Pleasanton and the Tri-Valley are expected to see a near-record-high temperature of 106 degrees today in what the National Weather Service says could be the last of the 100-plus-degree days of the year.
The continued hot weather prompted the Bay Area Air Quality Management District to announce a second Spare the Air alert this summer. Officials announced that regional air quality and ground level ozone or smog will continue to reach levels considered unhealthy today, according to the air district.
For Wednesday, the temperature in the Tri-Valley will moderate to a high of "only" 99 degrees. Temperatures will then start dropping significantly with highs in the 70s by Friday and a high predicted for Sunday of only 69 degrees.
The record high for today was 107 degrees in 1932.
A strong ridge of high pressure off the California coast is credited with this week's warming trend, after a summer in which unusually cool temperatures have preempted the need to declare any Spare the Air alerts until today, said Air Quality District spokeswoman Kristine Roselius.
"We've been very lucky this year," Roselius said. "By this time last year we'd had 10 Spare the Air alerts."
Those in the Tri-Valley are urged to take public transportation, avoid grilling food outside and try not to use aerosol products such as hairspray.
"We're really encouraging people to carpool whenever possible and limit time on the road," Roselius said.
Smog is known to cause throat irritation and chest pain, and can be particularly harmful for young children and seniors, who are urged to stay inside and avoid strenuous physical activity during active Spare the Air alerts.