This report presents a summary of air quality data collected throughout the State of Illinois during calendar year 2016. Data is presented for the six criteria pollutants (those for which air quality standards have been developed – particulate matter (PM
10 and PM
2.5), ozone, sulfur dioxide, nitrogen dioxide, carbon monoxide, and lead – along with some heavy metals, volatile organic compounds and toxic compounds. Monitoring was conducted at 64 different site locations collecting data from more than 140 instruments.
In terms of the Air Quality Index (AQI), air quality during 2016 was either good or moderate 92% of the time throughout Illinois. There were two days when air quality was considered unhealthy (category red). This compares with one unhealthy day in 2015. The unhealthy days were due to elevated ozone concentrations in June and July. There were 27 days (all due to ozone) when air quality in some part of Illinois was considered Unhealthy for Sensitive Groups (category orange). This compares with five Unhealthy for Sensitive Groups days reported in 2015.
Air quality trends for the criteria pollutants are continuing to show downward or stable trends well below the level of the standards. Examples of percentage changes over the ten-year period 2007-2016 are as follows: annual particulate matter (PM
2.5) 21% decrease, 1-hour sulfur dioxide 69% decrease, annual nitrogen dioxide 31% decrease, 8-hour carbon monoxide 58% decrease, and 8-hour ozone 1% decrease.
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, 2016. Emission estimates are for the calendar year 2015 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 2015. There has been a trend toward decreasing emissions over this time period.