Air district officials extended a Spare the Air alert through Tuesday and urged Bay Area residents to avoid driving during the holiday weekend to lessen the buildup of smog.
The air alert for smog is paired with an air quality advisory for smoke that's also extended through Tuesday, the Bay Area Air Quality Management District said.
A combination of high temperatures, vehicle exhaust and wildfire smoke are expected to increase smog, or ozone accumulation.
Many Bay Area residents were able to enjoy Labor Day under clear skies. But even as families gathered at parks and other public spaces, the downside to a Spare the Air alert in effect remained.
"Ozone pollution builds up from vehicle exhaust and high temperatures," explained Tina Landis, Bay Area Air Quality Management District PIO.
This combination is bad for people's lungs.
"If you're planning to go for a bike ride or a jog, or even a hike, try to do it in the morning hours or evening, when the temperatures are cooling down," Landis said.
If possible, residents should stay inside with windows and doors closed until smoke levels subside, if temperatures allow. When it's too hot indoors, people should visit an air-cooling center or other building that provides filtered air.
The air district also recommends that people impacted by smoke set air conditioning units and car vent systems to re-circulate to prevent outside air from moving inside.
Air quality readings are available at baaqmd.gov/highs .
To find out when a Spare the Air Alert is in effect, residents can sign up for text alerts by texting the word "START" to 817-57, register for email AirAlerts at www.sparetheair.org, call 1(800) HELP-AIR, download the Spare the Air App or connect with Spare the Air on Facebook or Twitter.