A Spare the Air alert will be in effect throughout the Bay Area on Saturday and Sunday, due to high ozone concentrations that nudge into the unhealthy range.
The alert, issued by the Bay Area Air District, falls on the weekend of Hardly Strictly Bluegrass, the major outdoor festival in San Francisco. Hot weather is expected on both weekend days.
Concentrations of ozone are forecast to remain moderate in much of the North Bay as well as the South Central Bay, but they will tip into the “unhealthy for sensitive groups” range in the Coast and Central Bay zone (which includes San Francisco); the East Bay; and the Santa Clara Valley. Groups with respiratory sensitivities, including children, should be particularly careful to limit their time outside…