Illinois Annual Air Quality Report

Illinois Annual Air Quality Report 2005

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A Message from the Director

Air quality in Illinois was either good or moderate 90 percent of the time throughout Illinois in 2005. This is a decrease from 2004; however, it is consistent with the air quality trends the state has experienced in the past. Air quality trends show air pollution well below the level of the standards on a statewide basis.

In 2005, Illinois as well as other Midwestern and Northeastern states experienced one of the most unusual air quality episodes in recent history. For the first time in Illinois, Air Pollution Action Days were called outside of the ozone season (May through September), with 3 action days being called for February 2nd, 3rd and 4th due to elevated levels of fine particulate matter (PM2.5). This unusual episode provided the Illinois EPA with the opportunity to thoroughly discuss fine particulate matter with the media in the Northeastern region of the State, which led to the beginning of educating the public about this unfamiliar pollutant.

The graphic used on the cover of this report is a snapshot of the Midwest on February 4, 2005. That was the third consecutive day when fine particulate matter levels in most metropolitan areas reached the orange “unhealthy for sensitive groups” or red “unhealthy” category according to the Air Quality Index. Scientists determined that a combination of a stagnating regional air mass and region wide winter fuel combustion was the main cause of this incident.

The 35th Annual Air Quality Report consists of data collected from a large network of air monitoring equipment throughout the State of Illinois. The Illinois EPA operates and maintains more than 80 air monitoring sites featuring over 200 instruments, which measure air pollutants and toxic compounds.

While annual trends show the statewide levels well below the federal standards, there are still some areas in Illinois that do not meet these standards. The Illinois EPA continues its commitment to improve air quality throughout the State and the region.

The 2005 Annual Air Quality Report has been developed to provide information to businesses, organizations and individual citizens. The Illinois continue our commitment to work further with individuals, businesses and industry to build on our past successes and continue environmental gains in Illinois. Please contact the Illinois EPA with comments and/or questions regarding this report or air pollution control programs.

Douglas P. Scott
Director

Executive Summary

This report presents a summary of air quality data collected throughout the State of Illinois during the calendar year - 2005. 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 over 80 different site locations collecting data from more than 200 instruments.

In terms of the Air Quality Index (AQI) air quality during 2005 was either good or moderate more than 90 percent of the time throughout Illinois. There were 2 days (all due to ozone) when air quality in some part of Illinois was considered Unhealthy (category Red). There were 32 days (25 for 8-hour ozone and 13 for PM2.5, 6 days were high for both ozone and PM2.5) when air quality in some part of Illinois was considered Unhealthy for Sensitive Groups (category Orange). This compares with 7 Unhealthy for Sensitive Groups days in 2004. Air quality trends for the criteria pollutants are continuing to show downward trends or stable trends well below the level of the standards. Percentage changes over the ten year period 1996 – 2005 are as follows: Particulate Matter (PM10) 2 percent decrease, Sulfur Dioxide 33 percent decrease, Nitrogen Dioxide 14 percent decrease, Carbon Monoxide 25 percent decrease, Lead 36 percent decrease, and Ozone 15 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, 2005. Emission estimates are for the calendar year 2005 and are for the pollutants: particulate matter, volatile organic material, sulfur dioxide, nitrogen oxides and carbon monoxide. Emission trends of these pollutants has been given for the years 1996 to the present. Emissions reported with the Annual Emissions Report have been provided starting with 1996 and are currently available through 2004. In general there has been a trend toward decreasing emissions over this time period.