Bay Area air quality officials have declared Wednesday a Spare the Air Day, meaning burning of wood products and other solid fuels is prohibited, indoors and out, for the 24-hour period.
It's the fifth Winter Spare the Air Day this year - all occurring in the past eight days, during which a high pressure zone overhead has created stagnant air conditions likely to trap soot particles close to the earth.
The Bay Area Air Quality Control District forecast the poorest air quality Wednesday in the North Bay area.
Conditions were expected to improve somewhat Thursday, according to the agency website.
More information is available at www.sparetheair.org.