Address: General Electric store, Highway 94,
               next to fire station
               West Alton, MO 63386
County: St. Charles
Date established: Nov. 1, 1968
Pollutant monitored: Ozone (O3)
Pollutants no longer monitored: nitrogen dioxide (NO2); sulfur dioxide (SO2), particulate matter (PM10) and fine particulate matter (PM2.5)
For information, go to dnr.mo.gov/sunshinerequests.htm.
Site coordinates
   * Latitude: 38.8725°
   * Longitude: -90.226389°

Ozone (O3) Data*

Weekly summary of preliminary data from all ozone sites

  • Eight-hour ozone design values
  • Four highest eight-hour ozone values since beginning of ozone season
  • Information on exceedances
  • Map of ozone monitoring network
  • Daily eight-hour average maximums since beginning of ozone season

Preliminary one-hour averages from West Alton

  • Ozone data in third and fourth columns. "P" stands for primary monitor. "S" stands for secondary monitor
  • Data from 10 days ago through current date
  • Central Standard Time
  • Concentration of ozone in parts per million (ppm)

Preliminary eight-hour forward-rolling averages from all ozone sites

  • Hourly data equal to average of that hour and the following seven hours
  • Data from 10 days ago through current date
  • Central Standard Time
  • Concentration of ozone in parts per million (ppm)

Preliminary one-hour ozone averages from all sites

  • Data from 10 days ago through current date
  • Central Standard Time
  • Concentration of ozone in parts per million (ppm)

Department's webpage about ground-level ozone
   • Description
   • Health effects
   • Tips to reduce ozone
   • 2008 and 2015 standards plus related documents

Graph of design values for ozone sites in the St. Louis area, beginning in 2003

*Technical issues can affect ability to deliver quality data.
Access a table of symbols indicating technical issues

Related Links

Missouri's network of air monitoring sites on interactive map

National standards for pollutants

Real-time views from cameras in Kansas City, St. Louis

Department's webpage about air quality
   • Air quality forecasts for St. Louis, Kansas City and Springfield during ozone season: March 1 through October 31
   • Tips for improving air quality
   • Tips for breathing better when air quality is forecasted to be unhealthy for sensitive groups (orange) or unhealthy (red)

Daily Air Quality Forecast (AirNow) gives forecasts for cities nationwide

EPA Air Toolbox for Citizen Scientists

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