All 32 exceedances of national air quality standards in Iowa so far this year have been recorded in Muscatine.
The National Ambient Air Quality Standards (NAAQS) are levels of pollution considered "harmful to public health and environment," and include air pollutants ozone, sulfur dioxide, carbon monoxide, nitrogen oxide, lead and particulate matter.
As of Nov. 9, the air quality standard for sulfur dioxide (SO2) in Muscatine was exceeded 30 times and twice for particulate matter of less than 2.5 microns (PM2.5).
On April 3, the Musser Park monitor in Muscatine recorded SO2 concentrations reaching 323 parts per billion, resulting in an Air Quality Index (AQI) for that day of more than 200.
An AQI greater than 200 is defined as "very unhealthy," and would "trigger a health alert signifying that everyone (not just sensitive groups such as children, older adults and those with lung disease) may experience more serious health effects," according to the U.S. Environmental Protection Agency (EPA) AirNow web site.
However, the Iowa Department of Natural Resources (IDNR) did not issue any public warnings on the high SO2 pollution levels April 3, or for any subsequent exceedances in Muscatine.
IDNR officials said the state has issued warnings (related to PM2.5 levels) in the past because those involved regional air masses, while the Muscatine SO2 levels affected a much smaller area.
The Iowa Environmental Commission last April recommended action against Grain Processing Corporation (GPC) of Muscatine for failing to obtain needed air pollution permits and failure to comply with the emission limits of air quality construction permits. The Iowa Attorney General's office has yet to act on the commission recommendation.
The company announced in May it plans to spend $100 million over the next five years to lower emissions of sulfur dioxide (SO2) and fine particulate matter of less than 2.5 microns (PM 2.5).
CLICK HERE to download Iowa Air Quality Exceedance Report of Nov. 9
CLICK HERE to learn more about the Air Quality Index (AQI)
