ODOR IMPACT ASSESSMENTS BASED ON DOSE-RESPONSE RELATIONSHIPS AND SPATIAL ANALYSES OF POPULATION RESPONSE

Odorous emissions arise from many industrial, agricultural and municipal facilities but, unfortunately, the owners and operators of such facilities lack effective strategies for assessing their impacts on surrounding communities. At present, the most widely-used method for odor quantification is through estimates of odor concentration at impacted receptors throughout a community. While this approach is useful, especially from the point of view of regulating odors, it fails to account for the full range of dilutions over which the odor is experienced in a community, the wide range of sensitivities of individuals to odors, and the odor's offensiveness. In recognition of these drawbacks, dose-response relationships were developed for odors in which responses were expressed in terms of probability of response and degree of annoyance as functions of odor concentration. Once the dose-response parameters for a particular odor have been evaluated, dispersion modeling may beused in conjunction with the dose-response relationships to estimate contours of probability of response and degree of annoyance throughout the surrounding community under a wide range of meteorological conditions. These contours serve as the basis for the development of a variety of odor impact parameters that reflect various dimensions of odor concentration, probability of response, and annoyance, population impact and areal extent of the zone of impact. The use of this approach for odor impact assessments has been demonstrated for an industrial facility. In addition, spreadsheet-based software that was developed to aid in the calculation of these parameters is presented.