GAINS - Greenhouse Gas and Air Pollution Interactions and Synergies

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. The GAINS model addresses emission control strategies that simultaneously address air pollutants and greenhouse gases in order to maximize benefits at all scales.

The RAINS model

The Regional Air pollution INformation and Simulation (RAINS) model, developed by the International Institute for Applied Systems Analysis (IIASA) in Austria, combines information on expected trends in anthropogenic activities that cause transboundary air pollution with data on the available options for reducing emissions from these activities and their costs. Dispersion models are used to calculate how these emissions are transported over Europe and how they influence air quality. With the resulting ambient concentrations and deposition fields of the various pollutants, 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 the model 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 RAINS extension to greenhouse gases

With some extensions, the multi-pollutant/multi-effect approach of the RAINS model could become a useful tool for addressing the positive and negative interactions between climate change and classical air pollution. As a first step, the RAINS model has been complemented to include emissions of the greenhouse gases covered by the Kyoto Protocol, their abatement measures and costs. This extension should allow insights into the optimal choice of emission reduction measures in Europe that meet air quality objectives simultaneously with targets on the emissions of the Kyoto greenhouse gases.

Emission estimates for the six Kyoto gases (CO2 , CH4 , N2O, HFC, PFC and SF6 ) are based on methodologies and emission factors proposed by the IPCC emission reporting guidelines. The large number of control options for greenhouse gases have been grouped into approximately 150 packages of measures. These control options span a wide range of cost-effectiveness. There are certain advanced technical measures that will involve very high costs, there is a variety of measures with moderate costs, and measures exist for which the economic assessment suggests even negative costs, if major side impacts (cost savings) are considered. Cost curves for the six gases rank the options for reducing emissions of these gases according to their cost effectiveness, starting with the cheapest and ending with the most expensive measures. These cost curves are developed for each country in Europe for the period 2000 to 2030.

While energy policy was considered as an exogenous input to the previous model calculations for air pollution, changes in energy structures are key elements in greenhouse gas reduction strategies. Thus, the extended RAINS model (Figure 1) allows the user to explore the cost-effectiveness of structural changes in the energy systems, such as fuel substitution and energy conservation, for the reduction of emissions.

Figure 1: Diagram of the RAINS model including the extension to greenhouse gases

Responsible for this page: Markus Amann
Last updated: 15 Dec 2004