They're urging people to carpool, take light rail or the bus.
"The number one thing people can do is reduce driving. 70% of our air pollution is caused by emissions from cars and trucks. We recommend that people take their lunch to work so they don't have to go out in the middle of the day and also use public transportation."
Jamie Arno is with the Sacramento Metropolitan Air Quality Management District.
She says you should also avoid using gas-powered yard tools, reduce household energy use and hold off on jogging or any other strenuous outdoor physical activity.
Today is only the second "Spare the Air Day" of the season. Arno says it's because we've had a relatively cool summer.
Tomorrow is not forecast to be a "Spare the Air Day".