2012 Air Quality Report

A Message from the Director

The Illinois EPA has published an Annual Air Quality Report for more than 40 years. Over these past decades, Illinois has made great strides in regard to improving air quality. Illinois air pollution control programs and regulations at both the national and state level have had a significant impact on bringing the state’s air quality to the levels we are experiencing today. While some portions of Illinois do fall short of a few of the current National Ambient Air Quality Standards (NAAQS), these areas have achieved compliance with the previous standards and are much closer to achieving compliance with the newly tightened standards than they were twenty, or even ten years ago.

Each day, representatives from the Illinois EPA issue an air quality forecast for fourteen sectors throughout the state. Those forecasts require the examination of current air quality levels, as well as meteorological conditions across the state. Air quality can change significantly as a result of several factors that include temperature, atmospheric pressure, precipitation, wind speed and even wind direction. Agency meteorologists review all of these factors along with modeling data to accurately provide the daily air quality forecasts. At times, representatives from multiple states within our region will consult with one another to determine forecasts.

States, and even regions, will periodically experience unusual weather patterns that will result in an elevated concern for air quality. For Illinois, and much of the country, 2012 was a notable year in terms of meteorology and its impact to air quality. As noted in the U.S. EPA write-up included on the inside cover, “weather is especially favorable for ozone formation when it’s hot, dry and sunny, and winds are calm and light.” In Illinois, high temperature records were broken throughout the state in 2012. For St. Louis Metro-East and Chicago, 2012 was the warmest year on record, and it was the second warmest recorded year in Springfield. The Metro-East region had 26 record highs broken or tied, with 23 consecutive days of 90+ degree temperatures and 10 consecutive days of 100+ degree temperatures. The Chicago region experienced record breaking weather early, registering the warmest March on record. The region’s summer season (June, July and August) had no days where more than one inch of rain was recorded. The seasonal rain total was just 6.63 inches compared to the normal 12.05 inches.

The 2012 Annual Air Quality Report reflects the extraordinary weather experienced throughout the year. As you will see in the executive summary, ozone levels resulted in multiple days at the Red or Unhealthy category according to the Air Quality Index. A higher number of Orange or Unhealthy for Sensitive Group days were also recorded in 2012. Although such levels do cause concern at the time they are experienced, 10-year air quality trends show that Illinois continues to make progress and improvements on air quality overall.

It is a goal of the Illinois EPA to provide residents with accurate and current air quality information. Individuals can view daily  air quality data through the Agency’s website. For additional question and/or comments regarding this report or other air pollution control programs, please contact the Illinois EPA.

Lisa Bonnett


Executive Summary

This report presents a summary of air quality data collected throughout the State of Illinois during the calendar year 2012. 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, nitrates, sulfates, volatile organic and toxic compounds. Monitoring was conducted at 75 different site locations collecting data from more than 170 instruments.

In terms of the Air Quality Index (AQI) air quality during 2012 was either good or moderate 86 percent of the time throughout Illinois. There were 11 days (all for 8-hour ozone) when air quality in some part of Illinois was considered unhealthy (category red). This compares with zero unhealthy days in 2011. There were 40 days (34 for 8-hour ozone and 6 for PM2.5) when air quality in some part of Illinois was considered unhealthy for sensitive groups (category orange). This compares with 31 Unhealthy for Sensitive Groups days reported in 2011. Air quality trends for the criteria pollutants are continuing to show downward or stable trends well below the level of the standards. Percentage changes over the ten year period 2003 – 2012 are as follows. 24-hour Particulate Matter (PM10) 8 percent decrease, annual Particulate Matter (PM2.5) 21 percent decrease, 1-hour Sulfur Dioxide 50 percent decrease, annual Nitrogen Dioxide 30 percent decrease, 8-hour Carbon Monoxide 48 percent decrease, Lead 5 percent decrease, and 8-hour Ozone 1 percent decrease.

Stationary point source emission data has again been included. The data in the report reflects information contained in the Emission Inventory System (EIS) as of December 31, 2012. Emission estimates are for the calendar year 2012 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 2011. In general there has been a trend toward decreasing emissions over this time period.