This is raw data. It has not been validated and may contain errors.

  1. The data is obtained from automated, continuous instruments; no human has reviewed or checked the accuracy of this data.
  2. The data has been subject to only preliminary automated quality assurance procedures.
  3. Special conditions such as power outages and equipment malfunction can produce data that is invalid.
  4. This data is made available for the purpose of public awareness and should not be used in any medical or other scientific study.
  5. Quality assured data can be obtained by contacting the Missouri Department of Natural Resources Air Pollution Control Program. 

Current Air Quality Index Reports

St. Louis


Kansas City

Rural Missouri

Users Guide

The Current Air Quality Index Report for Kansas City,  St. Louis and Springfield areas is updated hourly every day. All data is recorded using Central Standard Time, regardless of local time changes to daylight-saving time.

This report, using current real time data, is an approximation of the official Air Quality Index for today.  The official Air Quality Index, also known as AQI, for any day cannot be calculated until all air pollutant data for that day is available (approximately 8 a.m. the following day).

During the ozone season (April 1 to October 31) this real time Air Quality Index report is used as the basis for the Ozone Action Day programs in the St. Louis and Kansas City areas. An index of 100 represents a threshold level of pollution, which may cause health problems in normally healthy humans. However, sensitive individuals or highly active individuals may experience health effects at lower concentrations of pollutants.

Public Notice: The Air Quality Index is in transition.

The default Air Quality Index reports from the data acquisition system report the maximum ‘rolling 24-hour average’ PM10 and PM2.5 concentration over the 24-hour period as a surrogate for the Air Quality Index. These Air Quality Index values may differ from the 24-hour average of the discrete hourly concentrations monitored midnight to midnight on a given day.

The new ozone Air Quality Index regulation is in place for the 2008 ozone season.

Revised 2008 8-Hour Ozone Standard Boundary Recommendation

Revised 2008 8-hour Ozone Standard Boundary Recommendation (12/11)

On Sept. 22, 2011, the U.S. Environmental Protection Agency released a memorandum to clarify for states the status of the 2008 Ozone National Ambient Air Quality Standard. In this document, EPA explicitly stated that the current standard is 0.075 parts per million, or 75 parts per billion. EPA also announced their intentions to move forward with designations under the 2008 National Ambient Air Quality Standard, starting with the recommendations made by states in 2009, and then updating them with the most current, certified air quality data from the 2008 to 2010 monitoring period.   

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