The St. Louis ozone forecast is delivered daily from about Mid-May to Mid-September by KMOV Channel 4, The St. Louis Clean Air Partnership and the American Lung Association of Eastern Missouri. A hot, sunny, windless day, typical of St. Louis summers, provides an ideal environment for ozone formation. The final ozone forecast is issued at about 4:00 p.m. The final ozone forecast is broadcast on KMOV at about 5:15 p.m.

The Environmental Protection Agency monitors the St. Louis' air quality closely. When we surpass the clean air standards, or when we "exceed" specified air quality levels, an exceedance is recorded. If a certain number of exceedances are recorded, the region can be penalized. Exceedances usually occur on red days, but a red ozone forecast does not necessarily mean that we will exceed. When a red ozone day is forecasted, this means that unless the region takes action to reduce ozone-causing emissions, we will exceed. For data on air quality in past years, click here.

Here's the important part:
If the people of the region does take action, we can all positively impact air quality and keep the region from having dangerous ozone pollution levels.