The Orchard Farm air monitoring station is located downwind of St. Louis. It helps to characterize ozone concentrations downwind of the St. Louis area and determine exposure to ozone of the population of the St. Louis Metropolitan Statistical Area and monitor attainment or nonattainment of the ambient air quality standards.
Pollutants
Ozone Pollutant
The primary National Ambient Air Quality Standard for ozone is 0.070 parts per million averaged over eight hours (annual fourth-highest daily maximum 8-hour concentration, averaged over three years). The federal ozone season for monitoring runs from March 1 to Oct. 31.
Departmental information about ozone (O3)
- Description
- Health effects
- Tips to reduce ozone
- 2008 and 2015 standards plus related documents
- Eight-hour ozone design values
- Four highest eight-hour ozone values from beginning of ozone season
- Running list of sites with exceedances from beginning of season
- Monthly number of exceedances, 2022 and 2023
- Daily maximum average eight-hour concentration for each site from beginning of season
- Map of Missouri's ozone monitoring sites
Technical issues can affect ability to deliver quality data. Access a table of symbols with explanation of the problems they represent.
- "P" stands for primary monitor. "S" stands for secondary monitor
- Data from 10 days ago through current date
- Central Standard Time
- Concentrations of pollutant in parts per million (ppm)
2165 Hwy V
St. Charles, MO 63301
United States
Air Pollution Control Program
Division of Environmental Quality
P.O. Box 176
Jefferson City, MO 65102-0176
United States