Bay Area Air Quality Management District spokeswoman Lisa Fasano said the air district has been receiving calls from people who report smelling smoke, but so far the district's air monitors have not detected air pollution levels above the federal air quality standards.
Levels of particulate matter in San Francisco, San Jose and Napa, however, were beginning to approach levels considered dangerous by the Environmental Protection Agency this morning, Fasano said.
Large amounts of smoke remain in the upper atmosphere, which has been causing the hazy skies in the region, but as winds shift, some of that smoke has been coming back down and mixing with ground-level air. Some of the smoke may also be blowing over from the fires themselves.
The amount of smoke people can smell at the ground depends on the wind, which has been unpredictable, Fasano said.
People who smell or see smoke should limit outdoor activity and those who are particularly sensitive to air pollution should stay inside with the air conditioner on re-circulation, Fasano said.
The air district will issue an air quality advisory if pollution reaches unsafe levels.
Meanwhile, firefighters have taken advantage of favorable weather over the last week to make significant progress in containing the fires still burning. Of the 2,093 fires started by the June 20 thunderstorm, only 27 are still active, Cal Fire reported today.
The fires have burned more than 1 million acres and involved the efforts of more than 12,000 firefighting personnel, including assistance from agencies across the state, nation and from several foreign countries, Cal Fire said.
There have been 158 residences destroyed by the fires, along with one commercial building and 139 outbuildings, Cal Fire said.
Areas of Trinity and Humboldt counties are still under evacuation orders at this time, while voluntary evacuation orders currently exist in certain areas of Monterey and Siskiyou counties.