IIASA has been a pioneer in developing the methodology and tools necessary for assessing atmospheric pollution and the decision support analysis techniques for reducing and controlling it.

Research into atmospheric pollution goes back to the early days of IIASA when scientists modeled the effects of acid rain and transboundary air pollution within Europe.

The evolution of IIASA programs on air pollution is as follows:-

1986: The Acid Rain Project 

1991: The Transboundary Air Pollution Program

2000: The Atmospheric Pollution and Economic Development (APD) Program.

Today: The Mitigation of Air Pollution & Greenhouse Gases (MAG) Program

The methodology has also evolved from RAINS, the Regional Air pollution INformation and Simulation (RAINS) model, used as the basis for much international legislation, to the GAINS model, the extended RAINS model,  which explores the synergies between the simultaneous reduction of air pollution and greenhouse gases.

RAINS: The multi-pollutant, multi-effect model

RAINS, the Regional Air pollution INformation and Simulation (RAINS) model was developed at IIASA in the late 1980s. It combines information on expected trends in anthropogenic activities causing transboundary air pollution with data on the options available for reducing emissions from these activities and their costs.

After calculating how air pollutants are transported over Europe and how they influence air quality, RAINS estimates the impacts on human health and ecosystems. These expected impacts can then be compared with environmental targets, highlighting areas where the assumed measures fail to meet the environmental policy objectives.

A unique feature of RAINS is its ability to investigate the optimal distribution of further reduction efforts across the whole of Europe (from Norway to Italy and from Spain to the Urals) to meet air quality objectives. For this, the current RAINS model balances controls for SO2 , NOx , NH3 , VOC and particulate (PM) emissions to reduce impacts on human health, acidification and eutrophication.


The GAINS model, first launched in the early 2000s and refined and developed to this day, addresses emission control strategies that simultaneously address air pollutants and greenhouse gases in order to maximize benefits at all scales.

Many of the traditional air pollutants and greenhouse gases have common sources, their emissions interact in the atmosphere, and separately or jointly they cause a variety of environmental effects at the local, regional and global scales. With some extensions, the multi-pollutant/multi-effect approach of the RAINS model became a useful tool for addressing the positive and negative interactions between climate change and classical air pollution.

For a further description and information on the GAINS model, click here.

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Last edited: 19 July 2013


Markus Amann

Senior Research Scholar

Pollution Management Research Group

T +43(0) 2236 807 432

The GAINS Model

International Institute for Applied Systems Analysis (IIASA)
Schlossplatz 1, A-2361 Laxenburg, Austria
Phone: (+43 2236) 807 0 Fax:(+43 2236) 71 313