Below follows an alphabetic list of various collaborative, international research networks.
There are two reasons for having the list:
1) It enables users to get a quick overview of existing (and previous) networks within atmospheric dispersion;
2) For those networks interested, it provides a platform for interaction and collaboration with anybody on the globe. Networks with a collaboration platform here on the Wiki are marked with the logo 
The list should be much more comprehensive - please make additions!
- ACCENT (Atmospheric Composition Change - European Network of Excellence) aims to promote a common European strategy for research on atmospheric composition change. ACCENT is funded by the Sixth Framework Programme of EU.
- Air4EU (2004-2006) has provided recommendations on Air Quality assessment by monitoring and modelling for regulated pollutants in Europe. It has produced a mapping tool and a considerable number of recommendations (link to reports).
- CityDelta (2002-2004). A European modelling exercise with intercomparison of long-term model responses to urban-scale emission-reduction scenarios
- CLEAR Cluster of European Air Quality Research
- COST 710 (1994-1997). An international action on "Harmonization in the preprocessing of meteorological data for dispersion models"
- COST 715 (1998-2004). An international action "Meteorology applied to Urban Air Pollution Problems" aimed at increasing knowledge of, and accessibility to, the main meteorological parameters which determine urban pollution levels.
- COST 728 (2004-2009). Enhancing meso-scale meteorological modelling capabilities for air pollution and dispersion applications.
- COST 732 (2005-2009). An international action "Quality Assurance and Improvement of Micro-Scale Meteorological Models" aimed to improve and assure the quality of micro-scale meteorological models that are applied for predicting flow and transport processes in urban or industrial environments. Here is acces to a COST 732 forum on the present wiki web site.
- COST ES0602 (2007-2011). Towards a European Network on Chemical Weather Forecasting and Information Systems.
- EionetEionet is a partnership network of the European Environment Agency (EEA) and its member and participating countries, involving approximately 900 experts and more than 300 national institutions. The network supports the collection and organisation of data, and the development and dissemination of information concerning Europe’s environment
- FAIRMODE Forum for Air Quality Modelling. FAIRMODE is a modellers' network in support of the EU Air Quality Directive. It is a joint initiative of the European Environment Agency (EEA) and the European Commission Joint Research Centre (JRC). It has had annual plenary meetings since 2008. It has produced a guidance document on use of models in the context of the European Air Quality Directive, and other guidance documents are being prepared. Several workgroups and subgroups have been established. The network is open and seeks involvement of persons working within the field.
- Harmonisation initiativeInitiative on "Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes". Focuses on increased cooperation, i.a. through conferences and tools for model evaluation. Stands behind the present Wiki. For all conferences since 2001 the proceedings (5-page extended abstracts) are freely available online.
- TRAPOS (1998-2000). Network on Optimisation of Modelling Methods for Traffic Pollution in Streets within the EU Training and Mobility of Researchers Programme.
- Urban Air Quality conferencesA series of International conferences on Urban Air Quality is being held every second year in March - the next will be March 2012 in Athens.