ST. LOUIS – On the heels of Memorial Day weekend, there could be concerns about the air quality for some around the St. Louis region.

The City of St. Louis and many nearby counties are under an “orange” air quality rating on Tuesday from 10 a.m. to 8 p.m., according to the National Weather Service.

The “orange” rating is based on the U.S. Air Quality Index, which means the index values are between 101 and 150. During such advisories, health experts say members of sensitive groups may experience health effects, but the general public is less likely to be affected.

When an “orange” rating is deemed, certain populations should consider precautions or limits with their outdoor activities. That may include, but not be limited to, people with lung diseases, older adults, children and people who are active outdoors.

According to the National Weather Service, an orange air quality forecast “means that maximum ozone concentrations are expected to reach levels that pose a health risk. Adverse health effects increase as air quality deteriorates. Ground-level ozone is an air contaminant which can cause breathing difficulties.”

The National Weather Service has been warning of the developing air quality situation since Sunday. The Missouri Department of Natural of Resources has reported “moderate” air quality, or the stage right before orange, in St. Louis for several consecutive days.

Meanwhile, the clean air partnership urges people to switch up their commutes to help with air quality, whether taking public transit, carpooling, vanpooling, walking, biking or telecommuting.