Collaboration between researchers from the Department of Applied Physics and the European Organisation for Nuclear Research, CERN, dates back several years.
- Text by Marianne Mustonen
- Photo by Raija Törrönen
The researchers’ aerosol measurements constitute part of the large, international CLOUD project involving research groups from all over the world.
“At CERN, we aerosol researchers have access to a large steel chamber, where we study aerosol formation under various atmospheric conditions in different ways. One of the objectives of our measurements is to create increasingly realistic climate models,” Postdoctoral Researcher Tuomo Nieminen says.
Last autumn, researchers from the University of Eastern Finland spent a couple of months at CERN, and they even took two pieces of their own measurement equipment with them. One of the devices was used to measure particle hygroscopicity, that is, how much water can become condensed in particles under certain conditions. This provides insight into their chemical composition. A mass spectrometer, on the other hand, was used to accurately measure the mass of very small charged clusters of molecules, providing information on their atomic composition.
“The thermally insulated steel chamber has 26 cubic metres of space, and we can make precise adjustments to the temperature, relative humidity and gas mixtures. The inside of the chamber is filled with artificial air made of liquid nitrogen and oxygen,” Nieminen explains.
Tiny amounts of other gases, such as sulphur dioxide produced by human activity or monoterpenes, volatile organic compounds produced by plants, are introduced in the chamber. These gases interact with one another, creating new compounds and, eventually, aerosols.
“The amounts are really small, one billionth to one trillionth of all air molecules, but our mass spectrometer can detect that one-in-a-trillion molecule.”
“At the moment, for example, we are studying how aerosols from forests and marine aerosols differ from one another,” Postdoctoral Researcher Angela Buchholz says.
Even though researchers work during a measurement campaign in three shifts around the clock, that is often not enough: measurements have to be made over the course of several years in order to obtain sufficient data.
“In the CLOUD project, last year’s measurement campaign was the 12th consecutive one. The University of Eastern Finland has been involved ever since the start of the project in 2009,” Nieminen says.
“The next measurements will be conducted next autumn. Before that, we of course need to define what we want to investigate. The measurement data generated in the project is made openly accessible to all research groups. We work together to plan new campaigns and discuss our findings, and we also co-author publications.”
“CERN is heaven for researchers – science is everywhere around you. One can really focus on scientific research there. The scientific community at CERN is also very laid-back and inclusive,” Buchholz adds.
“The CLOUD project, on the other hand, is a good platform for networking. This allows us to gain international visibility and to significantly strengthen our research.”
Photo caption (main photo): Researcher Tuomo Nieminen working in the lab.