The Marsh Fire has burned more than 500 acres near the shoreline of Bay Point and Pittsburg since May. The smoldering fire is now mostly consuming peat, a spongy material formed by the partial decomposition of organic matter, usually plant material found in wetlands.
Millions of gallons of water have been pumped into the area from the Delta and Contra Costa Water District diverting water at Mallard Slough since last week.
Smoke has been impacting the areas of Pittsburg, Antioch, Oakley and Brentwood.
The fire started May 28 near a Bay Point homeless encampment. It flared up more than a week ago and threatened PG&E lines and homes near Pittsburg before firefighters got it back under control.
The air quality advisory is not a Spare the Air alert, but people with sensitivities to smoke and other pollutants are advised to take precautions such as staying indoors with the windows and doors closed and using re-circulated air in vehicles when driving.
