Modelling Tools

These tools help for the modelling of simulation chamber experiments, the experimental design and the comparison model/measurement.

E2020-pyACPIM cloud model

PyACPIM is a cloud parcel model including detailed, bineed cloud microphysics. It has been specifically designed to aid the understanding of experiments conducted in cloud chambers. The model comes with a graphical user interface which allows easy of use of the model. To run this software, please have a look at help file. To use the software, please have a look at user guide.


UManSysProp is an online facility for calculating the properties of individual organic molecules, ensemble mixtures and aerosol particles. It is built using open source chemical informatics and is accessible through the link


PyCHAM is an open-access computer code (written in Python) for simulating aerosol chambers by coupling chemistry and aerosol microphysics.

AtChem Online

AtChem Online is an open source, free to use on-line zero-dimensional box modelling toolkit, developed for use by laboratory, field and chamber scientists. Any general set of chemical reactions can be simulated, in particular subsets of the Master Chemical Mechanism (MCM ( In order to run this model you will require a username/password (available from An online tutorial can be found here (


AtChem2 is an updated, standalone off-line version of Atchem Online. It allows the user to run longer, more complex simulations containing the full MCM, such as those needed for modelling of intensive field campaigns, as well as to perform batch model runs for sensitivity studies. AtChem2 is installed, set up and configured using semi-automated scripts and simple text configuration files, making it easy to use even for non-experienced users. The AtChem2 code and documentation are available at

GECKO-A Online

GECKO-A Online is a web facility providing rate constants and thermodynamic properties (Henry’s law coefficient and saturation vapor pressure) for organic compounds based on Structure Activity Relationships. Gas phase oxidation mechanisms up to the first generation products can be downloaded. The tool generates mechanisms and properties for most acyclic and monocyclic hydrocarbons and related oxidation products (alcohols, carbonyls, nitrates, hydroperoxides, alkoxy and peroxy radicals, ...).


COSIMA is the web version of aerosol behaviour code COSIMA describing the structure and dynamics of irregularly formed or compact particles based on statistical mechanics and fractal scaling laws.