A Spare the Air alert has been issued for today in the Bay Area as heat, light winds and automobile exhaust combine for an unhealthy level of smog.
The alert is the 23rd this season.
Smog, or ozone, can irritate throats, cause congestion and chest pain, trigger asthma, inflame the lining of the lungs and worsen bronchitis and emphysema, air quality district representatives said. Long-term exposure can damage the lungs.
Smog can be particularly harmful to young children, seniors and people with respiratory and heart conditions, according to air quality
Also today, a red flag warning is in effect for the North Bay mountains until this afternoon because of hot, dry weather and gusty winds expected in the area, National Weather Service officials said.
The warning is an alert to the potential for extreme wildfires and is in effect until 3 p.m. for all elevations above 1,000 feet.
Sustained northeast winds of about 38 mph are expected through this morning over Napa and eastern Sonoma counties, the areas of greatest
concern, according to weather officials. Winds may gust up to 55 p.m.
The winds will follow and precede warm to hot daytime temperatures and the nighttime humidity won't restore moisture to areas that dry out
during the day.
Any fires that begin will likely spread rapidly, weather officials said.
Winds will generally be lighter after today.