Dust emissions are calculated online in the Land Model.  The method is currently being updated: https://github.com/ESCOMP/CTSM/issues/1604 

A global dust emissions tuning factor is set in CAM (atm_in): dust_emis_fact

To change the dust emissions in your simulation, add dust_emis_fact to your user_nl_cam.

The dust_emis_fact is applied as dust emission flux / dust_emis_fact, so to reduce emissions from a previous run, increase the dust_emis_fact value.

New Dust

A new dust scheme has been developed by Danny Leung: https://acp.copernicus.org/articles/24/2287/2024/