Linn County Air Quality Division
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Response to USA Today Reports

Initial Response to USA Today Report on Air Toxics and our Schools

James Hodina, Air Pollution Control Officer
Linn County Public Health

*** Update: 1/27/2009 A presentation on the Linn County Air Quality and Air Toxics pertaining to the USA Today article is now available by clicking here ***

My name is Jim Hodina and I am the Supervisor of the Air Quality Division at Linn County Public Health.  We are staffed locally and work to represent the public health interests of the community in which we live.  It is our responsibility at Linn County Public health to monitor, assess, and protect our air quality and we are digging deeply into the information presented in the newspapers as well as the information we have collected on the matter.  We have been actively responding to the USA Today article and have begun our own independent analysis of the air toxics risks represented by the newspaper.

Based on our research to date, this is what we know about the USA Today study and how they came to ranking the health risk for our community, including our schools, so highly.  You may have read my quote in the Gazette on Tuesday that I question the outcomes of their analysis.  My basis for challenging the analysis is because I think USA Today used questionable techniques, not because I think pollutants in the air cannot be harmful.  We are currently performing an analysis using much better information and better analytical methods that include the source of the pollution, how it is released into the environment, and at what concentrations the public may be exposed.  We will certainly report this information when we have results but it will take us a little time to complete.

USA Today used data reported by industry to EPA on a variety of toxic pollutants that they release into the environment.  USA Today took the data submitted for 2005 and put this into a computer model called “Risk-Screening Environmental Indicators” or RSEI.  This computer model was run to estimate relative risk to the public from possible exposure to those pollutants.  This model was developed by EPA as a planning tool to be used by communities.  As the name implies, it is screening tool to help planners focus on areas of concern that might be most relevant.   The RSEI model’s results are only meant to be used in comparison with other model results and do not calculate a specific level of risk. EPA has more information posted on their website about this model at

The RSEI computer model requires a lot of information to determine how pollutants are dispersed into the environment.  The model determines a predicted concentration of the pollutant after it has been dispersed; it then calculates relative health risk based on the toxicity of the pollutant.  While the USA Today analysis has some good information on the toxicity of the pollutant it has very little information on how the pollutant is released from each facility into the environment.  Information on a facility smokestack (such as height, gas exit velocity, and gas temperature), local meteorological data (such as wind speed and direction) and topography are all critical factors in the evaluation of pollutant dispersion and human exposure.  Since USA Today did not have this information for each of the facilities in the study, they used default settings for all emission sources throughout the country.  The work Linn County Public Health is doing will use actual measured values for all of these parameters.

The RSEI computer model results ranking for many of the Cedar Rapids Community Schools is based on the release of manganese and manganese compounds reported by Cedarapids, Inc.  In 2005, Cedarapids Inc. reported the release of 776 pounds of manganese and manganese compounds as an “onsite fugitive release to air.”  The term “fugitive” means that it is not emitted through a smokestack.  I visted and inspected Cedarapids Inc. regarding the source of this release, which comes from the torch-cutting of metal inside their building.  Many industries in Cedar Rapids perform a variety of cutting and sanding in their facilities.  Much of this “dust” stays within the building and is cleaned up and disposed with the other solid waste generated at the facility.  A percentage though may still be emitted to the atmosphere through building ventilation.  Additionally, the release of a pollutant through a building vent is much different than a release through the smokestack or might be released from an outdoor storage pile.  These are all factors that we want to factor into our assessment, which USA Today did not.

The other important part of the analysis is assessing the toxicity of manganese and manganese compounds at the levels people are exposed.  EPA has a very extensive database called “IRIS” on chemical hazards, which is used in the RSEI model.  The following link will take you to the EPA website for the IRIS report on Manganese.

In summary, the EPA IRIS report states that manganese is considered essential to human health.  However, when inhaled at significant concentrations over a period of time, manganese has been demonstrated to cause neurological disorders.  The IRIS report also states that existing studies are inadequate to assess the carcinogenicity of manganese.  The few animal studies performed are suggestive of carcinogenicity at high or limited doses and cannot be considered conclusive. EPA lists the “Reference Concentration for Chronic Inhalation Exposure (RfC)” (e.g. a threshold at which no health affects are observed) to be 0.05 mg/m3 with a critical effect of “impairment of neurobehavioral function” and not classifiable as to human carcinogenicity.  The USA Today report indicates that their model results indicate a risk ranking for exposure to cancer-causing toxics is relatively high.  But based on this information, I cannot see how they came to this conclusion.

I recognize that I was technical in some parts of this email and may have glossed over other aspects as well.  Please contact me with any further questions.  I am very willing to speak personally with any person or group who is interested discussing this further.  We are continuing our work to provide more detailed analysis on this issue.  I will share the results as soon as they are complete, which we will post on our website at


Jim Hodina


James Hodina, QEP
Supervisor - Air Quality Division
Linn County Public Health