department of Environmental Quality.

Smoke from more than 100 fires burning near the California/Oregon border is expected to remain in the Rogue Valley for several days, officials say.

DEQ measuring stations at Medford's Grant and Belmont streets and in Shady Cove, Cave Junction and the Applegate Valley all recorded unhealthy levels of small particulates in the air this morning.

The stations record the amount of particulates in the air, and the DEQ rates pollution in its air quality index. A "green" ranking means the air is healthy to breathe. "Yellow" or "orange" is unhealthy for some groups and "red" is unhealthy for all groups.

Rankings this morning at the Medford, Shady Cove, Cave Junction and Applegate Valley stations were in the red zone.

When air quality reaches the red zone, the DEQ advises all people to avoid prolonged or heavy exertion outdoors. People with heart or lung disease, older adults and children can be particularly sensitive to particle pollution.

— Staff reports