"Wildfire Smoke Chokes Bay Area: Northern California and Oregon Fires Cause Air Quality Concerns"

The Bay Area is experiencing unhealthy air quality due to smoke from wildfires in California and Oregon, prompting the extension of a Spare the Air Alert until Friday. The National Weather Service canceled a Red Flag Warning for Napa and Sonoma counties, but it may take until Friday for air quality to improve. PG&E has raised the possibility of power shutoffs in Napa County, affecting only seven customers. Experts recommend staying indoors, keeping windows closed, and using N-95 masks to protect against the smoke. Air purifiers and indoor air quality monitors are also recommended. The poor air quality has led to the cancellation of sports practices and adjustments in schools and businesses in the Bay Area.