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.