The Washington State Department of Ecology has issued a burn ban for Franklin and Columbia counties until at least 10 a.m. Sunday.
A burn ban earlier was issued for Walla Walla County because of poor air quality caused by stagnant weather condition.
All outdoor burning is prohibited. In addition, uncertified fireplaces, wood stoves and inserts are prohibited unless they are a home’s only adequate source of heat.
Benton County is under the authority of the Benton Clean Air Agency, which has asked that residents curtail the use of indoor wood heating unless it is the only source of heat.
Benton County air quality was rated as unhealthy for sensitive groups Wednesday.
Infants, children, adults older than 65, pregnant women and those who have had a stroke or have heart or lung disease, asthma or diabetes should limit time spent outdoors, according to the Department of Ecology.