A model to assess emission and pollution reduction strategies that combat air pollution and climate change simultaneously.

GAINS provides an authoritative framework for assessing strategies that reduce emissions of multiple air pollutants and greenhouse gases at least cost, and minimize their negative effects on human health, ecosystems and climate change.


GAINS was launched in 2006 as an extension to the RAINS model which is used to assess cost-effective response strategies for combating air pollution, such as fine particles and ground-level ozone.

GAINS is used for policy analyses under the Convention on Long-range Transboundary Air Pollution (CLRTAP), e.g., for the revision of the Gothenburg Protocol, and by the European Commission for the EU Thematic Strategy on Air Pollution and the air policy review.

Scientists in many nations use GAINS as a tool to assess emission reduction potentials in their regions.

For the negotiations under the United Nations Framework Convention on Climate Change (UNFCCC), a special version of GAINS has been developed to compare greenhouse gas mitigation efforts among the Annex-I countries.


  • GAINS is used as part of the standard modeling framework for negotiations under the Convention on Long-range Transboundary Air Pollution and the European Union.
  • Annex I parties to the Kyoto Protocol—developed countries—can interactively compare their mitigation efforts using the free online GAINS Mitigation Efforts Calculator.
  • In the atmosphere, many air pollutants contribute to climate warming or cooling. As these substances are generally shorter-lived in the atmosphere than greenhouse gases, reducing air pollution will yield climate change benefits much earlier than greenhouse gas reductions alone (see Related Articles) 

How GAINS works

GAINS estimates historic emissions of 10 air pollutants and 6 GHGs for each country based on data from international energy and industrial statistics, emission inventories and on data supplied by countries themselves. It assesses emissions on a medium-term time horizon, with projections being specified in five-year intervals through the year 2050.

GAINS estimates for each country/region the potential emission reductions that are offered by about 2000 specific emission control measures and their costs. For user-specified packages of measures, GAINS calculates resulting effects on ambient air quality (fine particles, ground-level ozone, deposition of sulfur and nitrogen), and the subsequent impacts on human health and ecosystems (see figures generated by GAINS showing estimates of losses in statistical life expectancy estimates under two GHG emissions scenarios (below).


The GAINS model shows estimated loss in statistical life expectancy due to exposure to anthropogenic PM2.5 in 2020. In (1) GHGs rise by 3%. In (2) GHGs are reduced by 20%, in line with the EU target.

GAINS-matrix © IIASA

The GAINS model provides a systems perspective to the multi-pollutant/multi-effect nature of air pollution control

The GAINS model can be operated in two ways:

  • In "scenario analysis" mode, it follows emission pathways from sources to impacts, providing estimates of regional costs and the environmental benefits of alternative emission control strategies.
  • In "optimization" mode, it identifies where emissions can be reduced most cost-effectively. The models identifies a balance of concrete measures for different pollutants, sectors, and countries/regions that achieve air quality and greenhouse gas reduction targets at least cost, considering the contributions of different pollutants to different air quality and climate problems.

Some key findings

GAINS helps identify measures to mitigate local air pollution and thus global climate change. For instance, world-wide implementation of 17 emission reduction measures targeting black carbon and ozone precursors could reduce future global warming by 0.5°C and could avoid the loss of 1-4% of the global production of maize, rice, soybean and wheat each year.

According to estimations made in the course of the GAINS-Asia assessment, application of advanced emission control technologies could reduce health impacts in China by 43% in 2030. GAINS in optimization mode was also able to identify the most cost-effective portfolio of measures to achieve these health improvements, but at 20% of the costs.