Scientific Highlights

The composition of particulate matter can influence its harmfulness to human health just as much as the amount, PSI researchers show in a newly published study. Experiments and computational modelling showed that in Europe high concentrations of particulate matter harmful to human health occur mainly in metropolitan areas.

Researchers at the Paul Scherrer Institute PSI have developed a new method to analyse particulate matter more precisely than ever before. With its help, they disproved an established doctrine: that molecules in aerosols undergo no further chemical transformations because they are enclosed in other particulate matter.

Clouds consist of tiny droplets. These droplets form when water condenses around so-called aerosols – small particles in the atmosphere. To understand how in turn aerosols come into existence scientists have now created a comprehensive computer model simulation based on profound experimental data. This simulation revealed that in addition to sulphuric acid, two other substances are crucially involved in the formation of aerosols: organic compounds and ammonia. These results have now been published in the renowned journal Science.

Researchers have shown how fine particles are formed from natural substances in the atmosphere. These findings will improve our knowledge about clouds in the pre-industrial era and thus will contribute to a more accurate understanding of both the past and future evolution of our climate.

For years, studies have proved that fine dust from petrol engines can damage our health. Modern engine technology does not help, either, as researchers from the University of Bern and the Paul Scherrer Institute (PSI) reveal.

In some towns small mopeds cause more air pollution than carsNot cars or trucks, but mopeds with their two-stroke engines are the main source of fine particles and other air contaminants in many towns in Asia, Africa and southern Europe. This is revealed by the study of an international research team headed up by researchers at the Paul Scherrer Institute PSI. The reasons for the high emissions are the combustion properties in two-stroke engines and the overly lenient emission requirements for small two-wheelers. The study findings are to be published on 13 May 2014 in the journal Nature Communications.

PSI-researcher Martin Gysel receives prestigious European funding (ERC Consolidator Grant) for his studies on the role of soot in cloud formation and global warming.

Clouds consist of cloud droplets that are formed from tiny particles floating in the atmosphere. How these particles develop, however, largely remains a mystery. The formation of particles from amines and sulphuric acid has now been described for the first time à a milestone in atmospheric research.

Data of the Paul Scherrer Institute from the High-Alpine Research Station Jungfraujoch yield important information.The eruption of the volcano Eyjafjallajokull in Iceland has stalled flight traffic in large parts of Europe. Decision makers had to base their decisions mainly on model calculations for the volcanic plume dispersion. How dangerous is this volcanic ash layer for planes?

Up to the present time, the nucleation or new formation of particles in the atmosphere has been a great enigma. Until recently, research was based on the assumption that sulphuric acid played the central role in particle formation. However, laboratory experiments and field tests have consistently provided conflicting results. In the lab, considerably higher concentrations of sulphuric acid are required for nucleation to take place than in the atmosphere itself. Now scientists from the Paul Scherrer Institute (PSI) have found out the cause for these conflicting results from their smog chamber. These findings will advance climate research to a significant degree.

Researchers from the Paul Scherrer Institute, the University of Colorado and 29 other research institutions in various countries have investigated the composition of the organic constituents of the fine particulates found in various regions of the world, and have identified the original substances from which they are formed in each case. For the first time ever, this has enabled them to explain the role played by the individual components of emissions in the development of fine particulates.