Model-3 is a flexible system designed to simplify the development and use of air quality models and other environmental decision support tools. It is designed for applications ranging from regulatory and policy analysis to understanding the complex interactions of atmospheric chemistry and physics. The 2001 release of Models-3 contains a Community Multi-Scale Air Quality (CMAQ) modeling system for urban to regional scale air quality simulation of tropospheric ozone, acid deposition, visibility, and fine particles. The major improvements in CMAQ since the June 2000 release include the Modified Euler Backwar Iterative (MEBI) chemical solver for use with CB4 gas-phase mechanisms, improved horizontal diffusion, and an improved aerosol module. Principal changes to other parts of the Models-3 system improvements include the replacement of the former emission modeling system with provision to use the Sparse Matrix Operator Kernel Emission (SMOKE) modeling system (available at no cost from MCNC, North Carolina Supercomputing Center), and SMOKE Tool to create input files for SMOKE. This Installation Manual is for both new installations and upgrades, and includes an overview of the Models-3 server and clients, establishing users, Models-3 start-up and shut-down, loading of data sets, description of system administration functions, and illustrative examples. Release notes describing system changes (including SMOKE Tool) are in the Appendices.

"EPA/600/R-01/046." "PB99-139180." "Models-3 version 4.1." Microfiche.