The number of exceedances of National Ambient Air Quality Standards declined sharply in 2015 compared with 2014, due in large part to reductions in pollution emitted by Grain Processing Corporation's (GPC) corn-milling operations in Muscatine.
According to the Iowa Department of Natural Resources (IDNR) air quality report for 2015, 17 exceedances of the sulfur dioxide ambient air standards were recorded and 8 exceedances of the PM 2.5 (fine particulate) standard.
All 17 SO2 exceedances and one of the eight PM 2.5 exceedances occurred at Muscatine air monitors.
All of the Muscatine air quality exceedances occurred before GPC switched its boiler fuel from coal to natural gas and put in place new pollution control equipment as part of a court-approved consent decree with the Iowa Attorney General's office.
The vast majority of air pollution exceedances recorded in Iowa over the past five years occurred in Muscatine, with sulfur dioxide pollution the primary issue there and statewide.
The National Ambient Air Quality Standards (NAAQS) monitoring network is designed to alert the public about air pollution levels that may threaten their health. A "NAAQS exceedance" occurs when air pollution exceeds the threshold level where adverse health effects occur among "sensitive groups," including asthmatics, children and the elderly.
Muscatine's GPC was fined a record $1.5 million and ordered to cut air pollution emissions under a court-approved consent decree issued in March 2014 which settled a lawsuit filed by the Iowa Attorney General. The Muscatine firm, owned by Kent Corporation, announced a $100-million capital improvement program for the GPC plant after the lawsuit was filed.
The other exceedances in 2015 included three at Davenport air monitors (Hayes and Jefferson Elementary Schools) and involved fine particulate matter. Oer exceedances occurred in Clinton (Chancy Park and Rainbow Park), one in Iowa City (Hoover Elementary) and one in Cedar Rapids (Linn Public Health).
CLICK HERE to download a copy of the IDNR's annual report on air quality.
CLICK HERE to download the IDNR's long-term analysis of air quality issued in April.
