The Bay Area Air Quality Management District has extended its air quality advisory for wildfire smoke in eastern Contra Costa County through Friday.
Smoke from the smoldering, six-week-old Marsh Fire is still impacting Pittsburg, Antioch, Oakley, and Brentwood. Daytime onshore winds are expected to disperse smoke, but as winds die down overnight localized pollution levels may rise during night and early morning hours.
Air district officials don't expect pollutant levels to exceed the national 24-hour health standard. A Spare the Air alert is not in effect and air quality is expected to be in the moderate range overall. The air district will be closely monitoring air quality throughout the region for smoke impacts from this and other fires.
The Marsh Fire started on May 28 in a Bay Point homeless encampment. After burning 500 acres, including 75 during a flare-up Saturday, the fire is now mostly burning peat, a spongy material formed by the partial decomposition of organic matter, usually plant material found in wetlands.
"The peat dirt is made up of decomposed materials that have accumulated over the course of many, many years," Contra Costa County Fire Protection District official Steve Aubert said.
Fire officials say peat fires are very difficult to extinguish, though this one is nearly out of fuel. They are considering flooding the marsh land where the fire originated, but in order to do so, they would need approval from a number of state and local officials, which doesn't happen quickly.
"You will still see smoke in the air. It’s still coming up, moving around," Aubert said. "It still has an odor to it. That will continue on until we're able to actually start flooding the property."
Air district officials said if the smell of smoke is present, it's important to avoid exposure. If possible, stay inside with windows and doors closed until smoke levels subside, if temperatures allow. It is also recommended that those impacted by smoke set their air conditioning units and car vent systems to re-circulate to prevent outside air from moving inside.
People can check for real-time air quality readings at http://baaqmd.gov/highs.
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