Publications : 2019

Scott PK, Abramson MM, Bare JL, Barlow CA. 2019. Air dispersion modeling for historical community exposure reconstruction: An evaluation of the approach and its uncertainties. EM-Mag Environ Mgrs, January


Widespread industrial asbestos use began in the early 1900s resulting in asbestos being incorporated into thousands of commercial and consumer products. Historical manufacturing of these asbestos-containing products [has] resulted in intermittent environmental release of asbestos into surrounding communities. While some facilities may have historical industrial hygiene measurements available, in the absence of these data, estimation of airborne concentrations may be necessary using facility information on the consumption of asbestos, types of emissions, and presence of air pollution control devices. While these estimates will be limited by the availability of historical information, this type of historical exposure reconstruction can produce bounding estimates of community exposure over time that are better than those based on limited or no measured air sampling data. AERMOD, the U.S. Environmental Protection Agency’s (EPA) preferred model for a wide range of regulatory applications in all types of terrain, is often used for this purpose.

This article describes a case study using the AERMOD model to estimate air concentrations for a historical exposure reconstruction of community exposures to a hypothetical asbestoscontaining friction product manufacturer (e.g., a brake manufacturer). To better understand how uncertainties in the selection of model parameters may affect the results, a sensitivity analysis was performed that included varying the modeled asbestos particle size, changing the fugitive emission model type, using different methods to calculate the emission rate from asbestos handling, and evaluating the impact of control technologies. A similar approach could also be adapted for other chemicals and facility types in order to estimate historical air concentrations in the absence of an adequate historical air sampling database.