Bld vs run script hierarchy

What take precedence when running bld and run scripts? If one MECH is defined in the Bld script, but a different MECH is defined in the RUN script, which will it CMAQ use? It would seem that since build is the generating an executable, it would use that MECH and the 5.2 manual says “CMAQ chemical mechanism. Must match Mechanism variable setting in the ICON build script.” But
but then the executable my be just looking for a MECH variable defined by the RUN script because the manual also says “The environment variables listed here are invoked during execution of the program and are set in the BCON run script.”

The mechanism is set at build time. The provided run scripts use the shell variable MECH to point to specific files that have the mechanism name embedded in them.

If the setting of MECH in the run script does not match the setting of Mechanism in the bld script, the run script will abort before model execution with the message that the appropriate mechanism-specific data files (e.g., CSQY_DATA and the species namelist files) are not found.

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