Shifting winds are expected to blow smoke from the Valley wildfire in Lake County into the North Bay and possibly other parts of the Bay Area on Thursday, air pollution officials warned.

People sensitive to smoke are advised to limit their time outdoors, keep doors and windows closed at home, and set air conditioners to recirculate, the Bay Area Air Quality Management District advised Wednesday.

Napa County is expected to be the first Bay Area location to get the smoke, but other counties may be affected as well, officials said.

The pollution district plans to set up extra monitors in the North Bay to check for smoke, and then report the concentrations at http://1.usa.gov/1iQiHUs on the web.

Tiny particles in smoke can trigger asthma attacks, cause eye and lung irrigation, and increase the risk of strokes.

Contact Denis Cuff at 925-943-8267. Follow him at Twitter.com/deniscuff.