Version 4.42 provides important updates and bug fixes to the PSAT Probing Tool option. We recommend that all CAMx users who run the PSAT option download this version.

Version 4.40 provides the following additional capabilities and features over previous versions:

• PM chemistry and Particle Source Apportioment Technology (PSAT) have been added to the PiG sub-model.  As part of this change, PiG now includes dry and wet deposition.  Also, the GREASD PiG algorithms have been fully unified with IRON PiG. GREASD PiG continues to treat only early inorganic chemical reactions in large NOx plumes.
• Model speed has been increased by revising the time step calculation approach.  The maximum allowable time step has been increased for the Bott advection algorithm because it has demonstrated numerical stability for CFL numbers near 1.
• CAMx can now optionally write concentration fields to HDF5 files following the conventions of the Regional Atmospheric Modeling System (RAMS).  Both core model and probing tool fields can be written in HDF, for both computational and PiG sampling grids.  Use of HDF requires that HDF5 libraries have been installed and built on the machine that is running the CAMx Makefile.
• The output average, deposition, and surface Probing Tool fields for each grid (computational and PiG sampling) are now separately output to individual files in the standard UAM format, which is consistent with the formats of the CAMx input emissions, input initial conditions, and master grid output format.
• The SAPRC chemical mechanism has been enchanced to include three additional optional species: Ethanol (ETOH), Methyl Tertiary Butyl Ether (MTBE), and Methylbutenol (MBUT), and gas-phase reactions involving these species.  The SAPRC99 (Mechanism 5) chemstry parameters file now uses molecular units for reaction rate parameters.
• The Integrated Processes Rate (IPR) component of PA has been updated to include aerosol chemistry and PM species.