Despite a canopy of haze over Marin yesterday, air quality has improved significantly since northeasterly winds began blowing smoke from a wildland fire in Napa and Yolo counties earlier this week, report air quality officials.
The 39,138-acre Rumsey fire is 80 percent contained, according to the state Department of Forestry and Fire Protection. It was expected to be fully contained this evening.
The spread of the smoke and small particle pollution it carried caused the Bay Area Air Quality Management District to issue a health warning Tuesday.
Children, seniors and anyone with respiratory problems were advised against going outside until the levels decreased.
The warning was lifted on Thursday.
“It’s improved vastly,” said Luna Salaver, a spokeswoman for the air quality district.
The level of small particle pollution dropped from 201 micrograms per cubic meters on Tuesday to a high of 55 and low of 31 yesterday, Salaver said.
Particulate levels must reach 65.5 to be considered unhealthy, Salaver said.
The fire began Sunday night in rugged terrain off Highway 16 near Guinda in Yolo County. The fire then spread to the Lake Berryessa area of Napa County. A voluntary evacuation order of 75 homes in that area was lifted Thursday.
Public health officials in Marin were not aware of health problems that may have been caused by the elevated pollution levels.