The SCREEN3 model is the US EPA’s current regulatory screening model for many New Source Review (NSR) and other air permitting applications. The SCREEN3 model is based on the same steady-state Gaussian plume algorithms as the ISCST3 model. Like ISCST3, SCREEN3 is applicable for estimating ambient impacts from point, area, and volume sources out to a distance of about 50 kilometers. In addition, SCREEN3 can be used to model flares. SCREEN3 also includes algorithms for addressing building downwash influences, including the cavity recirculation region, and incorporates the Valley 24-hour screening algorithm for estimating complex terrain impacts.
The original SCREEN model was released by EPA in 1988 as a replacement for the PTPLU screening model, and was developed by PES meteorologist. PES has continued to support EPA’s maintenance and further development of the SCREEN3 model for the past decade, including the implementation of an improved area source algorithm. One of the non-regulatory options for treatment of mixing heights in SCREEN3 is based on an approach developed by a PES meteorologist.
The SCREEN3 model utilizes a matrix of meteorological conditions covering a range of wind speed and stability categories. The model is designed to estimate the worst-case impact based on the meteorological matrix for use as a conservative screening technique.
You can download the current version of SCREEN3 here, including source code, executable, test case, and user’s guide:
For more information on the SCREEN3 model, visit PES’ Frequently Asked Questions (FAQs) on SCREEN3, or contact PES at Roger.Brode@pes.com. You can also run the SCREEN3 model on-line by clicking here.