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Environmental Fate Models, with Emphasis on Those Applicable to Air
Published in James N. Seiber, Thomas M. Cahill, Pesticides, Organic Contaminants, and Pathogens in Air, 2022
James N. Seiber, Thomas M. Cahill
Another popular air dispersion model is U.S. EPA’s AERMOD (Table 5.5). The AMS/EPA Regulatory Model (AERMOD) is an air dispersion model based on planetary boundary layer theory. It is a steady-state dispersion model designed for short-range (up to 50 km) dispersion of air pollutant emissions from stationary industrial sources. AERMOD utilizes a similar input and output structure to ISCST3 and shares many of the same features, as well as offering additional features. It is used extensively to assess pollution concentration from a wide variety of sources. A few examples of the many uses of the dispersion model include an assessment of exposure to air pollutants (NO2 and SO2) in an industrial complex setting in Thailand (Jittra et al., 2015) and assessment of mass loss of sulfuryl fluoride from two structure fumigation operations in California (Tao, 2019). In the Thailand study, emission data were obtained from 292 point sources in an industrial area. Modeled concentration data were compared to measured data from 10 receptor sites. Overall results revealed that AERMOD provided accurate predictions compared to the measured concentrations for both NO2 and SO2. In the California study, total mass loss of the fumigant from the tarped structures was determined, based on measured air concentrations, and estimated using AERMOD with a back calculated flux value (Johnson et al., 2010; Ross et al., 1996). The estimated total mass loss compared well with the measured values (see also Chapter 8, Fumigants).
Development, evaluation, and implementation of building downwash and plume rise enhancements in AERMOD
Published in Journal of the Air & Waste Management Association, 2022
Ron L. Petersen, James O. Paumier, Sergio A. Guerra
AERMOD (American Meteorological Society/U.S. Environmental Protection Agency Regulatory Model) is the U.S. Environmental Protection Agency’s (EPA) recommended model (Cimorelli et al. 2005) for assessing compliance with National Ambient Air Quality Standards (NAAQS). Included in AERMOD is a formulation for predicting the effect of building wakes on plume rise and dispersion referred to as PRIME (Plume Rise Model Enhancements) (Schulman et al. 2000). Petersen, Guerra, and Bova (2017) published a critical review of PRIME and documented several problems. First, they found that PRIME assumes that the turbulence increase and velocity decrease in the wake is constant up to the height of wake (Schulman et al. 2000) and presented wind tunnel and CFD (Computational Fluid Dynamics) simulation results showing that the turbulence increase and velocity deficit actually decrease quickly back to ambient levels above the top of the building. They also showed that the equations for predicting streamlines in the wake have a discontinuity, there is no equation to account for a corner vortex (Banks et al. 2000) which quickly brings the plume to ground-level and provided references showing AERMOD overpredicts for certain building configurations by factors of 2 to 8.
Particulate matter emission factors using low-dust harvesters for almond nut-picking operations
Published in Journal of the Air & Waste Management Association, 2019
El Jirie N. Baticados, Sergio C. Capareda, Amado L. Maglinao
In order to estimate the harvester PM emissions, in terms of kg/km2, a back-modeling approach (Faulkner 2013; Faulkner and Capareda 2012; Goodrich et al. 2009) was used using the American Meteorological Society/Environmental Protection Agency Regulatory Model (AERMOD) by Lakes Environmental (Ontario, Canada). AERMOD is a steady-state plume model that incorporates flow and dispersion to estimate downwind pollutant concentrations from a given pollutant source even in complex terrains. The horizontal dispersion of pollutants throughout the planetary boundary layer (PBL) is assumed to follow Gaussian distribution. The vertical dispersion in the convective boundary layer (CBL) is described using a bi-Gaussian probability density function (U.S. EPA 2004). The measured downwind net PM concentrations were used to estimate back the ground-level area emissions coming from each test plot. Each sampler downwind concentration provided independent estimates of PM2.5, PM10 and TSP emission factors such that for each plot, three sets of emission factors can be calculated based from S1, S2 and S3 sampler sets (three PM2.5 EF, three PM10 EF and three TSP EF). These measurements were considered repeated emission factor estimates of a given plot.
Performance of AERMOD and CALPUFF models on SO2 and NO2 emissions for future health risk assessment in Tema Metropolis
Published in Human and Ecological Risk Assessment: An International Journal, 2019
Patrick Amoatey, Hamid Omidvarborna, Hannah A. Affum, Mahad Baawain
This study employed the USEPA-regulated AERMOD modeling system to estimate SO2 and NO2 emissions from flue and flare stacks in the surrounding areas of TOR. Five performance indices were utilized to understand and assess the reliability and the accuracy level of AERMOD and the reported CALPUFF results of the same data from TOR. The results showed that the performance of AERMOD in the prediction of measured values was better than that of CALPUFF. In other words, the performance of AERMOD agreed with the observed values with three statistical indices against two indices for CALPUFF in SO2 and four indices against one for NO2. AERMOD model results predicted that the concentrations of pollutants were within the acceptable limits for both local and international standards. Pollutant dispersions were assessed for three seasons with distinct meteorological conditions, which were the main determinants of SO2 and NO2 levels in the study area. The model results showed slight variations in concentration of the pollutants with respect to the local Harmattan wind and sea breeze factors within the seasons; however, they showed significant variability in their distributions. Although, there were a number of limitations associated with this study, the AERMOD could yield reliable results of future health risk assessment projects within the Tema Metropolis and its surrounding locations. The results of this study can be used both in providing a fair understanding about the concentration of pollutants and in future epidemiological studies within the metropolis.