Inland Mendocino County, from Covelo to the Ukiah Valley, was blanketed in a haze of forest fire smoke Wednesday, prompting health and air quality officials to issue health warnings.

Air quality, especially in the Covelo region where wildfires continue to rage, had reached pollution levels considered hazardous, according to the Mendocino County Air Quality Management District. The fire has burned 32,675 acres in 12 days.

The agency advises residents in smoky areas to stay indoors as much as possible, close all doors and windows and turn air conditioners to recirculation mode.

"I would definitely curtail my (outdoor) exercise, especially anyone with any kind of pulmonary problems," said Mendocino County Public Health Officer Craig McMillan.

Covelo is closest to the fires and is experiencing the highest pollution concentrations, but winds have pushed the smoke as far south as Cloverdale and then east to southern Lake County, officials at the Lake County Air Management District reported.

Lake County's air remains at healthy levels, officials said.