CHEEC Seed Grants: FY 2001

Emission Estimation, Measurement, and Modeling of Ambient Ammonia Concentrations
PT O'Shaughnessy, KJ Donham, Department of Occupational and Environmental Health, G Carmichael, Department of Chemical and Biochemical Engineering, The University of Iowa

Assessment of Low-level Hydrogen Sulfide Exposure Among Wastewater Treatment Workers 
SJ Reynolds, Department of Occupational and Environmental Health, The University of Iowa; JC Johnson, Environmental Health Systems, Iowa City, Iowa

 


Emission Estimation, Measurement, and Modeling of Ambient Ammonia Concentrations 
Investigators: PT O'Shaughnessy, KJ Donham, Department of Occupational and Environmental Health, G Carmichael, Department of Chemical and Biochemical Engineering, The University of Iowa 
The profusion of swine confinements in Iowa has led to many areas in Iowa where local populations are continuously exposed to atmospheric ammonia, and other gases, generated by these facilities. The research for this pilot grant will center on collecting the data necessary for the development of ammonia-emission and dispersion models to determine the levels of ammonia in the vicinity of swine confinements. For this, sensitive analytical instruments are needed to measure the low levels (<1 ppm) of ammonia expected in the atmosphere. Studies will be conducted to establish the accuracy of several ammonia sampling instruments in the laboratory prior to application in the field. Field work will also include the sampling required to estimate ammonia emissions from a working swine confinement. A box model and plume dispersion model will be developed to relate emissions to expected ambient concentrations. Future work will then involve the development of a sophisticated three-dimensional combined meteorological and ammonia exposure model to estimate ambient ammonia given the various chemical reactions ammonia undergoes in the atmosphere.

Assessment of Low-level Hydrogen Sulfide Exposure among Wastewater Treatment Workers
Investigators: SJ Reynolds, Department of Occupational and Environmental Health, The University of Iowa; JC Johnson, Environmental Health Systems, Iowa City, Iowa 
Hydrogen sulfide (H2S) is a toxic gas generated in significant quantities from a variety of industrial processes, including wastewater treatment. Acute exposures to high levels of H2S (> 1000 ppm) have been fatal in many instances. Conflicting and sometimes inconclusive studies regarding the health effects associated with low level (<20 ppm) chronic exposure to H2S have led to increased interest in H2S both as an occupational and an ambient air pollutant. Very limited quantitative data exist on the longer-term low-level H2S exposures likely to be encountered everyday by workers in the wastewater treatment industry. By characterizing H2S exposures during specific tasks in four large and four smaller waste treatment facilities over an extended period, the study will collect information needed to conduct future risk assessments or epidemiological studies in order to characterize the health risks, if any, that may be involved in exposure to low concentrations of hydrogen sulfide. The study will also identify factors associated with potential high-level exposures.

Publication:  Lee A, Johnson J, Reynolds S, Thorne P, O'Shaughnessy P; Indoor and outdoor air quality assessment of four wastewater treatment plants. J Occup Environ Hyg. 2005; 3(1):36-43