The Bay Area Air Quality Management District has issued a "Spare the Air" alert for Thursday because of elevated levels of smog expected in the region.

The alert is the first issued in 2023 by the air district for smog, otherwise known as ozone. Light winds and temperatures expected in the 80s for most of the Bay Area are expected to combine with motor vehicle exhaust to create unhealthy air quality.

It's a shift from the hazy skies seen near Downtown San Francsico on Tuesday which the agency attributed to gusty winds stirring up salty air and did not deem a threat to air quality.

Smog can cause throat irritation and chest pain and is considered particularly harmful for children, seniors and people with respiratory and heart conditions. On "Spare the Air" days, people are encouraged to only do outdoor exercise in the early morning hours when smog levels are lower.

"As temperatures heat up and our roadways become increasingly crowded, air quality is expected to be unhealthy," air district Executive Officer Philip Fine said in a statement. "This Spare the Air highlights the need to reduce cars on our roadways and find alternatives to driving alone such as taking transit, working remotely, walking or biking."

People can find out when a "Spare the Air" alert is in effect by registering at sparetheair.org, calling 800-HELP-AIR (800-435-7247), downloading the Spare the Air app or connecting with Spare the Air on Facebook or Twitter.