2018 Air Quality Report

Executive Summary

This report presents a summary of air quality data collected throughout the State of Illinois during calendar year 2018. Data is presented for the six criteria pollutants (those for which air quality standards have been developed – particulate matter (PM10 and PM2.5), ozone, sulfur dioxide, nitrogen dioxide, carbon monoxide, and lead – along with some heavy metals, volatile organic compounds and toxic compounds. Monitoring was conducted at 63 different site locations collecting data from more than 150 instruments.

In terms of the Air Quality Index (AQI) air quality during 2018 was either good or moderate 92% of the time throughout Illinois. There were seven days when air quality was considered unhealthy (category red). This compares with one unhealthy day in 2017. The unhealthy days were due to elevated ozone concentrations in May, June, and July. There were 22 days (20 for ozone and two for fine particulates) when air quality in some part of Illinois was considered Unhealthy for Sensitive Groups (category orange). This compares with 27 Unhealthy for Sensitive Groups days reported in 2017. Air quality trends for most of the criteria pollutants are continuing to show downward or stable trends below the level of the standards.
Stationary point source emission data has again been included. The data in the report reflects information contained in Illinois EPA’s Integrated Comprehensive Environmental Management System (ICEMAN) as of December 31, 2018. Emission estimates are for the calendar year 2018 and are for the pollutants: particulate matter, volatile organic material, sulfur dioxide, nitrogen oxides, and carbon monoxide. Emission trends of these pollutants have been given for the years 1998 to the present. Emissions reported with the Annual Emissions Report have been provided starting with 1998 and are currently available through 2017. There has been a trend toward decreasing emissions over this time period.