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CAMx Overview

CAMx is an Eulerian (gridded) photochemical dispersion model that allows for integrated "one-atmosphere" assessments of tropospheric air pollution over spatial scales ranging from neighborhoods to continents.  It is a "state-of-the-science" open-source system that is computationally efficient, flexible, and available at zero cost.  Meteorological fields are supplied to CAMx from separate weather prediction models (we specifically support WRF, MM5 and RAMS).  Emission inputs are supplied from external pre-processing systems (e.g., SMOKE and EPS3).

Version 6.40 offers expanded capabilities over previous versions.  Detailed information about all of these features is provided in the CAMx User's Guide (pdf).

In addition to the features it shares with other photochemical grid models, the most notable features of CAMx are:

  • Flexibile two-way grid nesting on several map projections
  • Multiple gas phase chemistry mechanism options (CB6, CB05, SAPRC07)
  • Advanced external photolysis model (TUV) with in-line cloud and aerosol adjustments
  • Comprehensive aerosol chemistry with two particle size treatments (modal and sectional)
  • Plume-in-Grid (PiG) module for sub-grid treatment of selected point sources
  • Multiple dry deposition options (Wesely89, Zhang03)
  • Surface chemistry / re-emission model
  • Probing Tools:
    • Ozone and Particulate Source Apportionment Technology (OSAT/PSAT)
    • Decoupled Direct Method (DDM/HDDM) for source sensitivity of ozone, PM and other species
    • Multiple Process Analysis (PA) options
    • Reactive Tracer treatment (RTRAC/RTCMC) for air toxics
  • Mass conservative and consistent transport numerics:
    • Multiple horizontal advection solvers (PPM, Bott)
    • Multiple vertical diffusion methods (K-theory, ACM2)
  • Parallel processing using Open-MP on shared-memory systems
  • Parallel processing using Message Passing Interface (MPI) on distributed-memory systems