PES’ experience with air quality dispersion modeling includes the full range of model design, development, evaluation, and application, as well as model training and meteorological processing. Some examples of PES experience in these areas are provided below:

MODEL DEVELOPMENT AND EVALUATION

PES restructured and reprogrammed the Industrial Source Complex (ISC2/ISC3) dispersion models for the US EPA, and developed and evaluated an improved area source algorithm for the ISC3 models. PES also incorporated an open pit algorithm, complex terrain algorithm, dry and wet deposition algorithms, and the CALPUFF dry deposition algorithm for gaseous pollutants into ISC3.

PES assisted US EPA with the development and evaluation of an improved dispersion model, called AERMOD, that includes advanced boundary layer algorithms for modeling the dispersion of point, area and volume sources. PES has also developed the meteorological and terrain preprocessors for AERMOD, called AERMET and AERMAP, respectively.

PES performed comparisons of estimated concentrations from the CALMET/CALPUFF modeling system with measured tracer concentrations for two field studies involving long range transport of puff releases.

PES developed the US EPA SCREEN2 and SCREEN3 dispersion models, and enhanced the SCREEN3 model to include a new area source algorithm. PES also developed the toxics screening model, TSCREEN.

PES evaluated the performance of improved deposition algorithms in the Industrial Source Complex (ISC3) model for estimating particulate matter impacts from surface coal mining operations.

MODEL APPLICATION FOR PERMITTING AND RISK ASSESSMENT

PES meteorologists have extensive experience in performing dispersion modeling analyses in support of construction/operating permits (NSR/PSD and State), operating permit renewals, permitting for air toxics, and health risk assessments. This experience includes modeling for the following industrial sectors: utility/power generation; pulp and paper; mining; textiles; food processing; chemical manufacturing; rubber products manufacturing; medical waste incineration; and printing.

PES has performed dispersion modeling in support of air toxic risk assessment activities for several US EPA Regional Offices, including the following: application of the CALPUFF model and CALMET meteorological processor for toxic releases from several facilities for Region 5; application of ISCST2/ISCLT2 for about 700 pollutant species for the City of Chester, Pennsylvania in Region 3; application of ISCST2 and COMPLEX1 for several cement kilns subject to BIF regulations in Region 6; and application of the COMPDEP model to estimate ground-level concentrations and dry and wet deposition fluxes from a BIF-regulated cement kiln in Region 7.

PES performed dispersion modeling of criteria pollutants using ISCST3 to evaluate compliance with Federal and State air quality standards in support of a Title V permit application for Hickam Air Force Base in Hawaii.

PES developed guidance on the application of the ISCST3 model to estimate air toxic impacts from area and point sources across an urban area. As part of this effort, PES applied the ISCST3 model to estimate the impacts of five selected pollutants for the Phoenix and Houston areas.

PES applied a tiered approach to evaluating the residual risk associated with application of MACT standards to selected source categories across a statewide area. The dispersion modeling included a screening and refined level analysis using the SCREEN3 and ISCST3 models, respectively.

 

PES offers training on the ISCST3, ISC-PRIME and AERMOD models as part of an alliance with Lakes Environmental Software. The two-day course provides basic model theory and hands-on training using Lakes Environmental Software’s ISC-AERMOD View.  Course and registration information can be found at the Lakes Environmental web site.

PES developed a PC-based instructional tool for the atmospheric boundary layer based on the AERMOD modeling system, and presented a two-day advanced modeling workshop on AERMOD for Regional, State and local air quality modelers.

PES developed a series of training/tutorial packages for several PC-based dispersion models for US EPA, including the ISC2, SCREEN2, TSCREEN and CTSCREEN models. These tutorial packages are available from EPA’s SCRAM website.

PES presented a two-hour session on the CTSCREEN model as part of the Air Pollution Training Institute (APTI) Telecourse 423 on Air Pollution Dispersion Models.

PES meteorologists have extensive experience processing meteorological and terrain data for input to dispersion models, such as ISC3, RTDM, CTDMPLUS, CALPUFF, and AERMOD. This experience includes both on-site and off-site meteorological data, and the following meteorological processors: PCRAMMET, MPRM, METPRO, CALMET, and AERMET.

PES modified the PCRAMMET and MPRM meteorological processors to incorporate the meteorological algorithms needed to support the new dry and wet deposition algorithms in the ISC3 dispersion model.

PES analyzed the potential affects on dispersion model results of the use of meteorological data obtained from the Automated Surface Observing System (ASOS) being implemented at National Weather Service observing stations. The use of ASOS data instead of observer data will alter the type of cloud data available to the meteorological preprocessors for several dispersion models.

PES developed the wind rose plotting program, WRPLOT, for the US EPA, and prepared wind roses for the ozone season for all major National Weather Service (NWS) stations.

PES has performed numerous sensitivity analyses on the ISC3 model, including an evaluation of the effect of using off-site (airport) versus on-site meteorological data for use in estimating impacts from Superfund site remediation activities, an analysis of the effect of different mixing height algorithms on design concentrations, and an analysis of wet and dry deposition algorithms in simple and complex terrain applications.

rbrode@rtp.pes.com