## Advanced / Configuration Setup / Variables Not Set in the GUI

MAXDIM (1) - is the maximum number of pollutants that can be attached to one particle. Otherwise, if multiple pollutants are defined they are released as individual particles. This feature is only required with chemical conversion modules, which are not part of the standard distribution. However, the species 1->2 conversion option will automatically set MAXDIM=2, but the standard emissions routine will still put each species on a different particle in its appropriate array element. The only emissions routine that is enabled to release multiple species on the same particle is the emissions file option. Setting MAXDIM greater than one forces all the species on the same particle with the limitation that the number of defined pollutants must equal MAXDIM. No other combinations are permitted. The advantage of this approach is that not as many particles are required for the calculation as in the situation where every pollutant is on its own particle. The limitation is that each species on the particle should have comparable dynamic characteristics, such that they are all gases or have similar settling velocities, otherwise the transport and dispersion simulation would not be very realistic.

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