New light on the atmospheric impact of aerosols

The climate cooling effect of aerosols will decrease considerably by 2030 if emission regulations and sulphur emission filtering technologies are widely adopted.

A recently completed international research project has produced more detailed information than before on the effect that small particles in the atmosphere have on the earth’s radiation balance. Academy Professor Markku Kulmala headed the project.

New European calculations for air pollution and small particle content show that the regulation of nitrogen compound emissions – ammonia emissions in particular – effectively decreases the amount of small particles in the atmosphere. Moreover, such regulation would improve air quality. The amount of sulphur dioxide emissions will also be of great significance in the future, because their regulation would considerably decrease the climate cooling effect of small particles.

– Any possible emission regulations and filtering technologies will further increase climate warming by approximately one degree Celsius, says Kulmala.

– In other words, aerosols work in two ways, contributing to both climate warming and cooling. Here in Finland, forests and the small particles they release into the atmosphere serve as a natural thermostat that cools the climate.

Thus far, the atmospheric effect of small particles has been the greatest single uncertainty related to climate change and its prediction. The new results reduce this uncertainty by about 50 percent.

– International climate change policies would benefit from our research results. During the four-year European Integrated Project on Aerosol Cloud Climate and Air Quality Interactions (EUCAARI), these results have been presented in 400 scientific articles in Science, Nature and many other journals, says Kulmala.

The results are based on extensive measurements and measurement campaigns, during which the atmosphere over Europe was observed both from the ground and from aircraft. Researchers also developed measuring equipment technology for small particles and established measurement stations in areas important for the global monitoring of air pollution: Brazil, South Africa, China and India.

Main results of the EUCAARI project »»

Overview of the EUCAARI project »»

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Text: Minna Meriläinen-Tenhu
Photo: Ari Aalto
Translation: AAC Global
University of Helsinki, digital communications

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