Spare the Air Alert extended through Thursday

The ozone in the lowest levels is expected to be unhealthy at times on Thursday.

As the thermometer has gone up again, so, too, have the number of Spare the Air alerts.

On Wednesday, the Bay Area Air Quality Management District added the sixth alert of 2024 to the calendar. An alert already out for Wednesday was extended through Thursday.

The ozone in the lowest levels of the atmosphere is expected to be at times unhealthy for sensitive groups, including those who are very young, elderly, or who have health conditions, health officials said. The air throughout the region is expected to be mostly moderately healthy Thursday, as it is on Friday.

The extension of the alert through Thursday comes as the final blast of heat bakes the region. It’s coming from a high-pressure ridge that made temperatures exceedingly hot last week and is building again. That heat wave has shattered records since the system first hit the region on July 2.

Temperatures were expected to peak between 104 and 107 degrees on Wednesday in the hottest areas, according to the National Weather Service. In other areas, not quite as far in the interior, the weather service said the gauge would run from 95-100. The hotter areas along the bay coast and in the Peninsula will peak in the low-to-mid 80s, and San Francisco will get into the 70s.

The weather service issued an excessive heat warning that began at 11 a.m. Wednesday and runs through 8 p.m. Friday. The East Bay hills and interior valley areas, San Jose and the Santa Clara Valley, the Eastern Santa Clara hills, and the North Bay interior mountains all fall within the boundaries of the warning.