LAKE COUNTY, Calif. – After air quality warnings were issued earlier in the week due to wildland fire smoke pouring into the air basin, local air quality officials reported that conditions on Friday are expected to be better.

Lake County Air Quality Management District said conditions are improving and good air quality is forecast once again for Lake County on Friday.

However, the district urged community members to exercise caution, as conditions can change rapidly.

District officials attributed the smoke and haze that degraded air quality this week to the Mill Fire in the Colusa County portion of the Mendocino National Forest.

The fire, burning since Sunday, had scorched nearly 19,000 acres by Thursday night, according to U.S. Forest Service officials.

Neighboring Mendocino County also is under air quality health alerts due to the fire.

Lake County Air Quality Management District reported that the fire resulted in ozone and particulate levels exceeding allowed state and federal health-based standards in the past two days on Wednesday and Thursday. The standards are designed to protect sensitive groups of the population from small respirable particulate, ultrafine inhalable particulate and ozone.

Smoky conditions such as those seen in Lake County this week can cause irritation of the eyes, nose and air passages, which can be hazardous in young children, the elderly, individuals with heart conditions or chronic lung disease such as asthma, bronchitis and other respiratory conditions.

Weather patterns – including sustained westerly transport winds – and the growing control of the Mill Fire resulted in improved healthful air beginning Thursday afternoon, according to the district.

However, residual haze and particulate from the wildfires can be expected to intermittently impact areas of Lake County until fire is out, the district reported.

Smoke impacts in Lake County are still possible, at times smoke can be transported to sea within a circulation cell, and then return back over Northern California in a wide band of smoke filled air, or the wind can shift due to changing weather patterns transporting smoke directly into the basin, according to the district.