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Welcome to the MCM website

The Master Chemical Mechanism (MCM) is a near-explicit chemical mechanism which describes the detailed gas-phase chemical processes involved in the tropospheric degradation of a series of primary emitted volatile organic compounds (VOCs). Currently, the degradation of methane and 142 non-methane VOCs is represented.

The MCM was originally developed to provide accurate, robust and up-to-date information concerning the role of specific organic compounds in ground-level ozone formation in relation to air quality policy development in Europe. However, it also provides a research tool for investigating other areas where a detailed representation of the chemistry is required, e.g. the generation of distributions of speciated radical and closed-shell intermediates formed during VOC degradation.

The main intention of this web site is to provide a flexible, easily utilised platform for the MCM that is readily accessed by the research and user communities, and to help promote its development and validation.

Browse the mechanism

View the list of primary VOCs from which you can navigate through the mechanism either from reactants to products, or vice-versa. Help

Construction methodology

Detailed information about the MCM and its history. New in MCMv3.3.1

Search the mechanism

Enter a SMILES string or MCM name to jump straight to matching species in the mechanism. Help

MCM Workshops

Information and presentations from the MCM development and user workshops.

Extract a subset

Select your own list of primary species and extract a complete mechanism for them. Mechanisms can be viewed as HTML or exported in a range of formats. Help


Learn more about how to use the MCM. Tutorials are available on using the MCM with either AtChem Online or FACSIMILE

AtChem Online Tutorial
Facsimile Tutorial


FACSIMILE input files for box model and trajectory model runs are available for current and previous versions of the MCM.

EUPHORE Chamber Simulations

Notes on simulating EUPHORE chamber experiments.


Details of the correct citation for MCM


Various tools for use with the MCM


Useful tropospheric chemistry links.


Access to the Common Representative Intermediates mechanism (CRI v2) via a parallel searchable and extractable facility

MCM Archive

Archived website for MCMv3.2


Join the MCM mailing list or contact the maintainers directly.

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Andrew Rickard, Jenny Young
[ Admin. page ]