Hollins DM, Scott PK, Bare JL, Barlow CA, Nembhard M, Maskrey JR, Paustenbach DJ. 2017. Estimating asbestos emissions from former industrial sites and estimating resulting airborne concentrations in the surrounding community: A review of methodologies. Abstract #3248. Poster Presentation at Society of Toxicology (SOT) Annual Meeting, Baltimore, MD, March 2017.
Historical manufacturing and handling of asbestos-containing products has sometimes resulted in the environmental release of asbestos into surrounding communities. Airborne asbestos concentrations in the vicinity of various industries (i.e., point sources), in general, have been reported to range from 0.0001 to 0.03 f/cc. This data, of course, depends on the timeframe, type of emission, locations sampled, topography, and presence of air pollution control devices, among other factors. While the potential for community exposure to asbestos from industry emissions has been discussed in the literature since the mid-1960s, concerns have recently intensified regarding the possible impact these historical emissions have had on community health. In the absence of monitoring data, the US EPA AERMOD modeling program has been the preferred air dispersion model for estimating particulate releases. However, the model is generally incapable of considering the difference between particles and fibers (especially those longer than 5 to 100 µm). The model attempts to convert the fibers into equivalent spheres but this methodology was initially developed to deal with irregularly shaped particles rather than asbestos fibers. This analysis presents estimates of community exposures at various distances from facilities, using current defaults assumptions and the AERMOD model. We found that average yearly ambient air concentrations resulting from historical manufacturing operations were estimated to range from 0.0003 to 0.01 f/cc, at distances of 500 to 5,000 feet (based on the default assumptions and depending on emission control measures, time period, production and use). If fiber morphology and their transport in air are considered, the model results may be further refined.