Officials with the Sacramento Metropolitan Air Quality Management District say the air is "unhealthy for sensitive groups". But it's not bad enough to prompt a "Spare the Air Day."
Meanwhile, experts say - try to limit your exposure to the sun if you're going outside.
Doctor Angelica Ha is with Kaiser Permanente Roseville Medical Center:
"The FDA recently has recommended new changes in the labeling of sunscreen. So we do recommend a sunscreen that says 'broad spectrum' which includes protection against UVA and UVB rays. And then it's very important that people remember to reapply their sunscreen every two hours."
The National Weather Service forecasts another hot day Wednesday with highs around 100-degrees. But temperatures are expected to return to the low 90s on Thursday.