| June 16, 2005 | |
| Sacoby Wilson presents his doctoral dissertation final oral defense on June 16 at 1:30 PM in the Ibrahim Seminar Room (1301 McGavran-Greenberg).Full details follow:
Environmental Monitoring and Spatial Assessment of Atmospheric Ammonia Levels Near hog CAFOs and Human Receptor Sites in Eastern North Carolina Hog concentrated animal feeding operations (CAFOs) release contaminants to the atmosphere including ammonia (NH3), hydrogen sulfide, VOCs, and particulate matter. Most of these operations are found in the coastal plain of the state and can create potential health hazards for nearby human populations. Limited work has been performed to measure, map, and estimate NH3 at the community level to assess potential human exposure. In an effort to address this issue, a study was designed to characterize NH3 levels near hog CAFOs and human receptor sites in Eastern North Carolina. NH3 data was collected using passive diffusion tubes in triplicate set out at twenty sites for one week at a time. Sampling occurred continuously from occurred from October 2003 to May 2004 and from July 2004 to October 2004 at twenty-three sites setup at varying distances from a hog CAFO in close proximity to human receptor sites. Average weekly NH3 levels measured as mass (5g NH3-N) near human receptor locations were significantly higher than normal background levels (less than .03 5g NH3-N ) and reached as high as 3 5g NH3-N. The data also revealed that exposed sites (less than 2 km from a hog CAFO) had significantly higher levels than reference sites (greater than 2 km from a hog CAFO). Statistical analyses confirmed that source-related terms such as distance to a hog CAFO and liveweight per operation and temperature, wind speed, wind direction were important predictors of NH3. The study further demonstrated that passive sampling in conjunction with GIS methodologies could effectively measure and estimate NH3 levels at the community scale. ArcGIS 8.3 and the BME framework were utilized to map and estimate atmospheric ammonia levels using interpolation methods such as kriging and cokriging. The collected data and constructed ammonia concentration or index maps act as indicators of relative exposure for human populations that live near a hog CAFO. The closer a populace is to the hog CAFO, the more intense the exposure. The study confirms potential exposure risks for human populations near hog CAFOs. These results require more validation in the field. Committee: For further information please contact Rebecca Riggsbee Lloyd by email at Rebecca_Lloyd@unc.edu |
