With temperatures expected to get into triple digits this weekend, the Bay Area Air Quality Management District issued the first and second Spare the Air Alerts for smog in 2018. Air quality is forecast to be unhealthful Friday and Saturday.
The National Weather Service forecasts the Napa to hit 95 degrees on Friday, 102 degrees on Saturday, then drop to 86 degrees on Sunday. The Upvalley is expected to be hotter, with Friday reaching 101 degrees, Saturday 104 degrees and Sunday 92 degrees.
Light winds combined with high temperatures and exhaust from motor vehicles are expected to cause unhealthful ozone accumulation in the Bay Area.
The Weather Service has issued a heat advisory for Saturday from 11 a.m. to 8 p.m.
Concentrations of ground-level ozone pollution are harmful to breathe, especially for young children, seniors and those with respiratory and heart conditions, according to the District.
Residents are encouraged to reduce driving Friday and Saturday, and outdoor exercise should be done only in the early morning hours when ozone concentrations are lower.