Illinois Annual Air Quality Report

Illinois Annual Air Quality Report 1998

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A Message from the Director

Since 1970, the Clean Air Program at the Illinois Environmental Protection Agency (EPA) has been working to combat air pollution. To comply with the federal Clean Air Act and its amendments, the Agency issues permits to air pollution sources and works to reduce air pollutants. Clean air efforts have progressed to creating partnerships that encourage both voluntary pollution-reducing activities and that promote preventing pollution before it starts.

Our remaining major air pollution problem affects a substantial portion of Illinois' population. Both the Chicago and East St. Louis metropolitan regions still do not meet the federal air quality standard for ozone (smog), which is associated with human respiratory problems as well as ecosystem damage. There were eight occurrences of unhealthful air quality in one or more portions of Illinois during 1998-seven due to ozone and one due to particulate matter-compared with six in 1997 and eight in 1996.

Although this document shows that the trend in Illinois air pollution has been a steady decrease in emissions, there is still much to do to ensure that our residents enjoy the best air quality possible. Recent efforts to combat ozone include asking residents and businesses in the Chicago ozone non-attainment areas for help by voluntarily altering their activities that contribute to ozone formation on Ozone Action Days.

This 28th Annual Air Quality Report highlights information obtained in 1998 from the Bureau of Air's statewide air monitoring network, which incorporates more than 300 monitors that track the measurements of a variety of pollutants and air toxic compounds.

We hope you find this report helpful. We welcome any comments or questions you may have so that we can better address your information needs.

Thomas Skinner
Director

Executive Summary

This report presents a summary of air quality data collected throughout the state of Illinois during calendar year 1998. Data is presented for the six criteria pollutants (those for which air quality standards have been developed -- particulate matter, ozone, sulfur dioxide, nitrogen dioxide, carbon monoxide, and lead) along with some heavy metals, nitrates, sulfates, volatile organic compounds and PM_2.5. Monitoring was conducted at more than 100 different site locations collecting data from more than 200 instruments.

In terms of the Pollutant Standards Index, air quality during 1998 was either good or moderate more than 98 percent of the time throughout Illinois. There were four days statewide that exceeded an air quality standard for any pollutant -- one for particulate matter and three for ozone. These exceedances occurred in Cook, Jersey and St. Clair counties (ozone) and LaSalle County (particulate matter). Air quality trends for the criteria pollutants are continuing to show downward trends or stable trends well below the level of the standards.

In 1998 monitoring was conducted at 10 locations in Cook and Madison counties for PM_2.5 (fine particulate matter of size less than 2.5 microns). In July 1997 the U.S. EPA finalized new ambient air quality standards for particulate matter that included the fine particulates as measured by PM_2.5. The monitoring network to fully assess these standards will be phased in during 1999 and 2000.

Stationary point source emission data has again been included. The data in the report reflects information contained in the Emission Inventory System as of Dec. 31, 1998. Emission estimates are for the calendar year 1998 and are for the following pollutants: particulate matter, volatile organic material, sulfur dioxide, nitrogen oxides and carbon monoxide. Emission trends of these pollutants has been given for the years 1981 to the present. Emissions reported with the Annual Emissions Report have been provided starting with 1992. In general there has been a trend toward decreasing emissions over this time period.