Aerosols in CAM-Chem are represented using the 4-mode version of the modal aerosol model (MAM-4) from Lui et al., 2016. Background and a description of the basic aerosol model performance can be found in Liu et al., 2012The species that are included in the base chemical mechanism are:

Secondary organic aerosol is treated using a volatility basis set (VBS) scheme derived from Hodzic et al., 2015, including updates to the chemical reaction rates from GECKO-A. The release version of CESM 2.0 also includes diagnostics for surface PM2.5 and three dimensional fields of PM2.5

Currently in development for release are the inclusion of ammonium and nitrate aerosols, along with their aqueous-phase heterogenous chemical reactions following the MOSAIC scheme combined with MAM4.