Environmental Services Program

Missouri Air Quality Index Reports

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.

Due to recent changes in the 2.5 particulate National Ambient Air Quality Standard and the time required to develop and formally adopt a new Air Quality Index regulation, the legally required 2.5 Air Quality Index posted here does not reflect the current scientific understanding of air quality health effects. As soon as a new 2.5 Air Quality Index regulation is adopted by the U.S. Environmental Protection Agency, the "official" Air Quality Index and the estimate posted here will be modernized. 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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