PyCHAM (v2.1.1): a Python box model for simulating aerosol chambers

Abstract. In this paper the CHemistry with Aerosol Microphysics in Python (PyCHAM) box model software for aerosol chambers is described and assessed against benchmark simulations accuracy. The solves coupled system of ordinary differential equations gas-phase chemistry, gas–particle partitioning gas–wall partitioning. Additionally, it can solve coagulation, nucleation particle loss to walls. PyCHAM open-source, whilst graphical user interface, modular structure, manual, example plotting scripts, suite tests troubleshooting tracking effect modifications individual modules have been designed optimal usability. paper, modelled processes are individually simulations, key parameters described. Examples output when also provided. Sensitivity relevant illustrated along convergence increasing temporal resolution number size bins. latter sensitivity analysis informs our recommendations setup. Where appropriate, parameterisations specific chosen their general applicability, rationale detailed here. It intended aid design chamber experiments, comparison observations allowing improvement process understanding that be transferred ambient atmosphere simulations.