Comparison of the Industrial Source Complex and AERMOD Dispersion Models: Case Study for Human Health Risk Assessment

Abstract

Air quality models are typically used to predict the fate and transport of air emissions from industrial sources to comply with federal and state regulatory requirements and environmental standards, as well as to determine pollution control requirements. For many years, the U.S. Environmental Protection Agency (EPA) widely used the Industrial Source Complex (ISC) model because of its broad applicability to multiple source types. Recently, EPA adopted a new rule that replaces ISC with AERMOD, a state-of-the-practice air dispersion model, in many air quality impact assessments. This study compared the two models as well as their enhanced versions that incorporate the Plume Rise Model Enhancements (PRIME) algorithm. PRIME takes into account the effects of building downwash on plume dispersion. The comparison used actual point, area, and volume sources located on two separate facilities in conjunction with site-specific terrain and meteorological data. The modeled maximum total period average ground-level air concentrations were used to calculate potential health effects for human receptors. The results show that the switch from ISC to AERMOD and the incorporation of the PRIME algorithm tend to generate lower concentration estimates at the point of maximum ground-level concentration. However, the magnitude of difference varies from insignificant to significant depending on the types of the sources and the site-specific conditions. The differences in human health effects, predicted using results from the two models, mirror the concentrations predicted by the models.

NO2 and SO2dispersion modeling and relative roles of emission sources over Map Ta Phut industrial area, Thailand

“…EPA, 2004). It is a new regulatory dispersion model in place of its predecessor the Industrial Sources Complex Short Term (ISCST) model, and it has been used in environmental impact assessment (Huertas et al, 2012;Perry et al, 2005;Silverman and Tell, 2007;Venkatram et al, 2001). The system consists of four main processors: AERMAP as the terrain processor, AERSURFACE as the surface property/ characteristic processor, AERMET as the meteorological processor, and AERMOD as the main dispersion model processor.…”

Impact of air pollutants from surface transport sources on human health: A modeling and epidemiological approach

“…AERMOD is an integrated system of three modules: a steady-state dispersion model (which is a Gaussian model and designed for shortrange~50 km dispersion of air pollutants), AERMET (meteorological data pre-processor) and AERMAP (a terrain pre-processor). It can estimate emissions from point and line sources by treating them as area sources (Cohan et al, 2011), along with improved handling of ground dispersion (Silverman et al, 2007). Therefore, the current study considers vehicles used in an area of 4 km 2 as a single area source for estimating pollutant concentrations for these specific locations.…”

“…This is due to its inherent improved ground dispersion handling capability (Silverman et al, 2007;Singh et al, 2006), better performance in complex terrain (US EPA, 2003) and high sensitivity to small changes in wind speed (Faulkner et al, 2008). AERMOD is an integrated system of three modules: a steady-state dispersion model (which is a Gaussian model and designed for shortrange~50 km dispersion of air pollutants), AERMET (meteorological data pre-processor) and AERMAP (a terrain pre-processor).…”

Dispersion modeling of air pollutants in the atmosphere: a review

“…There are several other Gaussian models available like CALINE3 for highway air pollution, OCD for coastal areas, BLP and ISC for industrial sites or ALOHA for accidental and heavy gas releases (see [33] for a detailed list). They are widely used by authorities, environmental protection organizations and industry for impact studies and health risk investigations [34,35]. Their short runtime allows the users to make long-term statistical simulations [36,37] or detailed sensitivity studies [5,38], and provide immediate first-guess information in case of an accidental release.…”