AERMOD: A Dispersion Model for Industrial Source Applications. Part II: Model Performance against 17 Field Study Databases

Abstract

The performance of the American Meteorological Society (AMS) and U.S. Environmental Protection Agency (EPA) Regulatory Model (AERMOD) Improvement Committee's applied air dispersion model against 17 field study databases is described. AERMOD is a steady-state plume model with significant improvements over commonly applied regulatory models. The databases are characterized, and the performance measures are described. Emphasis is placed on statistics that demonstrate the model's abilities to reproduce the upper end of the concentration distribution. This is most important for applied regulatory modeling. The field measurements are characterized by flat and complex terrain, urban and rural conditions, and elevated and surface releases with and without building wake effects. As is indicated by comparisons of modeled and observed concentration distributions, with few exceptions AERMOD's performance is superior to that of the other applied models tested. This is the second of two articles, with the first describing the model formulations.

Assimilative Capacity Analysis of Air Pollutants over the Dawai Industrial Complex

“…Predicted results are used to designate for the upper limit of air emission rate of factory, located in the industrial complex. Details of the study and evaluation are as follows: [4]. AERMOD predicts concentration of ambient air quality by explaining a planetary boundary layer of about more than 100 meters during nighttime and up to 1-2 kilometers during daytime.…”

AERMOD performance evaluation for three coal-fired electrical generating units in Southwest Indiana

“…The DV was calculated for both the observed and predicted values and compared using a DV ratio (predicted DV/observed DV). Design value ratios within a factor of two (0.5-2.0) are considered acceptable for the purpose of regulatory performance evaluation (Table 3) (Perry et al, 2005).…”

“…RHC ratios within a factor of two (0.5-2.0) are considered acceptable for the purpose of regulatory performance evaluation (Table 4) (Perry et al, 2005).…”

“…Although previous model validation work conducted by the U.S. Environmental Protection Agency (EPA) has demonstrated acceptable performance by AERMOD at sites similar to Gibson and P/R (Perry et al, 2005), due to the precise nature of the hourly SO 2 NAAQS, concerns about model accuracy have prompted recent validation studies (Dresser and Huizer, 2011;Chapman, 2011). An urban study conducted in northwest Indiana in 2011 reported overprediction of the 99th percentile 1-hr SO 2 concentrations by as much as a factor of 10 (Chapman, 2011).…”

“…Model performance criteria were taken from Cox and Tikvart (1990), Perry et al (2005), and the American Society for Testing and Materials method D6589 (ASTM, 2010). These measures are comprised of both paired (in time and space) and unpaired model performance statistics.…”