“…The use of such a box model isolates gaseous and aerosol chemical kinetics from other atmospheric processes such as emissions, transport, and depositions, on which the speedup is focused in this study. Three numerical solvers are implemented to solve CACM in the box model: the quasi steady state approximation solver (QSSA) (Hestveldt et al, 1978), the RosenBrock solver (ROS3) (Sandu et al, 1997a(Sandu et al, , 1997b, and the sparse-matrix vectorized Gear's solver (SMVGEAR) (Jacobson and Turco, 1994). The box model is set up for a one-day simulation starting 12:00 GMT (corresponds to 8 a.m. Eastern Daylight Time (EDT)), with a time step of 1 min for integration of gas-phase chemistry and aerosol processes.…”