The high-pressure system building over the region won’t be strong enough to fend off some cool ocean air, but it will exact a typical nasty toll on Bay Area skies.
As the thermometer continued its slow climb upwards Thursday, the Bay Area Air Quality Management District issued a Spare the Air alert for Friday. It is expected to be the first day of the intense part of a heat wave that for much of the region is expected to peak on Saturday.
The air-quality forecast earlier in the week did not indicate dirty air.
“We anticipated the possibility of unhealthy conditions coming later in the week due to the increasing temperatures,” air district spokeswoman Tina Landis said. She added the district didn’t have confidence in the bad air conditions until Thursday.
Temperatures by Saturday are expected to be in the 100s in the far interior region, 90s in more centralized locations, and in the 70s and 80s closer to the coastal areas.
On Friday, some areas of the region are expected to have air with enough particulate matter that it will be unhealthy for sensitive groups. The air will come from concentrations of ground-level ozone pollution, the district said.
Officials said active children and adults and those with respiratory disease such as asthma should limit outdoor exertion.
The best air quality in the region on Friday will only be moderately healthy, according to the air district. Unusually sensitive people should avoid outdoor exposure in those circumstances.
According to the district, this will be the third Spare the Air day in 2023.