The PSI is making a fundamental change into researching particulate matter. Researchers at the institute have discovered that molecules undergo chemical transformation in particulates as well, and in some cases emit substances unto the atmosphere that are dangerous for our health, as outlined in a press release. Their insights have been published in the Science Advances journal and will help improve understanding of global processes behind cloud formations and air pollution, in addition to allowing relevant models to be fine-tuned.
“Up to now it was thought that such molecules are protected from further transformations once they have landed in particulate matter", says Andre Prévôt of the Laboratory of Atmospheric Chemistry (LAC) at PSI. "It was believed that they then would not change any more, but would simply spread out over the atmosphere and eventually rain down."
Simulation models that can be derived from this help to reproduce the atmospheric processes. In this way, for example, it would be possible to predict how a reduction in certain emissions could affect air quality. These measurements have been made possible by the smog chamber at PSI. To this end, the researchers developed a time-of-flight mass spectrometer in conjunction with Tofwerk, a company based in Thun BE. In contrast to previous methods, this allows the researchers to separately record each individual molecule.
The new analysis method can be used both in the laboratory and directly on site. Over the previous winter, PSI researchers used it to investigate particulates contained in the air around Zurich. Additional measurement campaigns are planned in cities with over one million inhabitants in China and India.